Clinical Investigations: Electrophysiology
Clinical significance of ST-segment elevation in lead V1 in patients with acute inferior wall Q-wave myocardial infarction

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Abstract

Background This study was designed to determine the clinical significance of ST-segment elevation in the precordial leads (leads V1 and V2) in acute Q-wave inferior wall myocardial infarction. Methods and Results One hundred fifty-eight consecutive patients with acute Q-wave inferior wall myocardial infarction were classified into 3 groups on the basis of the initial ST-change in V1 (group 1 = 29 patients with ST elevation, group 2 = 97 patients with ST depression, and group 3 = 32 patients with no ST-segment change). The right coronary artery was the infarct-related artery in all the patients in group 1. Although there was no significant difference between groups 1 and 2, the number of left ventricular asynergic segments was larger and the incidence of major in-hospital arrhythmias was higher in groups 1 and 2 compared with group 3. Patients in group 1 had a significantly higher incidence of proximal lesion (86%) and right ventricular infarction (69%) than the other 2 groups did. When ST elevation in leads V1 and V2 was considered, 14 of 15 patients (93%) with ST elevation only in V1 had right ventricular infarction, whereas 6 of 14 patients (43%) with ST elevation in both V1 and V2 had right ventricular infarction (P =.011). Conclusions ST-segment elevation in V1 on admission in patients with acute Q-wave inferior wall myocardial infarction indicates a right coronary artery lesion associated with a larger infarct size and a higher incidence of major in-hospital arrhythmias. (Am Heart J 2001;141:615-20.)

Section snippets

Patients

We studied 158 consecutive patients (aged 37 to 86 years) with their first Q-wave inferior wall myocardial infarction who had coronary angiography on admission to have direct percutaneous transluminal coronary angioplasty between February 1988 and August 1997. Inclusion criteria were (1) admission to the coronary care unit <12 hours from the onset of chest pain, (2) no prior history of myocardial infarction or chronic lung disease, and (3) sinus rhythm without intraventricular conduction

Clinical characteristics (Table I)

. Baseline characteristics

Empty CellGroup 1 (n = 29)Group 2 (n = 97)Group 3 (n = 32)P value
Age (y)61 ± 1364 ± 1164 ± 11.496
Men/women21/870/2722/10.927
Hypertension12 (41%)43 (44%)11 (34%).612
Diabetes mellitus11 (38%)38 (39%)9 (28%).525
Hypercholesterolemia9 (31%)27 (28%)11 (34%).771
Cigarette smoking16 (55%)49 (51%)19 (59%).665
Time to reperfusion (h)5.3 ± 2.34.6 ± 2.25.3 ± 2.4.066

Group 1, Patients with ST elevation in V1; group 2, patients with ST depression in V1; group 3, patients with no ST change in V1.

Discussion

The patients with inferior wall myocardial infarction are a heterogeneous group, dependent on whether posterior left ventricular segments or the right ventricle are also involved. Therefore the ability to identify high-risk subgroups by the admission electrocardiogram is necessary to estimate the severity of myocardial infarction.1, 2, 3, 4, 5, 6, 7 Moreover, because nearly half the incidences of inferior wall myocardial infarction with total occlusion of the proximal right coronary artery are

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Reprint requests: Tetsuro Sugiura, MD, Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu Oko-cho Nankoku City, Kochi, Japan 783-8505. E-mail:[email protected]

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