Masquerading Bundle Branch Block in a Patient with Heart Failure in Nigeria

Masquerading bundle branch block (MBBB) is a rare and important electrocardiographic pattern. It consists of right bundle branch block (RBBB) in precordial leads and left bundle branch block (LBBB) in limb leads. It indicates advanced conduction system abnormality usually associated with severe underlying heart disease. MBBB is associated with poor prognosis. MBBB patients are at increased risk of complete atrioventricular (AV) block. To our knowledge, there is no previous published report of MBBB in heart failure in Nigeria.

To present a case of an African patient with heart failure and masquerading bundle branch block, a rare and important finding on 12-lead electrocardiogram.

To highlight the electrocardiographic feature of masquerading bundle branch block in a heart failure patient in our environment and the need for early recognition and close monitoring.

A 65-year-old man, known hypertensive and asthmatic, who presented with cough productive of whitish frothy sputum, bilateral leg swelling, and difficulty in breathing of 3 weeks duration. There was associated paroxysmal nocturnal dyspnea, orthopnea, and early satiety. No central chest pain on exertion or at rest.

The 12-lead electrocardiography (ECG) showed precordial type MBBB with right bundle branch block in V1 and LBBB without deep and wide S waves in leads V5 and V6. Echocardiography confirmed heart failure with reduced ejection fraction of 19%, grade 3 diastolic dysfunction with E/A velocity ratio of 2.31, E/e' of 29.7. Chest X-ray revealed unfolded aorta and cardiomegaly with cardio-thoracic ratio (CTR) of 65%. Patient was stabilized on anti-failure drugs and is being followed up.

We have reported electrocardiographic feature of MBBB in an African patient with heart failure. Early recognition of this rare electrocardiographic pattern, close monitoring and follow-up of these patients is important because of its association with poor prognosis.