The effect of VVI pacing on P-wave dispersion in patients with dual-chamber pacemakers

Right ventricular outflow tract septal pacing is superior to right ventricular apical pacing

Background

The effects of right ventricular apical pacing (RVAP) and right ventricular outflow tract (RVOT) septal pacing on atrial and ventricular electrophysiology have not been thoroughly compared.

Methods and Results

To identify a more favorable pacing strategy with fewer adverse effects, 80 patients who had complete atrioventricular block with normal cardiac function and who were treated with either RVAP (n=42) or RVOT septal pacing (n=38) were recruited after an average of 2 years of follow‐up. The data from electrocardiography and echocardiography performed before pacemaker implantation and at the end of follow‐up were collected. The patients in the RVOT septal pacing and RVAP groups showed similar demographic and clinical characteristics before pacing treatments. After a mean follow‐up of 2 years, the final maximum P‐wave duration; P‐wave dispersion; Q‐, R‐, and S‐wave complex duration; left atrial volume index; left ventricular end‐systolic diameter; ratio of transmitral early diastolic filling velocity to mitral annular early diastolic velocity; and interventricular mechanical delay in the RVOT septal pacing group were significantly less than those in the RVAP group (P<0.05). The final left ventricular ejection fraction of the RVOT septal pacing group was significantly higher than that of the RVAP group (P<0.05).

Conclusions

Compared with RVAP, RVOT septal pacing has fewer adverse effects regarding atrial electrical activity and structure in patients with normal cardiac function.

Outcome of cardioverter-defibrillator implant in patients with arrhythmogenic right ventricular cardiomyopathy

The aim of the present study was to investigate outcomes of implantable cardioverter-defibrillator (ICD) treatment in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). We reviewed baseline/follow-up data of 15 consecutive ARVC patients (mean age 55 +/- 15 years) and 30 randomly drawn patients with coronary artery disease (CAD) (mean age 60 +/- 10 years) with matching durations of follow-up (all implanted with ICDs for primary/secondary prevention of sudden death). At implant, appropriate placement of the RV lead was more difficult in ARVC patients. During follow-up (median 41 months), appropriate interventions for any ventricular tachyarrhythmias occurred in 8 (53%) ARVC patients and 17 (57%) CAD patients, but the occurrence of high rate (>240 beats/min) ventricular tachyarrhythmias was higher in ARVC patients. Inappropriate ICD interventions occurred in 5 (33%) ARVC patients and 10 (33%) CAD patients. Lead-related adverse events requiring surgical revision occurred in 7 (47%) ARVC patients as compared with 4 (13%) CAD patients (P = 0.0004). While ICD implantation is highly effective for prevention of sudden death in ARVC, it does carry elevated burdens of long-term lead-related adverse events. These findings underline the need of careful follow-up in ARVC aimed at early recognition of complications that can impair ICD function.