Chronic Heart Failure Flashcards
What is the mortality rate of heart failure?
- up to 40-50% of patients with HF die within 5 years of diagnosis
What is heart failure?
a clinical syndrome with subsets of conditions due to cardiac dysfunction
- this occurs when the heart is unable to deliver adequate supply of oxygenated blood to meet the metabolic demands of the organs
- associated with the structural abnormality that develops over time secondary to a sudden or insidious injury
What kind of heart failure provides a reduced ejection fraction?
- systolic failure
Is the ejection fraction compromised in diastolic failure?
- it is
What conditions will decrease the contractility of the heart?
- rheumatic heart disease
- cardiomyopathy
- coronary heart disease/MI
What conditions will increase the after load of the heart?
- hypertension
- aortic stenosis
What conditions will increase the preload of the heart?
- increased sodium and water retention
- malfunction of the aortic valve
- drugs (steroids, NSAIDs)
What causes a high output failure?
anemia
Cardiac output is the function of what?
CO= SV x HR
What factors influence stroke volume?
- preload
- contractility
- after load
What is the definition of cardiac output?
- volume of the blood pumped out of the heart per minute
What is the definition of heart failure?
- those with an ejection fraction less than 40%
What is the definition of ejection fraction?
- fraction of blood ejected form the left ventricle
What is the formula for ejection fraction?
EF = (EDV - ESV) / EDV
What is the definition of the preload?
- degree of filling from the left atrium (venous return, end-diastolic volume)
What is the definition of the after load?
- arteriolar resistance the heart must pump against to eject stroke volume
What is the definition of the end diastolic volume?
- this is the volume that is filling the left ventricle at the end of the diastole
- this is used as the concrete measure of the preload
- need to have a normal functioning contractility in order to eject the normal stroke volume from the heart
What happens in the frank sterling relationship when a person has mild dysfunction?
- when the preload increases, you require a higher amount of pressure or preload to maintain the same stroke volume - you need to increase the preload significantly to have the same output
What happens in the frank sterling relationship when someone has severe dysfunction?
when someone has severe heart failure, you will never be able to achieve the same pressure no matter how much you increase the preload
What are the three general patterns of remodelling?
- concentric ventricular remodelling
- eccentric left ventricular hypertrophy
- mixed concentric/eccentric hypertrophy
Sarcomeres added in parallel adds to the ___________
thickness of the ventricular wall
What is eccentric hypertrophy?
- the sarcomeres here are being stretched here, the ventricles are being stretched here, ventricles are being enlarged but the wall thickness here is still unchanged
What does the body do to increase the preload?
- the body starts to retain water and salt, and the body activates the RAAS system
- angiotensin 2 accomplishes vasoconstriction and leads to water retention
What body attempts to maintain CO and BP by doing what?
Increasing preload
- increasing the venous retire in an attempt to increase CO
- sodium and water retention
- activation of the renin angiotensin system
Vasoconstriction
- increase after load
- increase systemic vascular resistance (sympathetic stimulation, activation of renin angiotensin system)
What are some of the compensatory mechanisms associated with cardiac heart failure?
- tachycardia and increased contractility
- sympathetic stimulation - neurohormonal stimulation
- compensatory release of hormones in response to hypovolemia - renin, NE, antidiuretic hormones
- in the long term these contribute to the progression of structural abnormalities
What does angiotensin 2 do?
- increase protein synthesis, cardiac myocytes hypertrophy
What causes a hypertrophied heart?
- diastolic heart failure
What causes a dilated heart?
- systolic heart failure
What is heart failure with reduced ejection fraction also known as?
- also known as systolic heart failure
What structural abnormalities are involved in heart failure with reduced ejection fraction?
- low output (congestive) heart failure
- hypo-functioning left ventricle, decreased contractility
- ventricles enlarge (dilate as retain blood)
What is heart failure with preserved ejection fraction known as?
- diastolic heart failure
What are the structural issues involved in heart failure with preserved ejection fraction?
