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.

Angiographic and clinical implications of combined ST-segment elevation in anterior and inferior leads in acute myocardial infarction.

Background: The clinical and angiographic findings of patients suffered from acute myocardial infarction (MI) and presented with combined ST elevation in both anterior and inferior leads remain unclear.

Hypothesis: These patients might have >/= 1 coronary arteries occluded.

Methods: From January 2002 to December 2006, 49 consecutive patients were found to have ST elevation in both anterior and inferior leads during myocardial infarction.

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.

Intrathoracic impedance monitoring in patients with heart failure: correlation with fluid status and feasibility of early warning preceding hospitalization.

Background: Patients with heart failure are frequently hospitalized for fluid overload. A reliable method for chronic monitoring of fluid status is therefore desirable. We evaluated an implantable system capable of measuring intrathoracic impedance to identify potential fluid overload before heart failure hospitalization and to determine the correlation between intrathoracic impedance and standard measures of fluid status during hospitalization.

Tissue Doppler echocardiographic evidence of reverse remodeling and improved synchronicity by simultaneously delaying regional contraction after biventricular pacing therapy in heart failure.

Background: Biventricular pacing has been proposed to improve symptoms and exercise capacity in patients with advanced heart failure and wide electrocardiographic wave complexes. This study investigated the effect of biventricular pacing on reverse remodeling and the underlying mechanisms.

Methods And Results: Twenty-five patients with NYHA class III to IV heart failure and electrocardiographic wave complex duration >140 ms receiving biventricular pacing therapy were assessed serially up to 3 months after pacing and when pacing was withheld for 4 weeks.