期刊
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
卷 304, 期 12, 页码 H1697-H1707出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00166.2013
关键词
hibernating myocardium; subendocardial ischemia; sudden cardiac death; ventricular fibrillation; ventricular tachycardia
资金
- Department of Veterans Affairs, National Heart, Lung, and Blood Institute [HL-55324, HL-61610]
- Albert and Elizabeth Rekate Fund
- Mae Stone Goode Trust
- John R. Oishei Foundation
Many survivors of sudden cardiac death (SCD) have normal global ventricular function and severe coronary artery disease but no evidence of symptomatic ischemia or infarction before the development of lethal ventricular arrhythmias, and the trigger for ventricular tachycardia (VT)/ventricular fibrillation (VF) remains unclear. We sought to identify the role of spontaneous ischemia and temporal hemodynamic factors preceding SCD using continuous telemetry of left ventricular (LV) pressure and the ECG for periods up to 5 mo in swine (n = 37) with hibernating myocardium who experience spontaneous VT/VF in the absence of heart failure or infarction. Hemodynamics and ST deviation at the time of VT/VF were compared with survivors with hibernating myocardium as well as sham controls. All episodes of VT/VF occurred during sympathetic activation and were initiated by single premature ventricular contractions, and the VT degenerated into VF in similar to 30 s. ECG evidence of ischemia was infrequent and no different from those that survived. Baseline hemodynamics were no different among groups, but LV end-diastolic pressure during sympathetic activation was higher at the time of SCD (37 +/- 4 vs. 26 +/- 4 mmHg, P < 0.05) and the ECG demonstrated QT shortening (155 +/- 4 vs. 173 +/- 5 ms, P < 0.05). The week before SCD, both parameters were no different from survivors. These data indicate that there are no differences in the degree of sympathetic activation or hemodynamic stress when VT/VF develops in swine with hibernating myocardium. The transiently elevated LV end-diastolic pressure and QT shortening preceding VT/VF raises the possibility that electrocardiographically silent sub-endocardial ischemia and/or mechanoelectrical feedback serve as a trigger for the development of SCD in chronic ischemic heart disease.
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