Cardiology
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- Created by: LBCW0502
- Created on: 06-04-21 16:14
What is heart failure? (1)
A clinical syndrome characterized by typical symptoms (e.g., breathlessness, ankle swelling and fatigue) that may be accompanied by signs (e.g., elevated jugular venous pressure, pulmonary crackles and peripheral oedema)
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What is heart failure? (2)
Caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/ or elevated intracardiac pressures at rest or during stress
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How do we measure the heart's pumping ability?
Measure the ejection fraction of the left ventricle
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What is the value for normal EF?
>55%
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What is the value for reduced EF?
<40% (patients with an EF 40-50% range represent a grey area)
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What is heart failure with a reduced ejection fraction?
Enlarged and weakened ventricles. Reduced force of contraction due to overloading of the left ventricle. This leads to muscle contraction becoming less efficient. Larger heart.
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What is heart failure with a preserved ejection fraction?
Stiff ventricles fill with less blood than usual
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In a failing heart, what are the key neurohormonal systems activated? (1)
As cardiac output decreases, the heart tries to compensate by activating two key systems: RAAS. Renin is secreted by the kidneys in response to low blood volume. Angiotensin-II causes peripheral vasoconstriction and aldosterone causes sodium retention
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In a failing heart, what are the key neurohormonal systems activated? (2)
Sympathetic NS - baroreceptors in aortic arch detect reduction in arterial pressure and increase sympathetic activity. Angiotensin II causes NA to be released from nerve endings and adrenaline from adrenal glands. Increased HR and force of contraction
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In a failing heart, what are the key neurohormonal systems activated? (3)
NA causes systemic vasoconstriction increasing pre-load
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What is the Frank-Starling Law?
CO = HR x SV. The ability of the heart to change its force of contraction and stroke volume in response to changes in venous return.
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How do we diagnose heart failure? (1)
Patient history, signs and symptoms, chest x-ray, echocardiogram, NTproBNP (natriuretic peptide, prohormone, secreted by cardiomyocytes, due to stretching – could also be due to kidney function, PE, HTN).
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How do we diagnose heart failure? (2)
NT-proBNP – used as a rule out test. Above 2000 – urgent referral and have echo-cardiogram (within 2 week target). Within 400-2000 – seen within 6 weeks. <400 – less likely to be heart failure, look at other causes of symptoms
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What are the symptoms of heart failure?
Increased time to recover after exercise, paroxysmal nocturnal dyspnoea, shortness of breath, orthnopnoea, reduced exercise tolerance, fatigue
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What are the signs of heart failure?
Elevated jugular venous pressure, tachycardia, peripheral oedema, irregular pulse, creptiations/wheeze
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What is the New York Heart Association Classification System? (1)
Class 1 (No limitation of physical activity. Ordinary physical activity does not cause undue breathlessness, fatigue or palpitations).
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What is the New York Heart Association Classification System? (2)
Class II - slight limitation of physical activity. Comfortable at rest but ordinary physical activity results in undue breathlessness, fatigue or palpitations
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What is the New York Heart Association Classification System? (3)
Class III - Marked limitation of physical activity. Comfortable at rest but less than ordinary physical activity results in undue breathlessness, fatigue or palpitations
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What is the New York Heart Association Classification System? (4)
Class IV - Unable to carry on any physical activity without discomfort. Symptoms at rest can be present. If any physical activity is undertaken, discomfort is increased
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What are the common causes of heart failure?
Coronary artery disease, congenital heart disease, valvular disease, arrhythmias, cardiomyopathy, hypertension
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What are the aims of heart failure treatment?
Relieve signs and symptoms. Prevent hospital admission. Improve survival. Improve the quality of life. Prevent disease progression. (Most clinical trials are based on HFrEF)
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Which medicines are used in HFrEF?
