Nature of heart failure in patients with ventricular septal defect

Abstract

To assess the contributions of systolic and diastolic dysfunction to congestive heart failure (CHF) in ventricular septal defect (VSD), we studied 13 children with VSD at catheterization using a Millar catheter. Eight children had CHF, whereas five did not. Phenylephrine was infused at a rate of 5 micrograms.kg-1.min-1, and M-mode echocardiography and pressure were measured simultaneously. Systolic left ventricular (LV) function was assessed by maximum LV pressure (LVP), rate of pressure development (dP/dt), and by the end-systolic pressure-diameter relation (ESPDR). Systolic myocardial function was assessed by the end-systolic stress-strain relation. Diastolic chamber function was assessed by the isovolumic relaxation time constant (tau) and by the end-diastolic pressure-diameter relation (EDPDR). Diastolic myocardial function was measured by the end-diastolic stress-strain relationship. With phenylephrine, maximum LVP increased from 99 +/- 5 to 119 +/- 4 mmHg with CHF and from 106 +/- 6 to 149 +/- 10 mmHg without CHF. +dP/dt was lower with CHF (1,582 +/- 96 mmHg/s) than without CHF (2,300 +/- 200 mmHg/s). The maximum slope of the ESPDR was 39 +/- 8 with CHF and 94 +/- 14 mmHg/cm without CHF. The maximum slope of the midwall stress-strain relation was 223 +/- 37 with CHF and 395 +/- 93 g/cm2 without CHF. tau was 25 +/- 2 without CHF compared with 32 +/- 3 ms with CHF. The EDPDR was shifted leftward with failure, whereas the stress-strain relation was similar for all patients. CHF in patients with VSD results primarily from systolic dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)