- normal contractility and heart size
- impaired left ventricular filling during diastole
- left ventricular stiffness and inability to relax during diastole
- results in increased resting pressure within the ventricle
- the increased pressure impedes ventricular filling, therefore reducing stroke volume (EF preserved)
- can see with thickened left ventricle or stiff ventricle (restrictive cardiomyopathy)
Compensatory mechanisms eventually induce symptoms of heart failure due to what?
- vasoconstriction: leads to decreased CO
- increased HR: leads to increased oxygen utilization
- increased preload: leads peripheral and pulmonary edema
- decreased exercise tolerance
What are the main signs and symptoms associated with left sided heart failure?
PULMONARY CONGESTION
- dyspnea on exertion
- orthopnea
- paroxysmal nocturnal dyspnea
- pulmonary edema
What are the main signs and symptoms associated with right sided heart failure?
SYSTEMIC VENOUS CONGESTION
- organomegaly
- jugular venous distention
- hepatojugular reflex
- lower extremity peripheral edema
What are other non-specific findings associated with heart failure?
- weakness
- exercise intolerance
- fatigue
- CNS
- cold, pale, clammy skin
What is class 1 heart failure?
- uncompromised cardiac function
- able to perform ordinary physical activity
What is class 2 heart failure?
- slightly compromised
- ordinary physical activity results in symptoms
What is class 3 heart failure?
- moderately compromised
- less than ordinary physical activity results in symptoms
What is class 4 heart failure?
- severely compromised function
- symptoms may be present at rest
What are the signs on clinical exams of heart failure?
- auscultation of heart and lungs (rales of the lungs)
- edema
- jugular vein distention
- hepatojugular reflux
- dyspnea
- chest X ray
What are the symptoms of heart failure?
- weakness, fatigue
- exercise tolerance
What are the medical management strategies associated with heart failure?
- eliminate exacerbating factors
- control associated diseases
- restrict activity when acute
- sodium restricted diet
- exercise conditioning when stabilized
- drug therapy
What is the purpose of diuretics in CHF?
- relieve breathlessness and edema in patients with symptoms of signs of congestion
- reduce intravascular volume, deem, preload and pulmonary congestion
- achieve diuresis through inhibiting reabsorption of sodium in thick ascending limb and distal convoluted tubule
What diuretic works on the thick ascending limb?
loop diuretics
What diuretic works on the distal convoluted tubule?
- thiazide diuretics
In what stage of heart failure are diuretics always used?
- stage 3 and 4 heart failure
What is the dose of furosemide that should be used in those with CHF?
- initiate 20-40 mg daily
- increase the dose accordingly achieve edema free state (dry weight); once symptoms are relieved, use the lowed possible maintenance dose
- possible diuretic resistance is severe refractory HF - sodium/water reabsorption markedly increased
_____ diuretics are unlikely to be effective with significant renal dysfunction (eGFR <30 ml/min)
thiazide
Why are loop diuretics and thiazide diuretics usually used together?
– loop diuretics stop the adoption of Na in the ascending loop- by having both diuretics you are blocking the reabsorption in both the ascending and the distal loop
What is the usual dose of HCTZ?
- starting dose is 25 mg, usually dose up to 100 mg/day
What is the usual dose of metolazone?
- starting dose is 2.5 mg, usual dose is 2.5-10 mg/day
What are the adverse events associated with diuretics?
- volume depletion (leads to dehydration, and reduction in BP and CO)
- loss of K and Mg (can induce or potentiate digoxin toxicity)
- renal impairment
What is the biggest risk associated with diuresing too aggressively?
renal failure- you need to make sure that you are monitoring the creatinine clearance
What factors determine the efficacy of the diuretics?
- daily weight
- input/output
- jugular venous distention
- peripheral edema
- sitting/standing HR and BP
- organ congestion (pulmonary rales and hepatomegaly)
Renal function and electrolytes should be checked ______ after initiation and after dose increase
1-2 weeks
What is the rationale behind using beta blockers after HF?
