This work was supported by an Industrieel OnderzoeksFonds/Strategisch Basisonderzoek (IOF/SBO) research grant (PID34923) and a Geconcerteerde Onderzoeksactie (GOA) grant (PID36444) of the University of Antwerp; by a Senior Clinical Investigator fellowship (to VFS) and research grants of the Fund for Scientific Research Flanders (Application numbers 1842219N, G021019N, G0D0520N, and G021420N); by a research grant of ERA.Net RUS Plus (2018, Project Consortium 278); by a Vlaamse Interuniversitaire Raad/Interuniversitair Bijzonder OnderzoeksFonds (VLIR/iBOF) grant (20-VLIR-iBOF-027). We thank the firms Abbott and Boston Scientific for sponsoring a large part of the pacemaker leads and the firms, Medtronic and Biotronik, for the loan of a pacemaker programmer. We thank the animal staff of the University of Antwerp animal facility for their excellent care of the animals.

This protocol has been approved by the University of Antwerp Ethical Committee for Animal Testing (case number 2019-29) and follows the animal care guidelines of the University of Antwerp. Seventeen 6-month-old Aachener minipigs (male, castrated) weighing ~20 kg were selected for this study.
1. Medication and anesthesia
<ol>
	<li>Premedication
	<ol>
		<li>Ensure that the pigs are fasted for 12 h, but with unlimited access to water.</li>
		<li>For sedation, administer the following in one intramuscular injection: atropine 0.05 mg/kg, ketamine 10 mg/kg, midazolam 0.5 mg/kg.</li>
		<li>Determine the exact weight of the pig after it has lost consciousness (approximately 10 min post dose). Transport the pig to the operating theater.</li>
		<li>Place the pig on a heating pad.</li>
		<li>Apply ECG monitoring, pulse oximeter, and perform an initial thermometry.</li>
		<li>Insert an over-the-needle catheter (22 G) into the marginal ear vein or the external saphenous vein.</li>
	</ol>
	</li>
	<li>Anesthesia
	<ol>
		<li>For the induction of anesthesia, administer a bolus of propofol (1-4 mg/kg IV) before starting intubation. If superficial anesthesia is noted, administer an extra bolus of midazolam 0.2 mg/kg IV, and proceed to the intubation after ~5 min.</li>
		<li>Intubation
		<ol>
			<li>Place the pig in prone position.</li>
			<li>Ask an assistant to hold the mouth of the animal open using two slings of gauze and/or a mouth spreader. Spray 1 mL (10 mg) of lidocaine in the larynx with a 2 mL needleless syringe, wait for 30-60 s to desensitize the larynx, and then continue.</li>
			<li>Place an endotracheal tube (ETT) with an internal diameter of 6.5 mm using a laryngoscope. Use a laryngoscope to visualize, displace the epiglottis from the soft palate, and place a stylet into the ETT for better manipulation. 
			NOTE: The pig&#39;s mouth cannot be opened widely, and the distance from the nose tip to the larynx is long. Therefore, visualization of the rima glottis is limited. Hence, the ETT and the stylet help visualization.</li>
		</ol>
		</li>
		<li>When connecting the ventilator, give supplementary medication if needed: midazolam 0.5 mg/kg IV and/or alfentanil 30 &#181;g/kg IV.</li>
		<li>Use the following ventilator settings: volume control ventilation (VCV) with a pre-set tidal volume of 10 mL/kg, leading towards a peak inspiratory pressure (PIP) of 11-15 cmH20, a positive end-expiratory pressure PEEP of 2-5 cmH20; respiratory rate: 12-16 Brpm to maintain end-tidal CO2 (ETCO2) between 35-45 mmHg; FiO2: 50% (to be reduced when saturation is 100%); sevoflurane 2.5%.</li>
		<li>For analgesia, use alfentanil 0.5-1 &#181;g&#183;(kg&#183;min)-1 CRI.</li>
		<li>Administer a bolus of 10 mL/kg of plasmalyte 3-5 mL&#183;(kg&#183;h)-1 over 10-20 min to correct hypotension due to hypovolemia.</li>
		<li>Administer 1 g of cefazoline IV. For every 2 h of surgery, administer an extra 500 mg of cefazoline IV. 
		NOTE: For an overview of the emergency medication to have at hand in the operating theater, see Table 1. Urinary bladder catheterization is difficult in male pigs and, in general, not necessary for this procedure.</li>
		<li>Shave the thoracic and neck region of the animal.</li>
		<li>Apply vet ointment to the eyes to prevent dryness and eye irritation during anesthesia.</li>
		<li>Continuously monitor the vital parameters. Check the depth of anesthesia at least every 10 min by assessing whether the jaw tonus is relaxed, the palpebral reflex is absent, the eyes are rotated, and there are no behavioral signs of excitation. Check the color of the mucosa and capillary refill time to evaluate tissue perfusion. Record all data, together with all administered medication, in an individual anesthetic chart.</li>
		<li>Arterial line placement
		<ol>
			<li>Prepare the pressure conducting system. Add 5000 IU of heparin to an IV bag of 500 mL of 0.9% NaCl.</li>
			<li>Return the animal to supine position. Extend the leg and locate the femoral artery using ultrasound with the vascular probe in carotid setting. Disinfect the inguinal zone with chlorhexidine.&#160;Use umonium for sterilization of the ultrasound probe (or use a sterile transducer cover) and use sterile gloves to assure antiseptic technique.</li>
			<li>Puncture the femoral artery using ultrasound guidance. Insert a 3 Fr sheath using the Seldinger technique. 
			NOTE: Because of the small diameter of the femoral artery, it can be helpful to let an assistant insert the guide wire through the needle. Just the action of lifting the ultrasound probe may dislocate the needle tip.</li>
			<li>Fixate the sheath with a suture. Connect the sheath to the transducer and flush. Monitor the arterial blood pressure in real time.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
2. Surgery
<ol>
	<li>Preparation
	<ol>
		<li>Ensure that the animal is supine in a stable position. For extra stability, place prewarmed IV bags in a paraspinal position to support the animal.</li>
		<li>Place the earthing plate of the electrocautery underneath the animal. Use a small amount of ultrasound gel to ensure proper contact with the skin.</li>
		<li>Skin preparation: shave the animal in the following regions: neck, upper limbs, anterior thorax, upper part of the abdomen, inguinal and ECG electrode sites. Perform three alternating scrubs with alcohol 70% and iodine 2% to properly disinfect the skin.</li>
		<li>Place sterile drapes. Wrap the claws of the animal in sterile sheets or gloves as well. Use sterile gauze to retract them.</li>
		<li>To ensure sterile conditions, drape the surgical area with sterile surgical covers, use sterile instruments, and work under sterile conditions until skin closure. 
		NOTE: Throughout the procedure, surgeons must wear a hair cap, a mouth mask, a surgical gown, and sterile gloves.</li>
	</ol>
	</li>
	<li>Surgical placement of a permanent central venous catheter (CVC)
	<ol>
		<li>Make a 5 cm incision in the groove at the medial border of the sternocleidomastoid muscle. Bluntly dissect until the internal jugular vein is reached.</li>
		<li>Remove fibrous tissue around the vein and place a squared suture (= &#160;3 to 4 stitches forming a circle) with Prolene 6-0 around the desired catheterization site to gain vessel control.</li>
		<li>Cannulate the internal jugular vein with a 3 French triple-lumen CVC using the Seldinger technique. Tighten the Prolene 6-0 suture around the catheter.</li>
		<li>Fixate the handle of the catheter to the sternocleidomastoid muscle.</li>
		<li>Tunnel the three catheter lumina separately: use a large pair of blunt dissecting scissors to create the tunnel and an atraumatic clamp pull the catheter lumina through the tunnel. &#160;Attach the ends of the catheter firmly to the skin andput on the needle-free injection port. The exit sites of the catheter lumina are situated behind the ear and as far away as possible from the incision site to ensure a maximal trajectory length of the catheter under the skin.</li>
		<li>Close the incision site in two layers.</li>
	</ol>
	</li>
	<li>Sternotomy
	<ol>
		<li>Make a median incision from the manubrium of the sternum to 3 cm below the xiphoid process until the sternum becomes apparent.</li>
		<li>Bluntly dissect caudally from the xiphoid process. Put a finger on the visceral side of the sternum and remove connective tissue as far as possible following the visceral sternal surface. 
		NOTE: The connective tissue is removed to prevent myocardial injury whilst performing sternotomy.</li>
		<li>Use the sternum saw to cleave the sternum. Control all bleeding sites. Use the sternum spreader to enlarge the access to the thoracic cavity. Avoid damaging the pleura.</li>
		<li>Open the pericardium carefully and use suspension sutures to keep it out of the surgical field.</li>
	</ol>
	</li>
	<li>Pacemaker lead placement (see Figure 1)
	<ol>
		<li>Place a pacemaker lead on the left atrium.
		<ol>
			<li>Test the extension and retraction mechanism of the lead&#39;s fixation screw. Then, put the tip on a (curved) forceps and curve the stylet by 60&#176; if necessary.</li>
