Right Bundle Branch Block as a Screening Test for Pulmonary Embolism in Chronic Spinal Cord Injury

Abstract

Frisbie JH, Sharma GVRK. Right bundle branch block as a screening test for pulmonary embolism in chronic spinal cord injury. Objectives To evaluate right bundle branch block (RBBB) on electrocardiograms (ECGs) as a screening tool for the diagnosis of pulmonary embolism (PE) in a chronic spinal cord injury (SCI) population and to determine the prevalence of PE. Design Retrospective analysis. Setting Boston Veterans Affairs Healthcare System. Participants Consecutive SCI participants (N=112) who were followed at this institution until death between 1999 and 2005 at an average age of 71 years, a duration of paralysis of 31 years, with a tetraplegic level in 62%, and no useful motor function in 84%. Intervention Not applicable. Main Outcome Measures PE, as a cause of RBBB, was diagnosed by autopsy, a source of thromboembolism, imaging, or other ECG signs of PE. Chronic obstructive lung disease was diagnosed by pulmonary function tests and myocardial infarction by ECG or echocardiogram. Results Twenty-nine participants (26%) had RBBB (6 with incomplete RBBB). Evidence that PE caused RBBB was found in 21 (72%), with 4 (3 massive) found by autopsy, 4 by the presence of an embolic source, 3 by imaging, 2 by the intermittent course of RBBB, 1 by abrupt onset of RBBB before death, and 7 by other ECG signs. RBBB represented chronic obstructive lung disease or myocardial infarction in the remaining 8. The onset of RBBB occurred either within months of SCI in 5 (1 before SCI) or years after SCI in 24 (6–50y, median 32y). RBBB was constant in 27 and intermittent in 2. The duration of RBBB ranged from 20 minutes to 31 years, median 4 years. Conclusions RBBB may be a useful initial screening test for PE complicating chronic SCI. PE, often recurrent and sometimes fatal, is prevalent in chronic SCI.