Diagnosis

Cardiomyopathy

Etiology

Dilated Cardiomyopathy [3by]

• Etiology:

  • Genetics

  • Cardiovascular disease: ischemia, hypertension, valvular disease, tachycardia

  • Infectious: viral, rickettsial, bacterial, fungal, metazoal, protozoal, Whipple disease, Lyme disease

  • Metabolic: hyperthyroidism, hypothyroidism, acromegaly, myxedema, hypoparathyroidism, hyperparathyroidism, diabetes mellitus, electrolyte imbalance (potassium, phosphate, magnesium)

  • Nutritional: thiamine deficiency (beriberi), protein deficiency, starvation, carnitine deficiency

  • Toxic: drugs (cocaine), poisons, foods, anesthetic gases, heavy metals, ethanol

  • Systemic diseases with cardiac involvement: Rheumatoid arthritis, Systemic lupus erythematosus, Systemic sclerosis, Polymyositis, hemochromatosis, Sarcoidosis, amyloidosis, Loffler endocarditis, endomyocardial fibroelastosis, glycogen storage disease, malignancy with chemotherapy (doxorubicin)

  • Physical agents: extreme temperatures, ionizing radiation, electric shock, nonpenetrating thoracic injury

  • Neuromuscular disorders: muscular dystrophy (limb-girdle, Duchenne, fascioscapulohumeral), Friedreich disease, myotonic dystrophy

  • Primary cardiac tumor (myxoma)

  • Senile

  • Peripartum

  • Immunologic: postvaccination, serum sickness, transplant rejection

  • Stress-induced cardiomyopathy (Takotsubo cardiomyopathy)

• Pathophysiology:

  1. Continuing ventricular enlargement and normal left ventricular wall thickness

  2. Primary systolic but also diastolic dysfunction

  3. Progressive dilation --> significant mitral and tricuspid regurgitation

  4. Clinical presentation: heart failure, ventricular and supraventricular arrhythmias, conduction system abnormalities, thromboembolism, and death.

Hypertrophic Cardiomyopathy [ttd][icf]

• Etiology:

  • Genetic disorder (autosomal dominant) --> risk of sudden death

• Pathophysiology:

  1. Inappropiate asymmetrical myocardial hypertrophy in the absence of hypertrophic stimulus (Possible cause: Increased number of calcium channels -> abnormal calcium fluxes -> increases intracellular calcium concentration -> hypertrophy and cellular disarray)

  2. Abnormal diastolic function impairs ventricular filling (increased filling pressure)

  3. Malfunction of the myocardium and reduced cardiac output

  4. Shortsighted physiologic compensation (increased stroke volume, heart rate, vascular tone and water retention through adrenaline, renin, angiotensin, aldosterone)

  5. Eventually symptoms of chronic heart failure

• Complications:

  • Ventricular arrhythmias

  • Congestive heart failure

  • Infective endocarditis of the mitral valve

  • Atrial fibrillation

  • Embolic phenomenon

  • Sudden death

Restrictive Cardiomyopathy [skd]

• Etiology:

  • Usually caused by systemic diseases (Hemochromatosis, Amyloidosis, Sarcoidosis, Systemic sclerosis, Radiation, malignancy)

• Pathophysiology:

  1. Increased stiffness of the myocardium (reduced compliance)

  2. Diastolic dysfunction and restricted ventricular filling

Epidemiology

Incidence per 100.000 [owa][g41]

Prevalence per 100.000 [owa][g41]

Approach

• Blood test

• Thyroid function test

• BNP

• Chest x-ray

• ECG

• Echocardiography

• MR cor

• Biopsy

• Cardiac Catheterization

Treatment

Treatment goal: Control heart failure symptoms and manage arrhythmias [3by]

1. Medications:

   • Angiotensin-converting enzyme (ACE) inhibitors

   • Angiotensin II receptor blockers (ARBs)

   • Beta-blockers

   • Aldosterone antagonists

   • Cardiac glycosides

   • Diuretics

   • Nitrates

   • Vasodilators

   • Anticoagulation

2. Left ventricular assist device (LVAD)

3. Cardiac resynchronization therapy (biventricular pacing)

4. Automatic implantable cardioverter-defibrillators (ICD)

5. Ventricular restoration surgery

6. Heart transplantation

Differential diagnoses

Amphetamine toxicity, Aortic stenosis, Beriberi, Cardiac tamponade, Cocaine toxicity, Fabry disease, Glycogen storage disease, Heart failure, Hyperthyroidism, Lead toxicity, Myocardial infarction, Myocarditis, Pericarditis, Pulmonary edema