Restrictive cardiomyopathy Flashcards
Definition
an abnormally stiffened myocardium (because o fibrosis or an infiltrative process) leading to impaired diastolic relaxation, but systolic contractile function is typically normal or near normal
Typical example of HF with preserved EF
Presentation
signs of heart failure
Dyspnea- exertional Orthopnea Fatigue Pulmonary edema pulmonary rales, Loud S3 Heart size may be normal or enlarged Similar to constrictive pericarditis , jugular venous distention may paradoxically worsen with inspiration (the Kussmaul sign) because the sti ened RV cannot accommodate the increased venous return
(Decreased cardiac output )
Presentation
Features of RV failure
Systemic congestion (o ten more prominent than pulmonary congestion in this syndrome) leads to Raised JVP Hepatomegaly Edema Ascites
Presentation
Other findings
Presentation similar to constrictive pericarditis
Atrial fibrillation in 75% of patients
Other arrhythmias - including AV block + atrial + ventricular origin
ECG
Non specific T wave + ST changes
Pathological Q waves , in the abscence of previous MI
LVH
May have sinus tachycardia,Afib,AV block
In amyloidosis : microvoltage of QRS complex
Xray
Heart size is often normal or even small with signs of pulmonary congestion
May be enlarged in late stage amyloidosis or hemochromatosis
Echo
Normal systolic function
Dilated atria may be present
Myocardial hypertrophy may be present ( increased wall thickness)
Helps to differentiate from restrictive pericarditis
This whould show thickened pericardium
RCM : Big atria , small ventricles
e wave + a wave , the amplitude of e wave compared to amplitude of a wave >2
BULLET POINTS
abnormally rigid (but not necessarily thickened) ventricles with impaired diastolic filling but usually normal, or near normal, systolic unction
Clinical mani estations o cardiac involvement are most common in which type of amyloidosis?
primary (AL) form
of amyloidosis and typically relate to the development of restrictive cardiomyopathy because
of the infiltrating amyloid protein. Diastolic dysfunction is the prominent cardiac abnormality; systolic dysf unction may also develop later in the disease. Orthostatic hypotension is
present in about 10% o patients, likely contributed to by amyloid deposition in the autonomic nervous system and peripheral blood vessels. Infiltration of amyloid into the cardiac conduction system can cause arrhythmias and conduction impairments, which can result in
syncope or sudden death
Pathophysiology
Reduced compliance o the ventricles in restrictive cardiomyopathy, whether due to inf ltration or f brosis, results in an upward shi t o the passive ventricular f lling curve , leading to abnormally high diastolic pressures. This has two major consequences:
(1) elevated systemic and pulmonary venous pressures, with signs o right- and le t-sided
vascular congestion, and
(2) reduced ventricular cavity size with decreased f lling, stroke volume, and cardiac output
The most useful diagnostic tools to differentiate restrictive cardiomyopathy from constrictive pericarditis
transvenous endomyocardial biopsy, computed tomography (CT), and MRI
For example, in restrictive cardiomyopathies, transvenous endomyocardial biopsy
may demonstrate the cause of the condition (e.g., the presence of amyloid fibrils in amyloidosis, or iron deposits in patients with hemochromatosis [a condition of iron overload]).
CT or MRI scans accurately identify the thickened pericardium present in most patients
with constrictive pericarditis, a finding that is not present in states causing restrictive cardiomyopathy.
Treatment of restrictive pericarditis
of underlying cause
For example, phlebotomy and iron chelation therapy may be helpful in the early stages of hemochromatosis. Symptomatic therapy or all etiologies includes :
- salt restriction
- cautious use of diuretics to improve symptoms of systemic and pulmonary congestion.
Unlike the dilated cardiomyopathies, vasodilators are not helpful because systolic function is usually preserved.
Maintenance of sinus rhythm (e.g., converting atrial
fibrillation i it occurs) is important to maximize diastolic
filling and forward cardiac output. Some
restrictive cardiomyopathies are prone to intraventricular thrombus formation, thus warranting chronic oral anticoagulant therapy.
In the case o primary (AL) amyloidosis, chemotherapy followed by autologous bone marrow stem cell transplantation has proved efective in
selected patients with early cardiac involvement
Examples of Restrictive Cardiomyopathy
Noninfiltrative
Idiopathic
Scleroderma
Infiltrative
Amyloidosis
Sarcoidosis
Storage diseases Hemochromatosis Glycogen storage diseases Endomyocardial disease Endomyocardial fibrosis Hypereosinophilic syndrome Metastatic tumors Radiation therapy
Endocrine + Metabolic diseases
Carcinoid
Hypothyroidism
Acromegaly
Cardiotoxicity Rx therapy (breast cancer ,Hodgkin) Antitracyclines HCQ Metisergida Serotoninergic agents
Genetic Sporadic /familial autosomal dominant (Tn,Ttn,actin,lamin,DSP,desmin,BAC cochaperon 3,filamia C) Endomyocardial fibrosis Loffler Endocarditis Idiopathic
Physiopathology from lecture
Restrictive cardiomyopathy is characterised by loss of elasticity of ventricular walls -> alteration of diastolic filling of one or both ventricles
- 🠕 stiffness of the myocardium /endocardium
- rapid 🠕 in ventricular filling pressure
- Specific pattern of diastolic pressure curve :
‘‘dip and plateau’’ - Predominant involvement of RV (+/- VS)
- Marked atrial dilatation with normal ventricular cavities
Predominantly , signs of RVF : 🠕 CVP
Clinical manifestations
They correlate with the severity of atrial pressure 🠕
LV failure
Exercise intolerance :inability to 🠕 CO due to diastolic dysfunction
Dyspnea
Severe asthenia = 🠗 CO
Signs of high CVP ( central venous pressure)
- Jugular vein distention .hepatomegaly , ascites edema,anasarca
- Progressive development , hardly reversible
Atrial fibrilation = frequent ventricular arrhythmias = cause of death
Advanced stages - frequent ventricular arrhythmias = cause of death
1/3 of cases - thromboembolic events
Lab tests and investigations
BNP > 400 pg/ml NT-pro BNP > 2000 pg/ml Changes with specific pathologies - High creatinine,urea,changes with protein electrophoresis in amyloidosis - High sideremia in hemochromatosis
Diagnosis
- Echocardiography
- Cardiac magnetic resonance
- Cardiac catheterization , endomyocardial biopsy
