Study on Mechanism and Clinical Significance of the Precordial ST Segment Deviations in Acute Inferior Myocardial Infarction Involving Adjacent Area

Objective:To study the mechanism and clinical significance of the precordial ST segment deviations in acute inferior wall myocardial infarction (AIMI) involving adjacent area. Methods: Characteristics of electrocardiogram were analyzed in 118 patients with AIMI. Results:(1)The magnitude of ST segment elevation of inferior wall leads (Ⅱ,Ⅲ and aVF) was significantly negatively correlated with that of precordial leads (P0.01). (2)The changed magnitude of ST segment of lead V2 (0.63± 1.82 mm) and V2/aVF ratio (0 .84 ±1.61) in 16 cases associated with right ventricular infarction were significantly higher than those of only inferior wall myocardial infarction group ( V2:0.35±1.65 mm,V2/aVF ratio:0.29 ± 1.28)(P0.05 and P0.05). (3)The magnitude of ST segment fall of lead V2( - 1.20±1.52 mm) and V2/aVF ratio ( -0.33±1.15) in 38 cases associated with lateral-posterior wall in farction were higher than those of only inferior wall infarction group (P0.05). (4)If the cases associated with right ventricular and lateral-posterior wall infarction were not included, the ST segment correlation coefficient between inferior and precordial leads would significantly increase in AIMI (r=-0.797, P 0.01) . Conclusion: The directions of ST segment deviations of precordial leads elevate in cases associated with right ventricular infarction and fall in cases associated with lateral-posterior wall infarction in AIMI.