The absence of Q waves coupled with the presence of depressed rather than elevated ST segments, characteristic of the "current of injury," used to convey a modicum of reassurance. True, the patient suffered an acute myocardial infarction, but it was after all only subendocardial, not transmural. The extent of the damage was limited, and the associated clinical manifestations and complications were less severe than in infarcts involving the entire thickness of the myocardial wall.
Although still reassuring with regard to short-range complications of shock and congestive heart failure, the long-range prognosis of subacute myocardial infarction—Levy et al1 inform us—is anything but heartening. Comparing data on 119 patients at a mean follow-up period of 36 months with corresponding data on 36 patients whose infarcts were subendocardial, these investigators found that the latter group had a higher (33% vs 15%) incidence of sudden death from other cardiac causes. Survivors of subendocardial
Vaisrub S. Subendocardial Infarction: A Prognostic Paradox. JAMA. 1976;235(9):943–944. doi:10.1001/jama.1976.03260350047033