Preinfarct angina and exercise: yet another reason to stay physically active.

In the past, angina has been considered something bad. Though I still maintain that any ischemia is something the heart should avoid if possible, several studies suggest that preinfarct angina paradoxically may have protective effects (1–7). Our group observed this phenomenon in the Thrombolysis In Myocardial Infarction (TIMI-4) (1) study and then in the TIMI-9 study (2). Preinfarct angina reduced in-hospital death and congestive heart failure/shock and was associated with a smaller myocardial infarct size as measured by creatine kinase-MB fraction (CK-MB) release. In the second study, TIMI-9 (2), it appeared that for the benefit to be manifest, the preinfarct angina had to occur temporally close to the MI. Several other groups have observed benefits of preinfarct angina—ranging from a reduction in enzymatically determined myocardial infarct size to improved longterm survival, to improved left ventricular function, to reduction in arrhythmia (3–7). These studies were primarily ones in which myocardial infarcts were reperfused with