Prevalence of ST-elevation in right precordial leads in patients presenting with acute coronary syndrome without ST-elevation in standard 12-lead electrocardiography

Objective: The aim of this preliminary study was to determine the prevalence of isolated ST-elevation in the right precordial leads and the potential impact the addition had to risk stratification in patients with acute coronary syndrome. Methods: Right-sided precordial leads (V4R, V5R and V6R) were routinely added to standard 12-lead electrocardiogram (ECG) on all patients presenting with acute coronary syndrome at the Tygerberg cardiac unit for a 7-month period. Patients without ST-elevation on standard 12-lead ECG were selected and evaluated for isolated right-sided ST-elevation. Demographic data, ECG-characteristics and cardiac enzymes were also recorded. Risk scoring using the TIMI-risk score was done and patients with isolated ST-elevation in right-sided leads without ST-changes (i.e. depression) in 12-lead ECG were experimentally awarded another point. Coronary angiography if performed was also noted. Results: Seventy-seven patients were selected, among them 4 patients (5.19%) had isolated ST-elevation in right-sided ECG. Only 1 patient (1.3%) was awarded an additional point for ST-elevation in right-sided leads without ST-depression on 12-lead ECG increasing the TIMI score from 6 to 7. Angiography revealed no patients with isolated right-sided ST-elevation with non-dominant right coronary artery occlusion. Conclusion: The addition of right-sided leads did not alter risk scoring significantly and therefore the results of this study do not support the routine addition of such leads. This study also did not prove that isolated ST-elevation occurs in right-sided leads in patients with occluded non-dominant right coronary arteries.