Investigation on the ECG manifestation of acute myocardial infarction of inferior wall complicated by right ventricular infarction

Objective To investigate the ECG manifestation of acute myocardial infarction of inferior wall complicated by right ventricular infarction(RVAMI).Methods 118 cases of first attack of inferior wall AMI were included in present study within 12 hours after onset of symptoms.Their ECG was recorded very 2～8 hours on the first day of onset,and then repeated every 12～24 hours.Results In the 16 cases with RVAMI,ST V 2 and ST aVF were and respectively. There was no correlation between them (P0.05). In the 102 cases without RVAMI,ST V2 and ST aVF were and respectively. There was moderate inverse correlation between them (P 0.01 ). In diagnosing complicated RVAMI, the sensitivity of ST V 4R and ST V 5R 1 mm was 100% and that of ST V 3R 1 mm was 86.7%. The sensitivity of ST V 1/aVF 0.5 was 87.5% and its specificity was 62.7%. When the elevation of ST segments in Ⅱ and Ⅲ leads was used as a diagnostic index of complicated RVAMI, its sensitivity was 87.5% and specificity was 57.8%. Of 16 cases with RVAMI, 6 cases received coronary artery angiography and 1 case autopsy.All these 7 cases had lesions at proximal portion of RCA and manifestations of ST V 3R～V 5R 1 mm.Conclusions 1.The mirror phenomenon between ST segment elevation in precordial lead and ST segment depression in aVF lead is one of the manifestations of the cases without RVAMI. The cases with RVAMI do not have the mirror phenomenon. 2.In diagnosing RVAMI,ST V 4R and ST V 5R 1 mm has the highest sensitivity. 3. ST V 3R V 5R 1 mm may predict the occlusion of proximal portion of RCA.