Right ventricular pacing, mechanical dyssynchrony, and heart failure.

Cardiac pacing is a common treatment option for patients with sick sinus syndrome or atrioventricular block, with the ventricular pacing lead often secured in the convenient right ventricular (RV) apical location. While RV pacing reduces symptoms and limitations associated with heart block, it may have detrimental effects on cardiac structure and function, leading to heart failure (HF) in some patients. RV pacing creates electrical dyssynchrony similar to a left-bundle branch block, with conduction occurring cell-by-cell rather than through the His-Purkinje network. Studies have shown that impairment of myocardial metabolism, structure, and function related to RV pacing occurs regionally (most prominently near the pacing site) and globally, within the left ventricle. Strategies being studied to prevent or treat pacing-induced intraventricular mechanical dyssynchrony and HF include: initial biventricular rather than RV pacing in selected patients, programming to avoid or minimize RV pacing, use of alternate (non-apical) RV pacing sites, echocardiographic screening for development of pacing-induced dyssynchrony and HF, and upgrade to biventricular pacing.