We thank the patients for participating in this study. We are also grateful to the Biomedicine Electron Microscopy Laboratory of Basic Medical Science School of Central South University, particularly to Xiaoying Wu and Jin Li for technical support. This work was supported by the National Key Research and Development Program (No. 2018YFC1311204).

The Institutional Review Board approved the study protocol, and samples of the dilated left atrium (LA) tissues in the dextrocardia cases were collected for electron microscopy after written informed consent had been obtained.
1. Surgical procedure and ablation
<ol>
	<li>Perform a median sternotomy and suspend the left lateral pericardium after opening.
	<ol>
		<li>Cannulate the ascending aorta and the superior and inferior vena cava (SVC, IVC) to establish mild hypothermic ...

<ol>
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A., Guler, A., Kaya, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitral+valve+replacement+in+a+patient+with+situs+inversus+and+dextrocardia.">Mitral valve replacement in a patient with situs inversus and dextrocardia.</a> The Thoracic and Cardiovascular Surgeon. 59 (5), 305-306 (2011).</li><li>Uchimuro, T., Fukui, T., Matsuyama, S., Tabata, M., Takanashi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitral+valve+replacement+in+dextrocardia+and+situs+inversus.">Mitral valve replacement in dextrocardia and situs inversus.</a> Kyobu Geka. 65 (10), 858-861 (2012).</li><li>Atsumi, Y., Tokunaga, S., Yasuda, S., Fushimi, K., Masuda, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitral+valve+surgery+in+a+patient+with+dextrocardia+and+180+degrees+counter-clockwise+rotated+heart+due+to+congenital+agenesis+of+the+right+lung.">Mitral valve surgery in a patient with dextrocardia and 180 degrees counter-clockwise rotated heart due to congenital agenesis of the right lung.</a> Journal of Cardiac Surgery. 28 (6), 635-637 (2013).</li><li>Kikon, M., Kazmi, A., Gupta, A., Grover, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Left-sided+approach+for+mitral+valve+replacement+in+a+case+of+dextrocardia+with+situs+solitus.">Left-sided approach for mitral valve replacement in a case of dextrocardia with situs solitus.</a> Interactive Cardiovascular and Thoracic Surgery. 17 (5), 900-902 (2013).</li><li>Khan, J. 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M., 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=The+Cox+maze+III+procedure+for+atrial+fibrillation:+long-term+efficacy+in+patients+undergoing+lone+versus+concomitant+procedures.">The Cox maze III procedure for atrial fibrillation: long-term efficacy in patients undergoing lone versus concomitant procedures.</a> The Journal of Thoracic and Cardiovascular Surgery. 126 (6), 1822-1827 (2003).</li><li>Gaynor, S. 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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prediction+of+sinus+rhythm+in+patients+undergoing+concomitant+Cox+maze+procedure+through+a+median+sternotomy.">Prediction of sinus rhythm in patients undergoing concomitant Cox maze procedure through a median sternotomy.</a> The Journal of Thoracic and Cardiovascular Surgery. 148 (3), 881-886 (2014).</li><li>Damiano, R. J., Voeller, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biatrial+lesion+sets.">Biatrial lesion sets.</a> Journal of Interventional Cardiac Electrophysiology. 20 (3), 95-99 (2007).</li><li>Lawrance, C. P., Henn, M. C., Damiano, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+ablation+for+atrial+fibrillation:+techniques,+indications,+and+results.">Surgical ablation for atrial fibrillation: techniques, indications, and results.</a> Current Opinion in Cardiology. 30 (1), 58-64 (2015).</li><li>Gammie, J. S., 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+multi-institutional+experience+with+the+CryoMaze+procedure.">A multi-institutional experience with the CryoMaze procedure.</a> The Annals of Thoracic Surgery. 80 (3), 876-880 (2005).</li><li>Gaita, F., 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=Linear+cryoablation+of+the+left+atrium+versus+pulmonary+vein+cryoisolation+in+patients+with+permanent+atrial+fibrillation+and+valvular+heart+disease:+correlation+of+electroanatomic+mapping+and+long-term+clinical+results.">Linear cryoablation of the left atrium versus pulmonary vein cryoisolation in patients with permanent atrial fibrillation and valvular heart disease: correlation of electroanatomic mapping and long-term clinical results.</a> Circulation. 111 (2), 136-142 (2005).</li><li>Ad, N., Henry, L., Hunt, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+concomitant+cryosurgical+Cox-Maze+procedure+using+Argon+based+cryoprobes:+12+month+results.">The concomitant cryosurgical Cox-Maze procedure using Argon based cryoprobes: 12 month results.</a> The Journal of Cardiovascular Surgery. 52 (4), 593 (2011).</li><li>Ad, N., Holmes, S. 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Dextrocardia is a group of rare heart defects in which the heart is situated on the right side of the thoracic cavity instead of on the left side. One-third of all dextrocardia cases are mirror-image cases, which means the orientation of the cardiac chambers is a mirror image to levocardia (normally situated heart)12. It is estimated that situs inversus dextrocardia associated with situs inversus totalis occurs with an incidence of much less than 1 in 10,000-50,000 births1<...

