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)
secondary effects of digoxin
decreases HR
arterial and venous dilation
decreased venous pressure
normalized arterial baroreceptors
how does digoxin work as a positive inotrope?
inhibits Na K ATPase
indirectly results in increased intracellular calcium level
neurohormonal activation
activation of sympathetic system
activation of renin angiotensin aldoesterone axis
release of ADH
side effects of digoxin
really bad
low therapeutic index
affects all excitable tissues (GI, visual, neurologic, muscular, cardiac-arrhythmias)
toxicity enhanced with hypokalemia
drug interactions (quinidine, verapamil, amiodarone)
use of digoxin
not first line tx
use limited to heart failure pts with LV systolic dysfxn in atrial fibrillation or in some cases to pts in sinus rhythm who remain symptomatic despite maximal therapy with other therapies
furosemide side effect
hypokalemia
use of furosemide
widely used chronically for heart failure patients with reduced ejection fraction
use of chlorothiazide
rarely used alone
combo therapy with loop diuretics
side effect of chlorothiazide
hypokalemia
amiloride and triamterene effects as diuretic
weak, but limited K and Mg wasting
hydralazine
arterial vasodilator
mixed vasodilators ex
ACE inhibitors
ARBs
isorbide dinitrate/hydralazine combo
angiotensin has effects on
potent arterial constrictor (afterload)
Na and water retention through aldosterone secretion
promotes sympathetic activation by increasing neuronal and adrenal medullary catecholamine release
arrhytomogenic
promotes myocardial hypertrophy and apoptosis
aldosterone effects
promotes water and Na retention and potassium secretion
stimulates fibrosis in heart and vasculature
cardiac hypertrophy
side effects of ACE inhibitors
hyperkalemia
angioedema
hypotension
dry cough
use of ARBs
alternative for pts that cannot tolerate ACE inhibitors
use of isosorbide dinitrate/hydralazine combo
used when ACE inhibitors or ARBS not tolerated
aldosterone antagonist ex
spironolactone, eplerenone
side effect of aldosterone antagonist
hyperkalemia
uses of aldosterone antagonist
added with moderately severe to severe heart failure
non drug therapies for chronic heart failure involving reduced ejection fraction
salt restriction bi ventricular pacing implantable cardidefibrillator devices (ICD) left ventricular assist device heart transplant
tx of heart failure with preserved ejection fraction
diuretics to reduce pulmonary congestion and peripheral edema (but use cautiously to avoid under filling of LV)
note: all of the flashcards for drugs before this one (this is the last card) have been for chronic heart failure with reduced ejection fractions