- decreases the disease progression and all-cause mortality
- stops activation of RAAS
- slows remodelling of cardiac myocytes
What is the first line therapy after heart failure?
- beta blockers
- ACE inhibitors
What is the purpose of a positive ionotrope after an MI?
- it helps with the contractility of the heart
What is the choice of beta blockers by cardiologists?
- bisoprolol
- carvedilol
When should beta blockers be initiated those with heart failure?
- initiate when patients are stable and not in acute decompensated heart failure
- need to start with a very low dose
- increase dosage approx every 2 weeks
- aim for the highest dose tolerated
- avoid large dose reduction or abrupt withdrawal
- decrease dose if on ionotropes (d/c if patents are in cardiogenic shock)
What are the main AE associated with beta blockers?
- postural hypotension
- headache
- dizziness
- bradycardia
- bronchospasm
- fatigue
- decreased exercise tolerance and fluid retention
- insomnia, vivid dreams
- sexual dysfunction
- PAD, cold extremity
- caution in diabetic
What are the hemodynamic effects of ACEI?
- increase CO
- decrease preload
- decrease systemic vascular resistance
- decrease blood pressure
What are the hormonal effects of ACEI? (inhibit RAAS)
- decrease angiotensin II
- decrease aldosterone
- slow ventricular remodelling
What are the main adverse effects associated with ACEI?
- hypotension
- renal impairment
- hyperkalemia (concurrent use with K sparing diuretics, MRAs or K supplements, low salt substitutes with high K content)
- cough
- rash
- taste alterations
- angioedema (swelling of face, lips, tongue and larynx)
What ACE inhibitor is the most common to cause a rash as a side effect?
- captopril
What are the factors that will determines the efficacy of an ACEI?
- right and left sided symptoms
- exercise tolerance
- weight/fluid balance
How often should ACEI’s be monitored?
- should be monitored 1-2 weeks after dose initiation and 1-2 weeks after dose titration, then monitor every 3-4 months thereafter
What is the rationale for using mineralocorticoid/aldosterone receptor antagonists?
- aldosterone contributes to the sodium/water retention, sympathetic activation, myocardial and vascular fibrosis and other pathophysiologic effects seen in heart failure
When are mineralocorticoid/aldosterone receptor antagonists indicated?
- indicated for heart failure state 2-4 in addition to ACEI and BB
What are examples of MRAs?
- spironolactone
- eplerenone
What are the cautions behind using MRAs?
- hyperkalemia (risk increases with concurrent ACEI, renal impairment)
- exclude patients with SCr>220 mol/L
- caution if on digoxin (hyperkalemia will precipitate digoxin toxicity)
- male patients uncommonly develop breast discomfort or gynecomastia - consider switching to eplorenone
____ is the ARB shown to reduce cardiovascular mortality
candesartan
____ is the ARB shown to improve hospitalization rate due to HF
valsartan
Hydralazine and nitrate combination has shown to show a significant reduction in ____ and improvement in _____
reduction in mortality
improvement in exercise
What combination of antihypertensives should african americans be put on?
- ACEIs
- hydralazine/ISN combination
What is the rationale for using hydralazine/nitrate combination?
- vasodilation decrease cardiac work by overcoming detrimental effects of compensatory mechanisms
- achieved through reduction of preload (nitrates) and after load (hydralazine)
Hydralazine/nitrate combinations are generally used when a patient is unable to tolerate either _______
ACEI or ARB
What do angiotensin receptor neprilysin inhibitors (ARNI) act on?
- they act on RAAS and natriuretic peptides
What is the rationale for using ARNI?
