The nature of heart failure in patients with ventricular septal
defect.
Stewart, Julian M., Thomas H. Hintze, Paul K. Woolf, Michael S.
Snyder, Karen P. Seligman, and Michael H. Gewitz.
The New York Medical College, Departments of Pediatrics and
Physiology, Valhalla, New York, USA
APStracts 2:0181H, 1995.
To assess the contributions of systolic and diastolic dysfunction to
CHF in VSD we studied thirteen children with VSD at catheterization
using a Millar catheter. Eight children had CHF while five did not.
5[mu]g/kg/min phenylephrine was infused and M-mode echocardiography
and pressure were measured simultaneously. Systolic LV function was
assessed by maximum LVP, dP/dt, and by the end systolic pressure
-diameter relation. Systolic myocardial function was assessed by the
end-systolic stress-strain relation. Diastolic chamber function was
assessed by [tau], the isovolumic relaxation time constant, and by
the end-diastolic pressure-diameter relation. Diastolic myocardial
function was measured by 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 without CHF. +dP/dt was lower
with CHF (1582+/-96) than without CHF (2300+/-200). EmaxPD for the
end-systolic pressure-diameter relation was 39+/-8 with CHF and 94+/
-14 mmHg/cm without CHF. For the stress-strain relation Emax[sigma]
was 223+/-37 with CHF and 395+/-93 without CHF. [tau] was 25+/-2 msec
without failure compared to 32+/-3 msec with CHF. End-diastolic
pressure-diameter relation was shifted leftward with failure, while
the stress-strain relation was similar for all patients. CHF in
patients with VSD results primarily from systolic dysfunction.
Myocardial diastolic function is relatively preserved with heart
failure, but diastolic compliance is impaired even though diastolic
relaxation is normal in failed hearts.
Received 31 October 1994; accepted in final form 11 April 1995.
APS Manuscript Number H966-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 9 May 1995.