Heart Failure Flashcards
What is a syndrome that exists when the heart is unable to pump sufficient blood to meet the metabolic needs of the body?
Heart failure
What are the characteristics of heart failure?
Characterized by elevated cardiac filling pressures (preload) and/or inadequate oxygen delivery, at rest or during stress, caused by cardiac dysfunction
What is an impairment of the contraction of left ventricle such that stroke volume (SV) is reduced for any given end-diastolic volume (EDV) or filling pressure?
Systolic dysfunction
What is the left ventricular ejection fraction?
SV/EDV
Normal: 50 - 70%
Objective measure of systolic function
What is left ventricular ejection fraction measured by?
ECHO (Echocardiogram)
RNV (Radionuclide ventriculogram)
cardiac catherization
What is characterized by ventricular filling rate (increased HR) and the extent of filling are reduced (decreased EDV) or a normal extent of filling associated with an inappropriate rise of ventricular diastolic pressure, but a normal EF is maintained?
Diastolic dysfunction
Why is normal EF maintained during diastolic dysfunction?
Because the left ventricle is still functioning so the ejection fraction but the ability to fill is affected.
What is cardiac output?
Heart rate (HR) x Stroke volume (SV)
What is heart rate controlled by?
By ANS (SNS and PNS), typically under vagal (PNS) tone
What is SV dependent on?
Preload, afterload, and contractility
What is preload?
=Left ventricular end-diastolic pressure (LVEDP)
Represented clinically by pulmonary capillary wedge pressure (PCWP)
Pre-filling pressure determines by venous return and atrial contraction
What is afterload?
=Systemic vascular resistance (SVR)
aka afterload resistance to ejection, regulated by wall tension,
What are the causes of ischemic heart failure?
Coronary Artery Disease
Myocardial ischemia
Myocardial infarction
What are the causes of non-ischemic heart failure?
HYPERTENSION Primary myocardial muscle dysfunction Valvular abnormalities Structural damage and/or damage to myocardial walls Dilated Cardiomyopathy
What are the compensatory mechanisms of heart failure?
- -Increased SNS activity: Increase HR and SVR which increases BP
- -Frank-Starling mechanism: Increased LVEDP = Increased SV
- -Activation of Renin-angiotensin-aldosterone system (RAAS)
- -Myocardial Remodeling:Concentric hypertrophy, Eccentric hypertrophy
What are the components of neurohormonal mechanism of CHF?
Endothelin Vasopressin (ADH) Atrial Natriuretic Peptide Endothelium-derived Relaxing Factor RAAS SNS
What are the direct toxic effects of NE and AT2?
Arrhythmias
Apoptosis
What is the neurohormonal mechanism of CHF effects?
- -Impaired diastolic filling
- -Increased myocardial energy demand
- -Increased pre- and afterload
- -Platelet aggregation
- -Desensitization to catecholamines (don’t respond as well to NE and EP)
What happens when the heart starts failing?
The body starts to try and compensate making it worse and something has to be done or the patient will die.
What are the symptoms of LVF?
SOB, DOE, orthopnea, cough, PND, fatigue and weakness, memory loss and confusion, anorexia
What are the signs of LVF?
tachy, rales, diaphoresis, S3 and S4 gallops
What are the symptoms of RVF?
weight gain, transient ankle swelling, abdominal distention, anorexia, nausea
What are the signs of RVF?
JVD. Edema, hepatomegaly, ascites, (+) hepatojugular reflux
What NYHA function classification class involves no limitations of activity; ordinary activity does not cause symtoms?
Class I
What NYHA function classification class involves limitation of activity; ordinary activity results in symptoms?
Class II
What NYHA function classification class involves marked limitations of activity; less than ordinary activity results in symptoms?
Class III
What NYHA function classification class involves being unable to carry on any physical activity without discomfort; symptoms at rest?
Class IV
What is class I ACC/AHA CHF guidelines?
Conditions for which there is evidence and/or general agreement that a given procedure/therapy is useful and effective.
What is class II ACC/AHA CHF guidelines?
Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of performing the procedure/therapy
What is class IIa ACC/AHA CHF guidelines?
Weight of evidence/opinion is in favor of usefulness/efficacy
What is class IIb ACC/AHA CHF guidelines?
Usefulness/efficacy is less well established by evidence/opinion
What is class III ACC/AHA CHF guidelines?
Conditions for which there is evidence and/or general agreement that a procedure/therapy is not useful/effective and in some cases may be harmful.
What are the three levels of evidence that the ACC/AHA CHF guidelines?
