Difference between revisions of "Heart Failure, Treatment"

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Drug treatments can be used to:
 
Drug treatments can be used to:
*Decrease Preload (Decreases venous tone & fluid volume)
+
 
 
*Decrease Afterload (Increases flow by decreasing arterial tone)
 
*Decrease Afterload (Increases flow by decreasing arterial tone)
 
*Increase Myocardial Systolic Function
 
*Increase Myocardial Systolic Function
 
*Increase Myocardial Diastolic Function
 
*Increase Myocardial Diastolic Function
  
=====Decrease Preload=====
+
===Decrease Preload===
 
+
This decreases venous tone & fluid volume which can help to relieve congestion & edema  
*Benefit: To relieve congestion & edema  
+
Drugs in this class include:
 
+
#Diuretics: These decrease blood volume by increasing sodium loss from the kidneys. They include '''loop diuretics''', that act on the renal Loop of Henle such as Frusemide, and '''thiazide diuretics''' that act on the renal Distal Convoluted Tubule, such as Chlorothiazide or Hydrochlorothiazide. '''Potassium sparing diuretics''' act on the renal Collecting Duct and include Spironolactone and Amiloride.
*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  
 
  
  

Revision as of 19:44, 25 October 2010

Introduction

Goals of Treatment

  • Cure
  • Slow/Prevent Disease Progression
  • Symptomatic Relief

Treatments vary from surgical correction of underlying conditions, such as correction of a PDA, to management changes and pharmacological treatments.

Management Changes

  1. Avoid strenuous exercise
  2. Reduced Salt Diets (Reduces Preload)
  3. Potassium Supplements
  4. Taurine Supplements (Cats with dilated cardiomyopathy)
  5. L-carnitine Supplements (Dogs with dilated cardiomyopathy)
  6. 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.

Pharmacological Intervention

The following terms are usfule when desribing the effects of various pharmacological agents:

  • Preload=amount of maximal myocardial stretch (During Diastole)
  • Afterload=amount of maximal myocardial tension (During Systole)

Drug treatments can be used to:

  • Decrease Afterload (Increases flow by decreasing arterial tone)
  • Increase Myocardial Systolic Function
  • Increase Myocardial Diastolic Function

Decrease Preload

This decreases venous tone & fluid volume which can help to relieve congestion & edema Drugs in this class include:

  1. Diuretics: These decrease blood volume by increasing sodium loss from the kidneys. They include loop diuretics, that act on the renal Loop of Henle such as Frusemide, and thiazide diuretics that act on the renal Distal Convoluted Tubule, such as Chlorothiazide or Hydrochlorothiazide. Potassium sparing diuretics act on the renal Collecting Duct and include Spironolactone and 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)