Dextrocardia is a rare, congenital cardiac malformation in which the axis of the heart is indexed to the right side of the thoracic cavity. Dextrocardia with situs inversus totalis refers to all visceral organs, including the heart, being mirrored and is extremely rare1,2. Atrial fibrillation (AF) is the most common arrhythmia that affects millions of people and causes substantial morbidity and mortality, especially with respect to the increased risk of stroke3.
A literature survey was unable to demonstrate a definitive approach for the concomitant Cox-Maze procedure (CMP) and valve surgery in dextrocardia with situs inversus. There are only a few reports of mitral valve replacement in cases of dextrocardia with situs solitus and even less in situs inversus4,5,6,7,8,9. However, those strategies are not applicable to tricuspid valve surgery, not to mention the complex CMP-IV in dextrocardia.
This paper reports the surgical techniques and experience in three cases concerning the biatrial lesion set of the CMP-IV operation using cryoablation or radiofrequency ablation concomitantly with valve surgery in situs inversus dextrocardia. All surgeries succeeded in the maintenance of sinus rhythm (SR) at 12 months follow-up to each patient and at 48 months follow-up to the previous two. Electron microscopy was used to investigate the transmurality of the atrial cryoablation.
CASE PRESENTATION:
Patients and preoperative examination 
From February 2016 to September 2020, a 48-year-old female patient, a 55-year-old male patient, and a 39-year-old male patient were successively admitted to the cardiac center with similar complaints of palpitation, dyspnea, and easy fatigability on exertion lasting for years (Table 1). They all denied any familiar history of situs inversus dextrocardia or other cardiac health comorbidities. All patients were referred to electrocardiography (ECG), chest roentgenography (Figure 1), computed tomography (CT), and Doppler transthoracic echocardiography (TTE) routinely for preoperative examination.
Case 1: A 48-year-old woman presented with complaints of palpitation, dyspnea, and easy fatigability on exertion lasting for years. The anamnesis was unremarkable. During the physical examination, a grade 3 systolic blowing murmur was heard in the fifth intercostal space outside the midline of the right clavicle. X-ray plain film and CT scan showed that the contour of the dextrocardia was enlarged and situs inversus totalis. Transesophageal echocardiography revealed moderate to severe mitral regurgitation and mild tricuspid regurgitation after moderate mitral valve prolapse and tricuspid annular dilation. There was no thrombosis, and the diameter of the left atrium was 5.3 cm. AF with a rapid ventricular rate was detected by ECG.
Case 2: A 55-year-old man presented with similar symptoms for years. There was no history of cardiac health comorbidities; however, he had had a stroke about six months ago. On physical examination, a diastolic blowing murmur was heard at the left second intercostal space, radiating to the neck. Plain X-ray and CT scan revealed dextrocardia with an enlarged contour and situs inversus totalis. Transesophageal echocardiography showed moderate aortic valve regurgitation and mild to moderate tricuspid regurgitation following mild aortic prolapse and tricuspid annular dilation. The diameter of the left atrium was 4.5 cm without atrial thrombosis. AF with a rapid ventricular rate was detected by ECG.
