Study objective: Acute pulmonary embolism can produce abnormalities on ECG that reflect severity of pulmonary hypertension. Early recognition of these findings may alter the estimated pretest probability of pulmonary embolism and prompt more aggressive treatment before hemodynamic instability ensues, but it is first important to test whether these findings are specific to patients with pulmonary embolism. We hypothesize that ECG findings consistent with pulmonary hypertension would be observed more frequently in patients with pulmonary embolism.
Methods: Secondary analysis of a prospective, observational cohort of emergency department patients who were tested for pulmonary embolism. ECGs were ordered at clinician's discretion and interpreted at presentation.
Results: Six thousand forty-nine patients had an ECG, 354 (5.9%) of whom were diagnosed with pulmonary embolism. The frequency, positive likelihood ratio (LR+) and 95% confidence interval (CI) of each predictor were as follows: S1Q3T3 8.5% with pulmonary embolism versus 3.3% without pulmonary embolism (LR+ 3.7; 95% CI 2.5 to 5.4); nonsinus rhythm, 23.5% versus 16.6% (LR+ 1.4; 95% CI 1.2 to 1.7); inverted T waves in V1 to V2, 14.4% versus 8.1% (LR+ 1.8; 95% CI 1.3 to 2.3); inversion in V1 to V3, 10.5% versus 4.0% (LR+ 2.6; 95% CI 1.9 to 3.6); inversion in V1 to V4, 7.3% versus 2.0% (LR+ 3.7; 95% CI 2.4 to 5.5); incomplete right bundle branch block, 4.8% versus 2.8% (LR+ 1.7; 95% CI 1.0 to 2.7); tachycardia (pulse rate >100 beats/min), 28.8% versus 15.7% (LR+ 1.8; 95% CI 1.5 to 2.2). Likelihood ratios and specificities were similar when patients with previous cardiopulmonary disease were excluded from analysis.
Conclusion: Findings of acute pulmonary hypertension were infrequent overall but were observed more frequently in patients with the final diagnosis of pulmonary embolism compared with patients who do not have pulmonary embolism.
Copyright (c) 2009 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.