Heterozonal electrocardiographic changes in St-elevation myocardial infarction = Coinvolgimento del miocrdio remoto nel corso di infarto miocardico acuto con sopralivellamento del tratto ST: Le alterazioni ischemiche eterozonali all'elettrocardiogramma

Background. 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 ST↓) 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 ST↓ and the risk factors related to this condition. Methods. 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. Results. Patients were classified according to the presence (group I, 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.