[Reciprocal changes in the ST segment in acute inferior myocardial infarction. Value of delay in appearance].

The significance of a "reciprocal" ST depression (ST(-)) in the acute phase of myocardial infarction remains controverted. This may be due to ST(-) not having the same determinants when studied at an early stage (less than 6 hours) or later (greater than 6 hours). The purpose of this study was to find out whether "reciprocal" ST(-) correlates with the same parameters when measured on very early ECG's (before 6 hours) or at a distance from the onset of infarction. The parameters concerned are coronary lesions, extent of the infarction and left ventricular function. ECG was performed in 46 patients with inferior infarct aged from 26 to 70 years (mean 50.8 +/- 9.2 years) between 2-6 h, 6-12 h, 12-24 h and 24-48 h from the beginning of pain. The sum of ST(-) on V1V2V2V4 (V1-4), D1aV1V1 to V6 and L1aV1V5V6, and the sum of ST elevation on L2L3aVf were measured at each period of time. The extent of global and anterior territory hypokinesia, the ejection fraction and the left coronary impairment were evaluated between the 2nd and 4th weeks. At 2-6 hours (a) the sum of ST(-) was greater (though not significantly), and the sum of ST elevation on L2L3aVf was significantly greater (p less than 0.001) when the left anterior descending artery (LAD) was not involved than when it was involved; (b) there was no difference between patients with and without ST depression (on all lead groups) in the degree of left ventricular hypokinesia and ejection fraction value.(ABSTRACT TRUNCATED AT 250 WORDS)