The destruction of the World Trade Center and associated terrorist activities of September 11, 2001 have spurred interest in understanding the medical consequences of terrorist activity. Currently, there is a paucity of data regarding this subject. Potential effects, however, can be garnered by studying the medical effects of other acute stressors, such as earthquakes, missile attacks, and the like. None of these stressors have been studied extensively, but there is enough data available concerning earthquakes to indicate that in some instances, the effects of the earthquake may last at least a period of weeks, if not months, following the earthquake. Since the World Trade Center attack was associated with a rise in post-traumatic stress syndrome and affective disorders afterwards, there is accordingly interest in both the acute and more prolonged health effects that could be engendered following terrorist attacks. Known pathophysiological effects of acute stress, whether produced in a laboratory environment or by studying naturally occurring acute stressors, include: the induction or potentiation of cardiac arrhythmias; the induction of myocardial ischemia in susceptible patients with underlying coronary artery disease; acute increases in arterial blood pressure with its ability to cause shear stress; the precipitation of worsening endothelial function and/or endothelial injury; coagulation abnormalities; and hemoconcentration. These all represent important areas for study following the occurrence of future terrorist activity. Based on existing epidemiological and pathophysiological data concerning the cardiac effects of acute life stressors, it would behoove physicians to closely monitor high-risk cardiac patients following future terrorist events. In addition, physician-scientists should be well prepared to use new epidemiological markers which could provide rapid information following future events, such as the evaluation of patients using pre-versus post-event serum markers or tracing records available among patients fitted with implantable cardiovertor-defibrillators.