Restrictive Cardiomyopathy Differential Diagnoses

Updated: Aug 30, 2017
  • Author: Lindsay Reardon, MD; Chief Editor: Henry H Ooi, MD, MRCPI  more...
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Diagnostic Considerations

All causes of diastolic dysfunction are included in the differential diagnosis of restrictive cardiomyopathy (RCM). The more common forms of heart failure with preserved ejection fraction are typically related to advanced age, diabetes, obesity, coronary artery disease (CAD), and left ventricular hypertrophy. Some specific characteristics may help distinguish RCM as a cause, such as low-normal blood pressure, younger age, elevated B-type natriuretic protein (BNP) that is out of proportion to the clinical presentation, persistent positive troponin in the absence of CAD, low voltage-mass ratio on electrocardiography (ECG), increased left ventricular mass, and pericardial effusion. The high prevalence of clinical overlap between RCM and other causes of heart failure, however, continue to make it a diagnostic challenge. [4, 20]

Differentiating RCM from constrictive pericarditis (CP) is imperative. Although RCM has no specific therapy, CP is potentially curable with surgical pericardectomy. [21] Both processes show reduced left ventricular chamber compliance, but RCM is caused by abnormal elastic properties of the myocardium, whereas CP is constrained externally by the pericardium. Myocardial relaxation is impaired in RCM, whereas it remains normal in CP. [13]

The etiology of RCM has been confused with that of CP because of the similarity of their presenting symptoms and diagnostic findings. With respect to their history and clinical profile, pericardial constriction and RCM are often indistinguishable. In addition, the two conditions can coexist in the same patient; for example, radiation therapy affects the myocardium as well as the pericardium. There are certain clinical features, however, that help to differentiate the two conditions (see Table 1 below). 

Table 1. Clinical Features of Constrictive Pericarditis and Restrictive Cardiomyopathy (Open Table in a new window)

Clinical Features

Constrictive Pericarditis

Restrictive Cardiomyopathy

History

Prior history of pericarditis or condition that causes pericardial disease

History of systemic disease (eg, amyloidosis, hemochromatosis)

General examination

Peripheral stigmata of systemic disease

Systemic examination - Heart sounds

Pericardial knock, high-frequency sound

Presence of loud diastolic filling sound S3, Low-frequency sound

Murmurs

No murmurs

Murmurs of mitral and tricuspid insufficiency

Prior chest radiograph

Pericardial calcification

Normal results of prior chest radiograph

In the past, cardiac catheterization findings were not always conclusive, and the diagnosis of RCM was often made during surgery. Currently, as noninvasive imaging techniques continue to advance, the correct diagnosis can be strongly suggested by structural, mechanical, and hemodynamic findings on echocardiography and cardiac magnetic resonance imaging (CMRI). More advanced tissue tracking software allows myocardial functional data to be determined from both echocardiography and CMRI with equal ease and accuracy. Echocardiography and CMRI are comparable in their ability to differentiate RCM from CP. [22]

Echocardiographic findings consistent with RCM include normal or thickened right ventricular and left ventricular walls, normal or small left ventricular cavity size, and enlarged atria. Doppler ultrasonography shows a restrictive filling pattern of transmitral flow and reduced tissue Doppler peak early-diastolic mitral-annular velocities. In contrast, CP echocardiographic findings may show a plethoric (distended) inferior vena cava (IVC), abnormal septal wall motion, and respiratory variation of left ventricular inflow velocities. [22]

Other conditions to be considered include systemic hypertension, valvular aortic stenosis, and hypertrophic cardiomyopathy, all of which cause impaired diastolic distensibility secondary to left ventricular hypertrophy. The thickened left ventricle could be confused with amyloidosis on echocardiography, but the clinical findings are completely different. The final diagnosis of RCM is most commonly made on the basis of biopsy of fat tissue, such as abdominal wall fat.

Differential Diagnoses