Abstract
Systolic-time intervals and QRS morphology were studied in 52 patients with right ventricular pacing. In the patients who showed PEP/ET<0.8 (group I) and ≥ 0.8 (group II) subsequent PEP/ET remained<0.8 and ≥ 0.8, respectively. PEP was found a main determinant for separating both groups. LBBB type QRS was found only in group II. PEP/ET was smaller in the patients with downward QRS in V6, was larger in those with upward QRS in V6, and was between the former two in those with equally biphasic QRS in V6. These results may suggest that QRS morphology influence cafdiac performance through electrical activation process.
