The management of malignant ventricular arrhythmias will become gradually more important as life expectancy continues to increase. The incidence of sudden cardiac death and overall cardiac mortality is more pronounced in the elderly mainly as a reflection of the higher prevalence of ischemic heart disease. With the exception of beta-blocker therapy, antiarrhythmic drug therapy has not proven to be effective in the prevention of sudden cardiac death. Implantable cardioverter-defibrillator therapy has been shown to reduce both overall mortality and arrhythmic death when following current guidelines for implantation and appears to be applicable to any age group when sensible patient selection is implemented. The greater efficacy of this therapy relative to antiarrhythmic therapies supports its expanded use in the elderly population. Such therapy has a similar cost-effectiveness to other accepted interventions and does not appear to be associated with reduced quality of life or age-specific complications. The clinical approach to elderly patients at risk of sudden death from ventricular arrhythmias will continue to evolve as new technologies are developed, but the future of ventricular arrhythmia treatment in the elderly will likely emphasize an increasing utilization of both implantable cardioverter-defibrillator and beta-blocker therapies.

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Objective: Conduction velocity around the tricuspid valve annulus (TA) during typical atrial flutter (AFL) has been shown to be slowest in the inferior vena cava-tricuspid valve (IVC-TV) isthmus when compared to the septal or free wall segments of the TA. We investigated the conduction velocity in IVC-TV isthmus, dividing into three areas. Methods: We evaluated conduction velocity around the TA during typical AFL in 10 patients, using an electro-anatomic mapping system (CARTO^TM). Conduction velocity was calculated at six areas around the TA including the septal wall, upper wall, lateral wall, and isthmus wall, which was further divided into three areas, lateral isthmus, mid isthmus, and septal isthmus. Results: Conduction velocity around the TA during typical AFL was slowest in the IVC-TV isthmus. Further, conduction velocities (m/sec) in the mid isthmus (0.44±0.17) and septal isthmus (0.45±0.22) were significantly slower (p<0.05) than that in the upper wall (0.67±0.26). Conclusions: The relatively slower conduction in IVC-TV isthmus resulted from the relatively slower conduction in the area from mid to septal isthmus.

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This study sought to evaluate the efficacy of long-term flecainide therapy in maintaining sinus rhythms in patients with paroxysmal atrial fibrillation (AF) based on time of onset. Flecainide (150 mg/day) was administered as an antiarrhythmic drug to a total of 70 patients (54 men and 16 women: mean age 65±10 years) after sinus rhythm was restored spontaneously or by electrical and/or pharmacological cardioversion. Paroxysmal AF was divided into three categories based on time of onset: diurnal type (N=11), nocturnal type (N=13), and mixed type (N=46). The mean follow-up period was 37.7±17.7 months. The duration of sinus rhythm maintenance in patients with diurnal and nocturnal paroxysmal AF was 32.4±10.4 months and 20.8±8.3 months, respectively; the duration of sinus rhythm maintenance in those with mixed paroxysmal AF was only 7.2±2.1 months. Significant differences were observed in duration between diurnal and mixed cases (mean±S.E., P<0.05). Actuarial recurrence-free rates at 1, 3, 6, 9 and 12 months were 90.9%, 63.6%, 63.6%, 54.5%, and 54.5%, respectively, for diurnal cases; 84.6%, 76.9%, 53.8%, 38.5%, and 30.8%, respectively, for nocturnal cases; and 58.7%, 39.1%, 28.3%, 21.7%, and 15.2% respectively, for mixed cases. Significant differences in rates at 12 months were observed between diurnal and mixed cases (P<0.05). These results suggest that flecainide is highly effective in preventing AF recurrence in patients with diurnal paroxysmal AF.

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Background: The increasing incidence of damage to pacemaker leads for cardiac resynchronization therapy (CRT) is an emerging problem that should be prevented. The extrathoracic venipuncture approach has been suggested as a technique for venous access to avoid the problem. Methods and Results: 10 patients had pacemaker lead placement for CRT using the double target method. The lead was inserted in the extrathoracic portion of the subclavian and/or axillary veins without complications in all of the patients. Conclusion: This approach achieves accurate, safe, and speedy extrathoracic venipuncture and is especially suitable for multiple lead placements for CRT.

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The patient was a 64-year-old man with chronic atrial fibrillation with bradycardia. Left ventricular ejection fraction was 34%. He was treated with biventricular pacing. Heart failure improved from NYHA class III to II. Sympathetic nerve activity (SNA) was recorded during 6 minutes of biventricular (BV), right ventricular apical (RVA) and left ventricular (LV) pacing. SNA was significantly lower during biventricular pacing (49.5±4.0/min) compared with RVA (58.8±6.9/min, p=0.016) and LV (63.3±4.3/min, p=0.002) pacing. BV pacing improves hemodynamics and decreases SNA compared with RVA or LV pacing.

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We report a rare case of slow-fast form of atrioventricular nodal reentrant tachycardia with delayed activation in the low septal right atrium (His bundle area). During supraventricular tachycardia (SVT), electrocardiogram showed “pseudo-positive P waves” in II, III, and aV_F leads. SVT was induced by atrial extrastimulus with marked AH prolongation (i.e., jump phenomenon). Ventricular pacing showed a decremental retrograde conduction without jump phenomenon. Double atrial potentials were observed in the His bundle area during SVT and during ventricular pacing. The first electrogram of these split potentials, which was the earliest activation during SVT and during ventricular pacing, showed a dull and small deflection, whereas the second electrogram was sharp and clear. The interval of these discrete potentials was 70 msec during SVT. After a standard slow pathway ablation, SVT could never be induced by any programmed stimuli. It was concluded that in this case, the conduction disturbance across the tendon of Todaro was likely to cause the delayed atrial activation in the His bundle area, which created the pseudo-positive (biphasic) retrograde P wave.

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We present a patient with frequent episodes of palpitation who had idiopathic premature ventricular contraction (PVC) with QRS morphology exhibiting a right bundle branch block pattern with an inferior axis. Neither administration of procainamide, propranolol, lidocaine or verapamil could inhibit PVC, whereas administration of adenosine triphosphate, carotid sinus massage and Valsalva maneuver could effectively eliminate PVC. The earliest activation preceding the QRS complex by 25 msec at occurrence of the PVC was recorded at the distal site of the coronary sinus and within the left coronary cusp. Pacemapping in the supravalvular site during sinus rhythm produced a QRS complex more similar to PVC than that produced in the infravalvular site of the left ventricular outflow tract (LVOT). Radiofrequency catheter ablation was performed at the supravalvular site close to the epicardial LVOT, which resulted in successful elimination of PVCs.

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