Mitral annular disjunction as the cause of malignant ventricular arrhythmia in a young adult: a case report

Mitral annular disjunction (MAD) is associated with ventricular arrhythmias and sudden cardiac death (VA/SCD). Risk prediction for VA/SCD in individuals with MAD includes clinical, ECG and imaging markers. Imaging assessment for MAD includes transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMRI) and there are certain features in each modality to aid both diagnosis and risk assessment. A 23-year-old female with no medical history presented to hospital following out of hospital cardiac arrest. Effective bystander CPR and successful cardioversion from ventricular fibrillation to sinus rhythm by paramedics achieved return of spontaneous circulation. Focused transthoracic echocardiography and cardiac magnetic resonance imaging identified MAD. Notably, there were no specific high risk clinical or imaging features. The patient recovered completely and was discharged with implantable defibrillator for secondary prevention. MAD is a rare cause of VA/SCD. Arrhythmias secondary to MAD are more likely with abnormalities on cardiac imaging, including late gadolinium enhancement, fibrosis of the mitral annulus or papillary muscles, mitral valve pathology and ventricular ectopic beats. In this case, none of the traditional risk factors for VA/SCD were present. Thus, MAD remains an important differential in all patients with an otherwise unexplained cardiac arrest, even if high risk features are not present.