Heart Failure, Treatment
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Introduction
Goals of Treatment
- Cure
- Slow/Prevent Disease Progression
- Symptomatic Relief
Types of Treatment
A. Surgical
e.g. Correction of PDA)
B. Managemental
-Avoid strenuous exercise
-Reduced Salt Diets (Reduces Preload)
-Potassium Supplements
-Taurine Supplements (Cats with dilated cardiomyopathy)
-L-carnitine Supplements (Dogs with dilated cardiomyopathy)
-Nutraceuticals (e.g. Omega-3 fatty acids, Anti-oxidants, Co-enzyme Q10)
Heart failure patients can suffer from cardiac cachexia due to the high metabolic demands of this condition. Make sure the patient is eating enough calories per day to maintain their body weight.
C. Pharmacological
Preload=amount of maximal myocardial stretch (During Diastole)
Afterload=amount of maximal myocardial tension (During Systole)
Depending on Condition, Drug Treatments Are Used To:
-Decrease Preload (Decreases venous tone & fluid volume)
-Decrease Afterload (Increases flow by decreasing arterial tone)
-Increase Myocardial Systolic Function
-Increase Myocardial Diastolic Function
Symptomatic Drug Treatment
Decrease Preload
- Benefit: To relieve congestion & edema
- Techniques
1. Diuretics: Decrease blood volume by increasing sodium loss from the kidneys
-Loop Diuretics (Act on the renal Loop of Henle)
- Frusemide
-Thiazide Diuretics (Act on the renal Distal Convoluted Tubule)
- Chlorothiazide
- Hydrochlorothiazide
-Potassium Sparing Diuretics (Act on the renal Collecting Duct)
- Spironolactone
- Amiloride
2. Venodilation: Dilation of veins causes decreased venous pressures, blood redistribution, increased capacitance
-Venodilators
- Glyceryl trinitrate
-Balanced Vasodilators
- ACE inhibitors
- Alpha-antagonists
- Nitroprusside
Side Effects of Preload Reduction: hypovolemia, dehydration, hypokalemia, hyponatremia
Decrease Afterload
- Benefit: Reduce resistance to outflow, reduce cardiac work by decreasing systolic myocardial tension, increase blood flow
- Techniques
1. Arterial Vasodilators
- Hydralazine
2. Balanced Vasodilators
- ACE Inhibitors
enalapril (dogs & cats)
benazepril (cats)
Side Effects of ACE Inhibitors: vomiting, anorexia, diarrhea, hypotension, azotemia
Increase Myocardial Systolic Function
- Benefit: Helps with dilated cardiomyopathy & mitral valve disease (Dog & Cat)
- Contraindicated: Animals with hypertrophic cardiomyopathy (Dog & Cat)
- Techniques
1. Positive Inotropes
- Digitalis Compounds (e.g. digoxin, digitoxin)
- Calcium Sensitiser/Phosphodiesterase III. Inhibitor (e.g. pimobendan)
- Pure Phosphodiesterase Inhibitors (e.g. milrinone, amrinone)
- Catecholamines (e.g. dobutamine, dopamine)
Advantages:
-Stimulates myocardial contractility to improve cardiac output regardless of preload
Disadvantages:
-Increased myocardial work causes increased myocardial oxygen demand
Increase Myocardial Diastolic Function
- Benefit: Helps with hypertrophic cardiomyopathy and myocardial fibrosis where ventricular filling is compromised
- Techniques
1. Beta Blockers (e.g. atenolol, propranolol)
2. Calcium Channel Blockers (e.g. diltiazem)