electrophysiological-assessment-murine-atria-with-high-resolution

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and ...

Tokyo Medical and Dental University

We describe a case with three focal atrial tachycardias (ATs) and focal atrial fibrillation (AF) originating from the interatrial septum (IAS) near the atrioventricular node (AVN). Contrast-enhanced computed tomography demonstrated the association of fat deposition within the anterior IAS near the AVN with successful ablation sites of these ATs and AF. This is the first report that the intramural fat deposition in the IAS could be associated with the formation of AT and AF re-entry circuits originating near the AVN.

Association of intramural fat deposition in the interatrial septum with focal atrial tachyarrhythmias originating near the atrioventricular node.

Drug-induced bradycardia is common during antiarrhythmic therapy; the major culprits are beta-blockers. However, whether other antiarrhythmic drugs are also a significant cause of this, alone or in combination with beta-blockers, is not well known.

Severe iatrogenic bradycardia related to the combined use of beta-blocking agents and sodium channel blockers.

The purpose of this study was to clarify the relation between atrial defibrillation threshold (ADFT) for internal cardioversion (IC) and arrhythmogenicity of the superior vena cava (SVC).

High Atrial Defibrillation Threshold With Internal Cardioversion Indicates Arrhythmogenicity of Superior Vena Cava in Non-Long-Standing Persistent Atrial Fibrillation.

Dormant conduction (DC) induced by intravenous adenosine triphosphate (ATP) after pulmonary vein (PV) isolation (PVI) could predict subsequent PV reconnection (RC) sites. This study aimed to investigate the relationship between the DC and RC sites during the long-term follow-up.

Reappraisal of the clinical implications of adenosine triphosphate in terms of the prediction of reconnection sites in cases with electrical isolation of the pulmonary veins.

Ventricular fibrillation (VF) in Brugada syndrome (BrS) is known to occur more frequently during nighttime and from spring to early summer. In this study, we investigated whether early repolarization syndrome (ERS) has the same seasonal, weekly, and circadian distribution of VF events as BrS using data from the "J-wave associated with prior cardiac event" (J-PREVENT) registry.

Seasonal, weekly, and circadian distribution of ventricular fibrillation in patients with J-wave syndrome from the J-PREVENT registry.

                    
Telmisartan has been shown to exert an equivalent action as ramipril on the prevention of cardiovascular events, but the dose-dependent actions of telmisartan on the prevention of events remain unknown.We investigated the dose-dependent effects of telmisartan on the prevention of AF in patients associated with risk factors.One hundred hypertensive patients were randomized to take 40 mg (low-dose group: n=57) or 80 mg (high-dose group: n=43) of telmisartan for 24 months. The primary endpoints were defined as a new development and/or recurrence of atrial fibrillation (AF).The mean values of the blood pressure in both groups decreased significantly and to similar degrees after 24 months, in the low-dose (p < 0.01) and high-dose (p < 0.01) groups. At the end of the follow-up, the incidence of AF was lower in the high-dose group than in the low-dose group (p < 0.05). Moreover, the proportion of AF recurrences in the patients with a past history of paroxysmal AF was lower in the high-dose group than in the low-dose group (p < 0.05). Further, using a logistic regression model, there were no risk factors associated with the incidence of AF.The results indicated that telmisartan in low doses was as effective in controlling the blood pressure as in high doses, but high doses of telmisartan had beneficial effects on preventing the recurrence of AF in hypertensive patients.

Effect of High-dose Telmisartan on the Prevention of Recurrent Atrial Fibrillation in Hypertensive Patients.

Recent experimental studies have demonstrated that several microRNAs (miRNAs) expressed in atrial tissue promote a substrate of atrial fibrillation (AF). However, because it has not been fully elucidated whether these experimental data contribute to identifying circulating miRNAs as biomarkers for AF, we used a combined analysis of human serum and murine atrial samples with the aim of identifying these biomarkers for predicting AF.Methods and Results:Comprehensive analyses were performed to screen 733 miRNAs in serum from 10 AF patients and 5 controls, and 672 miRNAs in atrial tissue from 6 inducible atrial tachycardia model mice and 3 controls. We selected miRNAs for which expression was detected in both analyses, and their expression levels were changed in the human analyses, the murine analyses, or both. This screening identified 11 candidate miRNAs. Next, we quantified the selected miRNAs using a quantitative RT-PCR in 50 AF and 50 non-AF subjects. The individual assessment revealed that 4 miRNAs (miR-99a-5p, miR-192-5p, miR-214-3p, and miR-342-5p) were significantly upregulated in AF patients. A receiver-operating characteristics curve indicated that miR-214-3p and miR-342-5p had the highest accuracy. The combination of the 4 miRNAs modestly improved the predictive accuracy for AF (76% sensitivity, 80% specificity).

Kensuke Ihara

Department of Bio-informational Pharmacology,
Medical Research Institute,
Department of Bio-informational Pharmacology, Medical Research Institute

Tokyo Medical and Dental University

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

Kensuke Ihara

Department of Bio-informational Pharmacology,Medical Research Institute,Department of Bio-informational Pharmacology, Medical Research Institute

Tokyo Medical and Dental University

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

Department of Bio-informational Pharmacology,
Medical Research Institute,
Department of Bio-informational Pharmacology, Medical Research Institute