Electrocardiographic changes following primary blast injury to the thorax.

Profound physiological changes occur following primary blast exposure but the contribution of cardiac arrhythmias is unknown. Thirteen rats, under intravenous anaesthesia, were exposed to a blast wave directed at the thorax (Group II); 10 other animals underwent abdominal blast (Group III) and nine animals acted as controls (Group I). Animals were monitored before, during and after blast exposure. Group II animals demonstrated apnoea, bradycardia and hypotension. No significant physiological changes were seen in Groups I or III. Group II displayed a variety of ECG disturbances, from ventricular extrasystoles to ventricular fibrillation. All abnormalities reverted to sinus rhythm within minutes except in fatally injured animals. These ECG changes probably result from stress wave injury. Significant disturbances might account for some fatalities following primary blast exposure and may exacerbate the triad of apnoea, bradycardia and hypotension. Such observations may have important consequences for the management of blast casualties.