Cardiovascular IV - CHF Flashcards
When do symptoms of CHF become noticeable?
What are the adaptive responses to cardiac myocyte loss/dysfunction and/or persistant overload?
Only when the LV remodeling process is nearly completed
Myocardial hypertrophy and LV chamber dilation
In CHF what does chamber dilation augment? What does this result in?
Chamber dilation augments diastolic wall stress –> this leads to deformation of the LV wall, functional mitral regurgitation, as well as myocyte apoptosis
In response to CHF local neurohumoral systems become activated with increased? What occurs to the parasympathetic tone?
The structural and functional alterations constitue what is termed ____ ____.
Increased NE and angiotensin II; Parasympathetic tone is reduced
Ventricular remodeling
What is ventricular remodeling characterized by?
An increase in ventricular volume helps to maintain cardiac output but at the cost of? What produces further damage?
Myocyte hypertrophy and elongation
Maintain CO at the cost of increasing ventricular filling pressures; increase in diastolic stretch and pressure produces futher damage
Neurohumeral activation occurs with a decreased __ tone and increased ___ tone. Can result in?
What causes arterial vasoconstriction with resultant maldistribution of flow?
vagal; sympathetic; tachycardia
Activation of the renin-angiotensin system and increased sympathetic tone
Treatment of chronic CHF is directed initially at?
Goals for the treatment of CHF?
Improving organ perfusion and relieving excess fluid accumulation
a. Improve peripheral organ perfusion
b. Reduce ventricular size (decrease stress on myo.)
c. Reduce pulmonary congesion (decrease stress)
d. Reduce ventricular remodeling and cell death
5 Major classes of drugs used to treat CHF?
a. ACE Inhibitors
b. Beta-blockers
c. Diuretics (thiazides or loop)
d. Vasodilators (hydralizine or nitroprusside)
e. Digitalis
Thiazide or loop diuretics can relieve ____ with what two detriments?
Congestion; they dont improve long term surival and may exacerbate malignant remodeling
What is the only positive ionotrope CHF medication?
Digitalis
What can beta-blockers do?
Improve ejection fraction and mortality outcome with chronic treatment as well as decrease risk of sudden death
Vasodilator therapy:
- The failing heart could benefit by reducing what?
- How would this reduction help the patient?
- Reducing afterload (via arterial dilation) and pre-load (through venodilation)
- This would increase organ perfusion, relieve pulmonary congestion, and reduce ventricular chamber size.
Vasodilator therapy:
- Decrease in afterload causes a greater augmentation of ____ ____ in the failing heart than in the normal heart.
- Reduction of preload allows alleviation of? This is especially beneficial in what?
- stroke volume
- pulmonary congestion without severe reductions in stroke volume; this ies especially beneficial in reducing the phenomena of decompensation and acute severe congestion
Vasodilator therapy:
- In the presence of ventricular failure, the ___ length in ___ is increased.
- For the same relative change in afterload, the increase in shortening is greater where? Why?
- fiber; diastole
- Fiber shortening is greater in the failing ventricle due to the relative flattening of the end systolic force:length relationship
Vasodilator therapy:
- Normally, the ventricle operates on a steep starlinc curve with LVEDP < ____mmHg, where small changes in filling pressure yield?
- Also, normally, stroke volume is largely independent of the ____.
- 12; a large change in stroke volume
- afterload
Vasodilator therapy:
- In failure, what occurs to the Starling curve?
- The failing ventricle is highly afterload ____.
- It moves down and to the right
- dependent