Flashcards in Lec 5 Heart Failure I Deck (58):
What is definition of heart failure?
cardiac disorder that impairs ability of ventricles to eject blood [fwd failure] or fill with blood [backward failure] or both
What is equation for CO?
CO = HR * SV
What 3 factors can affect stroke volume?
What are signs of systolic CHF?
- decreased CO
- decrease LVEF [left ventricular ejection fraction] < 50% normal
often 2ndary to ischemic heart disease
What are signs of diastolic HF?
- normal LVEF [left ventricular ejection fraction]
- high LV, RV, end-diastolic pressures
normal contractility, impaired relaxation, impaired compliance
If you see decreased ejection fraction (<50% normal) what possible causes of the heart failure?
decreased EF --> decreased contractility or increased afterload
if impaired contractility:
- chronic volume overload [aortic or mitral regurgitation]
- dilated cardiomyopathy [DCM]
if increased afterload:
- AS [aortic stenosis]
What is equation for ejection fraction?
EF = SV / EDV
SV = EDV - ESV
If you see normal ejection fraction in heart failure what possible causes?
due to impaired diastolic filling
- LV hypertrophy
- restrictive cardiomyopathy
- myocardial fibrosis
- pericardial tamponade
What are 3 compensatory mech in heart failure?
- frank-starling mech
- ventricular hypertrophy
- neurohormonal activation
How does heart failure change starling curve?
- in heart failure:
---- shift right in curve [decreased contractility]
---- move right along new HF curve [compensatory try to increase stroke volume/pressure at cost of increasing congestion
What is equation for wall stress?
wall stress = pressure * radius / thickness
How does ventricular hypertrophy help failing ventricle?
increased thickness --> decreased wall stress of ventricle
What kind of ventricular hypertrophy if there is volume overload?
eccentric hypertrophy = new sarcomeres in series with old
What kind of ventricular hypertrophy if there is pressure overload?
concentric hypertrophy = new sarcomeres in parallel with old
What compensatory mech in HF?
hypertrophy --> increase ventricular mass --> increase atrial pressure
frank-starling --> increase ventricular end diastolic volume --> increase atrial pressure
What are the 3 neurohormonal systems that are compensatory mech in heart failure?
- adrenergic nervous system [sympathetic]
What is equation for systemic vascular resistance?
BP [svr] = CO * TPR
What are clinical symptoms of left sided heart failure?
- orthopnea [SOB when lie flat]
- PND [Paroxysmal nocturnal dyspnea]
What are clinical symptoms of right sided heart failure?
- right upper quadrant pain
What are clinical findings of left ventricle failure?
- pleural effusion
- systolic/diastolic dysfunction [S3/S4]
What are clinical findings of right ventricle failure?
- peripheral edema
What is first heart sound [S1]? Where is it loudest?
mitral and tricuspid valve closure
loudest at mitral area
What is 2nd heart sound [S2]?
aortic and pulmonary valve closure
loudest at left sternal border
What is 3rd heart sound [S3]?
in early diastole during rapid ventricular filling phase
associated with increased filling pressure and more common in dilated ventricles
What is 4th heart sound [S4]?
in late diastole
high atrial pressure, associated with ventricular hypertrophy
What are 4 stages of chronic HF?
Stage A: high risk of HF without structural heart disease or symptoms
Stage B: heart disease with asymptomatic LV dysfunction
Stage C: prior or current symptoms of HF with structural heart disease
Stage D: advanced heart disease and severely symptomatic or refractory HF
Why do you check CBC lab in CHF?
to check for anemia
Why do you check electrolyte/creatine lab in CHF?
before you start high dose diuretic
Why do you check fasting glucose lab in CHF?
diabetes can contribute to CHF
Why do you check thyroid function lab in CHF?
thyrotoxicosis and hypothyroidism can cause CHF
Why do you check iron lab in CHF?
check for hereditary hemochromatosis
Why do you check ANA [antinuclear antibody] lab in CHF?
check for autoimmune [SLE = lupus]
Why do you check viral studies in CHF?
check for viral myocarditis
Why do you check BNP lab in CHF?
usually elevates (>400) in pt with HF
What should you look for in HF chest xray?
- vascular redistribution interstitial edema
- alveolar edema
- pleural effusion
What should you look for in EKG in HF?
- ischemic heart disease
- 1st AV block, left anterior fascicular block
- idiopathic dilated cardiomyopathy [LVH]
What should you look for in echo in HF?
- get ejection fraction to help determine what type of HF
- tells you about structure/function of LV/RV and valves
When should you do coronary artery angiogram in HF? WHat does it tell you?
- in pt with HF and angina or significant ischemia or suspected CAD
measures CO, LV dysfunction, LV end diastolic pressure
How do you treat pulmonary/systemic congestion?
give diuretic = get rid of fluid
How do you treat low cardiac output in HF?
give vasodilator or ionotropic drugs
What is action/use of diuretics?
- promote elimination Na and water via kidney
- reduces venous return to heart and relieves pulmonary congestion
-- no mortality benefits just provides symptomatic relief
What happens if over diuresis?
fall in CO
What is action of nitrates?
- venous vasodilators
- increase venous pooling, decrease venous return to heart
What is action of hydralazine?
- arteriolar vasodilators
- decreases systemic vascular resistance [SVR]
- decreases LV afterload
- increases stroke volume
What is action of ACEI/ARBs?
arteriolar and venous dilators
What is action of ace inhibitors?
- inhibit formation angiotensin II and decreases aldosterone
- improves Na elimination --> decreased intravascular volume
What should you use if ace inhibitor not tolerated?
What is action of beta blockers?
improve overall and event free survival in class 2, 3, 4 CHF
What are contraindications of beta blockers?
- HR < 60/min
- symptomatic bradycardia
- peripheral hypoperfusion
- 2nd or 3rd degree AV block
What is digoxin?
inhibits Na/K ATPase causing indirect inhibition Na/Ca exhanger
- increases intracellular Ca
- increased contractility
- use to control HF symptoms
- decrease hospitalizations in HF
- no benefit to mortality
What are possible inotropes in HF?
- phosphodiesterase inhibitiors
- beta agonists
What is action of spironolactone and eplerenone?
- aldosterone antagonists
- increase diuresis, improve survival CHF
What is use of implantable defibrillator in HF?
- mortality of HF due to sudden cardiac death caused by arrhythmias
- increases survival benefit esp with cardiomyopathy and LVEF
What is use of cardiac resyncronization?
- increases LV systolic function
- increase exercise capacity
- decrease frequency of HF exacerbation
What do you use to treat diastolic HF dysfunction?
- problem is not a weak pump its a stiff un-relaxing pump
- treat underlying HTN or pericardiectomy
- don't give inotrope, be careful with diuretic
What is acute decompensated HF?
fluid goes into lungs secondary to high LA pressure and pulm venous and capillary pressures
--> cardiogenic pulmonary edema
What are causes of acute decompensated HF?
- acute mechanical event: rupture chordae tendinae/acute MR
- volume overload
- valvular defect [aortic stenosis]