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
- 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
- Advancing age
Contributing risk factors for heart failure
Path of blood through the heart
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
Afterload
- influenced by vascular resistance, blood pressure, blood viscosity, and aortic/pulmonic stenosis
Contractility
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