Congenital Dz Mutha Fucka Oh and Acquired too Flashcards
Common Dog Congenital Heart Conditions
- PDA – Patent Ductus Arteriosis
- Aortic & pulmonic stenosis
- Atrial Septal defect (ASD)
- Mitral Dysplasia
Common Cat Congenital Heart Conditions
- Not a big problem in cats
- AV dysplasia – most common VSD
- James like cock
- PDA
- Tetrology of Fallot
Describe a L —-> R PDA
**1st L—>R shunting, leads to volume overload (ECCENTRIC Hypertrophy) & L-HF
A Massive L—->R PDA can switch to R—->L
Describe a R —-> L PDA
**2nd R—>L shunting – VERY large PDAs – occurs 6-8 weeks old
“Pink in front & Blue in Back” – Right heart overloaded
***Stimulates EPO from the kidney – can lead to erythrocytosis & hyperviscosity
PDA clinical signs
L–>R = machinery murmur thrill, water hammer pulses (due to changes in pressure)
R–>L = may have systolic murmur, cyanosis, split S2, INCREASED PCV
“Blue in the back pink in the front”
Radiograph Dx PDA
1.
- -Ductus Diverticulum
- -Enlarged Aorta
- -L or R Heart Enlargement
- Lung Vessels
- –L-R = lung vessels are prominent – big LEFT heart
PDA definitive DX method
Contrast Echo for definitive Dx
PDA breed signalment
- Min/Toy Poodle, GSD, Collie
- Poodles = polygenic trait
Females (3:1)
PDA L—>R Sx closure complications
- Aorta, Vagus & Phrenic nerve
- PDA will tear & bleed badly 10% of time
- Branham sign = marked decrease in HR after tie off, Tx w/Atropine
- Animals will wake up PU/PD for a few hours after Sx
1 Predisposed location for Aortic Stenosis
Subvalvular
Aortic Stenosis is common in what type of dogs?
- *Common in LARGE BREED DOGS (Newfoudland, Retriever, Boxer, Rotties)
- *Cannot certify free of Dz until > 12 mo of age!
Pathophysiology of Aortic Stenosis
- Increased afterload —> concentric hypertrophy —-> wall thickens —> decreased contractility
- Clinical Signs
- Sudden death due to arrhythmias (DDx = VPC
Dx of Aortic Stenosis (US)
**Best way to Dx Heart Dz
- Look for concentric LEFT Ventricular Hypertrophy
- Narrowing of the left ventricular outflow
Tx of Aortic Stenosis
**Tx is palliative – Tx if see more than 3 VPDs
***Do NOT use Digoxin
DOC = Sotolol
Beta Blockers
Control arrhythmias w/ Sotolol, Lidocaine, Mexilitine
- **Sx – lowers pressure gradient but does NOT increase survival
- Balloon valvuloplasty
Aortic Stenosis Prognosis
***20% will die w/I 3 years – 70% w/I 1 year
***Predisposes to bacterial endocarditis —> CHF – why control of infections is important
What occurs with Pulmonic Stenosis?
- Usually valves – Subvalvular, Valvular (most common), or supravalvular
- Valves tend to be dysplastic/thickened & valve cusps can be fused together
- Narrowing hypoplastic annulus
- Dynamic Obstruction
Pathophysiology of Pulmonic Stenosis
**Resistance to ejection ===> CONCENTRIC hypertrophy of R Ventricle & Arrhythmias (pressure overload)
Pulmonic Stenosis breed signalment
**Beagle, English Bulldog, Chihuahua, Spaniel, ect.
Pulmonic Stenosis Clinical signs
- Incidental finding on PE normally
- Exercise intolerance, weakness, syncope, sudden death, etc.
- Systolic murmur near L heart base
- Weak Pulse & mm are normal
DX Pulmonic stenosis (Radiograph, US)
Radiographs
- R Atrial Enlargement
- Pulmonary Trunk dilation
US
- Right ventricular hypertrophy
- Flattening of the septum
- Enlarged right atrium
Describe what Ventricular Septal Defect is (VSD)
***Failure of septal development – hole in the heart
***Blood will be shunted (L-R) = volume overload ==>L heart enlargement and eventually failure
***Blood goes almost directly to pulmonary artery
Where is VSD loudest and prognosis?
