Lecture 3 Pathophysiology of Heart cardiomyopathies

Heart diseases in cardiology

1. PATHOPHYSIOLOGY OF HEART

2. CARDIOMYOPATHIES

3. Cardiomyopathies are a group of diseases (three major types) primarily involving the myocardium and characterized by myocardial dysfunction that is the result of hypertension, coronary atherosclerosis, valvular dysfunction, or pericardial abnormalities.

4. 3 TYPES. Dilated (congestive) cardiomyopathy Restrictive cardiomyopathy Hypertrophic cardiomyopathy.

5. DIALATED CARDIOMYOPATHIES (congestive)

6. Dilated Cardiomyopathy

7. Definition Dialated cardiomyopathy, the heart is enlarged, and both ventricles are dilated. Myocardial contractility is diminished, and cardiac output is reduced.

8. Etiology Idiopathic Familial Alcoholism Collagen vascular diseases Peri partum Nutritional effects Osteogenesis imperfect Hypocalcemia Heamatologic Heat stroke Infections Ischemia Hematologic diseases Prolonged tachycardia Amyloid End stage renal diseases

9. COMPARISION NORMAL Ejection fraction >55% LV diastole dimension <55mm LV wall thickness Atrial size Valvular regurgitation Common 1 st symptom Risk for arrhythmias DCM <30% >60mm Decreased Increased Mitral valve Excertional intolerance Vent tachy cardia , tachyarrhythmias , a.fibrillation

10. Idiopathic dilated cardiomyopathy is often familial and apparently healthy families and relatives may have latent, early, or undiagnosed established diseases. Echocardigraphic evaluation of family members is recommended.

11. Prognosis. Annual mortality rate is 20% in patients with moderate heart failure, and it exceeds 50 % in patients with severe heart failure. Patients with peripartum cardiomyopathy have a better prognosis than those with cardiomyopathy due to infiltrate myocardial diseases, HIV infection, or doxorubicin therapy.

12. Symptoms Dyspnea on exertion Fatigue Palpitations Systemic and pulmonary embolism Chest pain Resting tachycardia

13. Physical Findings Resting tachycardia Increased JVP Small pulse pressure Pulmonary rales Hepatomegaly Peripheral edema S3, S4 abnormal Mitral regurgitation, tricuspid regurgitation.

14. Diagnostic Studies Chest x-ray ECG Echocardiogram

15. Therapy Treat underlying diseases (SLE , alcoholism) Treat CHF (diuretics, ACE inhibitors, beta blockers) Limit activity when CHF is present.

16. Therapy Vasodilators (nitrates and ACE inhibitors) Prevent thromboembolism with oral anticoagulants Idiopathic DCM (diltiazem and ACE have been reported ,that they have beneficial effect) Growth hormone administration helps in improvement in hemodynamic status.

17. RESTRICTIVE CARDIOMYOPATHIES

18. Definition Restrictive cardiomyopathies is characterized by decreased ventricular compliance, usually secondary to infiltration of the myocardium. These patients have impaired ventricular filling and reduced diastolic volume, normal systolic function, and normal myocardial thickness.

19. Etiology Infiltrative disorders Scleroderma Radiation Idiopathic Endomyocardial fibrosis Metastatic cancer Diabetic cardiomyopathy.

20. RESTRICTIVE CARDIOMYOPATHY NORMAL Ejection fraction >55% LV diastole dimension <55mm LV wall thickness Atrial size Valvular regurgitation Common 1 st symptom Risk for arrhythmias RCM 25% - 50% <60mm Increased Increased and massive Mitral and tricuspid Exertional intolerance, SOB Vent fibrillation, atrial fibrillation

21. Symptoms and Physical Findings Edema, ascites, hepatomegaly. Fatigue, weakness. Kussmaul’s sign may be present Murmurs are common An early diastolic third heart sound is often heard.

22. Diagnostic Studies Chest X-ray ECG Echocardiogram MRI

23. Therapy Corticosteroid therapy Cytotoxic drugs There is no effective therapy for RCM. Death usually results from CHF or arrhythmias. Cardiac transplant can be considered.

24. HYPERTROPHIC CARDIOMYOPATHY

25. Hypertrophic Cardiomyopathy

26. In hypertrophic cardiomyopathy (HCM), there is marked hypertrophy of the myocardium and disproportionately greater thickening of the interventricular septum than that of the free wall of the left ventricle (asymmetric septal hypertrophy).

27. Pathophysiology During mid systole, the apposition of the anterior mitral valve leaflet against the hypertrophied septum can cause narrowing of the subaortic area and result in left ventricle outflow obstruction , because of this the diseases has been called idiopathic hypertrophic subaortic stenosis or hypertrophic obstructive cardiomyopathy. Patients with hypertrophic cardiomyopathy also have limited ability to dilate the coronary artery in response to increased myocardial oxygen demand.

28. COMPARISION NORMAL Ejection fraction >55% LV diastole dimension <55mm LV wall thickness Atrial size Valvular regurgitation Common 1 st symptom Risk for arrhythmias HCM >60% Decreased Increased Increased Mitral valve Chest pain, dyspnea V- tach , A-fib.

29. Symptoms Hypertrohphic cardiomyopathy may be suspected on the basis of abnormalities found on physical examination. Classic findings include: Dysnea Syncope (usually seen with exercise) Angina Palpitations Sudden death ( usuallly seen in young adults during exercise)

30. Physical Findings Harsh systole murmur sounds Abnormal S2 and S4 Double or triple apical impulse Rapid and forceful carotid upstroke.

31. Diagnostic studies Chest x-ray ECG Echocardiogram MRI Cardiac catheterization

32. Therapy Blocking the effect of catecholamines Use of beta blocker Ca channel blocker Intravenous saline solutions 24 hour holter monitoring Myotomy-myectomy (surgical intervention) Avoid use of digitalis and nitrates

33. Left ventricular outflow tract obstruction at rest is a strong, independent predictor of progression to severe symptoms of heart failure and of death.