			<li>Put a compress on the left ventricle and gently pull it aside to have a view of the left atrium. 
			NOTE: Pressure on the ventricle will quickly cause hypotension. Make sure the anesthesiologist anticipates this with low-dose norepinephrine through the CVC. Release the ventricle when the mean blood pressure drops below 40 mmHg for &#62;20 s. Only proceed when the blood pressure of the animal has normalized.</li>
			<li>Upon visualization of the left atrium, firmly put the lead tip on the left atrial free wall, as close as possible to the pulmonary veins and as far as possible from the ventricle. Screw it in by extending the helix into the atrial tissue, preferably with a slight inclination. Do this as fast as possible and release the pressure on the left ventricle immediately.</li>
			<li>Measure the sensing and pacing threshold and impedance of the lead using a programmable electrical stimulator or pacemaker programmer. Ensure that there is no ventricular overcapture (broad QRS on ECG) when pacing at high voltages (10 V). If not satisfied, retract the helix of the lead and start over from step 2.4.1.1. 
			NOTE: Normal pacing threshold should be &#60;1 V with a pulse width of 0.5 ms (typically ~0.5 V @0.5 ms).</li>
		</ol>
		</li>
		<li>Place a pacemaker lead on the right atrium, completely analogous to the placement of the left atrial lead.</li>
		<li>Ensure that both leads leave the thorax at the midline; the left atrial lead must be tunneled through the abdominal subcutaneous fat from the xiphoid process to the left flank, the right atrial lead to the right flank.</li>
		<li>Make a pacemaker pocket in the subcutaneous fat at the left and right flank of the pig. Connect the pacemakers to the leads and place them inside the pockets. Connect a pacemaker capable of performing (50 Hz) burst pacing with the left atrial lead (to allow pacing) and a pacemaker from a different manufacturer (in order to avoid crosstalk while reading out both pacemakers simultaneously) to the right atrial lead (to allow sensing). Close in 2 layers with classic single sutures, the inner layer with Vicryl 1-0 and the outer layer with Mersilene 0.</li>
	</ol>
	</li>
	<li>Induction of sterile pericarditis
	<ol>
		<li>Expose the atria again by gently pulling aside the ventricles. Cover up the ventricles with gauze (and take the gauze away afterward).</li>
		<li>Spray sterile talcum over the epicardial surface of both atria using the dispenser that is included in the pack. As bradycardia and hypotension will follow this manipulation, give the heart enough time to recover spontaneously after approximately one minute; if necessary, start or increase (the infusion rate of) a norepinephrine drip.</li>
		<li>Leave one layer of sterile gauze (5 cm x 5 cm) on the epicardial surface of both atria: one piece left and one right.</li>
		<li>Check the position of the pacemaker leads one last time before starting closure.</li>
	</ol>
	</li>
	<li>Closing the chest
	<ol>
		<li>Leave a drain in the mediastinum and tunnel it to the skin surface. Connect the drain to a sterile vacuum jar; open the connection when the first layer of the skin is closed (to avoid air leakage). Remove the drain when bringing the animal back to its stable.</li>
		<li>Close the pericardium with Prolene 6-0.</li>
		<li>Close the sternum using a classical cerclage technique with stainless steel wire.</li>
		<li>Close the subcutis in two layers with resorbable thread.</li>
		<li>Perform a sternal block by infiltrating 5 mL of 0.5% bupivacaine into the skin; ensure bone contact with the sternum to infiltrate the periosteum. 
		NOTE: Alternatively, it might be even better to use pre-emptive analgesia by performing the sternal block BEFORE incision of the sternum.</li>
		<li>Close the skin with a continuous intradermal suture using resorbable thread.</li>
	</ol>
	</li>
</ol>
3. Postoperative care
<ol>
	<li>Progressively, turn off all sedatives while closing the skin of the animal.</li>
	<li>Keep the animal in the surgery room with close monitoring of body temperature, ventilation and airway patency, oxygenation, and hemodynamic parameters.</li>
	<li>Due to a substantial drop in body temperature that frequently occurs during the procedure, keep the animal warm using blankets, heating pad, and hot packs. Provide oxygen during recovery, especially when shivering is noted.</li>
	<li>Apply a fentanyl patch of 50 &#181;g/h for postoperative analgesia. Because there is a delay of 6-8 h before the fentanyl patch becomes effective, administer 0.05-0.1 mg/kg of morphine subcutaneously to bridge this period.</li>
	<li>When the animal is stable, is showing an increase in body temperature; can lift its head; is swallowing; shows normal ocular reflexes; and is breathing spontaneously, freely, and deeply without an ETT in place, without signs of upper airway obstruction; it can be transported back to the pen. Provide means of heating during the recovery phase (e.g., infrared lamp, heating mat, blankets). 
	NOTE: Avoid putting the animal back in the pen too soon as respiratory arrest is possible, even hours after the cessation of narcotics.</li>
	<li>Perform a check-up on the animal: every 15 min during the first hour postoperatively, then hourly for the first 4&#8211;6 h or more frequently if the animal is not comfortable. When the animal shows signs of pain, administer supplementary morphine subcutaneously 0.025&#8211;0.05 mg/kg every 2 h until it is comfortable. Administer 1 g of cefazoline 8 and 16 h after surgery. 
	NOTE: Pain assessment consists of subjective elements such as attitude, behavior (standing, eating, drinking), and grimace. Objective signs of pain are elevated heart rate, elevated respiratory rate, and superficial respiration. The animal will return to its normal status and behavior within 24 h. Remove the fentanyl patch on day 3 post operation.</li>
</ol>
4. Atrial tachypacing for induction of AF
<ol>
	<li>Inject ketamine 10 mg/kg and midazolam 0.5 mg/kg intramuscularly (without atropine) and wait until a sufficient level of sedation is reached.</li>
	<li>Weigh the pig again for follow-up. Place the animal in a restraining sling and bring it to the operating theater.</li>
	<li>Attach ECG and oxygen saturation monitoring and place the programmer heads over their corresponding pacemakers. Interrogate the pacemakers.</li>
	<li>Check the pacemaker settings for the occurrence of spontaneous AF. Look for a ventricular lead warning when using a dual-chamber pacemaker.</li>
	<li>Determine impedance and sensing and pacing thresholds. When performing electrophysiology (EP) studies, always pace at twice the threshold voltage and watch for an increase in voltage threshold during the experiment.</li>
	<li>Determine the atrial effective refractory period (AERP) approximated by the shortest cycle length at which 1:1 capture is maintained during burst pacing. 
	NOTE: This method is different from clinical AERP determination but more relevant to this protocol.</li>
	<li>Determine the conduction time between left and right atrial leads by measuring the time between the initiation of the pacing spike and the atrial depolarization on the right atrial lead.</li>
	<li>For the first protocol, apply a burst pace for 20 s with a cycle length of AERP + 30 ms. After the cessation of the pacing, check for the presence of AF and measure how long the episode lasts. Pause for at least 5 s between each pacing session and wait until the sinus rhythm heart rate has recovered to baseline. Repeat this &#8805;10 times; note the display of the AF inducibility as a percentage-the proportion of &#34;successful&#34; attempts to the total amount of attempts to induce AF. 
	NOTE: Only episodes &#62; 5 s are considered relevant.</li>
	<li>For the second protocol, apply a burst pace for 20 s, starting with a cycle length of AERP + 20 ms. During the following burst, decrease the cycle length until the minimal cycle length with 1:1 capture. Repeat this at least 10 times. Note the AF duration and AF inducibility.</li>
	<li>For the third protocol, apply a burst pace for 5 s at 50 Hz. Repeat this at least 10 times. Note the AF duration and AF inducibility.</li>
	<li>Let the animal awaken or continue with other procedures (e.g., echocardiography, treatment, blood draw)</li>
</ol>
5. Euthanasia
<ol>
	<li>After the experiment &#9472; which lasted one month &#9472; the animals are euthanized with an overdose of IV pentobarbital (50 mg/kg, IV). Humane endpoints for euthanasia were persisting signs of severe pain or discomfort, despite adequate treatment. This is assessed clinically on a daily basis: alarming signs include hypertension, tachycardia, increased respiratory rate, behavioral changes (restlessness, immobilization, vocalization) and jaw clenching.</li>
</ol>
6. Sham surgery
<ol>
	<li>Perform the same protocol without spraying talcum over the atrial epicardium or leaving a layer of sterile gauze.</li>
</ol>