***Generates a murmur – loudest on the right ==> 1st 1 that is loudest on the right ==>
***louder the murmur = better prognosis is
VSD breed signalment
**Common in cats & bulldogs/Keeshunds
Clinical signs of VSD
- Small VSD ==> usually incidental as 1st vax appointment
- Large VSD ==> Stunted growth & may have Left CHF
- Systolic murmur on the RIGHT side – may be a thrill over R-Thorax ==> loud but NORMAL
4 parts contributing to Tetralogy of Fallot
- Pulmonic stenosis
- Overriding aorta ==> aorta opens in the middle of the septum
- VSD usually as large as aortic opening = severe stenosis/cyanosis BLUE ALL OVER
- Hypertrophy of the RIGHT Ventricle
No Murmur w/hyperviscosity
Dx of Tetralogy of Fallot (Lab, Rad)
- Lab – increased PCV from erythrocytes
- Rad
Enlarged right heart (R==>L)
Reduced pulmonary vasculature from undercirculation
Drug Tx for Tetralogy of Fallot
- Beta blockers for the right heart to relax
- Get rid of excess RBC
- Aspirin – increased PCV = prone to clots
- No vasodilators – will increase L-R shunt ==> hypoxemia
What is happening with Atrial Septal Defect (ASD)?
- Defect between the atria
- Blood flows preferentially to RIGHT ventricle
- Volume overload in RIGHT ventricle & pulmonary vessels
- More blood tries to go through the normal pulmonary outflow tract and can cause turbulence
ASD are common in what breed?
Boxers
Signs of ASD?
Murmurs
- *Most dogs are asymptomatic
- *Large defects can lead to heart failure
Pathophysiology of AV Valve Insufficency?
- Dysplasia of valve & muscles
- If on tricuspid side ==> regurgitation during systole & volume overload
- If on mitral side ==> regurg on left side
- stenosis
AV Valve Insufficiency signalment?
Cats & Large Breed dogs (Labs)
Endocardial Fibroelastosis signalment
Siamese & Bermese Cats
Endocardial Fibroelastosis Pathophysiology?
**Fibrosis of ventricular endocardium – stiffening of the L Ventricular walls
**Stops heart from filling properly
**Leads to dilation & failure by 2-4 months old
PRAA Pathophysiology
- PRSS ==> Ligamentum arteriosis constricts esophagus ==> megaesophagus
- Will regurgitate when eating solid food
- Ballooned esophagus in front of the heart
- NOT congenital
- May accidently aspirate food ==> foreign body pneumonia
Tx of Inherited Ventricular Arrhythmias in young GSD?
Give sotalol & Mexilitne until 18 mo – can taper off
3 phases of DCM in Dobermans?
- Arrhythmogenic Stage 2-5 yo
Arrhythmias
Dobermans = just VPDs
Irish Wolfhounds atrial fibrillation - Occult stage 3-6 yo
Left ventricular enlargement - Classic stage 6-9 yo
Dog in heart failure
Signs of DCM?
**Sudden death – VPD
**L or R HF signs (L-CHF is more common)
**Thin & wasting
**Atrial fibrillations & VPD
**Soft systolic murmurs
**S3 gallop
(Lab & Rad) Dx of DCM?
Lab
- *pre-renal azotemia
- *Increased liver enzymes
- *Low Taurine/Carnitine
Rad
- *Dilated heart
- *Lungs may show fluid ==>LCHF
DCM Treatment – ACM Stage
**Lone AF, Tx if average HR > 90
Use Holter Monitor
***Drugs to control increase HR = Beta Blockers, Diltiazem
**Digoxin slows heart but is a bad + inotrope – NOT good for controlling “Lone AF”
DCM Tx - Ventricular Arrhythmias
**Tx if they have clinical signs OR R-T phenomenon OR VPDs
***Beta blockers to control VPDs
***Sotolol or Mexilitine + Beta Blockers to control ventricular tachycardias
Tx - Occult Dilated Cardiomyopathy Stage
**Healthy but have decreased fractional shortening
Drugs used to delay onset of DCM:
===>Start @ lower dose and titrate upwards (ACE)
ACE inhibitors – cardioprotective
Beta-Blockers – cardioprotective if started early
Pimobendan: delays failure & increases survival time
Drugs to Tx @ home to prevent stress in Classic DCM & CHF – mild failure cases?
