Background : Right ventricular dysfunction (RVD) is associated with poor prognosis in patients with acute pulmonary embolism (APE). Echocardiography and CT-angiography may be difficult to perform serial follow up unlike electrocardiography (ECG). Thus, we compared serial ECG change with biomarkers to detect RVD and recovery timing of RVD in APE. Methods : The medical records of 81 consecutive patients diagnosed with APE using echocardiography or CT-angiography, at the Kangdong Sacred Heart Hospital, between January 2004 and February 2010 were reviewed retrospectively. Echocardiography and ECG were performed within 24 hours of admission and daily ECG follow up was performed in all patients. Patients with one of the following were considered to have RVD : 1) RV dilatation (end diastolic diameter > 30 mm in the parasternal long axis view), 2) RV free wall hypokinesia, 3) paradoxical septal systolic motion. Right ventricular strain was diagnosed in the presence of one or more of the following ECG findings : complete or incomplete right bundle branch block (RBBB), S1Q3T3, and negative T wave (NTW) in precordial leads. The outcome was death or clinical deterioration (need for catecholamine support, cardiopulmonary resuscitation, mechanical ventilation) during hospital stay. Results : Of the 81 patients with APE, 52 patients (64.2%) had RVD according to echocardiography. Among the patients with RVD, 34 patients (65.4%), 20 patients (38.5 %), and 16 patients (30.8%) showed NTW, RBBB, and S1Q3T3, respectively. At multivariate logistic regression analysis, NTW was a stronger independent predictor of RVD (OR=21.0, CI 3.58-235.01, p=0.006) than RBBB (OR=12.4, CI 1.15-133.68, p=0.038) and elevated BNP level (OR=5.5, CI 1.32-22.55, p=0.019). The sensitivity of NTW for prediction of RVD, was 63.5%, a specificity 96.6%, and a diagnostic accuracy 75.3%. But NTW was not associated with outcome (p=0.739). And time to normalization of NTW was associated with improvement of the RVD on echocardiography (R=0.84, p<0.01). Conclusion : NTW in precordial leads was the strongest predictor for early detection of RVD. And normalization of the NTW was associated with recovery of RVD in APE.