heart failure Flashcards
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)
HR is a
syndrome describing a constellation of signs and symptoms caused by many possible abnormalities of heart function
Poor FORWARD blood flow is a
- key requirement of HF
2. LOW FLOW (↓ cardiac output)
BACKWARD buildup of pressure
- is almost always present as well
- CONGESTION (↑ filling pressures)
- Typically a response to low flow
____ determines dysfunction
function
dysfunction: Displacement pumps
- Squeeze (contraction)
- Fill (relaxation)
- Failure of either systole or
- diastole causes HF
dysfunction: 2x pumps
left and right in series
Left, right, or both can fail
dysfunction: Coordinated by an
- electrical system
2. Too slow, too fast, asynchronous … all ↓ efficiency
dysfunction: Directed by
- 4x valves
2. Regurgitation (backflow) or stenosis (resistance) stress heart
dysfunction: Supplied by
- coronaries
- Regurgitation (backflow) or
- stenosis (resistance) stress heart
dysfunction: Encased in
- pericardium
- Regurgitation (backflow) or
- stenosis (resistance) stress heart
key mediators of blood flow
- intropy
- preload
- afterload
- stroke volume
- heart rate
- cardiac outpuut
Ventricular output increases in relation to
greater filling
Inotropy =
contractility
The more the LV is filled, the more it
will contract
↑ Preload produces
increased SV (and thus CO) for the same inotropic state
Same filling (preload) of LV produces a
greater squeeze of contraction
Determinants of inotropy
- Catecholaminergic / adrenergic stimulation
2. Calcium
↑ Inotropy produces increased
SV (and thus CO) for the same level of preload
↑ Preload cause ___ SV
(↑ SV)
↑ Inotropy causes ___ SV
(↑ SV)
↑ Afterload causes ___ SV
(↓ SV)
Weak / damaged myocardium = ___ failure
systolic
Systolic dysfunction
- problem with squeeze
- ↓contraction / ↓ inotropy
- ↓ SV
- lower generated systolic BP
hallmark of systolic dysfunction is
- Decreased ejection fraction
2. Ventricular enlargement
Ventricular enlargement
“dilated cardiomyopathy” = DCM
Decreased ejection fraction
- “HF with reduced ejection fraction” = HFrEF
2. “left ventricular systolic dysfunction” = LVSD
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 3. Volume overloaded heart muscle
Overstressed heart muscle
can be cause by
- Tachycardia-mediated HF
- Methamphetamine abuse
- Stress-provoked (tako-tsubo cardiomyopathy)
Volume overloaded heart muscle can be caused by
- Mitral regurgitation
- High cardiac output
- Shunting of blood
- Wet beriberi (thiamine B1 deficiency)
Direct destruction of heart muscle cells
can be caused by?
- Myocardial infarction
- Viral myocarditis
- Peripartum cardiomyopathy
- Ideopathic dilated cardiomyopathy
- Alcohol