Catastrophic apical ballooning in an obstructive hypertrophic cardiomyopathy patient treated with mavacamten: case...

Obstructive hypertrophic cardiomyopathy (oHCM) is a complex condition characterized by left ventricular outflow tract obstruction (LVOTO) in the setting of a hypercontractile and hypertrophic left ventricle. Obstructive hypertrophic cardiomyopathy can lead to exertional angina/dyspnoea, (pre)syncope, heart failure, and sudden cardiac death. A rare but life-threatening complication of oHCM is acute left ventricular ballooning. Standard oHCM treatment is medical (negative inotropic, chronotropic, and dromotropic drugs) or septal reduction in refractory cases (surgical myomectomy or percutaneous alcohol ablation). Recently, myosin inhibitors (mavacamten, aficamten) have been introduced to specifically counteract LVOTO. Because of its mechanism of action, left ventricular (LV) systolic dysfunction is a feared side effect.

We present a case of cardiogenic shock with apical ballooning in a 67-year-old oHCM patient treated with mavacamten since 6 weeks and suffering subacute emotional stress. The combination of LV systolic dysfunction with apical ballooning and compensatory aggravated LV outflow tract obstruction resulted in haemodynamic compromise and challenged the management, as strategies for both pathologies are conflicting. Veno-arterial extracorporeal membrane oxygenation (VA ECMO) was necessary to stabilize the patient. After VA ECMO weaning, however, acute cardiogenic shock relapsed and the patient died.

To the best of our knowledge, this is the first report describing apical ballooning in oHCM during mavacamten treatment. The causal role of mavacamten in this acute heart failure case is unproven, yet-being a cardiac myosin inhibitor and considering the shock recurrence after initial recovery-plausible.