Mitral valve prolapse (MVP) has an incidence ranging from 2 to 3%. It is usually a benign condition, but it can be associated with an increased risk of ventricular arrhythmias (VA) leading to sudden cardiac death (SDC). Our study aimed to evidence to victims of SDC, the incidental presence of MVP, and the associated histological alterations. In patients with MVP, we assessed the increased risk for VA, by studying the Heart Rate Variability (HRV) and Heart Rate Turbulence (HRT). Firstly, in 2021, we conducted a morpho-pathological study on 225 victims of SDC, and concomitantly, a clinical study was performed on 50 patients with MVP who underwent 24 hours Holter monitoring. In the first study, we evidenced in 8 subjects, alterations of the mitral valve (MV) suggestive of MVP, and associated with fibrotic lesions in the vicinity of MV. The patients included in the clinical study were divided into two groups based on age, clinical particularities, and 2D-echocardiographic aspect: group A: 23 subjects younger than 40 years with myxomatous degeneration of the MV and group B, 27 elderly patients with MVP and associated cardiovascular pathology. In patients with MVP, 24-hour Holter monitoring may evidence alterations of HRV and HRT, frequently related to the severity of mitral regurgitation (MR), which could explain the increased risk for VA.