APPLICATION OF CINE NUCLEAR-MAGNETIC-RESONANCE IMAGING FOR SEQUENTIAL EVALUATION OF RESPONSE TO ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR THERAPY IN DILATED CARDIOMYOPATHY

Cine nuclear magnetic resonance (NMR) imaging was used to serially measure cardiovascular function in 17 patients with New York Heart Association class II or III heart failure and left ventricular ejection fraction less-than-or-equal-to 45% who were treated for 3 months with benazepril hydrochloride, a new angiotensin-converting enzyme inhibitor, while continuing treatment with diuretic agents and digoxin. Interobserver reproducibilities for ejection fraction (r = 0.94, SEE 3.3%), end-systolic volume (r = 0.98, SEE 10.6 ml), end-diastolic volume (r = 0.99, SEE 8.29 ml), end-systolic mass (r = 0.96, SEE 15.4 g), end-systolic wall stress (r = 0.91, SEE 10 dynes.s.cm-5) and end-systolic stress/volume ratio (r = 0.85, SEE 0.13) demonstrated applicability of cine NMR imaging for the serial assessment of cardiovascular function in response to pharmacologic interventions in patients with heart failure. During 12 weeks of treatment with benazepril, ejection fraction increased progressively from 29.7 +/- 2.2% (mean +/- SEM) to 36 +/- 2.2% (p < 0.05), end-diastolic volume decreased from 166 +/-14 to 158 +/- 12 ml (p = NS), end-systolic volume decreased from 118 +/- 12 to 106 +/- 11 ml (p < 0.05), left ventricular mass decreased from 235 +/- 13 to 220 +/- 12 g (p < 0.05), end-systolic wall stress decreased 29% from 90 +/- 5 to 64 +/- 5 dynes.s.cm-5 (p < 0.05), end-systolic pressure decreased from 92.6 +/- 3.7 to 78.8 +/- 5.3 (p < 0.05) and end-systolic stress/volume ratio, a load-independent index of contractility, decreased from 0.83 +/-0.05 to 0.67 +/- 0.06 (p < 0.05), demonstrating that improved ejection fraction is due to afterload reduction.