The influence of premature ventricular contractions on left ventricular function in asymptomatic children without structural heart disease: an echocardiographic evaluation.

Abstract

Isolated monomorphic premature ventricular contractions (PVCs) are not uncommon in the pediatric population. The degree of cardiac dysfunction caused by PVCs in children without structural heart disease is unknown. To investigate the influence of PVCs on echocardiographic left ventricular (LV) systolic function in children without structural heart disease. Forty asymptomatic children with isolated monomorphic PVCs without structural heart disease were selected. The median age was 6 years, range of 3-12 years. The following subgroups were compared: frequent vs. infrequent PVCs (> or < or = 10/min); short vs. long coupling interval (RR'/RR ratio < or = or > 0.6); and short vs. long QT interval (QT < or = or > 400 ms). Using echocardiography the left ventricular ejection fraction (LVEF in percentage) and cardiac index (CI in L/min/m2) were measured for both normal sinus beats (SB-LVEF and CI), PVCs (PVC-LVEF and CI) and the average LVEF and CI were calculated. All values were expressed as means +/- SD. In all children LV dimensions and the SB-LVEF and CI were within normal limits. The PVC-LVEF (48 +/- 5) and PVC-CI (1.57 +/- 0.19) were significantly decreased and the average CI was 2.41 +/- 0.29. In 27 pts with > 10 PVCs/min the average LVEF and CI decreased to 53 +/- 5 and 2.08 +/- 0.24 respectively. In 16 pts with PVCs and a short coupling interval (RR'/RR < or = 0.6) the PVC-LVEF and PVC-CI was 43 +/- 0.03 and 1.50 +/- 0.14, which was significantly lower than in 24 pts with a long coupling interval (58 +/- 4, 1.88 +/- 0.11). In 11 pts with a prolonged QT interval (> 400 ms) the PVC-LVEF and PVC-CI was significantly lower than in the 29 children with a shorter QT interval, 41 +/- 5 vs. 55 +/- 4 and 1.46 +/- 0.13 vs. 1.86 +/- 0.15 respectively (all p < 0.01). In asymptomatic children with isolated monomorphic PVCs the average ejection fraction and cardiac output is markedly reduced if PVCs are frequent (> 10/min), have a short coupling interval or a prolonged QT interval.