Relation of electrocardiographic changes in pulmonary embolism to right ventricular enlargement

The electrocardiographic (ECG) findings in patients with pulmonary embolism (PE) and no previous cardiopulmonary disease are well documented; however, investigation of the relation of ECG abnormalities to right ventricular (RV) enlargement has been limited. The purpose of the present investigation was to assess further the relation of ECG changes in acute PE to RV cavity enlargement (dilation). The records of patients hospitalized from January 2009 to December 2012 with acute PE and no previous cardiopulmonary disease were reviewed. A total of 289 patients were included. RV cavity enlargement was present in 141 patients (49%). Normal ECG findings were less prevalent in patients with PE and RV enlargement than those with PE and no RV enlargement (35 of 141 [25%] vs 56 of 148 [38%]; p = 0.02). One or more of the traditional ECG manifestations of acute cor pulmonale (S1Q3T3, complete right bundle branch block, P pulmonale, or right axis deviation) was found in 18 of 141 patients (13%) with RV enlargement and 13 of 148 (8.8%) with a normal size RV (p = NS). None of the ECG abnormalities was sensitive for RV enlargement. The specificity of P and QRS abnormalities was high. The positive predictive values were ≤83% or had wide 95% confidence intervals. The negative predictive values ranged from 50% to 61%. In conclusion, ECG findings were not useful for the detection or exclusion of RV cavity enlargement in patients with acute PE.