Case 3: A 39-year-old male presented with progressive exertional dyspnea and intermittent palpitation without any history of situs inversus dextrocardia or other cardiac health complications. During the physical examination, a grade 3 systolic blowing murmur was heard in the fifth intercostal space outside the midline of the right clavicle. X-ray plain film and CT scan revealed that the contour of dextrocardia was enlarged and situs inversus totalis. Transesophageal echocardiography showed severe mitral valve regurgitation and tricuspid regurgitation after annular enlargement. There was no atrial thrombosis, and the left atrium diameter was 5.8 cm. A 24 h ambulatory ECG demonstrated paroxysmal AF with a total load of 165 min.
Diagnosis, assessment, and plan 
Case 1: A biatrial cryo-Cox-Maze IV procedure (cryo-CMP-IV) with mechanic mitral valve replacement and tricuspid annuloplasty were simultaneously performed.
Case 2: A biatrial cryo-CMP-IV procedure with concomitant mechanic aortic valve (AV) replacement and tricuspid annuloplasty was performed.
Case 3: A biatrial CMP-IV procedure, mitral valvuloplasty, and tricuspid annuloplasty were performed simultaneously.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>CryoICE</td>
			<td>AtriCure, Cincinnati, Ohio</td>
			<td>CRYO2</td>
			<td>Cryoablation in case 1 and case 2 was performed exclusively using it with a flexible 10cm in length metal cryoprobe.</td>
		</tr>
		<tr>
			<td>Medtronic Open Pivot Standard mechanical MV</td>
			<td>Medtronic, Minneapolis, Minn</td>
			<td>709291 / MHV 500DM27 STD MITRAL</td>
			<td>A 27-mm MV was adopted in case 1.</td>
		</tr>
		<tr>
			<td>Medtronic Open Pivot Standard mechanical AV</td>
			<td>Medtronic, Minneapolis, Minn</td>
			<td>646871 / MHV 500FA23 STD AORTIC</td>
			<td>A 23-mm AV was adopted in case 2.</td>
		</tr>
		<tr>
			<td>bipolar radiofrequency pen</td>
			<td>AtriCure Inc., Cincinnati, OH</td>
			<td></td>
			<td>Maze-IV in case 3</td>
		</tr>
		<tr>
			<td>bipolar radiofrequency clamps</td>
			<td>AtriCure Inc., Cincinnati, OH</td>
			<td></td>
			<td>Maze-IV in case 3</td>
		</tr>
		<tr>
			<td>Goretex</td>
			<td>W.L. Gore &#38; Associates, Inc., Elkton, Maryland</td>
			<td></td>
			<td>A surgical suture made of polytetrafluoroethylene.</td>
		</tr>
		<tr>
			<td>rigid mitral ring</td>
			<td>Kingstron Bio, Suzhou, China</td>
			<td>Element Force ARM32</td>
			<td>A 32 mm ring was adopted in case 3.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SBG0730 / SB30T</td>
			<td>A 30 mm ring was adopted in case 1.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SQB0240 / SB30T</td>
			<td>A 30 mm ring was adopted in case 2.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SBF0930 / SB28T</td>
			<td>A 28 mm band was adopted in case 3.</td>
		</tr>
	</tbody>
</table>

