The electrocardiogram as a predictor of right ventricular dysfunction in patients with pulmonary embolism

Introduction

Right ventricular dysfunction (RVD) is considered to indicate poor prognosis in patients with pulmonary embolism (PE). The electrocardiogram (ECG) is a low-cost, widely avaible method that may show changes associated with right ventricular strain secondary to PE.

Objectives

To evaluate the prevalence of ECG changes in patients with PE and its importance as a diagnostic tool in the diagnosis of RVD.

Patients and method

Data were collected from a cohort of 202 patients (84 men) enrolled in a multicenter prospective registry study of PE. The mean age was 70.9 ± 13.8 years. Patients were admitted to hospital between January 1998 and January 2001. The diagnosis of PE was confirmed if patients fulfilled at least one of the following criteria: (1) pulmonary artery thrombus visualization by pulmonary arteriography, helicoidal angiotomography, magnetic resonance or echocardiography; (2) high probability pulmonary scintigraphy; and (3) venous duplex scan with thrombus visualization and clinical signs and symptoms of PE. The ECG and transthoracic echocardiogram (TTE) were performed in 190 patients. RVD was established by TTE subjective analysis of the right ventricle contractive function. Abnormal ECG was considered to be indicative of right bundle branch block, S₁Q₃T₃ pattern, negative Twave from V1 to V4, or right AQRS axis deviation.

Results

ECG was abnormal in 33% of patients and TTE analysis showed RVD in 38%. In this latter group of patients 49% presented with at least one ECG change. At least one ECG change was found in 23% of patients without RVD (P < 0.0001). The accuracy of ECG for the diagnosis of RVD was: sensitivity 49%, specificity 77%, positive predictive value 57% and negative predictive value 71%. The likelihood ratio of a positive test was 2.1 and of a negative test was 0.6.

Conclusion

When transthoracic echocardiography is not available, ECG may be useful to exclude right ventricular dysfunction in patients with PE.