- *Furosemide
- *ACE inhibitors
- *Digoxin/Pimobendan
***Pimobendan vasodilates arteries & veins
What to do with severe cases of CHF?
- Hospitalize
**Tx w/ FONS = Furosemide, O2, Nitroglycerin, Sedation
**Improve contractility w/ Pimobendan (vetmedin)
- **Tx arrhythmias
- -Atrial Fibrillation = Digoxin + Diltiazem
- -Beta Blockers
At home Tx severe CHF?
**Maintain low dose Furosemide +
Max ACE inhibitors
**Exercise restriction & low Na diet
**Tx deficiencies
DCM Prevention?
**Use Holter Monitor from >2yrs in susceptible breeds
***Genetic marker enzymes – 1 Doberman = pyruvate dehydrogenase kinase isoenzyme 4
What 2 drugs increase life expectancy with DCM?
ACE & Pimobendan (Pimo safe in cats too)
DCM in cats can cause what signs?
**Acute onset of paresis/paralysis due to thromboembolism
***Dyspnea, Anorexia, Lethargy, Vomiting
What is commonly found on Physical exam with DCM in cats?
***Bands of focal retinal degeneration
**Thromboembolism
**Pleural effusion
Secondary HCM causes in cats?
***Genetic mutations in Main Coon & Ragdoll (mutation w/ myosin binding protein C)
- **HyperT4
- **Systemic Hypertension
- **Aortic Stenosis
- **Dysplastic Mitral Valve ==> Pressure Overload = HCM
What is Hypertrophic obstructive cardiomyopathy (HOCM)?
**Hypertrophied intraventricular septum encroaches on the LV outflow tract ==> obstruction
HOCM = Big L atrium
**Enlarged septum can cause misalignment of the mitral valve ==> mitral valve obstructs LVOT during systole
What is a SAM?
**Systolic Anterior Motion of the anterior mitral leaflets ==> regurg & mitral insufficiency (also LA enlargement)
Why does hypoxemia occur with HCM?
**Decrease capillary density
***Cells get bigger but capillaries do NOT increase ==> they get damaged from muscular force of enlarged cells
HCM DX? (Lab, Rad)
Lab
- **Biomarkers in blood = Increase cTn-1, Increase Pro-BNP, Increase CK, Increase K+
- **Normal coagulation
Rad
- **Valentine shaped heart
- -50%may just be big & round like DCM
***Left atrial enlargement – CONCENTRIC hypertrophy
HCM TX before HF?
- Slow heart w/ Beta Blockers (usually Atenolol)
* **Unless cat has asthma - ACE inhibitors if significant LA enlargement
- Ca+ Channel Blockers – Diltiazem to slow heart
- ACE inhibitors & low dose furosemide to prevent pulmonary edema
- PLAVIX
- LOW DOSE Aspirin (drops thromboxane)
- Low MW heparin
What does a “swirling smoke sign” indicate?
Predisposed to ATE
Cats with HCM should you give fluids?
No heart failure – give fluids
Heart failure – no fluids
HCM Tx once in HF?
- FONS!
- Traditional Additional Tx
**Beta Blocker for obstructed(HOCM)/Catecholamine release
**Non-obstructed = Diltiazem
Ace inhibitors
***Atenolol
***Spirolactone to block RAAS fibrosis & hypertrophy (can cause ulcerative facial dermatitis)
- **Na restricted diet
- **Reduce stress
Method for initially trying to dx the cause of HCM in cats?
**Diagnosis by exclusion of other non-genetic causes of
hypertrophy such as hyperthyroidism and systemic hypertension
HCM Clinical signs in cats?
–HF cats = bradycardia (give Dobutamine +inotrope)
- *Sudden death – VPD
- *Syncope
- **Dyspnea
- *Paresis from thromboembolism
- *Steroid administration recently
**Signs of CHF Murmurs – more predictive if they do NOT have murmurs **Ventricular heaves **Pulses (weak)** **S4 gallop *Vibration, can be normal in older cats
- *Arrhythmias
- *ATE – very painful
What is the Gold standard for Dx HCM in cats and if they have CHF?