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atrial+fibrillation+begets+atrial+fibrillation.+A+study+in+awake+chronically+instrumented+goats.">Atrial fibrillation begets atrial fibrillation. A study in awake chronically instrumented goats.</a> Circulation. 92 (7), 1954-1968 (1995).</li><li>Willems, R., Ector, H., Holemans, P., Van De Werf, F., Heidbuchel, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+different+pacing+protocols+on+the+induction+of+atrial+fibrillation+in+a+transvenously+paced+sheep+model.">Effect of different pacing protocols on the induction of atrial fibrillation in a transvenously paced sheep model.</a> Pacing and Clinical Electrophysiology. 24 (6), 925-932 (2001).</li><li>Pag&#233;, P. L., Plumb, V. J., Okumura, K., Waldo, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+animal+model+of+atrial+flutter.">A new animal model of atrial flutter.</a> Journal of the American College of Cardiology. 8 (4), 872-879 (1986).</li><li>Schwartzman, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+plasma-based,+amiodarone-impregnated+material+decreases+susceptibility+to+atrial+fibrillation+in+a+post-cardiac+surgery+model.">A plasma-based, amiodarone-impregnated material decreases susceptibility to atrial fibrillation in a post-cardiac surgery model.</a> Innovations. 11 (1), 59-63 (2016).</li><li>BCFI vzw. Vetcompendium BCFIvet Available from: <a target="_blank" href="https://www.vetcompendium.be/nl">https://www.vetcompendium.be/nl</a> (2021)</li><li>Swindle, M. M., Smith, A. 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None of the authors have any conflict of interest to disclose.

A reliable large animal model is a major asset for the study of atrial myopathy and AF and the development of novel therapies for AF. Implantation of pacemaker leads on the atrial epicardium allowed a longitudinal follow-up and repetitive electrophysiologic testing, which is difficult in small animals. Minipigs are easy to handle, and their hearts are structurally and physiologically similar to the human heart10.
The sterile pericarditis model is relatively straightforw...

