Prognostic value of prolonged QTc interval in patients with acute pulmonary embolism

Acute pulmonary embolism (PE) can be a life-threatening condition. Right ventricular function evaluated by echocardiography, brain natriuretic peptide levels and several patterns on the electrocardiogram have been utilized to guide treatment and prognosis. Case reports described heart rate corrected QT (QTc) prolongation as an ECG finding associated with PE. However, the prognostic value of QTc prolongation has not been studied.

Retrospective chart review of 300 consecutive patients (mean age 60.3 ± 17.6 years; 40.7% men) diagnosed with acute PE by computed tomography pulmonary angiography or ventilation perfusion scan were studied. Patients were divided into two groups: a prolonged QTc group with QTc >460 milliseconds (n=178) and a control group (n=122). We retrospectively reviewed medical records, electrocardiography, echocardiography and radiography results. Statistical analyses included unpaired t-test and Fisher's exact test using Stata version12.

The prolonged QTc group demonstrated significantly increased right ventricular dilatation and systolic dysfunction. Additionally, the duration of hospitalization and intensive care unit stay were longer in the prolonged QTc group. Further, the prolonged QTc group had more hypotensive episodes and received thrombolytic treatment more frequently. There was no statistical difference in in-patient mortality rates (4.5% for the study group and 4.2% for the control group, P=1).

Prolonged QTc may prove a novel predictor for evaluating prognosis in acute PE. Larger studies will need to confirm this finding.