cox-maze iv procedure concomitant with valvular surgery in situs inversus dextrocardia: a single-center experience in china

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The use of ablation technologies made the Cox-Maze IV procedure (CMP-IV) technically easier, faster, becoming the gold standard for the surgical treatment of AF. However, the efficacy and safety of CMP-IV in situs inversus dextrocardia are largely unknown. This paper summarizes the CMP-IV procedure performed concomitantly with valvular surgery in patients with situs inversus dextrocardia at this institution.
From February 2016 to September 2020, three dextrocardia patients with persistent AF and valvular diseases were referred to this institution for valvular and CMP-IV surgery. CMP-IV was performed using either cryoablation with a nitrous oxide (N2O)-based cryoprobe or a bipolar radiofrequency clamp and bipolar radiofrequency pen. Mechanical valve replacement or mitral vavuloplasty was performed in another patient in addition to tricuspid annuloplasty. Transmurality of the ablated atrial tissues was evaluated by electron microscopy. Heart function was assessed by transthoracic echocardiography. Cardiac rhythm was monitored by 24 h Holter at 3, 6, 12, 18, 24, and 48 months follow-up. 
All the AF was successfully eliminated in the ablation procedure without recurrence or other complications during hospitalization. The mean bypass and crossclamp times were similar in all the patients. The postoperative ventilator support time, the duration of stay in the ICU, and postoperative residence time were also not significantly different among the patients. Transmural atrial necrosis was detected in the ablated atrial tissues. Sinus rhythm maintenance was achieved at 3, 6, 12, 18, 24, and 48 months follow-up in all the patients. All valve protheses switched freely; no tricuspid regurgitation was observed. The results of the present study demonstrate that the CMP-IV is safe and effective in eliminating AF in dextrocardia patients concomitant with valvular surgery.

Surgical procedure and early postoperative period 
A mechanic MV replacement, tricuspid annuloplasty, and concomitant cryo-CMP-IV were performed simultaneously for the first patient. The second had undergone surgery of mechanic AV replacement, tricuspid annuloplasty, and concomitant cryo-CMP-IV. In the third patient, a biatrial CMP-IV procedure was performed simultaneously with mitral valvuloplasty and tricuspid annuloplasty. All operations were smooth, and each beating heart restored SR after resus...

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Cox-Maze IV Procedure Concomitant with Valvular Surgery In Situs Inversus Dextrocardia: A Single-Center Experience in China

We summarize the Cox-Maze IV procedure concomitant with valvular surgery performed in patients with situs inversus dextrocardia at this institution.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The use of ablation technologies made the Cox-Maze IV procedure (CMP-IV) technically ...

