Heart Failure and Treatment Flashcards
What is heart failure?
- The failure of the heart to pump blood at a sufficient rate to meet metabolic requirements. Characterised by typical haemodynamic changes and neurohumoral activation.
What are the common and less common causes of heart failure in the uk?
Common - Coronary artery disease, hypertension, idiopathic, toxins (alcohol/chemotherapy), genetics.
Less common - Valve disease, infections (Chaga’s), congenital heart disease, metabolic (hemochromatosis, amyloidosis) and pericardial disease (TB)
What are the different types of heart failure
Old nomenclature = Chronic/congestive or acute/decompensated.
- Reduced ejection fraction HF (Systolic HF): More likely to occur in younger patients, often men, due to coronary aetiology.
- Preserved ejection fraction HF(Diastolic HF so reduced filling): Older patients, commonly women due to hypertensive aetiology.
Explain the pathophysiology of heart failure
Myocardial injury leads to left ventricular systolic dysfunction.
- This causes perceived reduction in circulatory volume and pressure as the heart isn’t effectively pumping.
- This triggers neurohumoral activation: SNS, RAAS, arginine vasopressin, natriuretic peptides.
- This will then cause systemic vasoconstriction (making it harder for heart to pump against increased pressure) and cause renal sodium and water retention which will increase blood volume. Further causing left ventricular dysfunction.
Explain the signs and symptoms of heart failure
Symptoms - Orthopnoea, paroxysmal nocturnal dyspnoea and cough. Ankle swelling, tiredness and fatigue.
Signs - Peripheral oedema, elevated JVP, third heart sound, displaced apex beat, pulmonary oedema and pleural effusions
Describe the New York Heart Association (NYHA) claassification of heart failure
Class 1 - No symptoms or limitation with normal activity.
Class 2 - Mild symptoms/limitations with normal activity.
Class 3 - Marked limitation in activity due to symptoms.
Class 4 - Severe limitations and may experiance symptoms at rest.
What are the investigations for all patients suspected heart failure?
- ECG,
- Chest X ray (exlude lung pathology)
- Echocardiogram (look at chamber size, systolic and diastolic function and valves)
- Blood chemistry (U+Es, LFTs and urate)
- Haematology (HB, RDW)
- Natriuretic proteins (BNP and NT-proBNP
What are the investigations for selected patients
- Coronary angiography,
- Exercise test,
- Ambulatory ECG monitoring.
- Myocardial biopsy
- Genetic testing
What is the main diagnostic criteria for heart failure?
- Raised NT-proBNP or raised BNP.
- If not raised then HF diagnosis is excluded
What is the main pharmacological treatment for chronic heart failure?
- ACEi/Angiotensin Receptor Neprilysin Inhibitor
- Beta blocker,
- Mineralocorticoid receptor antagonist (spironolactone)
- SGLT2i (Gliflozin)
- Loop diuretics for fluid retention
What drugs are used in patients of afro-Caribbean descent?
Hydralazine (vascular muscle relaxant) and Isosorbine mononitrate
What is the normal function of angiotensin II
- Vasoconstriction,
- Sodium and water retention
- Triggers aldosterone secretion,
- Stimulates ADH release and SNS activation
- Increases blood volume and vascular resistance.
Name an example of an angiotensin receptor neprilysin inhibitor and its mechanism
LCZ696 - It is a combination of sacubitril and valsartan.
Sacubitril will inhibit neprilysin which is the enzyme what breaks down BNP. This is beneficial as the normal function of BNP is vasodilation, natriuresis (excretion of sodium in urine), diuresis and inhibition of pathological fibrosis.
This is now the preferred drug
What are the beta blockers used in heart failure and how do they benefit HF?
- Carvedilol, metoprolol, bisoprolol and nebivolol.
- They slow the heart rate which allows the ventricles to fill more in diastole and reduce renin release (could reduce cardiac output but overall beneficial)
What MRA’s are used in HF?
- Spironolactone/eplerenone
- Inhibit effects of aldosterone
