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

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.