- increase circulation of a-type natriuretic peptide and BNP by inhibiting neprilysin
- ANP and BNP enhances diuresis, natriuresis, myocardial relaxation and anti-modeling
- ANP and BNP also inhibits RAAS
- AT1 receptor blockage by ARB reduces vasoconstriction, sodium and water retention and myocardial hypertrophy
What is neprilysin and what does it do?
it is an enzyme that breaks down ANP and BNP- we are inhibiting neprilysin in the body so that we have more ANP and BNP peptides in the body
- these peptides promote diuresis and excretion of sodium- also increase the preload and the after load
What is the starting dose of sacubitril/valsartan?
- starting dose of 49/51 mg bid, target dose of 97/103 mg bid
- – should NOT be used at the same time as an ACEI, or within 36 hours of the last dose of ACEI
What are the clinical criteria to use an ARNI?
- NYHA class 2 and 3 HF
- reduced LVEF <40%
- patient has at least 4 weeks of treatment with a stable dose of an ACEI or an ARB
- in combination with a beta blocker and other recommended therapies, including an aldosterone antagonist
- initiation and up titration should be conducted by a physician experienced with the treatment of heart failure
What is the action of If channel inhibitors?
- inhibit f channels within SA node resulting in disruption of If ion current flow, thereby prolonging diastolic depolarization and reducing heart rate
- no effect on BP, myocardial contractility or AV conduction
What is the action of digoxin?
- increase force and velocity pf contraction through inhibition of Na-K-ATPase
- neurohormonal modulating effects through decreased sympathetic activity with digoxin concentration <1.0 mcg/L
- decreased AV conduction, used in AF and other atrial arrhythmias
Digoxin is a _____ ionotrope
positive
Digoxin is effective in heart failure associated with what?
- heart failure associated with fast atrial rate, severe HF, S3 gallop, low EF and enlarged heart size
- no mortality benefit
- decreases rate of hospitalization
What are the benefits of digoxin?
- improves symptoms, exercise performance, decrease hospitalizations
- improves quality of life
What is the role of digoxin in HF therapy?
- use in patients with persistent symptoms despite maximized use of vasodilators and diuretics
What are the toxicity symptoms of digoxin?
- noncardiac: N/V, confusion, altered colour vision, weakness, dizziness
- cardiac: AV conduction disturbances
- can very easily push a person into a dysarrhythmia
What are the factors that affect digoxin activity or toxicity?
- electrolyte disturbances
- renal function- decreased elimination
- drug interactions
(can increase bioavailability: tetracycline, erythromycin
can decrease bioavailability: antacids, cholestyramine
can decrease elimination: quinidine, verapamil, amiodarone
drugs that decrease K or Mg: diuretics) - elderly
- hypothyroidism
What is the treatment of digoxin toxicity?
- withdrawal of digoxin
- correction of electrolyte abnormalities
- anti-arrhythmic agents
- pacemaker
- digoxin specific antibodies
- oral activated charcoal
What are the properties of hawthorn extract?
- inotropic, vasodilating, lipid-lowering, antioxidant, anti-inflammatory
What is the evidence behind using hawthorn extract for HF?
- modest increase in exercise tolerance - uncontrolled trials and case series
What is the action of coenzyme Q10?
- component of the electron transport chain in the mitochondria
- micronutrient
- decreased levels in HF
- small studies- mixed results
What are some common drugs to avoid in HF?
- antiarrhythmic agents (pro arrhythmia, negative ionotropic effects, increased mortality)
- non-dihydropyridine calcium antagonists (direct negaitve ionotropic effects, contraindicated in patients with systolic chronic heart failure)
- TCAs (pro arrhythmic potential)
- NSAIDS (inhibit effects of diuretics and ACEI, cause salt and water retention and can worsen both cardiac and real function)
- corticosteroids (AE on salt and water retention)
- doxorubicin, trastuzamab (dose dependent cardiotoxicity)
What are some ways to non-pharmacologically manage HF?
- exercise
- salt and fluid restriction
- monitor daily morning weight
- no more than 1 alcoholic drink per day
- smoking cessation
- influenza and pneumonococcal vaccination
- aggressive risk reduction
- patient education is key (drug adherence, fluid and salt restriction)
