A new electrocardiographic approach to identify the coronary artery responsible for acute inferior myocardial infarction: a study in 100 patients.

OBJECTIVE: The objective of this study is to analyze the value of the electrocardiogram in the identification of the coronary artery responsible for acute inferior myocardial infarction.

MATERIAL AND METHODS: One hundred consecutive patients with acute inferior myocardial infarction were studied, 67 with a lesion in the right coronary artery and 33 in the circumflex artery. The ST segment changes in the inferior, lateral, precordial and right-chest leads were analyzed, as well as the arithmetic sum of the ST segment in the inferior and V2 leads (II + V2, III + V-2 and aVF + V2). We also developed a diagnostic process based on a stepwise approach of three electrocardiographic criteria: a) elevation of the ST segment in DI; b) arithmetic sum of the ST magnitude in DIII + V2 < 0; c) depression of the ST segment in V4R.

RESULTS: This study shows that the most useful parameters to predict (with a specificity of 100%) the lesioned coronary artery in acute inferior myocardial infarction are: a) the arithmetic sum of the ST segment: aVF + V2 > 0, for the right coronary artery; b) the arithmetic sum of the ST segment: III + V2 < 0, for the circumflex artery; c) the arithmetic sum of the ST segment: aVF + V2 > 1 mm, for the proximal right coronary artery.

CONCLUSIONS: The incorporation of these three criteria in an algorithm diagnostic system allows us to locate the coronary artery responsible for acute myocardial infarction with 100% sensitivity and specificity.