351Cannabinoids-induced toxic myocarditis underlying apical ballooning syndrome: a case proven by combined cardiac magnetic resonance and endomyocardial biopsy

Abstract

BACKGROUND. The relationship between cannabinoids abuse and cardiovascular effects has already been reported in previous studies. The current issues concerning their legalization enforce the need for a deeper knowledge of their potential cardiovascular consequences, even as a medication. CLINICAL PRESENTATION. We here describe the case of a 53 years-old woman who was admitted to the Emergency Department for syncope, followed by fever and respiratory distress. She reported chronic recreational abuse of cannabinoids, also on the day of admission. The electrocardiogram showed a ST-segment elevation in I-aVL leads with diffuse repolarization abnormalities. Because of TnI increase and heart failure signs, she was admitted to the Intensive Cardiac Care Unit. DIAGNOSTIC TECHNIQUES AND THEIR MOST IMPORTANT FINDINGS. A transthoracic echocardiogram showed severe systolic dysfunction (ejection fraction 17%) with diffuse mid-apical akinesia. A cardiac angiography was then performed, revealing normal coronary arteries and confirming mid-apical ballooning pattern. On the 3rd day, she underwent a cardiac magnetic resonance (CMR) which confirmed left ventricular (LV) mid-apical akinesia. On T2-weighted sequences, myocardial edema was present in the same regions (Fig.1, panel A and B) and no late gadolinium enhancement was detected (Fig.1, panel C and D). An endomyocardial biopsy (EMB) was performed showing an infective acute lymphocytic myocarditis (Fig.1, panel E). The molecular pathology study for viral genomes tested negative. Over the following days, the patient remained stable and a recovery of akinetic segments was observed. At 3-months follow-up she was still asymptomatic, the transthoracic echocardiogram revealed a complete normalization of the previous ECG and wall motion abnormalities. WHAT IS KNOWN. Coronary artery diseases, acute stroke, atrial and ventricular arrhythmias, sudden cardiac death and peripheral arteritis are some of the most observed effects related to cannabinoids, which frequently occur in patients with history of chronic abuse, and no other cardiovascular risk factors. The mechanisms are still not clear, but some evidences suggest the involvement of two specific receptors located in the central nervous system, in cardiac myocytes and in the smooth muscle of blood vessels. Therefore, cannabinoids would exert their effects through a strong b-adrenergic stimulation that could induce a critical hypercatecholaminergic state, like that responsible for the apical ballooning syndrome. WHAT WE LEARNT. In this clinical case, cannabi-noids abuse could have been the trigger of a toxic myocarditis, as proved by the CMR and EMB, showing a clinical presentation as an apical ballooning syndrome.