Assessment of right artrial mapping and P wave-triggered signal-average in patients with paroxysmal atrial fibrillation.

To assess right atrial mapping and P wave-triggered signal-averaged electrocardiogram (ECG) in patients with paroxysmal atrial fibrillation (PAF), this study examined right atrial electrograms using atrial mapping and parameters by P wave-triggered signal-averaged ECG in 39 patients without sick sinus syndrome. Subjects were divided into those with PAF (n = 13; 60+/-13 years old) and a control group (n = 26; 49+/-19 years old). The total number of abnormal right atrial electrograms per patient was significantly greater in the PAF group (3.2+/-1.9) than in the control group (1.1+/-0.9; P < .001). The longest duration of right atrial electrogram in the PAF group tended to be greater than that in the control group (P = .06). The filtered P wave duration was significantly longer in the PAF group than in the control group (144+/-21 vs 125+/-14 ms [P < .002]). The values of the root mean square of P wave-triggered signal-averaged ECG 15 ms from the onset (RMSi 15) and 20 ms from the offset (RMSe 20) were significantly lower in the PAF group (1.1+/-0.4 microV, 1.4+/-0.5 microV) than in the control group (1.9+/-1.1 microV [P < .02], 2.1+/-0.9 microV [P < .01]). The total number of right atrial electrograms in patients with RMSi 15 of < or =1.5 microV was significantly greater than in patients with RMSi 15 of >1.5 microV (2.2+/-1.8 vs 1.3+/-1.3 [P < .05]). Thus, the total number of abnormal right atrial electrograms per patient, the total filtered P wave duration, RMSi 15, and RMSe 20 may be good indices of PAF in patients without sick sinus syndrome. RMSi 15 may reflect the total number of the abnormal right atrial electrograms per patient.

[Radiofrequency catheter ablation therapy in elderly patients with supraventricular tachycardia].

138 patients with Wolf-Parkinson-White (WPW) syndrome (n = 96), atrioventricular nodal reentrant tachycardia (AVNRT; n = 27) and the other supraventricular tachycardia (n = 15), were divided into two groups, a control group (less than 65 years old; n = 108) and an elderly group (more than 66 years old; n = 30). We then estimated the success rate and safety of radiofrequency ablation for supraventricular tachycardia in elderly patients. For WPW syndrome, there were 76 (97%) successes and 9 (13%) recurrences in the control group (n = 78). In the elderly group of WPW patients, the number of successes was 18 (100%) and the number of recurrences one (63%). In 27 patients with AVNRT, the number of successes was 26 (96%) and there were no recurrences. In 15 patients with some other supraventricular tachycardia, there were 11 patients (73%) successes and one recurrence (11%). Major complications consisted of cardiac tamponade in 2 patients, dissecting aneurysm in one patient and cerebral embolism in one patients. All major complications occurred in patients with WPW syndrome. The cause of the complications, except the cerebral embolism was manipulation of the electrical or ablation catheter. Three of four patients with major complications belonged to the control group. It is possible that radiofrequency catheter ablation for supraventricular tachycardia in elderly patients is safe and highly effective. However, it is still invasive therapy. Ablation on a left accessory pathway by the transaortic valve approach especially needs meticulous care.

Electrophysiologic effects of a class I antiarrhythmic agent, cibenzoline, on the refractoriness and conduction of the human atrium in vivo.

We investigated the effects of a class I antiarrhythmic drug, cibenzoline, on human atrial muscle in vivo. Electrophysiologic measurements were performed in 44 patients (mean age 49 +/- 15 years), before and after an intravenous infusion of cibenzoline 1.4 mg/kg in 5 min. Extrastimuli at a basic cycle length (BCL) of 500 ms were delivered from the right atrial appendage. The effective refractory period of the right atrium (ERP-A), the conduction time from the high right atrium to the coronary sinus, maximum conduction delay (Max. CD), repetitive atrial firing zone (RAFZ), fragmented atrial activity zone (FAAZ), and conduction delay zone (CDZ) were measured. Patients were divided into two groups according to whether repetitive atrial firing (RAF) was induced (group A, n = 18) or not (group B, n = 26). Cibenzoline increased ERP-A from 198 +/- 25 to 214 +/- 26 ms (p < 0.05) and decreased Max. CD from 55 +/- 23 to 43 +/- 19 ms (p < 0.05). There were significant decreases in the RAFZ (10 +/- 17 to 4 +/- 10 ms, p < 0.05), the FAAZ (20 +/- 25 to 12 +/- 18, ms p < 0.05), and the CDZ (41 +/- 21 to 32 +/- 19 ms, p < 0.05). Cibenzoline significantly increased ERP.A (186 +/- 25 to 212 +/- 26 ms, p < 0.05) in group A, but not in group B. There were significant decreases in the RAFZ [25 +/- 19 to 9 +/- 15 ms (p < 0.05) and FAAZ 22 +/- 29 to 11 +/- 21 ms, (p < 0.05)] in group A, but not in group B. The results suggest that cibenzoline can suppress paroxysmal atrial fibrillation by prolongation of ERP-A and may also have preferential effects on the substrate of atrial fibrillation and RAF.