Cardiac Failure Flashcards
(36 cards)
Symptoms of cardiac failure
Oedema
Exercise intelerance
SOB
Fatigue
Tachycardia or irregular heart beat
What are the physiological responses to heart failure
- RAAS system (Renin angiotensin aldosterone)
-leads to sodium and water retention
-vasoconstriction - Norepinephrines
-Tachycardia- vasoconstriction
- Endothelium’s (peptides that cause vasoconstriction and increase BP)
- Beta adrenergic sensitisation
- Hypertrophy, Ischemic, arrhythmia
- Necrosis, fibrosis, left ventricular remodelling
What cause of heart failure leads to structural abnormality of the heart
Hypertension which leads to LV hypertrophy
What cause of heart failure lead to functional abnormality of the heart
Ischemia from coronary occlusion
Describe the sympathetic nervous system response to decrease in blood pressure
Decrease in Bp activates sympathetic nervous system
Activation of Beta 1 adrenoceptors of the heart which leads to increased cardiac output
Activation of Alpha 1 adrenoceptors on smooth muscles which leads to increased peripheral resistance (vasoconstriction)
Describe RAAS system response in dicrease in blood pressure
-Blood flow to kidneys low when low BP
-Activation of renin
-Renin causes Angiotensin 1 release
-Angiotensin 1 is converted into angiotensin 2
-Angiotensin 2 causes release of aldosterone
-Aldosterone causes retention of sodium and water
-Increases blood volume and cardiac output also increased.
What are the 5 main causes of Cardiac failure
Hypertension
Coronary artery disease
Cardiomyopathy
Valvular heart disease
Myocardial infarction
Thyrotoxicosis
Anaemia
Alcohol excess
Which drugs can precipitate cardiac failure
Oestrogens
Steroids
(Non-dihydropyridine) Calcium channel blockers
Beta-blockers
Non-steroidal anti-inflammatory drugs (NSAIDs)
Excessive diuretics
Tricyclic antidepressants
Non drug measures to treat heart failure
Exercise training
Flu immunization
Reduction in alcohol consumption
Cessation of smoking
Correction of anemia
Review
Drug measures for cardiac failure
ACE inhibitors
Beta blockers
Spironolactone
Isosorbide-hydralazine as adjunctive therapy.
Stepwise approach in management of chronic heart failure
- ACE inhibitor
-If the ACE-I cant be tolerated, an Angiotensin II receptor blocker can be used but this requires discussion with a specialist.
-If there the fluid retention is mild, a thiazide diuretic can be used, such as HCTZ (Ridaq), if it’s more significant, a loop diuretic Furosemide (Lasix) - Beta blockers - Carvedilol
- Spironolactone
- Digoxin- discussed with specialist
What are the potential adverse effects of ACE Inhibitors
Hyperkalemia
Hyponatremia
Hypotension
Renal dysfunction due to fall in GFR
Acute angioedema (rare)
Low output states
NSAIDS therapy
What are the contraindications of ACE inhibitors
Renal artery stenosis
Hyperkalemia
Pregnancy
Previous angioedema
How would you manage ACE inhibitor related angioedema
-Withdrawal of ACE inhibitor 1
-Supportive treatment
-Corticosteroids, antihistamine, Adrenalin
Which is the preferred antagonist between ACE inhibitor and Angiotensin receptor blocker
ACE inhibitor is better than Angiotensin 2 blockers
12% Lower risk of death
20% lower risk of lethal arrhythmias
Adverse effect of increased sympathetic nervous system in cardiac failure
Myocyte hypertrophy and death, dilatation
Ischemia
arrhythmias
Mechanism of action of beta blockers
Mechanism of action multifactorial
Protect against cardiotoxic effects of catecholamines
Decrease heart rate
Reduce renin secretion (blockade of renal B-receptors) Anti-arrhythmic
Vasodilating, anti-oxidant effects (carvedilol)
What are the long term effects of beta blockers
Reduce mortality
Improve LV ejection fraction
Examples of beta blockers
Carvedilol, bisoprolol, metoprolol
Indications of beta blockers
Cardiac failure with fluid retention
Contraindications of beta blockers
Bradycardia (<60bpm)
2nd or 3rd degree heart block
Symptomatic hypotension
Hyper reactive airway
Peripheral artery disease
Can beta blockers be stopped suddenly or gradually
Never stop them abruptly!
Effects of aldosterone
Increased sodium and water retention
LEFT VENTRICULAR FIBROSIS & HYPERTROPHY
Reduced K+ and Mg + + (due to fluid retention?)
Reduced arterial compliance, endothelial function
Indication for Spironolactone
NYHA III & IV despite treatment with ACE-I & β-blocker
