Congestive heart failure Flashcards
What is atherosclerosis?
- The process of progressive thickening and hardening of the walls of medium and large-sized arteries as a result of cholesterol deposition
Main pathological condition that causes ischaemic heart disease
How can atherosclerosis cause a heart attack?
- atheroma/plaque narrows lumen
- patients experience angina
- atheroma is very thrombogenic
- if blood comes into contact thrombus/clots can form which can completely occlude the artery
- it will cause heart attack/acute myocardial infarction
What are non-modifiable Cardiovascular Disease Risk Factors?
- Age
- Male sex
- Family History
- Low Birth weight
- Premature Birth
What are modifiable Cardiovascular Disease Risk Factors?
- Hypertension
- Smoking
- Diabetes mellitus
- Hypercholesterolemia
- Obesity
- Physical inactivity
Define heart failure?
- “A complex of symptoms—shortness of breath, fatigue, and congestion
- Due to an impairment of the heart’s ability to (contract) empty* or (relax) fill* properly,
- leading to inadequate perfusion of tissues during exertion (causes forwards symptoms), and retention of fluid (causes backward symptoms)”
What are some causes of heart failure?
• Decreased contractility, can be due to o Coronary heart dis. o Cardiomyopathies: Viral myocarditis o Drug: ß-adrenergic blockers o Arrhythmias
• Increased Afterload
o Hypertension
o Valvular disease
o HOCM (hypertrophic obstructive cardiomyopathy)
• Increased Output
o Anaemia
o Hyperthyroidism
o AV shunts
What is Acute Decompensation?
Means the patient had been treated, symptoms resolved but there’s a reappearance of symptoms
What can cause acute decompensation?
- Discontinuation of treatment
- ACS (new event)
- Arrhythmias (AF)
- Infection
- Anaemia
- Pulmonary Embolism
How does the New York Heart Association (NYHA) classify heart failure?
Class I
• No limitation of physical activity
• Ordinary physical activity does not cause SOB (dyspnoea) or fatigue
Class II
• Slight limitation of physical activity
• Ordinary physical activity result in dyspnoea or fatigue
Class III
• Marked limitation of physical activity
• Less than ordinary physical activity result in dyspnoea or fatigue
Class IV
• Inability to carry out any physical activity without discomfort
• Symptoms are present at rest
How is heart failure diagnosed?
- NT-proBNP (ANP derivative) – measured in the urine, if <400 ng/L then HF is unlikely
- ECHO cardiogram (ultrasound of heart): can show HFrEF (heart failure with reduced ejection fraction) or HFpEF (heart failure with preserved ejection fraction)
- Cardiac MRI (CMR)
- Other tests: ECG, CXR, U&Es, ABGs, D-dimer
- Look for cause(s) of decompensation: Troponin for ACS, ECG for Arrhythmias, etc..
What is ejection fraction?
- Ejection fraction (EF) is a percentage of how much blood the left ventricle pumps out with each contraction.
- EF of 60% means that 60% of the total amount of blood in the left ventricle is pushed out with each heartbeat – 50% is normal
- EF also called Fractional shortening
What are the types of HF
• Failure of filling of blood:
o Aka Diastolic HF in the past
o HFp EF (Heart failure with preserved ejection fraction >50%)
o HFpEF patients are older, female, hypertension, obesity, anemia, and AF
• Failure of ejection of blood:
o Systolic HF
o HFr EF (Heart failure with reduced ejection fraction ≤40%)
• HFmrEF (mid-range ejection fraction) – in between normal of 50 and abnormal of 40 (41-49%), now name changed to mildly reduced ejection fraction
Aims of heart failure treatment?
- Removal of the underlying or precipitating causes
- Improving survival & reducing mortality
- Relief of symptoms (& Improvement in quality of life)
- Prevention of re-admissions to hospital, recurrent ischaemic events, and further deterioration in left ventricular function
Ways of treating HF by removal of precipitating causes?
- Treatment of hypertension
- Correction of valvular lesions
- Treat anaemia, thyrotoxicosis, fluid overload, increased dietary salt intake
- Improve compliance with treatment
- Drugs: beta-blockers, salt-retaining drugs (NSAIDs, steroids) – can cause/worsen heart failure
What drugs may be used to treat heart failure?
- ACE inhibitors
- Beta Blockers
- Angiotensin receptor antagonists (ARBs)
- Aldosterone antagonists
- Hydralazine/nitrate
- Diuretics
- Digoxin
- Sacubitril-Valsartan (ARNI)
- SGLT2 inhibitors
How do beta blockers and renin inhibitors work?
Prevent ANG I production - interferes with the RAAS system
How do ACE inhibitors work?
Prevent ANG II production - interferes with the RAAS system
- Reduce angiotensin II levels thus induce arteriolar vasodilatation
- Reduce systemic vascular resistance
- Reduce norepinephrine release
- Decrease sympathetic activity
- Decrease aldosterone secretion
- Suppress vasopressin release
- Increase bradykinin levels
How do Angiotensin receptor antagonists/blockers (ARBs) work?
Prevent ANG II from binding to its receptor - no vasoconstriction or aldosterone
• Block angiotensin II type 1 receptors
Name a study for ACE inhibitors and say what it showed?
Acute Infarction Ramipril Efficacy (AIRE):
- Effect of Ramipril on mortality and morbidity of survivors of acute MI with HF
- 2006 patients, EF ≤ 35% post-MI
- Follow-up average 15 months
- Overall mortality significantly reduced 27%
- Development of severe heart failure reduced by 23%
Other uses for ACEi?
- Hypertension
- Post-Myocardial Infarction (LVD)
- Diabetic nephropathy
- Diabetic retinopathy
Side effects for ACEi?