Thoracic Radiographs
■ Apparently healthy cats; screening with a generally very poor NPV
■ Dyspneic cats; gold standard but still some limitations associated
with the lack of pathopneumonic findings for CHF
Echocardiography
■ Apparently healthy cats with heart murmurs, gallops, or
arrhythmias; gold standard with high PPV and NPV
■ Dyspneic cats; will tell you if there is underlying heart disease
of the type and severity that could lead to CHF but does not
diagnose CHF
Will a cat with asymmetric septal hypertrophy present with a murmur?
**Will present with murmur if cat has a HOCM ==> obstruction leading to mitral insufficiency ==> regurg back into L atrium during systole (Systolic Anterior Motion of the anterior mitral leaflets) = murmur
**No murmur if no obstruction present in LVOT, (no turbulance or increased peak flow velocity = no murmur) but still Diastolic filling problem
What is the key prognastic factor with cats in heart failure?
Left atrium size (>20mm = very poor prognosis)
What are the 3 forms of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
- Concealed form (VPDs)
- Overt form
==>Syncope, exercise intolerance, weakness, SUDDEN DEATH - Myocardial dysfunction form
Go into R CHF (less common)
Pathophysiology of Boxer Cardiomyopathy – familial Ventricular Arrhythmia (FVA)
Genetic in boxers
Response to dz
- **Connection 43 protein in gap junctions
- **Calstabin protein in endoplastic reticulum
Gene causing dz
***Striatin gene
ARVC Dx in Boxers?
***Post mortem to Dx – histo to see fatty infiltration
***Live animal = Halter Monitor - GOLD STD for Dx
**Heart generally looks normal
***Proteins in serum
cTn-1 levels in serum are higher in affected animals & directly proportional to the # VPCs/24 hours
When to Tx ARVC and what to Tx with?
- Asymptomatic w/ > 1000 VPDs, VT, or R on T phenomenon
- Sotalol (want to see at least 80% improvement) Or combo w/Mexillitene & Atenolol
- Evaluate Tx w/Holter Monitor
Carnitine can help with Boxers
ARVC in cats
**Fibrofatty infiltrate into the right ventricle leads to marked ventricular enlargement & failure
**Syncope because of Arrhythmias
Sotolol helps
What is Myxomatous AV Valvular degeneration?
- Degenerative disorder of the Mitral valve or tricuspid valve
- 75% of all CV Dz cases
***Thickening of the valve causes regurgitation of blood to the atrium during systole
***Chordae tendonae may become thickened & rupture causing prolapse of the valve during systole
How does the heart compensate in MAVVD w little regurg?
Increase sympathetic tone
When is RAAS activated in MAVVD?
When the dz is severe & animals is on diuretics (Furosemide)
What type of hypertrophy is associated w/ MAVVD?
Eccentric hypertrophy of L ventricle – Volume Overload
What do jet lesions cause?
Rupture of L atrium & cardiac tamponade
How do dogs w/ MAVVD present?
- Asymptomatic murmur (louder = more regurg/ worse prognosis)
- Large airway compression = Syncope
- L atrial rupture & cardiac tamponade
Acute heart failure
Chronic CHF
If a small dog comes in coughing – What is your DDx?
- Small airway dz
- Collapsing trachea
- Compression of bronchus from MAVVD
- MAVVD CHF
What is an early sign of MAVVD?
Systolic click
**Occurs when elongated chordaete tendonae snap tight as the degenerative valve protrudes into the L atrium in mod systole
How does MAVVD appear radiographically?
- L atrial enlargement ===> May not see in acute onset due to blown chordae tendinae
- Lung edema
- Enlarged heart (fills 3 ribs spaces)
How does MAVVD appear on echo?
*Function is normal
- *LA is enlarged
- *Valves look thickened & club shaped
When murmur is detected in asymptomatic dog what is the most likely cause?
MAVVD
How do you tx MAVVD dogs w/ a cough but not HF?
