Introduction : Heart failure is a functional and structural disorder that impair the heart from carrying out it's function as a pump to carry out physiological circulation....
Causes :
1. Reduced Ventricular contractility
Myocardial infarction
Myocarditis
Cardiomyopathy
2. Ventricular Outflow obstruction(pressure overload)
A. Left heart failure
Hypertension (HTN)
Aortic stenosis
B. Right heart failure
Pulmonary HTN
Pulmonary valve stenosis
3. Ventricular inflow obstruction
Mitral Stenosis
Endomyocardial fibrosis
Tricuspid Stenosis
Constrictive pericarditis
4. Ventricular Volume Overload
Mitral regurgitation
Pulmonary regurgitation
Increase metabolic demand
Ventricular Septal defect
Atrial Septal defect
Factors increasing or Reducing heart failure
Anemia
Thyrotoxicosis
Pulmonary embolism
Infective endocarditis
Myocardial infarction
Drugs e.g beta adrenoceptor antagonist
Obesity
Pregnancy
Arrhythmia
Pulmonary infection
Pathophysiology
Heart failure results from complex neurohormonal changes, renin,agiotenesin, aldosterone axis and sympathetic nervous system.
Initially these changes help the heart to optimize cardiac function by altering the preload and afterload and by increasing myocardial contractility....
However, they become counterproductive and cause reduction in cardiac output by causing increasing peripheral vascular resistance...
Investigation
FBC
Chest x-ray
Electrocardiogram
Echocardiography
Clinical features
Left side : dyspnea, orthopnea, chest pain, PND,
Right side: pedal edema, hepatic congestion, ascites
Drug used for treatment
1. Positive ionotropic drugs
a. _Digitalis_
Digoxin
Digitoxin
b. _Beta adrenoceptor stimulant_
Dopamine
Dobutamine
c. _Bipyridines_
Inamirinone
Milrinine
2. Negative ionotropic drugs
Ace inhibitors
Diuretics
Vasodilators
Beta adrenoceptor blockers...
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