1343979 - Myocardial Infarction With Non-Obstructive Coronary Artery Disease And The Key Role of Multimodality Imaging

A 37-year-old male with history of smoking, cannabis and alcohol abuse presented after an episode of sudden onset substernal chest pain that lasted 30 minutes at rest 12 hours prior to arrival. Vital signs were stable.

Diagnostic Techniques and Their Most Important Findings: ECG showed atrial fibrillation with rapid ventricular response and Q waves with ST elevation in the anterior leads. Troponin I was elevated (5.83 ng/ml). Emergent coronary angiography revealed non obstructive coronary arteries (Figure 1). Urine toxicology was positive for Cannabis. Echocardiogram revealed biventricular global hypokinesis, akinesis of the apex of the left ventricle, and moderate mitral regurgitation.

The coronary angiogram ruled out obstructive CAD, and spontaneous coronary artery dissection. Differential diagnosis included Takotsubo cardiomyopathy, Myocardial Infarction and Non-Obstructive Coronary Artery Disease (MINOCA) and acute myocarditis. A decision was made to proceed with Cardiac Magnetic Resonance Imaging (CMR) which showed a left ventricular apical thrombus in addition to transmural late gadolinium enhancement involving the apex confirming the diagnosis of myocardial infarction (Figure 2). CMR ruled out Takotsubo and myocarditis. The underlying etiology of MINOCA was thought to be secondary to cannabis induced vasospasm, or a coronary embolism related to atrial fibrillation. Patient was managed with warfarin, nitrates, statin and abstinence from cannabis.

Learning Points from this Case:

Patients with evidence of MINOCA are challenging to diagnose and manage. CMR plays an integral role in confirming the diagnosis of MINOCA, evaluating underlying pathophysiology and excluding other differential diagnoses