In most patients with mitral valve prolapse (MVP) without severe mitral regurgitation (MR), left ventricular (LV) function is preserved. There are, however, patients with MVP who have unexplained LV dilatation and/or decreased LV function. An association between MVP and sudden cardiac death has also been reported. LV size and function may be affected by the type of MVP, severity of regurgitation, and cause of MVP (myxomatous degeneration versus fibroelastic deficiency). There is increasing evidence suggesting an intrinsic cardiomyopathy associated with MVP. The cardiomyopathy associated with MVP can also affect the right ventricle (RV). Although the impact on ventricular dimensions and function are usually subtle, these abnormalities can affect clinical and echocardiographic estimation of the severity of MR and may thus have an impact on therapeutic decisions. Particularly in patients with the most extreme forms of MVP (Barlow disease), and in patients with Marfan syndrome or other connective tissue disorders, a cardiomyopathy affecting the LV and RV may thus occur occasionally. A better understanding of LV impairment associated with MVP is important for risk assessment and clinical decision-making.

Detection and evaluation of left ventricular hypertrophy of unknown etiology by echocardiography is important in every cardiology practice. Causes of left ventricular hypertrophy include sarcomeric protein disorders (classical hypertrophic cardiomyopathy), metabolic disease (glycogen storage disease including LAMP2 deficiency, PRKAG2 mutations, Fabry disease), syndromic hypertrophic cardiomyopathy (Noonan's syndrome, LEOPARD syndrome, etc.) and miscellaneous causes including systemic hypertension, amyloidosis, athlete's heart and pheochromocytoma. Although there are several echocardiographic changes quite typical for some of the disorders, most changes are not 100% specific. ECG findings and symptoms provide important additional information. Genetic testing is increasingly important. Nowadays, a combination of ECG findings, symptoms, family history, genetic testing and findings of echocardiography provide the best means for differentiation of left ventricular hypertrophy.