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, leading to significant morbidity, mortality, and healthcare expenses1. In many cases, AF is merely the electrical symptom of the underlying atrial myopathy, which is defined by structural, electrical, autonomic, and contractile remodeling of the atria. This atrial myopathy can lead to AF and stroke2,3. Most therapies only target the electrical remodeling but do not target the underlying structural changes in the atria (inflammation and fibrosis)4,5,6,7. This is probably one of the reasons why current therapies are only marginally effective, especially in more advanced atrial myopathy8.
A reproducible animal model is crucial to target the inflammation and fibrosis present in atrial myopathy. Atrial tachypacing models have been developed in several large animal species9,10,11,12. In these models, the atrial tissue is paced continuously for long periods to induce electrical and eventually structural changes. The major disadvantages of tachypacing models are the long duration before structural signs of atrial myopathy appear and their relevance only for clinical syndromes in which electrical abnormalities develop before the atrial myopathy. A theoretical risk is pacing-lead failure due to fibrosis during long follow-up9.
In models of sterile pericarditis, sterile talcum is sprayed over the epicardial surface of the atria to induce an acute inflammatory and fibrotic reaction, resulting in atrial myopathy13,14. Pigs have cardiac anatomy and physiology similar to that of humans, and therefore, porcine models have high translational relevance. The advantages of using minipigs are that they are easier to handle due to their smaller size than conventional pig strains and can be maintained for a long period without any significant increase in body weight10. All these reasons make sterile pericarditis in minipigs an excellent model for the investigation of atrial myopathy and fibrillation. This protocol and video aim to facilitate the setup of this model in different research facilities and standardize protocols to study the inducibility of AF.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aachener minipig, 6-months old, male, castrated, weight 15-25 kg</td>
			<td>Carfil</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesia and preparation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ECG electrodes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Endotracheal tube 6.5 mm ID</td>
			<td>Covidien</td>
			<td>115-65OR</td>
			<td></td>
		</tr>
		<tr>
			<td>External cardioverter-defibrillator</td>
			<td>Innomed</td>
			<td>Cardio-aid 200B</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td>OK.</td>
			<td>OUB 60321</td>
			<td></td>
		</tr>
		<tr>
			<td>Intravenous catheter 22 GA, 1 Inch</td>
			<td>BD</td>
			<td>381323</td>
			<td></td>
		</tr>
		<tr>
			<td>Laryngoscope blade size 4</td>
			<td>Miller</td>
			<td>SUS426601</td>
			<td></td>
		</tr>
		<tr>
			<td>Monitor</td>
			<td>GE Medical systems</td>
			<td>2600040-003</td>
			<td></td>
		</tr>
		<tr>
			<td>Respirator</td>
			<td>Datex-Ohmeda</td>
			<td>1009-9000-000</td>
			<td></td>
		</tr>
		<tr>
			<td>Shaver</td>
			<td>Aesculap</td>
			<td>GT 104 / REF 985203</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe driver pump</td>
			<td>Fresenius Kabi</td>
			<td>082470</td>
			<td></td>
		</tr>
		<tr>
			<td>Arterial and central venous line placement</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3-lumen central venous catheterization set, 7 French, 16 cm, 0.032 Inch guide</td>
			<td>Arrow medical</td>
			<td>EU-22703-EN</td>
			<td></td>
		</tr>
		<tr>
			<td>Arteral catheter 3 French, 8 cm</td>
			<td>Vygon</td>
			<td>1,15,090</td>
			<td></td>
		</tr>
		<tr>
			<td>Caresite Luer access device</td>
			<td>B. Braun</td>
			<td>415122-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluids: IV bags of Plasmalyte, Glucose 5%, NaCl 0.9% (500 mL or 1000 mL)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>heparinized saline</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Needles: 18 Ga / 40 mm and 22 Ga / 40 mm</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pressure monitoring set, 195 cm</td>
			<td>Edwards Lifesciences</td>
			<td>T005021M</td>
			<td></td>
		</tr>
		<tr>
			<td>Pressure tubing 180 cm</td>
			<td>Edwards Lifesciences</td>
			<td>50P172</td>
			<td></td>
		</tr>
		<tr>
			<td>suture with needle</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Syringes Luerlok: 2 mL, 5 mL, 10 mL, 20 mL, 50 mL</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasound gel</td>
			<td>Zealand coating</td>
			<td>446-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasound with vascular probe</td>
			<td>Philips healthcare</td>
			<td>EPIQ 7C / REF BZE1723</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical set</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Blunt-tip surgical scissors</td>
			<td>Martin</td>
			<td>11-934-25</td>
			<td></td>
		</tr>
		<tr>
			<td>60 degrees curved Debakey forceps</td>
			<td>Aesculap</td>
			<td>FB403</td>
			<td></td>
		</tr>
		<tr>
			<td>Anatomical forceps</td>
			<td>AS</td>
			<td>13-102-16</td>
			<td></td>
		</tr>
		<tr>
			<td>Debakey forceps</td>
			<td>Geister</td>
			<td>10-0634</td>
			<td></td>
		</tr>
		<tr>
			<td>Electrocautery module</td>
			<td>Alsa</td>
			<td>Alsatom SU 140/D MPC</td>
			<td></td>
		</tr>
		<tr>
			<td>Holders for stainless steel wire</td>
			<td>COBE</td>
			<td>013-123</td>
			<td></td>
		</tr>
		<tr>
			<td>Mosquito</td>
			<td>Leibinger</td>
			<td>32-01008</td>
			<td></td>
		</tr>
		<tr>
			<td>Needledriver, fine</td>
			<td>Delacroix-Chevalier</td>
			<td>50302-21</td>
			<td></td>
		</tr>
		<tr>
			<td>Needledriver, normal</td>
			<td>Aesculap</td>
			<td>BM 77</td>
			<td></td>
		</tr>
		<tr>
			<td>Rib spreader</td>
			<td>Martin</td>
			<td>24-178-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>Swann-Morton</td>
			<td>0511</td>
			<td>no. 24</td>
		</tr>
		<tr>
			<td>Scissors for stainless steel wire</td>
			<td>Jakobi</td>
			<td>411830</td>
			<td></td>
		</tr>
		<tr>
			<td>Spreaders</td>
			<td>AS</td>
			<td>16-058-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Sternum saw</td>
			<td>Eure-Power</td>
			<td>5000020</td>
			<td></td>
		</tr>
		<tr>
			<td>Sternum saw blade</td>
			<td>MicroAire</td>
			<td>ZR-032M</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical consumables</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Disinfectant: iodine, chlorhexidine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Electrocautery pencil with push button, cable 5 m</td>
			<td>Dongguan QueenMed Equipment</td>
			<td>ESPB4001LQ</td>
			<td></td>
		</tr>
		<tr>
			<td>Gastric tube</td>
			<td>Vygon</td>
			<td>390.12</td>
			<td></td>
		</tr>
		<tr>
			<td>Mersilene-0, 75 cm</td>
			<td>Ethicon</td>
			<td>F2505H</td>
			<td></td>
		</tr>
		<tr>
			<td>Monocryl 3-0, 70 cm</td>
			<td>Ethicon</td>
			<td>Y423H</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouth masks, hair nets</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oriflex-4 vacuum flask for surgical draining</td>
			<td>Oriplast Krayer</td>
			<td>VK00352</td>
			<td></td>
		</tr>
		<tr>
			<td>Prolene 6-0, 75 cm</td>
			<td>Ethicon</td>
			<td>8711H</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless steel monofilament non-absorbable suture</td>
			<td>Ethicon</td>
			<td>W995</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile drapes</td>
			<td>3M</td>
			<td>9010</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile gauze 20 x 10 cm</td>
			<td>Stella</td>
			<td>35921</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile gloves</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile surgical gown</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Steritalc PF3</td>
			<td>Novatech</td>
			<td>16863</td>
			<td></td>
		</tr>
		<tr>
			<td>Vicryl-0, 75 cm</td>
			<td>Ethicon</td>
			<td>V324H</td>
			<td></td>
		</tr>
		<tr>
			<td>Cardiac pacing</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar pacing lead Fineline II Sterox EZ 58 cm</td>
			<td>Boston Scientific</td>
			<td>4474</td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar pacing lead Tendril STS 58 cm</td>
			<td>Abbott</td>
			<td>2088TC</td>
			<td></td>
		</tr>
		<tr>
			<td>Ellegaard G&#246;ttingen Minipig Frame 3</td>
			<td>Lomir</td>
			<td>DF H1PU</td>
			<td></td>
		</tr>
		<tr>
			<td>Ellegaard G&#246;ttingen Minipig Sling Cover</td>
			<td>Lomir</td>
			<td>SS CEG1</td>
			<td></td>
		</tr>
		<tr>
			<td>Micropace cardiac stimulator</td>
			<td>Boston Scientific</td>
			<td>EPS 320</td>
			<td></td>
		</tr>
		<tr>
			<td>Pacemaker for pacing</td>
			<td>Medtronic</td>
			<td>Azure XT DR MRI SureScan</td>
			<td></td>
		</tr>
		<tr>
			<td>Pacemaker for sensing</td>
			<td>Biotronik</td>
			<td>Eluna 8 DR-T</td>
			<td></td>
		</tr>
		<tr>
			<td>Pacemaker programmer for pacing</td>
			<td>Medtronic</td>
			<td>CareLink Encore 29901A</td>
			<td></td>
		</tr>
		<tr>
			<td>Pacemaker programmer for sensing</td>
			<td>Biotronik</td>
			<td>ICS 3000 DS CD-W US</td>
			<td></td>
		</tr>
		<tr>
			<td>Medication</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adrenaline 1 mg/mL, 1 mL</td>
			<td>Sterop</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Atropine 0.5 mg/mL, 1 mL</td>
			<td>Sterop</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Catapressan 150 &#181;g/mL, 1 ml clonidine</td>
			<td>Boehringer Ingelheim</td>
			<td>BE021402</td>
			<td></td>
		</tr>
		<tr>
			<td>Cefazoline 2 g powder</td>
			<td>Mylan</td>
			<td>BE319794</td>
			<td></td>
		</tr>
		<tr>
			<td>Cordarone 50 mg/mL, 3 mL amiodarone</td>
			<td>Sanofi</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Durogesic 50 &#181;g/h fentanyl patches</td>
			<td>Janssen-Cilag</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose 5%, 500 mL</td>
			<td>Baxter</td>
			<td>AE0063</td>
			<td></td>
		</tr>
		<tr>
			<td>Ketalar 50 mg/mL, 10 mL</td>
			<td>Pfizer</td>
			<td>804101</td>
			<td></td>
		</tr>
		<tr>
			<td>Lanoxin 0.25 mg/mL, 2 mL digoxine</td>
			<td>Aspen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Marcaine 0.5% + adrenaline 1:200,000</td>
			<td>Aspen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Midazolam 5 mg/ml, 3 mL</td>
			<td>B. Braun</td>
			<td>3521740</td>
			<td></td>
		</tr>
		<tr>
			<td>Morfine 10 mg/mL, 1 mL</td>
			<td>Sterop</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl 0.9%, 500 mL</td>
			<td>Baxter</td>
			<td>AKE1323</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitro Pohl 1 mg/mL, 5 mL nitroglycerine</td>
			<td>Pohl Boskamp</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Noradrenaline 1 mg/mL, 4 mL</td>
			<td>Aguettant</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plasmalyte 1000 mL</td>
			<td>Baxter</td>
			<td>AKE0324</td>
			<td></td>
		</tr>
		<tr>
			<td>Propofol 10 mg/mL, 20 mL</td>
			<td>B. Braun</td>
			<td>3521810</td>
			<td></td>
		</tr>
		<tr>
			<td>Protamine 1400 IU/mL, 5 mL</td>
			<td>Leo pharma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rapifen 0.5 mg/mL, 2 mL</td>
			<td>Janssen-Cilag</td>
			<td>95103</td>
			<td></td>
		</tr>
		<tr>
			<td>Seloken 1 mg/mL, 5 mL metoprolol</td>
			<td>AstraZeneca</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sevorane Quick Fill 100% sevoflurane, 250 mL</td>
			<td>Abbvie</td>
			<td>1283-415</td>
			<td></td>
		</tr>
		<tr>
			<td>Tracrium 10 mg/mL, 5 mL atracurium</td>
			<td>Aspen</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