ACE-I (or ARB, hydralazine, ISMN), beta blockers, MRA (spironolactone/eplerenone), sacubitril/valsartan, ivabradine, digoxin and diuretics
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Outline the pathway for the RAAS
Bradykinin (cough, natriuresis, angioedema, vasodilation) - ACE - inactive metabolite. Angiotensinogen - renin - angiotensin I - ACE - angiotensin II - AT1 (HTN, vasoconstriction, aldosterone - decreased water/Na secretion, increased K secretion), and AT2
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Describe the mechanism of action of ramipril
Inhibits ACE to prevent production of angiotensin II to prevent vasoconstriction
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Describe the mechanism of action of losartan
Binds to angiotensin II receptor (type 1) to prevent the production of aldosterone
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Why are ACE-Is used in HF?
ACE-Is have been shown to reduce mortality and hospitalization in patients with HFrEF. They should be up-titrated to the maximum tolerated dose
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What are the adverse effects of ACE-Is?
Worsening renal function, hyperkalemia, symptomatic hypotension, cough, angioedema (rare)
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What are the contraindications of ACE-Is?
Angioedema, renal artery stenosis, pregnancy
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What is the washout period between stopping an ACE-I and starting Sacubitril / Valsartan?
36 hours
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Describe features of Sacubitril / Valsartan
Entresto. A combination drug of neprilysin inhibitor (sacubitril) which prevents the breakdown of the natriuretic peptide to improve diuresis and symptoms, and angiotensin II receptor blocker (valsartan)
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Which beta-blockers are licensed in HFrEF?
Bisoprolol: Highly b-1 selective adrenoceptor blocker (“cardioselective”). Carvedilol: Non-selective b-blocker, selective a-1 receptor blockade (reduces peripheral vascular resistance). Nebivolol: Selective beta-1-adrenoceptor blocker, mild vasodilating p
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What are the adverse effects of beta-blockers?
Bradycardia, fatigue, peripheral vasoconstriction, impotence, and exacerbation of asthma
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What are the contraindications of beta-blockers?
Severe brittle asthma, uncontrolled HF, heart block, sinus bradycardia (HR < 50bpm)
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What do you need to monitor when starting/increasing an MRA (i.e. spironolactone and eplerenone)?
Kidney function, potassium levels, side effects, blood pressure (don't need to check FBC)
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What are the adverse effects of MRAs?
Hyperkalaemia, hyponatraemia, symptomatic hypotension, GI upset, gynecomastia and impotence (with spironolactone). Eplerenone is more selective for mineralocorticoid activity therefore does not have hormonal adverse effects
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What are the contraindications of MRAs?
Hyperkalaemia, severe renal impairment, Addison's disease, hyponatremia (Na+ <135mmol/l), severe hepatic impairment
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State features of loop diuretics
No evidence of mortality benefit to patients. Not disease-modifying but improves QoL by reducing symptoms. Reduces blood volume/venous pressure (Na/water excretion), cardiac filling (reduce pre-load), arterial dilatation (reduce after-load). Decreases SV/
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What are the other recommendations for patients with HF?
Smoking cessation, avoid alcohol, reduced saturated fats, low salt diet, daily weights, limit fluid intake, annual flu vaccine, cardiac rehab. Adherence to medicines. Monitor symptoms daily
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Which medicines should be avoided in HFrEF? (1)
Glitazones (worsen HF/increase risk of hospitalization). Verapamil and diltiazem (negative inotropic effect causes worsening HF). NSAIDs and COX-2 inhibitors (cause Na/water retention and cardiotoxicity). Doxazosin (increase risk of HF).
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Which medicines should be avoided in HFrEF? (2)
ACE-I + ARB combination (increased risk of renal dysfunction and hyperkalemia). Herbal medications (caution - review for interactions)
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Which new drug is recently licensed for use in HFrEF?
Dapagliflozin. Initially licensed for type 2 diabetes mellitus but have consistently been found to improve heart failure outcomes. DAPA-HF has recently been licensed
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What are the two types of devices for cardiac resynchronization therapy?
CRT-D (cardiac resynchronization therapy defibrillator). CRT-P (cardiac resynchronization therapy pacemaker).
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Other cards in this set
Card 2
Front
What is heart failure? (2)
Back
Caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/ or elevated intracardiac pressures at rest or during stress
Card 3
Front
How do we measure the heart's pumping ability?
Back
Card 4
Front
What is the value for normal EF?
Back
Card 5
Front
What is the value for reduced EF?
Back
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