Angiotensin-converting enzyme inhibition limits dysfunction in adjacent noninfarcted regions during left ventricular remodeling.
OBJECTIVE
We hypothesized that angiotensin-converting enzyme inhibitors would limit dysfunction in the first 8 weeks after transmural infarction in adjacent noninfarcted regions, as well as attenuate left ventricular remodeling.


BACKGROUND
Angiotensin-converting enzyme inhibition limits ventricular dilation and hypertrophy and improves survival after anterior infarction, but its effect on regional function during remodeling is not well characterized.


METHODS
Thirteen sheep underwent coronary ligation to create an anteroapical infarction. At postinfarction day 2, eight sheep were randomized to therapy with the angiotensin-converting enzyme inhibitor ramipril, and five sheep received no therapy. Animals were studied with magnetic resonance myocardial tagging before and 8 weeks after infarction. Left ventricular volume, mass and ejection fraction were measured, as were changes in percent circumferential shortening within the subendocardium and subepicardium of infarcted and noninfarcted myocardium, both adjacent to and remote from the infarction.


RESULTS
Angiotensin-converting enzyme inhibition limited the increase in end-diastolic volume from a mean (+/- SD) of +1.5 +/- 0.7 ml/kg in control animals to +0.5 +/- 0.8 ml/kg in the treated group (p < 0.04). Segmental function within infarcted and remote noninfarcted tissue did not differ between groups. However, angiotensin-converting enzyme inhibition limited the decline in function in the adjacent noninfarcted region 8 weeks after infarction. Percent circumferential shortening in the subendocardium decreased by -13 +/- 5% in the control group compared with -5 +/- 5% in the treated group (p < 0.03).


CONCLUSIONS
In concert with a reduction in left ventricular remodeling after anterior infarction, angiotensin-converting enzyme inhibition limits the decline in function in the adjacent noninfarcted region. Dysfunction in adjacent noninfarcted regions may be an important determinant of left ventricular remodeling after infarction.
Department of Medicine, Medical College of Pennsylvania, Pittsburgh, USA.
C M
CM
Kramer
V A
VA
Ferrari
W J
WJ
Rogers
T M
TM
Theobald
M L
ML
Nance
L
L
Axel
N
N
Reichek
D000704:Analysis of Variance; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000503:physiopathology; D007703:Peptidyl-Dipeptidase A / Q000097:blood; D017257:Ramipril / Q000494:pharmacology* / Q000627:therapeutic use; D012756:Sheep; D013318:Stroke Volume / Q000187:drug effects; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000517:prevention & control*
D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A; D017257:Ramipril