Early Manifestation of Clozapine-Induced Cardiotoxicity: Detection, Pathophysiology, and Management

Schizoaffective disorder, bipolar type is a chronic mental health disorder that may manifest as mania. Clozapine is effective in treating acute mania and in achieving mood stabilization. However, on rare occasions, the use of clozapine has been associated with cardiotoxicity. Here, we present a case of a 31-year-old man who at baseline is known to have schizoaffective disorder, bipolar type, and cannabis dependence and was admitted to our hospital with a psychotic relapse. He was treated with clozapine, uptitrated to a maximum daily dose of 200mg twice daily by day 10. Thereafter he became febrile and experienced malaise, myalgias, and chest pain. He was noted on electrocardiogram to have sinus tachycardia without ischemic changes. In this context, he had a troponin leak, increased white blood cell count, serologies and cultures were negative and chest x-ray revealed no acute disease of the chest. Due to the suspicion of clozapine-induced cardiotoxicity, a transthoracic echocardiogram was done, which revealed mildly depressed left ventricular (LV) systolic function without pericardial effusion. Thereafter, clozapine was withdrawn and switched to lithium. Additionally, the cardioselective, metoprolol tartrate was initiated. Within 36-48 hours, he had resolution of symptoms and remained cardiovascularly stable. Clozapine uncommonly causes cardiotoxicity and early features may be non-specific. Awareness of this and recognizing early features aids in reducing the associated cardiovascular morbidity and mortality.