Cardiovascular effects of lightning strikes.
OBJECTIVES: The purpose of this study was to investigate the effects of lightning strikes on the cardiovascular system. BACKGROUND: A lightning strike can attack its victims in one of three ways: direct hit, splash or ground strike. The cardiovascular system can be affected directly by mechanical or electrical trauma during a direct hit or can be indirectly affected through effects on the total body with extensive catecholamine release or autonomic stimulation. Reported effects include hypertension, tachycardia, nonspecific electrocardiographic (ECG) changes including prolongation of the corrected QT (QTc) interval, transient T wave inversion and myocardial necrosis with creatine kinase-MB (CK-MB) fraction release. METHODS: Nineteen victims from five separate lightning strikes were studied over a 2-month period. Each patient was evaluated by serial ECG, CK-MB determinations and echocardiography. RESULTS: The early (0 to 72 h) effects of lightning were demonstrated on the ECG by ST segment elevation consistent with acute current of injury, prolonged QTc interval with direct hits and nonspecific ST and T wave changes. On echocardiography, segmental or global ventricular dysfunction was seen, and pericardial effusion was also detected. During the intermediate (3- to 14-day) period, new and often marked ECG changes consistent with pericarditis or ischemia were seen. No new echocardiographic changes were detected, however, and the early abnormalities including severe left ventricular dysfunction with cardiogenic shock have reversed. The late (1 to 12 months) period revealed only one patient with long-term sequelae (recurrent pericarditis that persisted for 5 months). CONCLUSIONS: Unless both entrance and exit sites are limited to the lower limbs, direct and splash lightning strikes cause myocardial damage as assessed by abnormal serum enzyme determinations or abnormal echocardiographic findings. Only direct hits resulted in echocardiographic abnormalities or a prolonged QTc interval. The degree of myocardial injury can be severe with left and right ventricular ejection fraction < 15% and can be reversible.