title: Sequential noninvasive assessment of left ventricular size, regional wall thickness and function during 3 hours of coronary artery occlusion and reperfusion: differential effects of reflow in dogs with small vs large areas at risk.
abstract: 1. The present study was undertaken to determine noninvasively the sequential changes in left ventricular (LV) size, wall thickness and regional contractile function occurring during 3 h of proximal left anterior descending coronary artery occlusion (CAO), and their modification by reperfusion (REP) over a 7-day period. 2. Twenty, closed-chest, anesthetized dogs underwent CAO for 3 h and were reperfused for 7 days. Hemodynamics (aortic, LV pressure, LV dP/dt) and regional LV function were measured sequentially during CAO and reperfusion. The animals were killed at 7 days and infarct size was measured using the triphenyl-tetrazolium-chloride technique. Regional function (systolic fractional area change, FAC) was measured in 40 LV segments of 5 two-dimensional echo short-axis planes (8 segments per section). 3. At three hours of CAO, 14 dogs developed extensive areas of akinesis or dyskinesis in more than 6 segments (Group I, large risk area), whereas 6 dogs developed akinesis or dyskinesis in 6 segments or less (Group II, small risk area). Four dogs died between 12 and 48 h after REP in Group I and none of Group II died. Recovery of regional function after REP was significantly different between Groups I and II: in hypokinetic segments, FAC improved from 16.7 +/- 0.9% (mean +/- SEM) at 3 h of CAO to 25.4 +/- 3.2% at 24 h and to 34.9 +/- 2.0% at 7 days (66.3 +/- 3.4% of baseline) after REP in Group I; in Group II, FAC increased from 16.6 +/- 1.5% at 3 h of CAO to 48.5 +/- 7.4% at 24 h and to 52.4 +/- 1.6% (92.7 +/- 2.8% of baseline) at 7 days after REP. In akinetic/dyskinetic segments, FAC increased from -9.2 +/- 2.4% at 3 h of CAO to 8.2 +/- 2.6% at 72 h and to 8.3 +/- 3.2% (15.1 +/- 5.8% of baseline) at 7 days of REP in Group I; in Group II, FAC rose significantly from -7.6 +/- 1.6% at 3 h of CAO to 39.9 +/- 7.3% at 24 h and to 50.8 +/- 4.3% (89.2 +/- 4.9% of baseline) at 7 days after REP. There was a significant inverse correlation between the magnitude of compensatory hyperkinesis in the nonischemic wall and the extent of hypokinesis at 60 min (r = -0.82, P less than 0.001), but this correlation was less significant at 24 h (r = -0.64, P less than 0.01), 72 h (r = -0.53, P less than 0.02), and 7 days (r = -0.50, P less than 0.05) after REP.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048.
authors.forename: R V
authors.initials: RV
authors.lastname: Haendchen
authors.forename: M C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: S
authors.initials: S
authors.lastname: Meerbaum
authors.forename: E
authors.initials: E
authors.lastname: Corday
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002404:Catheterization; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D004452:Echocardiography; D005260:Female; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000473:pathology; D015425:Myocardial Reperfusion; D013318:Stroke Volume