Synchrony analysis and left ventricular activation pattern using Gated SPECT studies in patients with Left Branch Block or Pacemaker Rhythm

Abstract

Aim: To compare synchrony parameters and analyze the LV activation pattern in two groups: LBBB vs pacemaker rhythm (PM). Methods: Patients (pts) with LBBB or PM rhythm were selected, excluding those with a history of coronary disease. Clinical and LV function parameters were evaluated and synchrony and LV activation sequence were evaluated with gated MPS, using Emory Tool Box software.
Results: We analyzed 38 pts. They were divided into two groups, Group 1 (G1), 24 pts with LBBB, and Group 2 (G2) 14pts in PM rhythm. For each of the groups, clinical parameters and cardiovascular risk factors were analyzed: only a significant difference was found for age G1 and
G2: 69.6 +/- 9.6 vs. 78 +/- 10.8 years (p 0.007). Regarding LV synchrony and function parameters for G1 and G2: they did not present significant differences. The start of LV contraction occured in the G1: from the septum 14 pts (58%), in G2: septum 8 pts (57%) p: NS. The completion of LV contraction activation for G1 vs. G2 is: lateral 16 pts (67%) vs. 10 pts (72%) p: NS. The lateral wall of most of the pts in both groups is the last segment to depolarize, but 33% in G1 and 28% in G2 do so in other regions. Conclusions: LBBB or PM rhythm show left ventricular dyssynchrony. We found no differences in terms of the activation sequence of the LV segments between both groups.