Relation between reversal of diastolic creep and recovery of systolic function after ischemic myocardial injury in conscious dogs.

Abstract

Although prolonged functional abnormalities after transient myocardial ischemia have been well described, the interrelationship between postischemic systolic and diastolic alterations remains controversial. Therefore, 24 chronically instrumented conscious dogs were studied with left ventricular and pleura] micromanometers, ultrasonic dimension transducers in the left anterior descending (LAD) coronary distribution, and vena caval and coronary artery occluders. The LAD was occluded for 15 minutes and reperfused for 24 hours while vena caval occlusions were performed at intervals to measure myocardial segment length at 0 mm Hg transmural diastolic left ventricular pressure (La). Coronary occlusion produced an immediate fall in systolic function as assessed by ejection shortening and stroke work and also induced a 16±4% increase in Lo, which was termed diastolic creep. Throughout reperfusion, reversal of diastolic abnormalities correlated strongly with recovery of segmental shortening and stroke work (p < 0.001). Correlation between systolic dysfunction and diastolic creep was also observed during alteration of inotropic state by dopamine, during initial reperfusion hyperfunction, and during pharmacologic manipulation of afterload. In 5 additional dog hearts fixed in diastole by rapid glutaraldehyde infusion after coronary occlusion, myocardial creep measured by the segment length transducers paralleled sarcomere elongation measured by electron microscopy. Thus, the direct correlation between diastolic creep and systolic dysfunction throughout reperfusion and during hemodynamic alterations suggests that diastolic properties of postischemic myocardium may not be entirely passive and that systolic and diastolic dysfunction induced by ischemia may have a common basis at the cellular level. Yet another explanation for postischemic dysfunction may relate to direct interaction between systolic and diastolic abnormalities. Edwards et al 10 showed that ischemia produced a time-dependent stretch of myocardial segments, which was termed "creep." In studies of ventricular overdistension, overstretch of myofilaments has been shown to cause prolonged myocardial dysfunction." Currently, few data exist regarding interaction between systolic and diastolic From the Departments of Surgery and Physiology, Duke University Medical Center, Durham, N.C., and The Department of Experimental Cardiology, Max Planck Institute, Bad Nauheim, FRG.The work was supported by NIH grants 2R01-HLO9315-17, R01 -HL29436-01, and HL06607-02; a John A. Hartford Fellowship grant; and grants from the Whitaker Foundation and the American Heart Association, North Carolina affiliate.This work was presented in part at the 56th Scientific Session of the American Heart Association, November 1983.Address for reprints: J. Scott Rankin, M.D., P.O. Box 3851, Duke University Medical Center, Durham, NC 27710.Received April 14, 1986; accepted February 13, 1987. dysfunction after ischemic injury. Interdependence of systolic and diastolic abnormalities, if present, woul...

The end-systolic pressure-volume relationship in conscious dogs.

“…A third but unlikely possibility is that the heart underwent creep or stress relaxation with increases in afterload. '4 45 ESPVR determinations made during the same inotropic state would then be seen as parallel shifts, or changes in Vd with the same Emax'…”

Regional Left Ventricular Systolic Function in Humans During Off-Pump Coronary Bypass Surgery

“…6,7 These regional myocardial geometric changes characterized by progressive increases in end-diastolic segment length and decreased end-diastolic wall thickness occur as a time-and load-dependent change identified as creep. 5 Owen et al 7 subsequently showed that significantly increased end-diastolic length persisted for hours after only a 15-minute period of regional ischemia in dogs and that late functional recovery correlated primarily with reversal diastolic creep.…”

“…[1][2][3][4][5][6][7][8][9][10][11] Previous studies have clearly shown that with the loss of active shortening during ischemia, regional systolic stress increases, contributing to regional ischemic dysfunction and facilitating passive elongation of ischemic myocardium. 6,7 These regional myocardial geometric changes characterized by progressive increases in end-diastolic segment length and decreased end-diastolic wall thickness occur as a time-and load-dependent change identified as creep.…”

“…Using this technology, Edwards et al 4 characterized the geometric alterations in myocardium during ischemia as a time-dependent stretch of myocardial segments called "creep." Glower and associates 5 showed that the reversal of diastolic creep correlated with recovery of systolic function after reversible ischemic injury.…”

“…This method generally uses local coronary occlusion, resulting in a brief period of myocardial ischemia. Although the effects of ischemia on regional myocardial function have been studied extensively in animal models, [1][2][3][4][5][6][7][8][9][10] the significance of limited periods of ischemia on human heart function is not well defined. The development of regional ultrasonic dimension analysis by Theroux and associates 2,3 allowed accurate determination of changes in regional myocardial function.…”