Restrictive Cardiomyopathy

Restrictive cardiomyopathy (RCM) is a rare form of myocardial disease that is characterized by restrictive filling of the ventricles. In this disease the contractile function of the heart and wall thicknesses are usually normal, but the filling phase of the heart is abnormal. This occurs because the cardiac muscle is stiff and poorly compliant and does not allow ventricular filling. This inability to relax and fill with blood results in a back-up of blood into the atria. RCM is the least common in children, accounting for 2.5-5% of the diagnosed cardiomyopathies. The average age at diagnosis is 5 to 6 years and it appears to affect girls somewhat more often than boys. There is a family history of cardiomyopathy in approximately 30% of cases. In most cases the cause of the disease is unknown (idiopathic), although a genetic cause is suspected in most cases of pediatric RCM.

Clinical presentation:

Children with RCM frequently have a history of repeated lung infections. Referral to a cardiologist occurs when symptoms of heart failure are reported or cardiomegaly is seen on a chest x-ray. In approximately 10% of cases, syncope may be the first symptom. Sudden death may also be the initial presentation in some patients. 

Making the diagnosis:


Table showing the common differences between constrictive pericarditis and restrictive cardiomyopathy


Constrictive pericarditis

Restrictive cardiomyopathy


Previous pericarditis, cardiac surgery, trauma, radiotherapy and connective tissue disease

May have a positive family history

Extra heart sounds

Early S3, high pitched pericardial knock. No S4

Later S3, low pitched triple rhythm. S4 in some cases

Mitral or tricuspid regurgitation




Normal P waves


Bi-atrial dilation



Pericardial calcification in 20-30% of the cases. Normal atria

Pericardial calcification rare. Severe atrial dilation

Atrial enlargement


Usually mild

Severe in most cases

Equilibration of end- diastolic pressures in all cardiac chambers

Within 5 mm Hg in nearly all cases

Rarely occurs


MR/CT imaging

Shows thick pericardium in most cases

Rarely shows thick pericardium


Endomyocardial biopsy

Normal, or non-specific abnormalities

Shows amyloid in some cases, rarely other specific infiltrative disease



Myocarditis is an inflammation of cardiac myocytes associated with necrosis and degeneration.

Infection with Coxsackie B virus or adenovirus is the most common cause of myocarditis. Many other viruses, as well as bacterial infections, mycoplasma, fungi, protozoa, spirochetes and rickettsia have also been reported to cause myocarditis.

Clinical presentation

The common presentation is a history of a recent viral infection followed by the development of signs and symptoms of CHF.

Making the diagnosis


Acutely sick patients require intravenous inotropic agents and diuretics until they can be transitioned to oral digoxin, afterload reducing agents and diuretics. The use of anti-inflammatory and immunosuppressive therapy is still controversial.  

Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy (HOCM) is the most common cause of sudden death in the young. The most important predictors of sudden death are a family history of sudden death and recurrent syncope. Mortality in children with HOCM is twice as high as adults. The condition is usually progressive and the symptoms depend on the age and mode of presentation.

HOCM is an inherited disorder of the cardiac muscle characterized by a hypertrophied, non-dilated left ventricle. The condition is associated with abnormal relaxation of the LV and sometimes with outflow tract obstruction. The mode of inheritance is most often autosomal dominant with variable penetrance and several genetic defects have been described.


The hallmark of HOCM is left ventricular hypertrophy (LVH) which is characteristically asymmetric with more involvement of the ventricular septum. This asymmetric septal hypertrophy often produces sub-aortic obstruction that is exaggerated by systolic anterior movement (SAM) of the anterior mitral valve leaflet and its apposition to the bulging septum. Histologically, there is extensive myocardial fiber disarray. The myocardial cells are disorganized and are separated by loose connective tissue. The coronary arteries sometimes run within the myocardium (intramural) and show increased intimal and medial thickening causing luminal narrowing.

Clinical Presentation

Affected individuals may be asymptomatic, may have recurrent exertional dyspnea, chest pain or syncope. The condition may be recognized only after sudden death has occurred. Infants may present with CHF and the diagnosis is often missed.

Making the diagnosis


Beta-blockers are helpful in the medical management by reducing the contractility and the heart rate; thereby prolonging the diastolic time. However, these agents have no effect on the degree of LV outflow obstruction or sudden death. Digoxin, other inotropic agents, and ACE inhibitors are contraindicated in HOCM as they worsen the obstruction, though they may have a role in the end-stage dilated thin-walled HOCM hearts with impaired LV systolic function. Diuretics are also usually contraindicated as they reduce the preload and enhance the LV obstruction

Surgical myomectomy may be needed to relieve the LV obstruction. Alcohol ablation of the septal perforating coronary arteries can produce a controlled infarction and relieves the sub-aortic obstruction. There is also a role for a pacemaker or implantable defibrillator (ICD).

Patients with HOCM should avoid strenuous exercise and their families should undergo genetic counseling.