Diastolic dysfunction of stunned myocardium.

The prolonged regional contractile failure of reperfused myocardium has usually been characterized in terms of systolic function, while only few reports on its diastolic function are available. None of these studies considered changes in the isovolumic diastole and the subsequent filling phase separately. Therefore, in the present study, the velocities of wall excursion during systole (Vsys), isovolumic diastole (Viso) and filling phase (Vfill) were determined in 12 anesthetized dogs. Additionally, post-ejection thickening (Pejt), a marker of left ventricular asynchrony, was determined. Measurements were performed under control conditions, during a 15 minute left circumflex (LCX) coronary artery occlusion (CAO) and at 10 minutes, 4 and 8 hours reperfusion. Heart rate, left ventricular pressure, and Vsys, Viso, Vfill, and Pejt of the anterior myocardium remained unchanged throughout the experiments. During CAO, systolic wall-thickening of the posterior wall was reversed to systolic wall-thinning. Upon reperfusion, Vsys started to recover (2.5 +/- 3.2 mm/s at 10 minutes) and gradually improved over 8 hours of reperfusion (4.6 +/- 3.2 mm/s at 4 hours, 6.4 +/- 1.5 mm/s at 8 hours). Viso became positive during CAO (9.4 +/- 7.1 mm/s vs. -5.6 +/- 3.9 mm/s under control conditions) and was unchanged at 10 minutes reperfusion (7.9 +/- 5.2 mm/s). After 4 hours and 8 hours of reperfusion, Viso recovered to 1.2 +/- 9.2 mm/s and -0.3 +/- 10.7 mm/s, respectively. Vfill also became positive during CAO (1.5 +/- 6.2 mm/s vs. -18 +/- 8.7 mm/s under control conditions). There was a quick recovery of Vfill (-9.4 +/- 7.5 mm/s) with the onset of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)