Level A if the data were derived from multiple randomized clinical trials
Level B when data were derived from a single randomized trial or nonrandomized studies
Level C when the consensus opinion of experts was the primary source of recommendation
What are the class I ACC/AHA guidelines for diuretics?
Class I: diuretics and salt restriction are indicated in patients with current or prior symptoms of HF and reduced LVEF who have evidence of fluid retention (Level of Evidence: C)
What is useful to decrease preload?
Thiazides can be used if GFR>30ml/min: Distal tubule
Loop diuretics- DOC: Ascending Loop of Henle, Dose BID or daily
Resistance: use combo therapy
Monitor K+, Mg2+, BUN, SCr
What are the class IIa ACC/AHA guidelines for diuretics?
Class IIa-Digitalis can be beneficial in patients with current or prior symptoms of HF and reduced LVEF to decrease hospitalization for HF (Level of evidence: B)
What is used for class IIa?
Digoxin
Digoxin- hemodynamic effects in HF
Increased CO Decreased PCWP (wedge pressure) Increased LVEF (left ventricular ejection fraction)
Digoxin- neurohormonal effects
Vagomimetic action Improved baroreceptor sensitivity Decreased NE serum concentration Decreased activation of RAAS Direct sympathoinhibitory effect Increased sympathetic CNS outflow at high doses Decreased cytokine concentration Increased release of ANP and BNP
Digoxin- electrophysiological effects
SA node: slowing of sinus rate
AV node: slowed conduction
Atrium: No effect or decreased refractory period
Ventricles and Purkinje fibers: no effect at low therapeutic doses
Digoxin- adverse effects
Inotropic (increase stroke volume) effect seen at low concentrations
Women may not derive benefit
Conditions likely to alter SDC (metabolism of digoxin) or predispose to toxicity:
Changing renal function
Drug interactions
hypokalemia
Digoxin- drug interactions
- -Amiodarone and quinidine decrease digoxin clearance
- -Empirically decrease digoxin dose by 50%
- -Diltiazem, verapamil, Abx, azole antifungals, propafenone decrease digoxin clearance
- -LASIX(furosimide)
What is most likely to make a patient on digoxin toxic?
Hypokalemia
Digoxin- toxicity
EKG changes: ventricular arrhythmias, heart block
Visual changes, anorexia, N/V/D, abdominal pain, confusion, HA
What do you treat digoxin toxicity with?
Digoxin Immune Fab (Digibind)
Binds with molecules of digoxin; excreted via kidneys
What is the ACC/AHA guidelines for ACEI for Class I?
Class I: ACEI are recommended for all patients with current or prior symptoms of HF and reduced LVEF, unless contraindicated. (Level of Evidence: A)
Why are ACEI so beneficial?
Because the body is trying to use angiotensin II to compromise and making it worse
What are the ACE inhibitors?
Enalapril Captopril Lisinopril Quinapril Ramipril Fosinopril
What was the results from the ATLAS study comparing “high” and “low” dose lisinopril for effects on mortality?
No difference in mortality
High-dose reduced hospitalizations for any cause (-13%) and for HF (-24%); p<0.05
ACEI- monitor
See patients in 1-2 weeks to monitor SCr, K+, BP and symptoms
ACEI- drug interactions
Aspirin may interfere with efficacy, recommend low-dose ASA (<160mg) if necessary (good to know when patient is on both drugs, good for them to stick with the lowest dose of ASA)
ACEI- side effects
Renal impairment
Hyperkalemia
Hypotension
COUGH
ACEI- intolerance
Cough ~5-10% in caucasians of European descent; ~50% in Chinese
Angioedema in 0.3mg/dL) with severe HF, 5-15% with mild to moderate symptoms
–Decrease diuretic dose?
–Decrease dose of ACEI or d/c??
What is the class I alternative for ACEI- intolerance?
ARBs approved for treatment of HF (valsartan, candesartan, losartan) in patients with current or prior symptoms of HF and reduced LVEF who are ACEI-intolerant (Level of Evidence: A)
What is the class IIb alternative for ACEI-intolerance?
A combo of isosorbide dinitrate & hydralazine might be reasonable in patient with current or prior symptoms of HF and reduced LVEF who can’t take ACEI or ARB because of drug intolerance, hypotension, or renal insufficiency (Level of Evidence: C)- this should not be the first thing you think about doing for patients.
Not generally something you should do
What are the ARD drugs?
Candesartan
Losartan
Valsartan
What are the nitrates/hydralazines?
Isosorbide dinitrate
Hydralazine
Bidil
Nitrates/hydralazines- monitor
f/u 1-2 weeks post-initiation and with each dose increase to check BP and HR