Management of Heart Failure

Question 1

Chronic causes of CHF

Answer 1

Chronic Degenerative Valve Disease (CDVD)
Dilated cardiomyopathy
Restrivtive/hypertrophic cardiomyopathy

Question 2

How does CDVD result in CHF?

Answer 2

Regurgitation of valve means less forward flow into aorta
Less blood getting into circulation
LA dilates and pressure increases
LA backs up into pulmonary vein resulting in pulmonary oedema

Question 3

How does DCM result in CHF?

Answer 3

Forward flow calls due to poor contractility
All chambers enlarged and thin alls
Blood backs up into LA the PV

Question 4

How does HCM result in CHF?

Answer 4

Forward failure due to failure to fill ventricle (diastolic failure)

Question 5

What are the considerations before managing heart failure?

Answer 5

Primary cause of heart disease
Non-specific treatment for disease
Treatment of heart failure
Any dysrhythmias
Complicating/co-exiting factors
Regular assessment
Owner expectations

Question 6

What is more common, L or R CHF

Answer 6

LCHF - pulmonary oedema

RCHF is often secondary to pericardial effusion or R valve disease (IN DOGS)
Leads to degree of left sided disease

Question 7

Typical Presentation of Heart Disease

Answer 7

• Heart failure
  ○ Cough
  ○ Dyspnoea
• Exercise intolerance
• Collapse
• Found incidentally at routine appointment
• Non specific weight loss

Question 8

Causes of Primary Heart disease

Answer 8

Mitral valve disease
Cardiomyopathy
Congenital issues
Pericardial issues
Metabolic issues
Deficiencies
Idiopathic

Question 9

What is DCM?

Answer 9

Dilated cardiomyopathy
Result of contractility failure

Question 10

What is the aim for treating DCM?

Answer 10

Improve contractility in order to improve cardiac output

Question 11

Which drugs will increase contractility?

Answer 11

Positive inotropes

Question 12

Examples of positive inotropes

Answer 12

Digoxin
Pimobendan
Dobutamine

Question 13

What is pimobendan?

Answer 13

Positive inotrope (improves contractility)
Inodilator (decreases pulmonary vascular resistance)
Calcium-sensitising
PDE III inhibitor
Also has antithrombotic activity

Question 14

What so PDE III inhibitors do?

Answer 14

Causes vasodilation to decrease systemic vascular resistance
Also increases oxygen supply to heart

Question 15

What is an inodilator and why is it useful for heart failure?

Answer 15

Decreases pulmonary vascular resistance
Reduced risk of pulmonary oedema

Question 16

DIgoxin

Answer 16

Positive inotope
Negative chronotrope (decreases HR)
Increases vagal tone (reduces SNS activity)
VERY NARROW THERAPEUTIC WINDOW
DON’T USE IN RENAL FAILURE

Question 17

What is dobutamine?

Answer 17

Positive inotrope - increases contractility

Question 18

Goal for HCM management

Answer 18

Need ventricles to relax to allow filling
(Diastolic failure)

Question 19

What treatment is used for HCM?

Answer 19

Positive lusitropes

DO NOT USE POSITIVE INOTROPE (Pimobendan)

Question 20

What are Positive lusitropes?

Answer 20

Help heart relax
Calcium channel blockers
* Diltiazem
* Verapamil
Beta blockers
* Atenolol
* Propranolol

Question 21

When can you treat HCM?

Answer 21

Once the cat is in heart failure
Can’t treat cats before

Question 22

What is diltiazem?

Answer 22

Positive lusitrope
May reduce LVH
Antidysrhythmic

Question 23

What are the overall goals of managing heart failure?

Answer 23

Reversing compensatory mechanisms
ontrol Salt & Water Retention
* Reduce Workload
○ Decrease afterload
○ Decrease physical activity and stress
* Improve Pump Function
○ (Improve systolic function)
○ (Improve diastolic function)
○ Reverse/modify myocardial remodeling

Question 24

Heart failure treatment in dogs

Answer 24

Endo or myocardial diseases leading to CHF are treated the same as the outcome is the same
* Diuretics
○ Furosemide
* Positive inotrope
○ Pimobendan
* ACE inhibitors
○ Glyceryl trinitrate
* Aldosterone antagonists
○ Spirinolactone

Question 25

What are the stages of heart disease

Answer 25

A B1 B2 C D

Question 26

Stage A

Answer 26

High risk of heart disease but no identifiable structural disorder of heart

Question 27

Stage B1

Answer 27

Murmur present Asymptomatic with no radiographic or echocardiographic evidence of remodelling

Question 28

Stage B2

Answer 28

Murmur present Asymptomatic with radiographic or echocardiographic evidence of left-sided heart enlargement

Question 29

Stage C

Answer 29

Past or current clinical signs of heart failure with associated structural heart disease

Question 30

Stage D

Answer 30

End-stage disease with clinical signs of heart failure that are refractory to standard therapy

Question 31

Stage B1 management

Answer 31

Weight control Regular re-assessment Client education No medical treatment

Question 32

Stage B2 management

Answer 32

Weight control Regular re-assessment Client education PIMOBENDAN

Question 33

Stage C management

Answer 33

1 - pimobendan 2 - ACE inhibitor 3 - diuretic 4 - aldosterone antagonist Don't always use all 4 - financial factors

Question 34

What are diuretics?

Answer 34

Reduce fluid accumulation in body Act on kidneys to increase urine output Can result in excretion of potassium (hypokalaemia) Controls oedema formation

Question 35

Loop diuretic examples

Answer 35

Furosemide Torasemide

Question 36

Potassium sparing diuretics

Answer 36

Spironolactone (Aldosterone antagonist )

Question 37

What is Furosemide

Answer 37

1st line diuretic VERY POTENT SAVES LIVES Monitor for azotemia and hypokalaemia

Question 38

What is spironolactone

Answer 38

* Aldosterone antagonist * Potassium sparing effect * Beneficial effects in CHF * Improvements in cough, dyspnoea, syncope, mobility

Question 39

Common problems with diuretics

Answer 39

Volume depletion leads to potential hypovolaemia Difficult in cats with HCM - They rely on preload Stimulates RAAS Can exacerbate azotaemia

Question 40

What are ACE inhibitors?

Answer 40

Venous dilators Decrease preload Reduce fluid build up Arterial dilators Reduce afterload Increase output Reduce valve leakage Vasodilation and decreased salt/water retention Will cause azotaemia and hypotension Need to monitor renal parameters

Question 41

Example of ACI inhibitors

Answer 41

Glyceryl trinitrate (venous) Hyralazinel (arterial)

Question 42

What is emergency CHF therapy?

Answer 42

Always start with furosemide Oxygen therapy Drain any pleural effusion/ascites/pericardial effusion Pimobendan in dogs with DCM Once stable start spironolactone Consider antidysrhythmic Wean off IV furosemide to oral

Question 43

Treatment for Feline THromboembolic disease

Answer 43

Clopidogrel - inhibits platelet aggregation Aspirin - thins blood