Heart Failure Flashcards
Heart Failure
clinical syndrome described as the inability of the heart to pump an adequate amount of oxygenated blood to meet the body’s demands.
-inadequate CO
Two problems of Heart failure
- Filling problem
- Contracting problem
Filling problem
poor compliance or lack of space to fill
contracting problem
poor contractility
How many in US have heart failure?
5.8 mil
cure for heart failure
-no cure, only preventative measures and tx of symptoms is available at this time
Primary risk factors for heart failure
- CAD
- Advancing age
Contributing risk factors for heart failure
- HTN
- DM
- Tobacco use
- Obesity
- High serum cholesterol
- AA descent
Path of blood through the heart
- blood from upper and lower body enters the R. Atrium
- moves to the right ventricle
- pumped to the lungs via the pulmonary artery
- returns to the left Atrium
- moves to the left ventricle
- pumped though the body via aorta
Goal for Heart failure patients
improve cardiac output
CO
the amount of blood ejected out of the ventricles each minute
CI
Cardiac Index: CO adjusted for body size
CI= CO/BSA
BSA= ht(cm) x wt(kg)/3600 to the 1/2 power
Stroke Volume
amount of blood ejected from the ventricles with each ventricular systole contraction
CO= HR x SV
CO norm
4-8 L/min
CI norm
2.5 L/min
SV norm
60-130 mls
HR norm
60-100 beats/min
Systemic Vascular Resistance
600-1400
Pulmonary Vascular Resistance
20-130
Preload
- measurement of volume
- amount of blood in the heart at the end of diastole
- increased with volume replacement
- decreased by blood loss and diuretics
Afterload
- measurement of resistance
- influenced by vascular resistance, blood pressure, blood viscosity, and aortic/pulmonic stenosis
Contractility
- cannot directly measure but can be see with echo
- strength of myocardial contraction
- influenced by preload (Frank Starling’s Law)
Frank Starlings Law (or Curve)
As you increase preload, contractility will improve….to a point.
-too much preload can overstretch the heart and weaken the cardiac muscle causing worsened contractility
Hemodynamics prinicipals review
CO = HR x SV
Preload (dumps blood into the heart)….Contractility (forces the blood out of the heart)…..Afterload (the resistance that the heart must work against
According to Frank Starling’s law, when preload is increased, what is the initial response of the heart?
Contractility increased
What causes the heart to fail?
- Impaired myocardial function
- increased cardiac workload
- Non-cardiac conditions
Impaired myocardial function
CAD, rheumatic fever, endocarditis, cardiomyopathy
Increased cardiac workload
HTN, valve disorders, anemia, congenital heart defects
Non-cardiac conditions
volume overload, hyperthyroidism, massive pulmonary embolus
Compensatory Mechanisms in Heart Failure
When the heart begins to fail the body attempts to compensate
- initially these compensatory mechanisms are helpful, but ultimately they harm the patient only worsening their heart failure
- muscle fibers have stretched heart chambers enlarges