Drugs for Congestive Cardiac Failure Flashcards
(28 cards)
what is heart failure?
what functions of the heart get affected?
Heart unable to provide adequate perfusion of peripheral organs to meet their metabolic requirements
- Reduction in cardiac output
- Systolic dysfunction- reduction in cardiac contractility
- Diastolic dysfunction- inadequate filling of ventricles during diastole
In acute heart failure, the short aim is to do what?
In acute heart failure, the short aim is to do what?
- stabilize, providing symptomatic treatment by IV
- not short, only long term and is through:
- relieving symptoms
- improving hemodynamics
Heart failure is usually accompanied by an increase in what?
- Sympathetic nervous system (SNS)
- Chronic up-regulation of the renin-angiotensin-aldosterone system (RAAS) and effects of aldosterone on heart, vessels and kidney
In a failing heart, the loss of contractile function leads to what?
Activation of SNS serves as a compensatory mechanism to maintain adequate cardiac output how?
a decline in CO and a decrease in arterial BP, Baroreceptors sense the hemodynamic changes and initiate countermeasures to maintain support of the circulatory system.
- Increasing myocardial contractility and heart rate (β1-adrenergic receptors)
- Increasing vasomotor tone (α1-adrenergic receptors) to maintain systemic blood pressure
what are the Consequences of hyperadrenergic state in the long term?
- irreversible myocyte damage
- cell death
- fibrosis
- increase in Left Ventricular afterload: because of the augmentation in peripheral vasomotor tone
Baroreceptor mediated activation of the SNS leads to release of what?
renin and then formation of Angiotensin 2
Angiotensin II acts through what receptors?
What is the overall effect of Angiotensin 2?
why is it important in Cardiac Heart Failure?
Angiotensin 1 and Angiotensin 2 receptors
vasoconstriction and stimulates aldosterone production
because it is the target of chronic CHF therapy
What is the goal during heart failure?
- Alleviation of symptoms
- Arrest ventricular remodeling, Prevent sudden death
- Reduce cardiac work
what drug therapy can be given in cardiac heart failure?
- Diuretics
- Vasodilators
- Beta blockers
- Digoxin
- Other Cardiac Inotropes – Dobutamine, Milrinone
when are diuretics useful?
what do they do?
what are the most commonly used?
in mild cases what is used?
- useful in reducing the symptoms of volume overload
- decreasing the extra cellular volume
- decreasing the venous return
- furosemide and bumetanide
- thiazides
what is the adverse effects of diuretics?
how is it overcome?
give an example of a drug that helps in overcoming the problem?
- Loop diuretics and thiazides cause hypokalemia.
- Potassium sparing diuretics help in reducing hypokalemia due to these diuretics.
- Spironolactone
what are the ACE inhibitor drugs?
What is the effect of these drugs?
- Captopril, Lisinopril, Enalapril, Ramipril, Quinapril.
1. Blockade of Angiotensin Converting Enzyme (ACE)
2. Decreased AT-II
3. Decreased aldosterone
4. Decreased fluid retention
5. Vasodilation
6. Reduction in arterial resistance (afterload)
7. Reduction in venous tension (preload)
8. Slows cardiac remodeling
what are the adverse effects of ACE inhibitors?
cough, postural hypotension, hyperkalemia, angioedema
what are the Angiotensin Receptor AT-1 blockers (ARB) drugs?
what are these type of drugs?
Losartan, Irbesartan, Candesartan
Competitive antagonists of Angiotensin II (AT-1).
what are the 3 types of Vasodilators?
Give an example drug of each.
Venodilators - Isosorbide dinitrate
Arteriolar dilators - Hydralazine
Both arteriolar & venodilators - Sodium nitroprusside
What will venodilators do?
when are they used?
- Reduce preload
- used in Acute and chronic heart failure & angina
What will arteriolar dilators do?
when are they used?
- Reduce BP and afterload
- Use of Hydralazine plus nitrates (BiDil) have reduced mortality
when are Both arteriolar & venodilators used?
hypertensive emergencies
what do inotropes do?
give 3 examples of these.
- Increase force of contraction by increasing intracellular cardiac Ca++ concentration
1. Digitalis (cardiac glycoside)
2. Dobutamine (β-adrenergic agonist)
3. Amrinone, milrinone (PDE inhibitor)
What is the mode of action of Digoxin?
What will it do?
- Inhibition of Na/K ATPase pump increase intracellular sodium concentration – eventually increase cytosolic calcium
- Enhances vagal tone (cardiac parasympathomimetic effect): slows sinus heart rate and atrioventricular conduction
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when is digoxin used?
- to reduce rapid ventricular rate in atrial flutter and atrial fibrillation
- Severe LV systolic dysfunction (CCF)
what will digoxin toxicity cause in CNS?
what will digoxin toxicity cause in GI system?
what will digoxin toxicity cause in cardiovascular system?
- Malaise, confusion, depression, vertigo, vision
- Anorexia, nausea, intestinal cramping, diarrhea
- Palpitations, syncope, arrhythmias, bradycardia, AV node block, tachycardia
- LOOK for BIGEMINY in EKG (premature ventricular contractions)
What Factors may help increase digoxin toxicity?
What drugs may help increase digoxin toxicity?
- hypokalemia: Because potassium competes with digoxin for binding sites on the Na+/K+-ATPase,
- Hypercalcemia: enhances digitalis toxicity as it increases in intracellular calcium
- Hypomagnesemia: sensitizes the heart to digitalis-induced arrhythmias.
- K+-depleting diuretics
- Quinidine, Amiodarone and verapamil can increase the plasma levels of digoxin
How do you Manage Digoxin toxicity?
- K+ supplementation
- For digoxin induced arrythmias: lidocaine, Phenytoin or propranolol can be used.
- Severe toxicity treated with Digibind, an anti-digoxin antibody.
