Difference between revisions of "Heart Failure, Treatment"

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== Goals of Treatment ==
  
===Introduction===
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The goals of treatment of heart failure are to either cure it, or to slow it down or prevent the progression of the disease. If no 'treatment' can be given then drugs can be used to provide symptomatic relief. Treatments vary from surgical correction of underlying conditions, such as correction of a [[Patent Ductus Arteriosus|PDA]], to management changes and pharmacological treatments.
  
 +
== Management Changes ==
  
===Goals of Treatment===
+
Certain things owners need to be made aware of in order to prevent exacerbation of the disease include avoiding strenuous exercise and feeding reduced salt diets as this reduces preload. They may also wish to give potassium supplements or in cats with [[Dilated Cardiomyopathy|dilated cardiomyopathy]], taurine supplements. L-carnitine supplements can be given to dogs with dilated cardiomyopathy. Nutraceuticals (e.g. Omega-3 fatty acids, Anti-oxidants, Co-enzyme Q10) can also be given. <br>
  
*Cure
+
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.
  
*Slow/Prevent Disease Progression
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== Pharmacological Intervention ==
  
*Symptomatic Relief
+
The following terms are useful when describing the effects of various pharmacological agents. These are 'Preload'. This is the amount of maximal myocardial stretch (during diastole). 'Afterload' is the amount of maximal myocardial tension (during systole).
  
 +
Drug treatments can be used to:
  
===Types of Treatment===
+
==== Decrease Preload ====
  
 +
This decreases venous tone and fluid volume which can help to relieve congestion & oedema. Drugs in this class include:
  
====A. Surgical====
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'''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.  
e.g. Correction of PDA)
 
  
 +
'''Venodilators ''', as their name suggests, dilate veins causing decreased venous pressures, blood redistribution, and increased capacitance. Venodilators include Glyceryl trinitrate and a group of drugs classified as '''balanced vasodilators''', which includes ACE inhibitors (Enalapril (dogs & cats), Benazepril (cats), alpha-antagonists and Nitroprusside.
  
====B. Managemental====
+
The side effects of preload reduction include: hypovolemia, dehydration, hypokalemia, hyponatremia.  
  
-Avoid strenuous exercise
+
==== Decrease Afterload ====
  
-Reduced Salt Diets (Reduces Preload)
+
Decreasing afterload increases flow by decreasing arterial tone. This reduces resistance to outflow which reduces the cardiac workload by decreasing systolic myocardial tension and increasing systemic blood flow. Arterial vasodilators include Hydralazine or any member of the balanced vasodilators mentioned above. ACE inhibitors such as Enalapril and Benazepril are commonly used - side effects include vomiting, anorexia, diarrhea, hypotension, and [[azotaemia]].
  
-Potassium Supplements
+
==== Increase Myocardial Systolic Function ====
  
-Taurine Supplements (Cats with dilated cardiomyopathy)
+
This helps with dilated cardiomyopathy and [[Degenerative Mitral Valve Disease|mitral valve disease]] (dog & cat) but is '''contraindicated''' in animals with [[Hypertrophic Cardiomyopathy|hypertrophic cardiomyopathy]] (dog & cat). '''Positive Inotropes''' can be used to stimulates myocardial contractility to improve cardiac output regardless of preload. This class of drug includes digitalis compounds (e.g. Digoxin, Digitoxin), calcium sensitisers/ phosphodiesterase III. inhibitor (e.g. Pimobendan), pure phosphodiesterase inhibitors (e.g. Milrinone, Amrinone) and catecholamines (e.g. Dobutamine, Dopamine).
  
-L-carnitine Supplements (Dogs with dilated cardiomyopathy)
+
The disadvantage of positive inotropes is that increased myocardial work causes increased myocardial oxygen demand.
  
-Nutraceuticals (e.g. Omega-3 fatty acids, Anti-oxidants, Co-enzyme Q10)
+
==== Increase Myocardial Diastolic Function ====
  
 +
This helps with hypertrophic cardiomyopathy and myocardial fibrosis where ventricular filling is compromised. Drugs include the beta blockers (e.g. Atenolol, Propranolol) and calcium channel blockers (e.g. Diltiazem).
  
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.
 
