Chronic heart failure
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Definition
This condition is a syndrome rather than a single pathological process. As such, it is defined by it's symptoms and signs.
Epidemiology
Pathophysiology
Two-thirds of heart failure is caused by coronary heart disease (i.e. myocardial infarction) with the rest being caused by hypertension, arrhythmias or valvular disease. Congenital heart defects may also cause heart failure but these are much rarer. Something has to make it harder for the heart to work which, when looking at it from a physics point-of-view means a reduction in cardiac output. Remember:
- Cardiac output = Stroke volume x heart rate
Risk Factors
Clinical Features
The definitive features of heart failure are breathlessness or exhaustion on less than normal exertion OR at rest. Reduced heart function and associated changes in other organ systems are also used in the definition.