Restrictive Cardiomyopathy
Introduction
-Definition: Heart muscle disease resulting in impaired ventr filling with decr diastolic volume
-ventricular walls are excessively rigid and impede ventricular filling
-Systolic function usually normal; wall thickness may be normal-increased
-hallmark increased stiffness of myocardiam: rise in ventricular vol -> precipitous rise pressure
-can affect either or both ventricles, usually right sided failure predominates
Diagnosis
-suspected when heart failure present but no systolic dysfunction
- symptoms typical of heart failure, but cardiomegally typically absent
- Kussmaul’s sign – jugular venous pulse may rise during inspiration
- Hemodynamics Characteristics -
1. Rapid early decline in Ventricular Pressure at onset of diastole
2. Early diastolic filling (high atrial Press as AV opens)
Ventricular Tracing: Square root sign
Atrial Tracing: rapid x and y descents present; most prominent wave is y descent (tric open)
Differentiating Constrictive Pericarditis
-distinction must be made because management dramatically different
-often very difficult to make distinction
-hemodynamic parameters same
-clinical history suggestive of pericarditis or TB makes constrictive peric more likely
-no single diagnostic technique reliable, may resort to pericardiectomy
-Echo: pericardial thickening; Cath: RVSP usu < 50
Pathogenesis
Amyloidosis
-Outside of the tropics, most common cause of restrictive CMP
-Cardiac amyloid usually a/w primary amyloid – overprod light chains by plasma cells in MM
-Secondary amyloid caused by deposition of other proteins (familial, senile, inflammatory dz)
-Restrictive CMP due to tissue injury 2/2 replacement of normal myocardiumby interstit deposits
-May result in thickened wall without cavity dilatation
-Amyloid deposits in SA/AV nodes -> heart block
-Granular, sparkling appearance on Echo is characteristic, not diagnostic
-Diagnosis made with endomyocardial biopsy tissue/immunohistochemical staining
Endomyocardial Fibrosis
-Most common cause worldwide; endemic in Africa/India/S. America/Asia
-Restrictive obliterative CMP a/w eosinophlia
-Intracytoplasmic granular contect of eos responsible
Idiopathic Restrictive Cardiomyopathy
-Sometimes familial, associated with distal skeletal myopathy and AV block
-Characterized by mild-moderate increase in cardiac weight
-Patchy endocardial fibrosis present; fibrosis of SA and AV nodes lead to CHB
Other infiltrative/storage dz: Gaucher’s, Hurler’s (mucopolysaccharide), Fabry’s (glycosphingolipid), Sarcoid
Other Restrictive Conditions: carcinoid (fibroblast proliferation), antrhacyclines, XRT
Treatment
-Maintain ventricular filling pressures
-Judicious use of diuretics for venous congestion / avoid nitrates
-Digoxin use with caution; arrhythmogenic in amyloidosis
-loss of atrial kick detrimental – maintain sinus (amio/DCCV/pacing)
-anticoagulation warranted due to propensity of thrombus formation in atrial appendage
-Amyloid: Median survival 2yrs; chemo dramatic benefits; transplant (recurrence can occur)
-Endomyocardial Fibrosis – steroids; if fibrotic, surgical excision of endocardium/valve replace
Marco Perez, CCU 1/04