Restrictive Cardiomyopathy

Restrictive cardiomyopathy (RCM) is a myocardial disorder that usually results from increased myocardial stiffness that leads to impaired ventricular filling. Biventricular chamber size and systolic function are usually normal or nearnormal until later stages of the disease. Affecting either or both ventricles, RCM may cause signs or symptoms of left or right heart failure. Arrhythmias and conduction disturbances are frequently encountered. RCM may result from inherited or acquired predispositions and disease or a combination thereof, which broadly can be classified as infiltrative, storage disease, noninfiltrative, and endomyocardial (Table 1). Because of the heterogenous nature of the origins and manifestations of the RCMs and the concomitant challenges in diagnosing these diseases, it is difficult to accurately estimate the incidence and prevalence of any of the RCMs. Based on the current evidence, RCM is the least common of the cardiomyopathies. There are regional differences among the prevalence of RCM according to the cause. For example, endomyocardial fibrosis is primarily seen in the tropics and sub-Saharan Africa, whereas cardiac amyloidosis (CA) is more commonly diagnosed in other regions. Most causes of RCM are acquired. However, mapping several gene mutations as a cause of RCM have been recognized. These include mutations in the sarcomere subunits, such as troponin T (TNNT2 gene), troponin I (TNNI3), α-actin (ACTC), and β-myosin heavy chain Cardiomyopathy Compendium