Quantifying Myocardial Ejection Asynchrony: Effective Stroke Volume Analysis

Abstract

Regional wall motion abnormalities (RWMA) are the most common cardiac contraction abnormalities seen in clinical practice. However, their impact on global left ventricular (LV) performance has not been quantified and is poorly understood. Furthermore, ventricular pacing and intraventricular conduction blocks may profoundly alter contraction synchrony and do so in subjects who can scarily afford to reduce myocardial performance further. Finally, new large clinical trials of ventricular pacing in subjects in left bundle branch block and heart failure are presently underway. Only slightly more than half the subjects who undergo these expensive and highly invasive procedures realize any cardiovascular benefit of such pacing and present analyses do not allow one to predict beforehand or during the time of catheterization which subjects will benefit and which will not. Realistically, this lack of analysis is due to difficulties in modeling RWMA as they impact on regional contraction relative to total LV contraction.