- First dose may cause hypotension
- Cough
- Angioedema – most dangerous, swelling of lips and tongue
- Rash
- Neuropathy
- Deterioration of renal function (in RAS)
Contraindications for ACEi
- Pregnancy & breast feeding
- Renal artery stenosis (bilateral, single k)
• Caution with patients that have: o Peripheral vascular disease o Low BP o High dose diuretic, hypovolaemia o Age >70 ys o Creatinine >150µmol/L o +NSAIDs
Alternatives if ACEi are contraindicated or untolerated?
- Other vasodilators: Angiotensin Receptor Blockers e.g. Candesartan, Losartan
- Hydrallazine & Nitrates
- Angiotensin receptor-neprilysin inhibitor (ARNI )
What study showed ARBs were effective?
ELITE study: (Evaluation of Losartan In The Elderly)
• 722 patients with CHF (congestive heart failure)
• Designed to study effects of losartan on renal function (vs captopril)
• All cause mortality was 46% lower
How do beta-blockers reduce chances of HF?
- Reduce sympatho-adrenergic activity
- Reduce afterload
- Decrease myocardial oxygen demand – important for patients that have angina
- Reduce ventricular remodelling
- Reduce renin release
- Coronary and peripheral vasodilatation
- Negative inotropic effect/direct weaking affect on the myocardium – can make HF worse,
What study shows that beta-blockers are effective for treating HF
MERIT-HF: • 39991 patients in USA & Europe • NYHA II- III • Metoprolol-XL 12.5mg up to 200mg od • Total mortality: Decreased by 34% • CV mortality: Decreased by 38% • Sudden death: Decreased by 41%
Benefit not clear in class I or class IV
Side effects of beta blockers?
- Fatigue
- Sleep disturbances
- Bradycardia
- Hypotension
- Heart failure (start low doses, slowly increase)
- Conduction disorders
- Bronchospasm
- GI disturbances
Cautions & Contraindications for beta blockers?
- Asthma, COPD – can be made worse
- Uncontrolled heart failure
- Severe bradycardia
- Hypotension or shock
- Pheochromocytoma (unless with a-blocker)
- Peripheral vascular disease
What is a diuretic used for HF?
Spironolactone
How does Spironolactone work?
- Acts through its active metabolite, canrenone
* Blocks aldosterone receptors on the distal convoluted tubule
What study shows spironolactone was effective?
RALES (Randomised Aldactone Evaluation Study)
• 1663 patients, severe heart failure (NYHA IV) (LVEF<35%)
• Rx ACEi + Loop diuretic ± Digoxin
• Spironolactone 25mg - 50mg od
• Total mortality : 30% reduction p<0.001
• Cardiac mortality : 31% reduction
• Hospitalization: 35% reduction
What are the side effects of spironolactone?
o Gynaecomastia in males (painful) – doesn’t reverse
o Testicular atrophy
o Menstrual irregularities
o Hyperkalaemia (esp. renal impairment
What aldosterone blocking agent is also used for HF?
Epleronone:
• Eplerenone produces less painful gynaecomastia than spironolactone
What study proves epleronone as effective?
EPHESUS study:
• 13% reduction in mortality from cardiovascular causes or hospitalization
• 21% reduction in sudden death
• Can cause hyperkalaemia and renal dysfunction
What does digoxin do?
- Inhibits Na+-K+ ATPase pump, inactivating Na+-Ca2+ exchanger, increasing Ca 2+
- Increases force of contraction
• Other effects
o Decrease in AV conduction
o Increase in vagal activity
o Decrease in heart rate
What are the uses of digoxin?
- Slowing ventricular rate in rapid AF (atrial fibrillation)
* Treatment of heart failure in patients who remain symptomatic despite optimal doses of diuretics and ACE inhibitors
Side effects of digoxin
o Nausea, vomiting, arrhythmias, confusion
o Toxicity enhanced by hypokalaemia
What trials show digoxin efficacy?
- Digoxin has no effect on mortality (DIG trial)
- Clinical effects are not dramatic
- Withdrawal of digoxin may cause clinical deterioration in 1/4 of patients stable on digoxin and diuretic ±ACEi (RADIANCE and PROVED trials)
What do diuretics do in treating HF?
- Only relieve symptoms
- Relieve circulatory congestion and pulmonary and peripheral oedema
- Reduce atrial and ventricular diastolic pressure
- Do not improve LV dysfunction
- Little impact on mortality
What are the side effects of Diuretics?
• Metabolic effects: o Hypokalaemia (low K) (arrhythmias) – most dangerous o Hyperglycaemia (high glucose) (diabetes) o Hyperuricaemia (high uric acid) (gout)
• Social disruption
o Frequency, urgency, incontinence
How are Hydralazine & Nitrate used for heart failure?
- Hydralazine in combination with nitrate (especially if the patient is of African or Caribbean origin and moderate to severe heart failure [NYHA class III–IV]
- V-HeFT (Vasodilator-Heart Failure Trial) - 43% reduction in mortality
- A-HeFT (African American-Heart Failure Trial)
What are Non-Drug Therapy of Heart Failure?
- Cardiac-Resynchronization Therapy (RCT)
- Surgery
How does Cardiac-Resynchronization Therapy (RCT) work?
- Using atrial-synchronized bi-ventricular pacing – different pacing wires in ventricles to make the heart work as one unit
- Indicated for patients with severe symptoms and intra-ventricular conduction delays i.e. QRS ≥120 msec
- Leads to dys-synchronous LV contraction, impaired emptying, MR
- Can reduce symptoms, improve functional capacity, reduce hospitalizations and increase survival
How does surgery work?
- Ventricular Assist Devices – a pump put into the left ventricle and aorta
- Cardiac Transplantation
- Xeno Cardiac transplantation (genetically modified pig heart) 7th January 2022
