Impacts of ventricular rate regularization pacing at right ventricular apical vs. septal sites on left ventricular function and exercise capacity in patients with permanent atrial fibrillation.

Aims: The deleterious effects of right ventricular apex (RVA) pacing may offset the potential benefit of ventricular rate (VR) regularization during atrial fibrillation (AF). Recent studies suggested that right ventricular septal (RVS) pacing may prevent the potential deleterious effects of RVA pacing and enhance the VR regularization (VRR) with ventricular pacing due to closer proximity of the pacing site to the retrograde atrioventricular conduction.

Methods And Results: We randomized 24 patients with permanent AF and symptomatic bradycardia to undergo RVA (n = 12) or RVS (n = 12) pacing.

The incremental benefit of rate-adaptive pacing on exercise performance during cardiac resynchronization therapy.

Objectives: The purpose of this research was to investigate the effect of using rate-adaptive pacing and atrioventricular interval (AVI) adaptation on exercise performance during cardiac resynchronization therapy (CRT).

Background: The potential incremental benefits of using rate-adaptive pacing and AVI adaptation with CRT during exercise have not been studied.

Methods: We studied 20 patients with heart failure, chronotropic incompetence (<85% age-predicted heart rate [AP-HR] and <80% HR reserve), and implanted with CRT.

Successful pulmonary vein isolation using transvenous catheter cryoablation improves quality-of-life in patients with atrial fibrillation.

Background: Recent studies have demonstrated that transvenous catheter cryoablation is a safe and effective technique for creating pulmonary veins (PVs) electrical isolation for the treatment of atrial fibrillation (AF). However, the impacts of this procedure on quality-of-life (QoL) have not been evaluated.

Methods And Results: We studied the effects of PV isolation using transvenous catheter cryoablation on QoL in 46 patients (34 men, mean age: 50 +/- 12 years) with drug-refractory AF.

Blood pressure response to transition from supine to standing posture using an orthostatic response algorithm.

Upon standing from a supine position, the normal response is an increase in heart rate to maintain blood pressure (BP). In patients with chronotropic incompetence, heart rate may not increase upon standing, and they may experience orthostatic hypotension (OH). We evaluated a new orthostatic response (OSR) pacing algorithm that uses an accelerometer signal to detect sudden activity following prolonged rest to trigger a 2 minutes increase in pacing rate to 94 bpm.

Functional abnormalities in patients with permanent right ventricular pacing: the effect of sites of electrical stimulation.

Objectives: We sought to evaluate the long-term effects of alternative right ventricular pacing sites on myocardial function and perfusion.

Background: Previous studies have demonstrated that asynchronous ventricular activation due to right ventricular apical (RVA) pacing alters regional myocardial perfusion and functions.

Methods: We randomized 24 patients with complete atrioventricular block to undergo permanent ventricular stimulation either at the RVA (n = 12) or right ventricular outflow (RVOT) (n = 12).