sterile pericarditis in aachener minipigs as a model for atrial myopathy and atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia caused by structural remodeling of the atria, also called atrial myopathy. Current therapies only target the electrical abnormalities and not the underlying atrial myopathy. For the development of novel therapies, a reproducible large animal model of atrial myopathy is necessary. This paper presents a model of sterile pericarditis-induced atrial myopathy in Aachener minipigs. Sterile pericarditis was induced by spraying sterile talcum and leaving a layer of sterile gauze over the atrial epicardial surface. This led to inflammation and fibrosis, two crucial components of the pathophysiology of atrial myopathy, making the atria susceptible to the induction of AF. Two pacemaker electrodes were positioned epicardially on each atrium and connected to two pacemakers from different manufacturers. This strategy allowed for repeated non-invasive atrial programmed stimulation to determine the inducibility of AF at specified time points after surgery. Different protocols to test AF inducibility were used. The advantages of this model are its clinical relevance, with AF inducibility and the rapid induction of inflammation and fibrosis-both present in atrial myopathy-and its reproducibility. The model will be useful in the development of novel therapies targeting atrial myopathy and AF.

Morbidity and mortality: 
When we started developing this model of sterile pericarditis in Aachener minipigs, we noticed perioperative mortality of 4 out of 17 pigs (23.5%): 3 out of 4 deaths occurred in the first 6 surgeries because of a &#34;learning curve effect.&#34; The etiologies were the following: 2 pigs died because of postoperative respiratory arrest; this problem was solved by reducing the dose of alfentanil. One pig died because of ventricular fibrillation during the first pacing session...

Watch this Scientific Journal Video about Sterile Pericarditis in Aachener Minipigs As a Model for Atrial Myopathy and Atrial Fibrillation at JoVE.com

Sterile Pericarditis in Aachener Minipigs As a Model for Atrial Myopathy and Atrial Fibrillation

We describe a sterile pericarditis model in minipigs to study atrial myopathy and atrial fibrillation (AF). We present surgical and anesthetic techniques, strategies for vascular access, and a protocol to study the inducibility of AF.

Atrial fibrillation (AF) is the most common arrhythmia caused by structural remodeling of the atria, also called atrial myopathy. Current therapies only ...

sterile-pericarditis-aachener-minipigs-as-model-for-atrial-myopathy

Research

JoVE Journal

Medicine

2.5K Views.  University of Antwerp. We describe a sterile pericarditis model in minipigs to study atrial myopathy and atrial fibrillation (AF). We present surgical and anesthetic techniques, strategies for vascular access, and a protocol to study the inducibility of AF.

