ch 34 HF Flashcards
is a complex clinical syndrome that develops in response to myocardial insult
Heart failure (HF)
results in the inability of the heart to provide sufficient blood to meet the oxygen (O2) needs of tissues and organs. The decreased cardiac output leads to decreased tissue perfusion, impaired gas exchange, fluid volume imbalance, and decreased functional ability.
Heart failure (HF)
percentage of the total blood volume in the left ventricle (LV) at the end of diastole that is pumped out of the LV with the next systole is called the l
left ventricular ejection fraction (LVEF)
a defect in either ventricular systolic function/LV contraction (heart failure with reduced ejection fraction [HFrEF]) and/or a defect in ventricular diastolic function/filling (heart failure with preserved ejection fraction [HFpEF]).1
HF manifestations occur due to
HTN and CAD are the
primary risk factors for HF.
congenital abnormalities (e.g., septal defects), infiltrative cardiomyopathies (e.g., sarcoidosis), infections and inflammatory processes (e.g., viral myocarditis), persistent dysrhythmias, and toxins (e.g., alcohol, drug use, chemotherapy).3
other causes of HF
(1) preload, (2) afterload, (3) myocardial contractility, and (4) HR
CO depends on
(1) primary causes
(2) precipitating causes
major causes of HF are divided into 2 subgroups:
often increase the workload of the heart, resulting in an acute condition and decreased heart function.
Precipitating causes
(heart muscle cell)
cardiomyocyte
responds to such a mutated gene.
body’s largest known protein, titin,
impair sarcomere function and disrupt chemical signaling, which negatively affects ventricular structure and stability.
Titin mutations
activated in response to myocardial dysfunction, leading to remodeling of myocardial structure and function (Fig. 34.1).
Manifestations of HF are the result of neurohormonal compensatory mechanisms
- Cardiomyopathy (e.g., viral, postpartum, substance use)
- Congenital heart defects (e.g., ventricular septal defect)
- CAD, including MI
- HTN, including hypertensive crisis
- Hyperthyroidism
- Myocarditis
- Pulmonary HTN
- Rheumatic heart disease
- Valvular disorders (e.g., mitral stenosis)
Primary Causes of Heart Failure
Systolic HF
(heart failure with reduced ejection fraction [HFrEF])
diastolic HF
(heart failure with preserved ejection fraction [HFpEF]).1
, results either from the inability of the LV to (1) empty adequately during systole or (2) fill adequately during diastole. We can further classify left-sided HF as HFrEF (systolic HF), HFpEF (diastolic HF), or a combination of the two.
most common form of HF, left-sided HF
an inability of the heart to pump blood effectively.
HFrEF results from
is 55% to 65%
Normal LVEF
< 40%
-can be as low as 5% to 10%.
Patients with HFrEF generally have an LVEF
impaired contractile function (e.g., MI), increased afterload (e.g., HTN), cardiomyopathy, and mechanical abnormalities (e.g., valvular heart disorders).3
HFrEF is caused by
Over time, the LV becomes dilated and hypertrophied.
LV in HFrEF loses the ability to generate enough pressure to eject blood forward through the aorta.
the inability of the ventricles to relax and fill during diastole.
HFpEF results from
(1) signs and symptoms of HF, (2) normal LVEF, and (3) evidence of LV diastolic dysfunction by echocardiography or cardiac catheterization
diagnosis of HFpEF is based on (HTN is the primary cause of HFpEF.)