Diastolic dysfunction in short-term hibernating myocardium

Journal of Clinical and Basic Cardiology 1999; 2 (1): 105-109

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Keywords: diastole,  diastolische Füllung,  hibernation,  isovolumetrische Relaxation,  Schwein,  diastole,  diastolic filling,  hibernating myocardium,  isovolumic relaxation,  pig

Short-term hibernating myocardium (STHM) is characterized by matching of systolic function to perfusion, recovery of metabolism and absence of necrosis. Data on regional myocardial function during the isovolumic relaxation and the subsequent diastolic filling phase in STHM, however, are lacking. Therefore, we retrospectively analyzed wall thickening velocities during the isovolumic relaxation (VI) and the diastolic filling phase (VF), which was further divided into three intervals, mainly representing rapid filling (VRF), diastasis (VD) and atrial contraction (VAC). Left ventricular (LV) passive elastic properties were determined from end-diastolic LV pressure/wall thickness relationships during aortic constriction. In 13 anaesthetized pigs, the left anterior descending coronary artery was hypoperfused for 90 minutes, such that an anterior myocardial work index (sonomicrometry, micromanometer) was reduced by approximately 60 %. At 5 minutes ischaemia, VI increased from 4.4 ± 2.9 (SD) to 15.1 ± 7.6 mm/s and VF from -28.4 ± 9.1 to -15.3 ± 4.3 mm/s (both p < 0.05). The increase in thickening velocity was more pronounced during the rapid filling phase (VRF: from -13.7 ± 9.1 to 5.1 ± 10.9 mm/s; p < 0.05) than during diastasis (VD: from -57.7 ± 24.9 to -44.5 ± 22.4 mm/s; NS) and atrial contraction (VAC: from -13.8 ± 14.5 to -6.6 ± 11.7 mm/s; NS). The end-diastolic LV pressure/wall thickness relationship was shifted leftwards, ie, end-diastolic wall thickness at a LV end-diastolic pressure of 7.6 ± 2.9 mmHg decreased from 9.79 ± 0.51 mm to 9.12 ± 0.44 mm (p = 0.07). At 85 minutes ischaemia, there were no further changes in systolic and diastolic function. J Clin Basic Cardiol 1999; 2: 105-9.