Video: Sterile Pericarditis in Aachener Minipigs As a Model for Atrial Myopathy and Atrial Fibrillation

High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation

Atrial fibrillation (AF) is a complex cardiac arrhythmia with high morbidity and mortality.1,2 It is the most common sustained cardiac rhythm disturbance seen in clinical practice and its prevalence is expected to increase in the coming years.3 Increased intra-atrial pressure and dilatation have been long recognized to lead to AF,1,4 which highlights the relevance of using animal models and stretch to study AF dynamics. Understanding the mechanisms underlying AF requires visualization of the cardiac electrical waves with high spatial and temporal resolution. While high-temporal resolution can be achieved by conventional electrical mapping traditionally used in human electrophysiological studies, the small number of intra-atrial electrodes that can be used simultaneously limits the spatial resolution and precludes any detailed tracking of the electrical waves during the arrhythmia. The introduction of optical mapping in the early 90's enabled wide-field characterization of fibrillatory activity together with sub-millimeter spatial resolution in animal models5,6 and led to the identification of rapidly spinning electrical wave patterns (rotors) as the sources of the fibrillatory activity that may occur in the ventricles or the atria.7-9 Using combined time- and frequency-domain analyses of optical mapping it is possible to demonstrate discrete sites of high frequency periodic activity during AF, along with frequency gradients between left and right atrium. The region with fastest rotors activates at the highest frequency and drives the overall arrhythmia.10,11 The waves emanating from such rotor interact with either functional or anatomic obstacles in their path, resulting in the phenomenon of fibrillatory conduction.12 Mapping the endocardial surface of the posterior left atrium (PLA) allows the tracking of AF wave dynamics in the region with the highest rotor frequency. Importantly, the PLA is the region where intracavitary catheter-based ablative procedures are most successful terminating AF in patients,13 which underscores the relevance of studying AF dynamics from the interior of the left atrium. Here we describe a sheep model of acute stretch-induced AF, which resembles some of the characteristics of human paroxysmal AF. Epicardial mapping on the left atrium is complemented with endocardial mapping of the PLA using a dual-channel rigid borescope c-mounted to a CCD camera, which represents the most direct approach to visualize the patterns of activation in the most relevant region for AF maintenance.

This report provides a detailed description of the methodology and results of simultaneous endocardial and epicardial optical mapping of electrical excitation in the intact left atrium of a Langendorff-perfused sheep heart during stretch-induced atrial fibrillation.

 Atrial fibrillation (AF) is a complex cardiac arrhythmia with high morbidity and mortality.1,2 It is the most common sustained cardiac rhythm disturbance ...

The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting an estimated 6 million people in the United States 1. Since AF affects primarily elderly people, its prevalence increases parallel with age. As such, it is expected that 15.9 million Americans will be affected by the year 2050 2. Ischemic stroke occurs in 5% of non-anticoagulated AF patients each year. Current treatments for AF include rate control, rhythm control and prevention of stroke 3.
The American College of Cardiology, American Heart Association, and European Society of Cardiology currently recommended rate control as the first course of therapy for AF 3. Rate control is achieved by administration of pharmacological agents, such as &beta;-blockers, that lower the heart rate until it reaches a less symptomatic state 3. Rhythm control aims to return the heart to its normal sinus rhythm and is typically achieved through administration of antiarrhythmic drugs such as amiodarone, electrical cardioversion or ablation therapy. Rhythm control methods, however, have not been demonstrated to be superior to rate-control methods 4-6. In fact, certain antiarrhythmic drugs have been shown to be associated with higher hospitalization rates, serious adverse effects 3, or even increases in mortality in patients with structural heart defects 7. Thus, treatment with antiarrhythmics is more often used when rate-control drugs are ineffective or contraindicated. Rate-control and antiarrhythmic agents relieve the symptoms of AF, including palpitations, shortness of breath, and fatigue 8, but don't reliably prevent thromboembolic events 6.
Treatment with the anticoagulant drug warfarin significantly reduces the rate of stroke or embolism 9,10. However, because of problems associated with its use, fewer than 50% of patients are treated with it. The therapeutic dose is affected by drug, dietary, and metabolic interactions, and thus requires detailed monitoring. In addition, warfarin has the potential to cause severe, sometimes lethal, bleeding 2. As an alternative, aspirin is commonly prescribed. While aspirin is typically well tolerated, it is far less effective at preventing stroke 10. Other alternatives to warfarin, such as dabigatran 11 or rivaroxaban 12 demonstrate non-inferiority to warfarin with respect to thromboembolic events (in fact, dabigatran given as a high dose of 150 mg twice a day has shown superiority). While these drugs have the advantage of eliminating dietary concerns and eliminating the need for regular blood monitoring, major bleeding and associated complications, while somewhat less so than with warfarin, remain an issue 13-15.
Since 90% of AF-associated strokes result from emboli that arise from the left atrial appendage (LAA) 2, one alternative approach to warfarin therapy has been to exclude the LAA using an implanted device to trap blood clots before they exit. Here, we demonstrate a procedure for implanting the WATCHMAN Left Atrial Appendage Closure Device. A transseptal cannula is inserted through the femoral vein, and under fluoroscopic guidance, inter-atrial septum is crossed. Once access to the left atrium has been achieved, a guidewire is placed in the upper pulmonary vein and the WATCHMAN Access Sheath and dilator are advanced over the wire into the left atrium. The guidewire is removed, and the access sheath is carefully advanced into the distal portion of the LAA over a pigtail catheter. The WATCHMAN Delivery System is prepped, inserted into the access sheath, and slowly advanced. The WATCHMAN device is then deployed into the LAA. The device release criteria are confirmed via fluoroscopy and transesophageal echocardiography (TEE) and the device is released.

The accompanying video describes a procedure for percutaneous placement of the WATCHMAN Left Atrial Appendage (LAA) Device. The WATCHMAN is a nitinol device designed to be permanently implanted at, or slightly distal to, the opening of the left atrial appendage (LAA) to trap blood clots before they exit the LAA, preventing thromboembolic stroke.

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting an estimated 6 million people in the United States 1. Since AF affects primarily ...

Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and disordered electrical activity in the atria gives rise to palpitations, fatigue, dyspnea, chest pain and dizziness with or without syncope 4, 5. Patients with AF have a five-fold higher risk of stroke 6.
Oral anticoagulation (OAC) with warfarin is commonly used for stroke prevention in patients with AF and has been shown to reduce the risk of stroke by 64% 7. Warfarin therapy has several major disadvantages, however, including bleeding, non-tolerance, interactions with other medications and foods, non-compliance and a narrow therapeutic range 8-11. These issues, together with poor appreciation of the risk-benefit ratio, unawareness of guidelines, or absence of an OAC monitoring outpatient clinic may explain why only 30-60% of patients with AF are prescribed this drug 8.
The problems associated with warfarin, combined with the limited efficacy and/or serious side effects associated with other medications used for AF 12,13, highlight the need for effective non-pharmacological approaches to treatment. One such approach is catheter ablation (CA), a procedure in which a radiofrequency electrical current is applied to regions of the heart to create small ablation lesions that electrically isolate potential AF triggers 4. CA is a well-established treatment for AF symptoms 14, 15, that may also decrease the risk of stroke. Recent data showed a significant decrease in the relative risk of stroke and transient ischemic attack events among patients who underwent ablation compared with those undergoing antiarrhythmic drug therapy 16.
Since the left atrial appendage (LAA) is the source of thrombi in more than 90% of patients with non-valvular atrial fibrillation 17, another approach to stroke prevention is to physically block clots from exiting the LAA. One method for occluding the LAA is via percutaneous placement of the WATCHMAN LAA closure device. The WATCHMAN device resembles a small parachute. It consists of a nitinol frame covered by fabric polyethyl terephthalate that prevents emboli, but not blood, from exiting during the healing process. Fixation anchors around the perimeter secure the device in the LAA (Figure 1). To date, the WATCHMAN is the only implanted percutaneous device for which a randomized clinical trial has been reported. In this study, implantation of the WATCHMAN was found to be at least as effective as warfarin in preventing stroke (all-causes) and death (all-causes) 18. This device received the Conformit&eacute; Europ&eacute;enne (CE) mark for use in the European Union for warfarin eligible patients and in those who have a contraindication to anticoagulation therapy 19.
Given the proven effectiveness of CA to alleviate AF symptoms and the promising data with regard to reduction of thromboembolic events with both CA and WATCHMAN implantation, combining the two procedures is hoped to further reduce the incidence of stroke in high-risk patients while simultaneously relieving symptoms. The combined procedure may eventually enable patients to undergo implantation of the WATCHMAN device without subsequent warfarin treatment, since the CA procedure itself reduces thromboembolic events. This would present an avenue of treatment previously unavailable to patients ineligible for warfarin treatment because of recurrent bleeding 20 or other warfarin-associated problems.
The combined procedure is performed under general anesthesia with biplane fluoroscopy and TEE guidance. Catheter ablation is followed by implantation of the WATCHMAN LAA closure device. Data from a non-randomized trial with 10 patients demonstrates that this procedure can be safely performed in patients with a CHADS2 score of greater than 1 21. Further studies to examine the effectiveness of the combined procedure in reducing symptoms from AF and associated stroke are therefore warranted.

Catheter ablation is combined with placement of the WATCHMAN Left Atrial Appendage Closure Device to prevent ischemic stroke in a patient with non-valvular atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting millions of individuals worldwide 1-3. The rapid, irregular, and ...

Robotic Ablation of Atrial Fibrillation

Background: Pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). During PVI an electrical conduction block between pulmonary vein (PV) and left atrium (LA) is created. This conduction block prevents AF, which is triggered by irregular electric activity originating from the PV. However, transmural atrial lesions are required which can be challenging. Re-conduction and AF recurrence occur in 20 - 40% of the cases. Robotic catheter systems aim to improve catheter steerability. Here, a procedure with a new remote catheter system (RCS), is presented. Objective of this article is to show feasibility of robotic AF ablation with a novel system. Materials and Methods: After interatrial trans-septal puncture is performed using a long sheath and needle under fluoroscopic guidance. The needle is removed and a guide wire is placed in the left superior PV. Then an ablation catheter is positioned in the LA, using the sheath and wire as guide to the LA. LA angiography is performed over the sheath. A circular mapping catheter is positioned via the long sheath into the LA and a three-dimensional (3-D) anatomical reconstruction of the LA is performed. The handle of the ablation catheter is positioned in the robotic arm of the Amigo system and the ablation procedure begins. During the ablation procedure, the operator manipulates the ablation catheter via the robotic arm with the use of a remote control. The ablation is performed by creating point-by-point lesions around the left and right PV ostia. Contact force is measured at the catheter tip to provide feedback of catheter-tissue contact. Conduction block is confirmed by recording the PV potentials on the circular mapping catheter and by pacing maneuvers. The operator stays out of the radiationfield during ablation. Conclusion: The novel catheter system allows ablation with high stability on low operator fluoroscopy exposure.

Pulmonary vein isolation (PVI) with an ablation catheter is a curative treatment for atrial fibrillation (AF). Robotic catheter systems aim to improve catheter steerability. Here, a procedure with a new robotic catheter system is presented. The goal of the procedure is electrical block between pulmonary vein and left atrium.

Background: Pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). During PVI an electrical conduction block between ...

Isolation of Atrial Cardiomyocytes from a Rat Model of Metabolic Syndrome-related Heart Failure with Preserved Ejection Fraction

In this article, we describe an optimized, Langendorff-based procedure for the isolation of single-cell atrial cardiomyocytes (ACMs) from a rat model of metabolic syndrome (MetS)-related heart failure with preserved ejection fraction (HFpEF). The prevalence of MetS-related HFpEF is rising, and atrial cardiomyopathies associated with atrial remodeling and atrial fibrillation are clinically highly relevant as atrial remodeling is an independent predictor of mortality. Studies with isolated single-cell cardiomyocytes are frequently used to corroborate and complement in vivo findings. Circulatory vessel rarefication and interstitial tissue fibrosis pose a potentially limiting factor for the successful single-cell isolation of ACMs from animal models of this disease.
We have addressed this issue by employing a device capable of manually regulating the intraluminal pressure of cardiac cavities during the isolation procedure, substantially increasing the yield of morphologically and functionally intact ACMs. The acquired cells can be used in a variety of different experiments, such as cell culture and functional Calcium imaging (i.e., excitation-contraction-coupling).
We provide the researcher with a step-by-step protocol, a list of optimized solutions, thorough instructions to prepare the necessary equipment, and a comprehensive troubleshooting guide. While the initial implementation of the procedure might be rather difficult, a successful adaptation will allow the reader to perform state-of-the-art ACM isolations in a rat model of MetS-related HFpEF for a broad spectrum of experiments.

Here, we describe an optimized, Langendorff-based procedure for the isolation of single-cell atrial cardiomyocytes from a rat model of metabolic syndrome-related heart failure with preserved ejection fraction. A manual regulation of intraluminal pressure of cardiac cavities is implemented to yield functionally intact myocytes suitable for excitation-contraction-coupling studies.

In this article, we describe an optimized, Langendorff-based procedure for the isolation of single-cell atrial cardiomyocytes (ACMs) from a rat model of ...

