Flashcards in Pathophys of heart failure Deck (17):
What is heart failure?
Heart failure is the inability of the heart to pump blood forward at a sufficient rate to meet the metabolic demands of the body (forward failure), or the ability to do so only if the cardiac filling pressures are abnormally high (backward failure)
Two basic components of HF
Low forward flow (decreased cardiac output) and congestion (increased filling pressures) in response to low flow
What are the causes of heart failure?
Failure of systole/diastole, pumps (left and/or right), dysfunctional electrical system, regurgitation or stenosis of valves or coronary arteries
Explain systolic dysfunction
Decreased contraction (decreased inotropy) results in decreased stroke volume and a lower systolic blood pressure
Hallmarks of systolic dysfunction
Decreased ejection fraction and ventricular enlargement (dilated cardiomyopathy)
what does the PV loop look like in systolic HF?
Primary causes of systolic HF
1. Direct destruction of heart muscle cells: Myocardial infarction, Viral myocarditis, Peripartum cardiomyopathy, Ideopathic dilated cardiomyopathy, Alcohol. 2. Overstressed heart muscle:Tachycardia-mediated HF, Methamphetamine abuse, Stress-provoked (tako-tsubo cardiomyopathy). 3. Volume overloaded heart muscle: Mitral regurgitation, High cardiac output
impaired filling (decreased lusitropy)
Hallmarks of diastolic dysfunction
Normal ejection fraction and ventricular wall thickening (left ventricular hypertrophy) decreases stroke volume
what does the PV loop look like in diastolic HF?
Primary causes of diastolic HF
1. High afterload/pressure overload: Hypertension (long-standing), Aortic stenosis, Dialysis (inadequate volume removal)
2. Myocardial thickening / fibrosis: Hypertrophic cardiomyopathy, Primary restrictive cardiomopathy. 3. External compression: Pericardial fibrosis / constrictive pericarditis, Pericardial effusion
Right sided heart failure can result in what?
decreased circulating blood flow (forward RV HF) or increased venous pressures (backward RV HF)
primary causes of right sided HF
1. Left heart failure, 2. Lung disease / pulmonary HTN / RV pressure overload: Called “cor pulmonale” when primary lung dz causes HF, COPD, primary pulmonary hypertension, sleep apnea
3. RV Volume overload: Shunt (interatrial septal defect),Tricuspid regurgitation. 4. Damage to the RV myocardium: Isolated RV infarct, Myocarditis
Describe Frank-Starling compensation in HF
Increased pre-load (end diastolic pressure) helps preserve stroke volume
How does Renin-Angiotensin activation affect HF?
Vasoconstriction and increased sodium retention inccreases blood volume which compensates for decreased LV filling short term. Long term, it actually promotes HF by increasing cardiac workload, ventricular hypertrophy/dilation, myocardial damage.
How does adrenergic activation affect HF?
vasoconstriction, tachycardia and inotropic augmentation compensate in the short term. Long term, it actually promotes HF by increasing cardiac workload, ventricular hypertrophy, etc.