The efficacy and safety of the Cox-Maze IV procedure in dextrocardia are largely unknown. This protocol summarizes the procedure concomitantly with the vulvular surgery performed in three patients with dextrocardia. CMP4 is safe and effective in eliminating atrial fibrillation in dextrocardia.Moreover, the 3D-printed heart model helps preoperative simulating and planning for the surgical ablation of AF.Begin the surgical procedure for a median sternotomy by cannulating the superior and inferior vena cava to establish a mild hypothermic cardiopulmonary bypass, or CPB. After establishing the bypass, have an operator switch position from the right side to the left of the operating table. To achieve cardioplegic arrest, give an antegrade cold-blood cardioplegia intermittently from the aortic root.Then, perform the right atrial incision on the left side of the heart parallel to the atrioventricular sulcus. Ensure the left-sided left atriotomy is located parallelly under the interatrial groove. Place a retractor on the wall of the left atrium, or LA.For cryoablation, design a cryolesion set to replicate the mirror image of the CMP4 lesion set and maintain the duration of the LA cryoablation for each lesion at minus 60 degrees Celsius for two minutes.After confirming that the posterior LA box lesion is composed of an LA incision and cryolesion encircling the left and right pulmonary veins, apply a cryolesion line connecting the left superior pulmonary vein with the left atrial appendage, or LAA. Then, form an ice ball to mark the coronary sinus using cryoablation from the epicardium. When performing the mitral isthmus line, place the cryoprobe at the inferior aspect of the left atriotomy and direct the tube to the mitral annulus at the 8:00 position across the posterior LA and coronary sinus, as marked with the ice ball.Then, apply right-sided LAA amputation. After the LA cryoablation, sample a 4x8-millimeter tissue of the cryoablated LA for the electron microscopic examination and sample a large non-ablated tissue from the margin of the LA incision for the control test. Perform the prosthetic valve replacement surgery with a 27-millimeter mechanical mitral valve or a 23-millimeter mechanical atrium valve using a 2-0 polypropylene running suture.With the heart warm and beating, perform the right atrium cryoablation during the cardiopulmonary bypass for two minutes at minus 60 degrees Celsius for each ablation lesion. Create the linear cryoablation lines from the inferior aspect of the left-sided right atriotomy up onto the superior vena cava and down to the inferior vena cava. Make a tricuspid isthmus linear cryolesion from the mid-portion of the right atriotomy directed endocardially toward the tricuspid annulus at the 10:00 position, followed by a lateral cryolesion from the mid-portion of the right atriotomy up to the tip of the right atrial appendage, or RAA.Use the derived cardiac CT data to perform a 3D printing of the heart. During the operation, access the left atrium through the interatrial groove and extend the mitral isthmus lesion to the posterior mitral annulus. Then, ablate the coronary sinus in the endocardium and epicardium with a bipolar radiofrequency pen.Make the other lesions using bipolar radiofrequency clamps as described in the manuscript. When done, dissect the Marshall ligament and separate the left atrial appendage using an epicardial atrial clamp closure device. Then, use bipolar radiofrequency forceps to ablate the entire right atrial lesion sets.After resecting the A1-ruptured cordi, implant a single, flexible, artificial cord with 4-0 expanded polytetrafluoroethylene in situ and close the residual leak of the anterior commissure and the A2 leaflet cleft. To stabilize the annulus, implant a 32-millimeter rigid mitral ring, ensuring the coaptation height is nine millimeter. After deairing and closure of the interatrial sulcus incision, remove the aortic clamp and then make a longitudinal incision on the surface of the right atrium.Perform the tricuspid annuloplasty by implanting a 30-millimeter tricuspid ring in an upside-down and mirror image inversion manner using 2-0 polyester interrupted sutures. Remove the holder before fixation of the annuloplasty ring. Ensure that the patient's sinus rhythm is restored without any atrial ventricular block before cardiopulmonary bypass weaning.After the cardiac surgery, fix temporary epicardial pacing wires. In the postoperative course during the hospital stay, atrial fibrillation or no other complications were observed in any patient. After discharge, all the patients were followed up for one to three years, the 3, 6, 12, 18, 24 and 36 months follow-up in two patients, and at 3, 6, and 12 months follow-up in a patient was carried out.At three months after the surgery, all the heart functional capacities were improved to New York Heart Association Class I.The electron microscope of the samples collected from the cryoablated left atrium displayed tissue necrosis in the endocardium and muscularis. However, only edema and degeneration were observed in the epicardium and neighboring muscularis. The lesion set in dextrocardia should be designed to replicate the mirror image of the CMP4 lesion set.The tricuspid band must be implanted in an upside-down and mirror image inversion manner. Following this procedure, other methods, including chemical and physical ablation, can be performed using the biatrial lesion set of the CMP4 operation. However, cryoablation is the most recommended for valve surgery concomitant surgical ablation.The 3D-printed heart model displaying the spatial relationship between the specific ablation lines and the key anatomical references may help simulate and modify the CMP4 procedure, especially in patients with rare malformations.

cox-maze-iv-procedure-concomitant-with-valvular-surgery-situs

Research

JoVE Journal

Medicine

3.1K vistas.  Central South University. La eficacia y seguridad del procedimiento Cox-Maze IV en la dextrocardia son en gran parte desconocidas. Este protocolo resume el procedimiento concomitantemente con la cirugía vulvular realizada en tres pacientes con dextrocardia. CMP4 es seguro y eficaz para eliminar la fibrilación auricular en la dextrocardia.Además, el modelo de corazón impreso en 3D ayuda a simular y planificar la ablación quirúrgica de la FA. Comience el procedimiento quirúrgico para una esternotomía medi...