Heart Failure Flashcards
heart failure
- the 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
heart failure is either
a filling problem (poor compliance or lack of space to fill)
OR
-a contracting problem (poor contractility)
HF stats
- over 5.8 million people in the US have heart failure
- most common reason for hospitalization in adults >65
- number one cause of readmission
- there is no cure for heart failure, only preventative measures and treatment of symptoms is available at this time
Etiology: who gets HF?
- primary risk factors: coronary artery disease(CAD); advancing age
- contributing risk factors: hypertension, diabetes, tobacco use, obesity, high serum cholesterol, African-American decent
The goal is to…
Improve cardiac output
cardiac output
the amount of blood ejected out of the ventricles each minute
cardiac index
-CO adjusted for body size
-CI=CO X BSA
BSA=body surface area. -calculated with height and weight
[height(cm) X weight (kg)] / 3600^1/2
stroke volume
the amount of blood ejected from the ventricles with each ventricular systole (contraction)
CO=HR*SV
preload
-measurement of volume
-the amount of blood in the heart at the end diastole
-increased with volume replacement (IV fluids, etc)
-decreased by blood loss and diuretics
lower preload= lower CO
-atria
afterload
- resistance heart has to overcome to get blood out of heart
- measurement of resistance
- influenced by vascular resistance, blood pressure, blood viscosity, and aortic/pulmonary stenosis
contractility
- cannot directly measure but can be seen with echocardiogram
- the strength of myocardial contraction
- influenced by preload (Frank starlings law)
Frank Starlings law (or curs)
-as you increase preload, contractility will improve, to a point. too much preoad can overstretch the heart and weaken the cardiac muscle causing worsening contractility
hemodynamics principle review
CO=HR*SV
preload dumps blood into heart
-contractility forces the blood out of the heart
-afterload is the resistance the heart must work against
What causes the heart to fail?
1) impaired myocardial function: CAD, rheumatic fever, endocarditis, cardiomyopathy
2) increased cardiac workload: hypertension, valve disorders, anemia, congenital heart defects
3) non-cardiac conditions: volume overload, hyperthyroidism, massive PE
compensatory mechanisms in HF
- when the heart begins to fail the body attempts to compensate
- initially these compensatory mechanisms are helpful, but ultimately they harm the pt only worsening the HF
HF affects every body system
- respiratory: fluid overload —> pulmonary edema
- neuro: poor CO –> confusion
- integumentary: poor perfusion and edema puts pts at risk for skin breakdown. (cyanosis, edema)
- GI: liver congestion and enlargement, ascites, malnutrition
- urinary: poor renal perfusion
The kidneys role in HF
1- decreased renal perfusion ( low CO)
2- angiotensin 2 and aldosterone are released
3- causes increased anti-diuretic hormone (ADH)
4- ADH causes kidneys to absorb more water
5-this combo of increased sodium & water leads to a further increased preload
6- the weak heart cannot handle the excess in fluid (preload) and congestion worsens, heart becomes more dilated and CO drops even more
systolic HF
- decrease in the amount of blood ejected from the ventricle
- -less blood pumoed out of the ventrices, weakened heart muscle can’t squeeze as well.
causes: heart attack, increased preload, cariomyopathy, mechanical abnormalities
diastolic HF
- when the heart cannot fill effectively, due to increased resistance to filling
- less blood fills the ventricles, stiff heart muscle cant relax normally
- causes: left ventricular hypertrophy from chronic HTN; aortic stenosis; hypertrophic cardiomyopathy(thickening of heart muscle)
left sided HF
- most common type of HF from left ventricular dysfunction
- the fluid back up reaches the pumonary bed and causes pulmonary edema
S/S of left sided HF
- cap refill >3secs
- orthopnea (SOB when laying flat)
- dyspnea on exertion
- nocturnal dyspnea
- tachypnea
- diaphoresis (sweat)
- basilar crackles or rhonchi
- cyanosis
- hypoxia (resp. acidosis)
- elevated pulmonary artery pressures
- tachycardia (usually)
- cough with frothy sputum (clear or pink, out of lungs, no infection, usually indicative of pulmonary edema)
S/S of left sided HF cont
- elevated pulmonary artery occlusive pressures
- audibke S3 and S4 heart tones
- mental confusion
- weight gain
- fatigue/weakness/lethargy
- murmur or mitral insufficiency
- enlarged left ventricle on X-ray
- enlarged left atrium on X-ray
- narrowing pulse presure
pulmonary edema
- a medical emergency
- the accumulation of fluid in the interstitial space tissue and alveoli of the lungs (pt is literally drowning in their own fluid overload)
- rapid interventions necessary or death is eminent
- treat pt with: diuretics to pull fluid out of lungs; nitrates to vasodilate and reduce systemic vascular resistance; morphine to reduce anxiety and vasodilate (sparingly)