Left anterior descending coronary artery flow impaired by right ventricular apical pacing: The role of systolic dyssynchrony

Abstract Introduction Right ventricular (RV) pacing may affect myocardial perfusion and coronary blood flow; however, it remains unknown whether this is related to systolic dyssynchrony induced by RV pacing. This prospective study was aimed to assess the relationship between dyssynchrony and the changes of coronary blood flow. Methods Seventy patients with sinus node dysfunction were prospectively enrolled. Coronary flow was evaluated by measuring diastolic velocity time integral (VTI) and duration at the distal-portion of left anterior descending coronary artery (LAD) with transthoracic echocardiography at baseline and follow-up. Systolic dyssynchrony was assessed with tissue Doppler imaging by time standard deviation to peak systolic velocity of 12 left ventricular segments (Ts-SD, cutoff value ≥33ms). Results Adequate data for analysis was available from 65 patients. At follow-up (mean follow up time: 127±45days), LAD velocity-time integral (LAD-VTI: 12.1±4.2 vs. 10.7±4.6cm, p χ 2 =31.1, p Conclusions RV pacing induced dyssynchrony is associated with reduced coronary flow and this may account for, in part, the deleterious effect of RV pacing on ventricular function over time.