[Heterozonal electrocardiographic changes in ST-elevation myocardial infarction]

It has been observed that in patients with ST-elevation myocardial infarction (STEMI) the presence of ST-segment depression (ST) in heterozonal electrocardiographic leads (remote STI) worsens the patient's prognosis. The aim of this study was to observe in an unselected population with a first STEMI the incidence of remote STI and the risk factors related to this condition.

We evaluated retrospectively 350 patients with a first STEMI; we excluded from our analysis 139 patients because no data about their coronary anatomy was available. ST-segment depression in the heterozonal myocardium was considered significant if > 0.1 mV at 60 ms from the J point, in at least two electrocardiographic leads.

Patients were classified according to the presence (group 1, 117 patients) or absence (group II, 94 patients) of remote ST. The two groups did not differ for age, sex and coronary anatomy. In group I we found more heterozonal wall motion abnormalities than group II (32 vs. 18%, p = 0.018). In this group there was a higher incidence of smokers (56 vs. 33%, p = 0.025) and less patients were treated with statins when the STEMI occurred (6 vs. 14%, p = 0.047). Patients with remote ST had higher total cholesterol (214.6 +/- 48.9 vs. 192.3 +/- 29.8 mg/dl, p < 0.001) and low-density lipoprotein cholesterol (138.7 +/- 40.7 vs. 123.2 +/- 22.9 mg/dl, p < 0.0001) levels. Conclusions. In patients with STEMI the presence of remote ST is rather frequent, and seems to indicate a real heterozonal ischemia, independently of an epicardial coronary stenosis of the non-infarct-related artery. Remote ST. is associated with a higher incidence of risk factors related to microcirculatory dysfunction, such as cigarette smoking, a worse lipid profile and less protective factors, such as the use of statins prior to acute myocardial infarction.