Abstract 2319: Total sum of ST Deviation is an Independent Predictor for the Development of Ventricular Fibrillation during a First Myocardial Infarction
Background: In an ongoing study among 230 patients with a first myocardial infarction complicated by ventricular fibrillation (primary VF) compared to 228 patients with a first MI without VF, cumulative ST-deviation was associated with VF (OR of 1.05 / mm for the development of VF, p< 0.0001). ST elevation is often observed after electric defibrillation. We assessed the hypothesis that the total sum of ST deviation is an independent predictor of primary VF and not merely a result of defibrillation.
Methods: We retrieved 50 pre-defibrillation ECG’s from 230 patients with a myocardial infarction complicated by VF. We compared these with 228 ECG’s of myocardial infarction patients without VF. All ECG’s were taken before reperfusion therapy. Maximal CKMB and time to maximal CKMB were used as indicators for infarct size. Cardiovascular risk factors, time to PTCA and culprit lesion were also assessed as possible risk factor for VF.
Results: The total sum of ST deviation in primary VF patients, measured before defibrillation was 35.6 mm ± 2.5. In patients without primary VF, ST deviation was 15.9 mm ± 0.67 (p for difference < 0.0001). Infarct size, culprit lesion and other clinical characteristics were equally distributed among both groups.
Conclusion: The total sum of ST deviation is an independent predictor for VF and not merely a result of defibrillation. Whether this increased ST-deviation is a hallmark of an electrophysiological mechanism underlying the predilection to VF, such as increased heterogeneity in repolarization, or increased injury current, remains to be elucidated.