Isolation of Atrial Myocytes from Adult Mice

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents responsible for the action potential can cause pro-arrhythmic substrates that underlie arrhythmias, such as atrial fibrillation, which are highly prevalent in many conditions and disease states. Isolating adult mouse atrial cardiomyocytes for use in patch-clamp experiments has greatly advanced our knowledge and understanding of the cellular electrophysiology in the healthy atrial myocardium and in the setting of atrial pathophysiology. In addition, studies using genetic mouse models have elucidated the role of a vast array of proteins in regulating atrial electrophysiology. Here we provide a detailed protocol for the isolation of cardiomyocytes from the atrial appendages of adult mice using a combination of enzymatic digestion and mechanical dissociation of these tissues. This approach consistently and reliably yields isolated atrial cardiomyocytes that can then be used to characterize cellular electrophysiology by measuring action potentials and ionic currents in patch-clamp experiments under a number of experimental conditions.

This protocol is used to isolate single atrial cardiomyocytes from the adult mouse heart using a chunk digestion approach. This approach is used to isolate right or left atrial myocytes that can be used to characterize atrial myocyte electrophysiology in patch-clamp studies.

The electrophysiological properties of atrial myocytes importantly affect overall cardiac function. Alterations in the underlying ionic currents ...

Cooling or Warming the Esophagus to Reduce Esophageal Injury During Left Atrial Ablation in the Treatment of Atrial Fibrillation

Ablation of the left atrium using either radiofrequency (RF) or cryothermal energy is an effective treatment for atrial fibrillation (AF) and is the most frequent type of cardiac ablation procedure performed. Although generally safe, collateral injury to surrounding structures, particularly the esophagus, remains a concern. Cooling or warming the esophagus to counteract the heat from RF ablation, or the cold from cryoablation, is a method that is used to reduce thermal esophageal injury, and there are increasing data to support this approach. This protocol describes the use of a commercially available esophageal temperature management device to cool or warm the esophagus to reduce esophageal injury during left atrial ablation. The temperature management device is powered by standard water-blanket heat exchangers, and is shaped like a standard orogastric tube placed for gastric suctioning and decompression. Water circulates through the device in a closed-loop circuit, transferring heat across the silicone walls of the device, through the esophageal wall. Placement of the device is analogous to the placement of a typical orogastric tube, and temperature is adjusted via the external heat-exchanger console.

The goal of this protocol is to describe the use of esophageal temperature modulation to counteract esophageal thermal injury from left atrial ablation for the treatment of atrial fibrillation.

Ablation of the left atrium using either radiofrequency (RF) or cryothermal energy is an effective treatment for atrial fibrillation (AF) and is the most ...

Transesophageal Atrial Burst Pacing for Atrial Fibrillation Induction in Rats

Animal studies have brought important insights into our understanding regarding atrial fibrillation (AF) pathophysiology and therapeutic management. Reentry, one of the main mechanisms involved in AF pathogenesis, requires a certain mass of myocardial tissue in order to occur. Due to the small size of the atria, rodents have long been considered 'resistant' to AF. Although spontaneous AF has been shown to occur in rats, long-term follow-up (up to 50 weeks) is required for the arrhythmia to occur in those models. The present work describes an experimental protocol of transesophageal atrial burst pacing for rapid and efficient induction of AF in rats. The protocol can be successfully used in rats with healthy or remodeled hearts, in the presence of a wide variety of risk factors, allowing the study of AF pathophysiology, identification of novel therapeutic targets, and evaluation of novel prophylactic and/or therapeutic strategies.

The present work describes an experimental protocol of transesophageal atrial burst pacing for efficient induction of atrial fibrillation (AF) in rats. The protocol can be used in rats with healthy or remodeled hearts, allowing the study of AF pathophysiology, identification of novel therapeutic targets, and evaluation of new therapeutic strategies.

Animal studies have brought important insights into our understanding regarding atrial fibrillation (AF) pathophysiology and therapeutic management. ...

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation

Atrial fibrillation (AF) is the most common form of arrhythmia. Atrial remodeling is considered the most critical mechanism for the presence and development of atrial fibrillation. Also, atrial remodeling can lead to the enlargement and dysfunction of the left atrium (LA), resulting in thrombosis and heart failure. Functional changes in left atrial strain and strain rate occur before structural alterations and are closely associated with structural remodeling and left atrial fibrosis. These parameters are sensitive biomarkers for atrial function. Cardiac magnetic resonance feature tracking (CMR-FT) is a novel, non-invasive, post-processing technique that can evaluate left atrial strain and strain rate. The CMR-FT was utilized in this investigation to assess the bilateral atrium strain rate in individuals with paroxysmal AF. Modifications in each segmental strain were evaluated using segmental analysis. The CMR-FT is recommended for non-invasive evaluations in the clinical assessment of atrial strain among existing strain imaging techniques. Further, it is a flexible parameter measurement with good reproducibility, high soft-tissue resolution, and post-processing based on standard cine balanced steady-state free precision (bSSFP) long-axis images without requiring a new sequence acquisition.

The atrial function is associated with the strain and strain rate. The cardiac magnetic resonance feature tracking (CMR-FT) technique was used in this study to quantify left and right atrial global and segmental longitudinal strain and strain rate in individuals with paroxysmal atrial fibrillation.

Atrial fibrillation (AF) is the most common form of arrhythmia. Atrial remodeling is considered the most critical mechanism for the presence and ...

Reduced Procedure Time and Variability with Active Esophageal Cooling During Radiofrequency Ablation for Atrial Fibrillation

Various methods are utilized during radiofrequency (RF) pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) to protect the esophagus from inadvertent thermal injury. Active esophageal cooling is increasingly being used over traditional luminal esophageal temperature (LET) monitoring, and each approach may influence procedure times and the variability around those times. The objective of this study is to measure the effects on procedure time and variability in procedure time of two different esophageal protection strategies utilizing advanced informatics techniques to facilitate data extraction. Trained clinical informaticists first performed a contextual inquiry in the catheterization laboratory to determine laboratory workflows and observe the documentation of procedural data within the electronic health record (EHR). These EHR data structures were then identified in the electronic health record reporting database, facilitating data extraction from the EHR. A manual chart review using a REDCap database created for the study was then performed to identify additional data elements, including the type of esophageal protection used. Procedure duration was then compared using summary statistics and standard measures of dispersion.&#160;A total of 164 patients underwent radiofrequency PVI over the study timeframe; 63 patients (38%) were treated with LET monitoring, and 101 patients (62%) were treated with active esophageal cooling. The mean procedure time was 176 min (SD of 52 min) in the LET monitoring group compared to 156 min (SD of 40 min) in the esophageal cooling group (P = 0.012). Thus, active esophageal cooling during PVI is associated with reduced procedure time and reduced variation in procedure time when compared to traditional LET monitoring.

This study utilized advanced informatics techniques to compare procedure duration in patients undergoing radiofrequency atrial ablation treated with active esophageal cooling to those treated with traditional luminal esophageal temperature monitoring. Contextual inquiry, workflow analysis, and data mapping were utilized. The findings demonstrated reduced procedure time and variability with active cooling.

Various methods are utilized during radiofrequency (RF) pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) to protect the ...