  
 +
{{Chapter}}
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{{Mansonchapter
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|chapterlink = http://www.mansonpublishing.co.uk/book-images/9781840761856_sample.pdf
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|chaptername = Congestive Heart Failure in the Dog (part of Congestive Heart Failure in the Cat)
 +
|book = Small Animal Emergency and Critical Care Medicine
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|author = Elizabeth Rozanski, John Rush
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|isbn = 9781840761856
 +
}}
  
====C. Pharmacological====
+
== References ==
  
Preload=amount of maximal myocardial stretch (During Diastole)
+
Ettinger, S.J. and Feldman, E. C. (2000)''' Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat '''Volume 2 (Fifth Edition) ''W.B. Saunders Company''
  
Afterload=amount of maximal myocardial tension (During Systole)
+
Ettinger, S.J, Feldman, E.C. (2005)''' Textbook of Veterinary Internal Medicine '''(6th edition, volume 2) ''W.B. Saunders Company''
  
 +
Fossum, T. W. et. al. (2007)''' Small Animal Surgery''' (Third Edition)'' Mosby Elsevier''
  
'''Depending on Condition, Drug Treatments Are Used To:'''
+
Merck &amp; Co (2008) '''The Merck Veterinary Manual '''(Eighth Edition)'' Merial''
  
-Decrease Preload (Decreases venous tone & fluid volume)
+
Nelson, R.W. and Couto, C.G. (2009) '''Small Animal Internal Medicine '''(Fourth Edition) ''Mosby Elsevier''
  
-Decrease Afterload (Increases flow by decreasing arterial tone)
 
  
-Increase Myocardial Systolic Function
+
{{review}}
  
-Increase Myocardial Diastolic Function
+
{{OpenPages}}
  
 
+
[[Category:Expert_Review]] [[Category:Heart_Failure]]
'''Symptomatic Drug Treatment'''
+
[[Category:Cardiology Section]]
 
 
=====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)
 
[[Category:To_Do_-_Cardiovascular]]
 

Latest revision as of 10:03, 1 July 2016


Goals of Treatment

The goals of treatment of heart failure are to either cure it, or to slow it down or prevent the progression of the disease. If no 'treatment' can be given then drugs can be used to provide symptomatic relief. Treatments vary from surgical correction of underlying conditions, such as correction of a PDA, to management changes and pharmacological treatments.

Management Changes

Certain things owners need to be made aware of in order to prevent exacerbation of the disease include avoiding strenuous exercise and feeding reduced salt diets as this reduces preload. They may also wish to give potassium supplements or in cats with dilated cardiomyopathy, taurine supplements. L-carnitine supplements can be given to dogs with dilated cardiomyopathy. Nutraceuticals (e.g. Omega-3 fatty acids, Anti-oxidants, Co-enzyme Q10) can also be given.

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 useful when describing the effects of various pharmacological agents. These are 'Preload'. This is the amount of maximal myocardial stretch (during diastole). 'Afterload' is the amount of maximal myocardial tension (during systole).

Drug treatments can be used to:

Decrease Preload

This decreases venous tone and fluid volume which can help to relieve congestion & oedema. 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.

Venodilators , as their name suggests, dilate veins causing decreased venous pressures, blood redistribution, and increased capacitance. Venodilators include Glyceryl trinitrate and a group of drugs classified as balanced vasodilators, which includes ACE inhibitors (Enalapril (dogs & cats), Benazepril (cats), alpha-antagonists and Nitroprusside.

The side effects of preload reduction include: hypovolemia, dehydration, hypokalemia, hyponatremia.

Decrease Afterload

Decreasing afterload increases flow by decreasing arterial tone. This reduces resistance to outflow which reduces the cardiac workload by decreasing systolic myocardial tension and increasing systemic blood flow. Arterial vasodilators include Hydralazine or any member of the balanced vasodilators mentioned above. ACE inhibitors such as Enalapril and Benazepril are commonly used - side effects include vomiting, anorexia, diarrhea, hypotension, and azotaemia.

Increase Myocardial Systolic Function

This helps with dilated cardiomyopathy and mitral valve disease (dog & cat) but is contraindicated in animals with hypertrophic cardiomyopathy (dog & cat). Positive Inotropes can be used to stimulates myocardial contractility to improve cardiac output regardless of preload. This class of drug includes digitalis compounds (e.g. Digoxin, Digitoxin), calcium sensitisers/ phosphodiesterase III. inhibitor (e.g. Pimobendan), pure phosphodiesterase inhibitors (e.g. Milrinone, Amrinone) and catecholamines (e.g. Dobutamine, Dopamine).

The disadvantage of positive inotropes is that increased myocardial work causes increased myocardial oxygen demand.

Increase Myocardial Diastolic Function

This helps with hypertrophic cardiomyopathy and myocardial fibrosis where ventricular filling is compromised. Drugs include the beta blockers (e.g. Atenolol, Propranolol) and calcium channel blockers (e.g. Diltiazem).



Sample Book Chapters
Publisher
Free chapter
Book
Authors
CRC logo small.png
Congestive Heart Failure in the Dog (part of Congestive Heart Failure in the Cat)
Small Animal Emergency and Critical Care Medicine
Elizabeth Rozanski, John Rush
Buy book


References

Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company

Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2) W.B. Saunders Company

Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier




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