Case report of a rare clinical triad in mitral valve prolapse: when ventricular arrhythmias coexist with thromboembolic complications.

Background: Mitral valve prolapse (MVP) has traditionally been considered a benign condition, yet malignant ventricular arrhythmias (VAs) may occur. This case illustrates a rare overlap of complex VAs, thromboembolic stroke, and myocardial infarction with non-obstructive coronary arteries (MINOCA) in a patient with MVP, underscoring the value of multimodality imaging and electrophysiological assessment for arrhythmic risk stratification. Case summary: A 50-year-old woman with MVP was referred to our centre for arrhythmic risk assessment after documentation of frequent premature ventricular complexes and polymorphic non-sustained ventricular tachycardia (NSVT) on Holter monitoring. Eight months earlier, she had been hospitalized for ischaemic stroke and 3 days later for a MINOCA. Echocardiography showed bileaflet MVP with mild mitral regurgitation, markedly thickened leaflets and severe left atrial (LA) dilatation. Cardiac magnetic resonance revealed transmural late gadolinium enhancement (ischaemic pattern) in the mid-lateral left ventricular wall. During electrophysiological study, a rapid polymorphic NSVT was induced. Given the coexistence of structural and arrhythmic high-risk features, a primary-prevention implantable cardioverter-defibrillator (ICD) was implanted. At follow-up, ICD monitoring detected paroxysmal atrial fibrillation (AF), prompting initiation of oral anticoagulation and flecainide therapy with marked suppression of VAs. Discussion: Severe LA dilatation suggested atrial cardiomyopathy favouring AF episodes, likely explaining the previous embolic events and the detection of myocardial ischaemic scar. This case highlights the complexity of risk assessment in MVP, where morphological abnormalities, atrial cardiomyopathy, and myocardial left ventricular fibrosis may coexist and synergistically amplify the arrhythmic vulnerability. A multidisciplinary clinical approach is pivotal to guide individualized clinical management and optimize outcomes.