100614 heart failure Flashcards
three major determinants of stroke volume
contractility, preload, afterload
afterload is related to
wall stress, which is directly related to aortic pressure and the radius of the ventricle and inversely related to wall thickness of the ventricle
point a on pressure volume loop is
mitral valve opening and beginning of diastole
point b-c on pressure volume loops is
isovolumic contraction after mitral valve closure
d-a on pressure volume loops
isovolumic relaxation after aortic valve closure
which pt on P-V loop represents end systolic volume?
d
which curve on PV loop is compliance?
ab
which curve on PV loops is afterload?
cd
what is stroke volume on PV loops?
b - d
heart failure is due to abnormal
emptying
filling
what are some precipitating factors for heart failure?
increased metabolic demands
increased circulating volume (increases preload)–like salt, renal failure
conditions that increase afterload
conditions that impair contractility
failure to takeheart failure meds
excessively slow HR
physical findings for left sided heart failure
diaphoresis
tachycardia, tachypnea
pulmonary rales
loud P2 S3 gallop (in systolic dysfxn) S4 gallop (in diastolic dysfxn)
NY heart association classification of heart failure
class I: mild. cardiac disease, but no limits in physical activity
class II: mild. slight limitation of physical activity. dyspnea and fatigue with moderate exertion.
class III: moderate. marked limitation of physical activity. dyspnea with minimal exertion. comfortable only at rest.
class IV: severe. severe limitation of activity. symptoms present at rest.
what is the long term effect of positive inotropes in treating chronic heart failure with reduced ejection fraction?
no beneficial long term effect
digoxin primary effects
positive inotrope-increases the contractile state of myocardium, increasing stroke volume
increases vagal tone (slows HR)