Pathophysiology of Cardiac Failure Flashcards
What is heart failure
Any Structural or Functional Cardiac Disorder that leads to Inability to Maintain Adequate Circulation
Heart Fails to Supply Enough Blood to Meet Metabolic Demand of the Tissues
How does HF develop
HF usually develops Gradually and Insidiously due to Cumulative Effects of Disorders of Various Etiology
What physiologic factor cause heart failure
- decreased preload (dysfunction in diastole/filling)
- increased afterload (systole)
- decreased ventricular contractility (systole)
Causes of impaired preload
- LV Hypertrophy
- Myocardial Fibrosis
- Restrictive Cardiomyopathies
- Constrictive Pericarditis
Causes of increased afteload
- Systemic Hypertension
- Aortic Stenosis
Causes of impaired contractility
- Coronary Atherosclerosis (IHD)
- Mitral Regurgitation
- Aortic Regurgitation
- Dilated Cardiomyopathies
How is HF characterised
Onset (acute/chronic)
Side (left/right)
Conraction or relaxation dysfunction (sytolic/diastolic)
Low CO/High CO
When would we have high CO HF
when the supply is normal but because of high demand it is not enough
When would we have high CO HF
when the supply is normal but because of high demand it is not enough
- chronic anemia
- increased metabolic rate (eg. thyrotoxicosis)
Causes of LSHF
*Hypertension
*IHD
*Aortic Stenosis
*Mitral Incompetence
Causes of RSHF
*COPD - Mitral Senosis
*LSHF
* Pulmonary Stenosis
*Tricuspid valve disease
What are the physiologic compensatory mechanism to inadequate supply
Inc. HR
Dilation
What are the pathologic compensatory mechanism to inadequate supply
Inc. HR
Dilatation
Hypertrophy
Neuro-hormonal (RAAS)
What is the effect of dilatation
Inc ventriular size = Inc contraction
Physiologic: active dilatation (not forced)
Pathologic: passive dilatation (forced)
= incomplete emptying
Pathologic effect of Inc. Heart rate
No sufficient time for complete emptying
What is the neurohormonal response in HF
