Electrocardiographic (ECG) signs of right ventricular strain could be used as a simple tool to risk-stratify patients with acute pulmonary embolism.
We studied consecutive patients aged ≥65 years with acute pulmonary embolism in a prospective multicenter cohort study. Two readers independently analyzed 12 predefined ECG signs of right ventricular strain in all patients. The outcome was the occurrence of an adverse clinical event, defined as death from any cause within 90 days or a complicated in-hospital course. We determined the interrater reliability for each ECG sign and examined the association between right ventricular strain signs and adverse events using logistic regression, adjusting for the Pulmonary Embolism Severity Index and cardiac troponin.
Overall, 320/390 patients (82%) showed at least one ECG sign of right ventricular strain. The interrater reliability for individual ECG signs was highly variable (ᴋ 0.40-0.95). Patients with ≥1 of the 3 classic signs of right ventricular strain (S1Q3T3, right bundle branch block, or T wave inversions in V1-V4) had a higher incidence of adverse events than those without (13% vs 6%; P = .026). After adjustment, the presence of ≥1 of the 3 classic signs of right ventricular strain (odds ratio 2.11; 95% confidence interval, 1.00-4.46) and the number of right ventricular strain signs present were significantly associated with adverse events (odds ratio 1.35 per sign; 95% confidence interval, 1.08-1.69).
ECG signs of right ventricular strain are common in elderly patients with acute pulmonary embolism. Although such signs may have prognostic value, their variable reliability and the rather modest prognostic effect size may limit their usefulness in the risk stratification of pulmonary embolism.