Short-term right ventricular apical pacing induced variable left ventricular dyssynchrony, with a significantly higher prevalence and degree in patients with lower baseline ejection fraction (P<0.001).
Observational (n=153)
Does short-term right ventricular apical pacing induce left ventricular dyssynchrony, and how does it correlate with baseline characteristics?
Right ventricular apical pacing induces variable degrees of left ventricular dyssynchrony, which is more pronounced in patients with higher baseline dyssynchrony, more dilated left ventricles, and lower ejection fractions.
p-value: p=<0.001
OBJECTIVES: Evaluation of left ventricular (LV) dyssynchrony in patients undergoing short-term right ventricular apical (RVA) pacing and correlation with baseline echocardiographic and clinical characteristics. BACKGROUND: RVA pacing causes abnormal ventricular depolarization that may lead to mechanical LV dyssynchrony. The relationships between pacing-induced LV dyssynchrony and baseline echocardiographic and clinical variables have not been fully clarified. METHODS: Tissue Doppler echocardiography was performed in 153 patients before and after RVA pacing. LV dyssynchrony was measured by the time between the shortest and longest electromechanical delays in the five basal LV segments (intra-LV). The prevalence and degree of LV dyssynchrony after RVA pacing was evaluated in three groups: baseline LV ejection fraction (LVEF) or=55%. The intrapatient effect of RVA pacing was determined as the percent increase in intra-LV value (Deltaintra-LV%). The pacing-induced intra-LV was correlated with baseline variables. RESULTS: The prevalence and degree of LV dyssynchrony after RVA pacing was significantly higher in patients with lower LVEF (P < 0.001). DeltaIntra-LV% was inversely correlated with baseline intra-LV and LVEF (B =-2.6, B =-4.2, P < 0.001). Baseline intra-LV and LV end-systolic volume correlated positively with intra-LV after RVA pacing (B = 0.49, B = 0.6, P < 0.001), whereas LVEF showed an inverse correlation. CONCLUSIONS: The degree of LV dyssynchrony induced by RVA is variable. Patients with higher baseline LV dyssynchrony, more dilated LV, and more depressed LVEF showed a higher degree of LV dyssynchrony during pacing. These findings may assume importance in predicting the risk of heart failure in pacemaker patients.
Pastore et al. (2008) conducted an observational in Patients undergoing right ventricular apical pacing (n=153). Right ventricular apical (RVA) pacing vs. Baseline (before pacing) was evaluated on Left ventricular dyssynchrony (time between shortest and longest electromechanical delays in five basal LV segments) (p=<0.001). Short-term right ventricular apical pacing induced variable left ventricular dyssynchrony, with a significantly higher prevalence and degree in patients with lower baseline ejection fraction (P<0.001).