Heart Failure Flashcards
heart failure definition:
-inability of the heart to pump sufficient blood to meet the metabolic needs of the body
myocardial failure definition:
- defective myocardial contraction
- results in heart failure!
circulatory failure definition:
- a condition in which an abnormality of some circulatory component (heart, vessels, blood volume, etc) is responsible for inadequate cardiac output
ex) hemorrhage
prevalence of heart failure:
- 23million worldwide
- 4.7 million in US (1.5-2%)
incidence of heart failure:
-declining rates!!
What is the neurohormonal mechanism of heart failure:
1) activation of sympathetic nervous system (with a concomitant suppression of parasympathetic NS)
- Inc adrenergic activation = more circulating NE = peripheral vasoconstriction
- dec myocardial NE =we dont know why
- Beta1 stim= inc HR and contractility
- alpha1 stim=mild inc in tropism and peripheral vasoconstriction
2) activation of the renin-angitensin system (happens later)
- decreased renal perfusion
- dec Na in distal renal tubule
- inc adrenergic stim = inc renin release
- more antiotensin I=more antiotensin II = organ fibrosis (heart and kidney) & enhanced NE release
Result of neurohormonal model in HF:
- peripheral arterial constriction
- Na/Water retention
- activation of inflammatory mediators of cardiac remodelling
LV remodelling:
1) dilation and shape change
- neurohormonal activation = changed function/shape
- pressure overload = parallel or concentric hypertrophy
- volume overload = SERIES or eccentric hypertrophy
- action potential prolongs in advanced HF (fetal gene activation)=contractile dysf
- contractile and reg proteins altered
- inc myocardial wall tension (LVEDV rises)
- MV regurg (papillary muscle separation)
Backward HF:
- as the LV fails to completely eject its contents - blood accumulates in the LA
- pressure rises in pulmonary circulation
- trasudation of fluid into the pulmonary interstitium = pulmonary congestion/edema
Forward HF:
- inadequate delivery of oxygen into arterial system (reduced cardiac output)
- results in dec perfusion of vital organs + mental clouding, weakness, and Na/water retention
RV HF -
1) most often a consequence of LV failure with pulmonary congestion
2) results in SYSTEMIC CONGESTION
- hepatomegally, mesentery and bowel edema, leg edema, ascites
- fluid retention becomes generalized in RV failure
LV heart failure is:
-true congestive heart failure due to central venous congestion
Systolic failure (LV):
- abnormal systoic function
- high EDV in ventricles
- poor perfusion –> na and water retained
Diastolic failure (LV)
- abnormal diastolic filing (heart cant fill-heart isnt stretching well)
- high LV filling pressure
- eventual pulmonary and systemic congestion
Pure R side failure due to
corpulmonale!!
Heart failure - precipitating causes:
- ischemia/infarction (MOST COMMON)
- hypertension
- arrhythmias (a fib)
- infectious/inflammatory
- pulmonary embolus
- physical, emotional, environmental stress
- cardiac toxins (chemo,alcohol)
- high output states
- reduction of therapy (LEAST COMMON)
Symptoms of HF:
1) short of breath (progressive)
- exertional
- paroxysmal nocturnal dyspnea
- orthopnea
- resting dyspnea
2) diminished exercise capacity
3) fatigue/weakness
4) nocturia
5) CNS impairment (memory, insomnia)
6) symptoms of RV faiure