cardiomyopathy for undergraduates

CardiomyopathyA group of diseases that primarily affects the heart

muscle and are not the result of congenital, acquired valvular, hypertensive, coronary arterial and pericardial

abnormalities.Prepared by: Fadziyah Zaira Bte Md Fadzil4th Year, GEF International Medical School, Bangalore, India

We are going to cover…1. dilated cardiomyopathy (DCM)

2. hypertrophic cardiomyopathy (HCM)

3. restrictive cardiomyopathy (RCM)

4. arrhythmogenic right ventricular dysplasia (ARVD)

5. obliterative cardiomyopathy (OCM)

Fundamental form of cardiomyopathy

1. Primary type-heart muscle disease predominantly involving the myocardium and of unknown etiology.

2. Secondary type- myocardial disease of known cause/ associated with a systemic disease.

Eg: amyloidosis, chronic alcoholic use.

Classification

Diagramatic representation of different cardiomyopathies

Dilated cardiomyopathyIs a disease of heart muscle characterised by

dilation of the cardiac chambersReduction in ventricular contractile function

EpidemiologyThe most common form of CMResponsible for 10,000 death and 46,000

hospitalizations per year.

Pathophysiology May be secondary to progression of any process

that affects myocardium

Dilation is directly related to neurohormonal activation

Associated with atrial and ventricular arrhythmia in 1 ½ patients (probably responsible for the high incidence of sudden death in the population)

Results in Tricuspid and Mitral regurgitation due to the effect of chamber dilatation on the valvular apparatus.

Diagnosis Clinical presentation

Symptomatic HF (syncope, dyspnea, volume overload) Some patients are asymptomatic ECG shows nonspecific changes

Sinus tachy/atrial fibrillationVentricular arrhythmiasLeft atrial abnormality

Physical exam Variable degrees of cardiac enlargement Pulse pressure is narrow JVP raised 3rd or 4th heart sound are common Mitral/ tricuspid regurgitation may occur

Diagnostic testingConfirm with echocardiography/radionuclide

venticulography.CTI and CMRI can also be done.2D and Doppler Echo is helpful to differentiate

from other CMAngiography reveals dilated, hypokinetic LV with

some degree of mitral regurgitation.

* In India, the most common diagnostic test used for DCM is 2D echocardiography.

Radionuclide venticulography

Red area indicates blood column.

Blue area indicates myocardial perfusion

Treatment Therapeutic strategy include control of total

body sodium and volume in addition to appropriate preload and afterload reduction using vasodilator therapy.

B-blocker should be used unless CI

Angiotensin receptor antagonist

Cardiac transplantation is the treatment of choice.

Hypertrophic CMMost common cause of sudden death in

young athletes.

Prevalence approx. 100 per 1 lakh population

Characterized by in appropriate and elaborate LV hypertrophy with misalignment of the myocardial fibres.

Hypertrophy may be generalized or confined largely to interventricular septum.

Heart failure may develop because stiff non-compliant ventricles impede systolic filling.

Septal hypertrophy may cause dynamic LV outflow obstruction.

Mitral regurgitation occur due to abnormal systolic anterior mitral valve leaflet.

Pathophysiology Condition is genetic disorder with Autosomal

Dominant transmission.

Due to single point mutation in one of the genes that encode sarcomeric contractile proteins.

Symptoms & SignsSymptoms

Angina on effortDyspnea on effortSyncope on effortSudden death

Signs Jerky pulsePalpable LV heaveDouble impulse at apexmid-systolic murmur –sign of LV outflow obstructionPansystolic murmur

TreatmentB-blocker and rate-limiting calcium antagonists (eg

verapamil)

No pharmacological treatment is known to improve prognosis

Arrhythmia is common and responds well to amiodarone.

Outflow tract obstruction can be improved bypartial surgical resection (myectomy) or iatrogenic infarction of basal septum (septal ablation)

Implantable cardiac defibrillation (ICD) for patient with risk of sudden death.

Restrictive CMRare condition

Ventricular filling is impaired because ventricles are stiff.

Lead to high atrial pressure with atrial hypertrophy, dilatation and later atrial fibrillation.

Amyloidosis is the most common cause.

Other form: Idiopathic perimyocyte fibrosisFamilial restrictive cardiomyopathy

InvestigationDiagnosis is difficult

Require complex Doppler echocardiography

CT and MRI and endomyocardial biopsy may be done.

Treatment Symptomatic

Usually prognosis is poor

Transplantation is the best treatment.

Arrhythmogenic Right Ventricular Dysplasia

In this condition, patches of the right ventricular myocardium are replaced with fibrous and fatty tissue.

Inherited as autosomal dominant trait

Prevalence in UK 10 per 1 lakh population.

Dominant clinical problems are ventricular arrhythmia Sudden death Right sided cardiac failure

ECG shows inverted T waves in the right precordial leads.

MRI useful diagnostic tool and used to screen 1st degree relatives from having the same pathology.

Obliterative Cardiomyopathy

It is also rare in India.

Involves the endocardium of one or both ventricles and is characterized by thrombosis and elaborate fibrosis with gradual obliteration of the ventricular cavities.

Mitral and tricuspid valves are regurgitant.

Heart failure and pulmonary and systemic embolism are prominent.

Associated with eosinophiliaEg: eosinophilic leukemia, churg strauss syndrome

Mortality is high (50% at 2 years of developing the symptoms)

Anticoagulation and antiplatelet therapy is advisable and diuretics may help symptoms of HF.

Surgery valve replacement with decortication of endocardium may be helpful in certain cases.