R-wave amplitude changes during exercise in adolescents with left ventricular pressure and volume overload

Abstract

To determine the diagnostic value of exerciseinduced R-wave changes in adolescents with congenital heart disease, the responses of 50 adolescents without significant heart disease were compared with those of 72 patients with either a left ventricular (LV) pressure or volume overload lesion. Among the pressure overload group, 24 patients had valvular aortic stenosis (AS) and 27 had coarctation of the aorta. The volume overload group included 12 patients with mitral regurgitation (MR) and 9 with aortic regurgitation (AR). Severity of the cardiac lesion was assessed using cardiac catheterization in patients with AS, physical examination in patients with coarctation of the aorta and clinical or angiographiec criteria, or both, in patients with valvular regurgitation. The R wave was measured in 10 consecutive QRS complexes in leads II, aVF and V5 at rest, maximal exercise and 1-minute recovery. At maximal exercise, control subjects had a mean decrease in amplitude ([Delta]R) of -3.6 mm (p > 12 mm Hg (n = 7), the decrease in [Delta]R was also greater than that in patients with LV end-diastolic pressure <= 12 mm Hg (n = 14) (p < 0.006). Among patients with volume overload, more severe valvular regurgitation was associated with a smaller [Delta]R (p < 0.03). In patients with AS an increased [Delta]R reflects ischemia or diminished LV compliance, or both, whereas in patients with volume overload a decrease in [Delta]R is an indicator of the severity of regurgitation.