Severe Conduction Disturbances Accompanying Anterior Wall Myocardial Infarction: An Infrequent Presentation to Remember

<b>Background:</b> Anterior ST-elevation myocardial infarction (STEMI) is frequently associated with severe complications, such as myocardial dysfunction and conduction abnormalities. Complete atrioventricular block (CAVB), especially when combined with bifascicular block, is a rare but critical presentation that reflects extensive myocardial damage, often linked to proximal left anterior descending (LAD) artery occlusion. <b>Case Presentation:</b> A 76-year-old male with a history of hypertension, diabetes mellitus, and dyslipidemia presented to the emergency department with a 6-day history of gastrointestinal symptoms and recurrent syncope. On arrival, he exhibited bradycardia, hypotension, and mottling, progressing to cardiac arrest. The return of spontaneous circulation was achieved after one cycle of advanced cardiovascular life support. Electrocardiography revealed CAVB with a ventricular escape rhythm displaying right bundle branch block morphology, left anterior fascicular block, and anterior ST-segment elevation. Emergency interventions included endotracheal intubation, Swan-Ganz catheterization, transvenous pacing, and vasopressor support. Echocardiography demonstrated severe left ventricular systolic dysfunction with an ejection fraction of 25%. Coronary angiography identified critical proximal stenoses in the LAD and circumflex arteries, managed with percutaneous coronary intervention and stent placement. Persistent conduction abnormalities and systolic dysfunction necessitated implantation of a cardiac resynchronization therapy defibrillator (CRT-D). Despite extensive rehabilitation efforts, the patient died after 60 days of hospitalization. <b>Discussion:</b> This case highlights the importance of rapid recognition and intervention in anterior STEMI complicated by CAVB and bifascicular block, signaling significant proximal LAD involvement. Advanced therapeutic options, including CRT-D, are crucial for addressing these rare, life-threatening conduction disturbances. The fatal outcome underscores the need for vigilant follow-up and individualized preventive strategies to improve prognosis in such complex STEMI cases.