Cardiomyopathy refers to a clinical disease that involves the muscles of the heart. Cardiomyopathy usually causes the heart muscles to grow thicker, and more rigid than the normal myocardium. The progressive scarring of the heart muscle may sometimes replace the physiologic role of the normal myocardium.
Patients diagnosed with Restrictive Cardiomyopathy will present with the following signs and symptoms:
Patients diagnosed with Dilated Cardiomyopathy will present with the following signs and symptoms:
The following laboratory work up and tests are done to investigate patients with impending cardiomyopathy:
For restrictive cardiomyopathy, therapeutic modalities are focused on the alleviation of the symptoms. Water and salt intake monitoring is paramount to prevent overload. In some case, patients are given diuretics to unload water retention in RCM. When heart failure become progressively worse, cardiac transplant may be the only option for RCM.
Dilated cardiomyopathy are medically treated with Angiotensin converting enzyme inhibitors, Angiotensin receptor blockers, beta blockers, digoxin, and diuretics . A pacemaker may be installed in patients with DCM to synchronize any irregular cardiac rhythm. Hypertrophic cardiomyopathy are given medications to relax the heart muscles like beta blockers and calcium channel blockers. Cardiac surgeries like septal myectomy and septal ablation are some of the surgical options elected to debulk the thickened muscles of the heart.
In both children and adult population the outlook for restrictive cardiomyopathy is generally poor. Most patient progress to low output heart failure which may complicate to thromboembolism or cardiac cirrhosis. There is a higher mortality rate in dilated cardiomyopathy associated with severe congestive heart failure (CHF), male sex, and increasing age. About half of the patients with DCM presenting with CHF will die within the first 5 years from diagnosis . Although patients with DCM having mild CHF carries a brighter outlook. Hypertrophic cardiomyopathy carries the best prognosis with only 1-3% mortality rating . Majority of the mortality seen in HCM is due to sudden death caused by ventricular tachycardia and fibrillation. Morbidity and mortality improves with early diagnosis and intervention of the HCM disease .
In the majority of cases of cardiomyopathy, the etiologic causation is often times unknown. The following pre-morbid causes has been implicated as the most common identifiable causes of cardiomyopathy in clinical practice:
In the world wide scale, the reported incidence of cardiomyopathy is up to 400,000 to 550,000 diagnosed cases per annum prevailing in up to 5 million people. In the United States, the most common form of restrictive myocarditis is the idiopathic type. The prevalence of endomyocardial fibrosis (EMF) abounds in the subtropical areas of Africa among children and young adults . Causing 25% of the deaths due to heart diseases in the same African regions.
Dilated cardiomyopathy can affect patients at any age but symptoms usually surface in the third and fourth decade of life. Hypertrophic cardiomyopathy (HCM) represents 0.5% of patient brought in for diagnostic echocardiography . The worldwide prevalence rate of HCM is only 50 to 200 cases per 100,000 population . HCM has a slight male predilection over the female population with a peak mean age of occurrence at the third decade of life. Although in the adult population, the majority of the diagnosed cases HCM are within the 30’s to 60’s age range.
In restrictive cardiomyopathy (RCM), the stiffness in the myocardium can give rise to an increased intra ventricular pressure even in the light of a smaller stroke volume . The restrictive effect on the ventricular volume can lead to diastolic heart failure because of the progressive loss of stroke volume due to the muscular restriction. Fibrotic changes in the heart muscles can cause cardiac scarring on the heart surface and cause bundle branch block in the electrophysiology of the heart.
In the dilated cardiomyopathy cases, the ventricle begins to enlarge due to the chronic left ventricular failure causing both systolic and diastolic type of heart failures. The progressive stretch of the heart’s myocardium reduces the volume of the cardiac output contributing to the development of congestive heart failure. The progressive dilatation of the ventricles can lead to the development of an acquired tricuspid and mitral valve regurgitation defects.
The progressive hypertrophy of the heart muscles in hypertrophic cardiomyopathy increases the pressure gradient in the outflow tracts of the circulating blood. Mitral valve dysfunction happens in hypertrophic cardiomyopathy when the hypertrophy involves the heart papillary muscles and the muscular septal hypertrophy displacing the outflow tract of the mitral valve. The thickening of the heart muscles can also impair the calcium channel physiology.
In most cases, cardiomyopathy could not be prevented. Patients can only modify some activities that may result in heart failure with cardiomyopathy like abstaining from alcohol or recreational drugs. A balanced diet with adequate vitamins and minerals can actively prevent heart failure in some cases of cardiomyopathies.
Cardiomyopathy is a general term given to abnormal heart muscles. Clinically, there are basically three types of cardiomyopathies: Restrictive, Dilated, and Hypertrophic cardiomyopathy. This abnormalities seen in the heart muscles retards the normal delivery of blood throughout the organ systems of the body. Cardiomyopathy can progress to serious heart failure if left untreated. Treatment approaches to cardiomyopathy grossly depends on the type and could be therapeutically corrected by either surgical or medical means.