Symptomatic complete heart block: A rare complication of anterior myocardial infarction in a young, fit male: A case report

Abstract

Background

Acute myocardial infarction (AMI) is a major cause of morbidity and mortality, typically affecting older individuals with multiple cardiovascular comorbidities. Complete heart block (CHB) is a rare but serious complication of AMI, requiring prompt intervention. We present a case of AMI involving total occlusion of the proximal left anterior descending (LAD) coronary artery, leading to CHB and alternating bundle branch blocks, requiring temporary pacing. The patient was discharged with good outcomes.

Case report

A 41-year-old Indian male with no significant past medical history presented with chest discomfort and abnormal electrocardiogram (ECG) findings. Emergency percutaneous coronary intervention (PCI) revealed critical proximal LAD occlusion and moderate disease in the other coronary arteries. The patient developed trifascicular block and subsequent episodes of alternating right and left bundle branch block, necessitating temporary pacing. Despite the complex arrhythmias resulting from his anterior AMI and the transient need for a temporary pacing wire, the patient showed remarkable improvement post-revascularization, with no requirement for a permanent pacemaker at discharge.

Why should an Emergency Physician be aware of this?

This case highlights that CHB can occur with anterior, not just inferior MI. When associated with anterior MI, there is extensive myocardial injury and a high risk of conduction abnormalities, which can potentially be permanent. While AMI can cause a range of complications, CHB tends to be rarer in LAD occlusion based on the anatomy it supplies. Recognizing and promptly treating both the primary lesion and its complications especially in the younger patients, can improve outcomes.