Circulatory Flashcards
Definition of heart failure
Circulatory failure where heart is unable to maintain an adequate circulation for rest of body.
Heart has some ability to compensate, so heart disease can be present for a while before body decompensates and animal presents as emergency or can be chronic that gradually worsens.
Acute heart failure
Cardiogenic shock Collapsed, pale mms Slow crt Weak femoral pulse First aid- reduce stress levels O2 therapy Cage rest or sit with them Monitor core temp Cool/warm Rr rate should drop if treatment success Vet may administer glyceryl trinitrate to inside of ear and diuretics iv
Left sided heart failure
- this side of heart accepts oxygenated blood from lungs
- failure of this side of heart leads to build up of blood within lungs
- leads to pulmonary oedema as the increased pulmonary blood pressure forcea fluid from blood vessels out into lung space
Symptoms of left sided heart failure
Coughing, dyspnoea, tachynpoea, murmurs and dysrthymmias(Common)
Exercise intolerance
Lethargy
Sometimes cyanosis
Right sided heart failure
Right side of heart normally accepts deoxygenated blood from body and pushes it off around the lungs.
Failure of this side of heart results in increased blood pressure in the systemic circulation.
This lead to fluid being forced out of blood vessels around body, especially in abdomen.
So ascites builds up very commonly.
Other symptoms of right sided heart failure
Hepatomegaly Splenomegaly Exercise intolerance Fatigue Lethargy Pale mms Tachycardia Weak femoral pulses Dyspnoea Tachynpoea Cyanosis many also have murmurs and dysrthymmias
Management of chronic heart failure
Small amounts of exercise and regular
Healthy bcs
Low salt, palatable diet, eg royal canine cardiac or hills HD. Hand feeding and warming may be needed.
Healthy treats
Monitor electrolytes as drug therapy can alter these.
Drug therapy-diuretics to reduce fluid build up) frusemide, spironolactone) and cardiac drugs (ace inhibitors like the benazipril ‘pril’ drugs, that reduce blood pressure and increase sodium excretion, or pimobendane (vetmedin, heartmedin) to increase contractility.
Diagnosing heart failure
Auscultation is primary diagnostic
Ecg(electrocardiograph)
Doppler u/s with colour flow (echocardiography)
Right lateral and dv radiograph
Blood tests-biochem (urea/crea to check for prerenal issues), electrolytes, NT proBNP
Patent ductus arteriosis
Most common congenital defect in dogs
Foetus does not use its lungs, so no need prior to birth for pulmonic and systemic circulations to be seperate
This connection should close at birth
If it stays open blood is shunted from aorta into pulmonary artery, overloads lungs
Leads to heart failure and death
Detected by loud machinery type murmur at first vax.
Tx is surgical closure
Aortic stenosis
Narrowing of aorta
Heart muscle thickens as it has to work harder
Heart murmur audible
Treat symptomatically no surgery
Pulmonic stenosis
Heart murmur audible
Hypertrophy of heart muscle present as with aortic stenosis
Surgical treatment available
Balloon valvuloplasty
Septal defects
Most common congenital in cats Holes in heart Connecting holes between atria or ventricles(so known as ventricular or atrial septal defects) Leads to heart failure Heart murmur audible Small defects are better tolerated
Tetralogy of fallot
The most common combo of defects
- ventricular septal defect
- pulmonic stenosis
- compensatory right sided hypertrophy
- an over Riding aorta
As no blood gets to lungs animals present cyanosis and guarded prognosis
Praa (persistent right aortic arch) aka vascular ring anomaly
- oesophagus passes through aortic arch and is constricted
- underweight pups who are very hungry but will regurgitate any solid pieces
- presents after weaning, liquid diet prior to this will hide any problems
- barium swallow radiograph will highlight stricture in oesophagus and usually a dilation just cranial to it.
- surgery to clamp and tie aortic arch usually produces excellent results
- Some aortic arches need dissecting off oesophagus
- Animal may have mega oesophagus permanently after surgical correction
Myocardial disease
- acquired
- diseases of the myocardium that produces cardiac dysfunction
- most common acquired heart disease in cats(usually hypertrophic cardiomyopathy or HCM)
- also seen in large and giant breeds of dog (commonly dilated cardiomyopathy or dcm)
Hypertrophic cardiomyopathy
- dyspnoea, tachynpoea, heart murmur, aortic thromboembolism
- diagnosed by r lateral and dv rads, Ecg, blood pressure measure, us of heart incl flow directions (echocardiography), clotting profile, biochem, haematology
- affects all ages of cat
- Tx aimed at improving cardiac relaxation and slowing heart rate-calcium channel blockers (diltiazem) and beta blockers (propranolol, atenolol)
- 30% maine coonand ragdoll cats are genetically predisposed
Dilated cardiomyopathy
Does affect cats too
All heart Chambers dilate and walls thin and lose power to pump blood efficiently
Familial disposition exist in doberman and great Danes and genetic testing is underway to identify genotype
Other breeds with familial disposition include boxers, Irish wolfhound and newfoundlands
Arrhythmias
Disturbance in electrical activity of heart
Can be from heart diseases or systemic cause like Addisons disease
Fast and slow arrhythmia tachy or brady
Collaps weakness, exercise intolerance
Diag-bloods esp electrolytes, Ecg, rads, u/s
Can be intermittent so a holter monitor Ecg can be supplied to be worn continuously
Infectious cardiac disease
Heartworm-dirofilaria immitus
Adult life stage lives in heart
Signs of right sided heart failed
Cardiovascular emergencies
Acute congestive heart failure
Cough esp at night Dyspnoea /tachynpoea Reluctant to exercise Poor pulse Tacycardia Pale mms Cyanosis Heart murmur Gallop rhythm
Diag- rads, Ecg, echocardiography (us of heart)
Tx keep patient calm, O2 therapy, iv catheter placement
Medical tx- thoracocentesis for pleural effusion (mostly cats)
Diuretics - furosemide
Glyceral trinitrate used topically to ear or groin