**Arteriodilators (Hydralazine, ACE inhibitors)
**bronchodilators
How do you tx MAVVD dogs w/ mild to moderate HF?
**Medical tx @ home
- Furosemide to control pulmonary edema
- ACE inhibitors (enalapril)
- Na restricted diet & limit exercise
How do you tx MAVVD dogs in severe HF?
***Tx in hospital
**Supplemental O2
**IV furosemide until RR has decreased by 10 breathes/min
- *Nitroprusside
- *ACE inhibitors
- *Spironlactone
- *Pimobendan
**Hydralazine
**Amlodipine (Ca channel blocker)
When should you not Tx with Pimobendan?
Do not use until onset of clnical signs because can be deleterious
What can pulmonary hypertension associated w/ MAVVD cause?
R heart failure
What is stage A of chronic valvular heart disease?
Normal dogs @ high risk
Cavelier king charles spaniel & small breeds
**Should have a yearly check up
**If there is a murmur, do NOT breed
Does not require drugs or diet therapy
What is stage B1 of chronic valvular heart dz?
***Structureal heart dz, but no signs of CHF
***Have no radiographic or echo signs of remodeling
**Recheck every year
Does NOT require Tx
What is stage B2 of chronic valvular dz?
***Have structural heart dz, but no clinical signs
***Do have radiographic & echo signs of L heart enlargement
Can tx w/ ACE inhibitors, beta blockers or mild Na restriction
What is stage C of chronic valvular dz?
***Have past or current signs of HF
***@ home Tx = furosemide, ACE inhibitors, Pimobendan, spirolactone, beta blockers, diet changes
In hospital = FONS
What is stage D of chronic valvular dz?
- ***End stage HF
- **Max furosemide dose
Free access to water
Remove body cavity fluid
***Nitroprusside + Ace inhibitor + Pimobendan
Diet change
**No Beta Blocker
Endocarditis commonly occurs in what part of the heart?
Normally develops in aortic & mitral valves
Endocarditis infection leads to?
- *Dysrhythmias
- *VPDs
- *Tachycardia
- *Heart block
- *Septic emboli
- **Glomerulonephritis & arthritis from immune response
What Hx is associated w/ dogs w/ endocarditis?
**Invasive Dx or Sx procedure
**Urinary, skin, or oral infection
Usually reports signs of systemic infection
How does endocarditis present on PE?
**Fever + heart murmur
**Bounding pulses
**Aortic insufficiency
May see pneumonia, renal or neuro signs caused by emboli
What so you see on lab work w/ endocarditis?
- Neutrophilic leukocytosis w/ L shift
- Anemia, thrombocytopenia
- elevated BUN, creatinine & liver enzymes
How does endocarditis appear on echo?
Appear has vegetations on the mitral/aortic valve
Affected valves are hyperchoic, thickened & irregular
How do you treat endocarditis?
Tx arrythmias & HF
Parenteral bactericidal ABX for @ least 1-2 weeks
Followed by oral ABX for 2-4 months
What ABX are used initially to Tx endocarditis?
Clindamycin
Enrofoxacin
What cardiac dz may predispose dogs to endocarditis?
Subvalvular aortic stenosis
What are the guidelines for prevention of endocarditis in heart sx?
Ampicillin or amoxicillin
1 hour before procedure & 2-3 days after
What are the causes of pericardial effusion?
CHF Hypoalbuminemia Pericarditis Hemorrhage Neoplasia Idiopathic
What tumors cause pericardial effusion?
Hemangiosarcoma
Heart base tumor-parpganglioma
Lymphosarcoma
mesothelioma
How do dogs w/ pericardial effusion present on PE?
Pale mm Slow CRT Muffled heart sounds Poor pulses Jugular distension Ascites No heart murmur
What is the predilection site for hemangiosarcoma?
R auricle & atrium
What is the predilection site for paragangliomas?
Base of aorta
Why are diuretics contraindicated in pericardial effusion?
They decrease blood volume & cause further collapse of the cardiac chambers
How do you Tx pericardial effusion?
Immediate percardiocentesis
What heart problems are seen in Boxers?
Boxer Cardiomyopathy (ARVCM) Dilated Cardiomyopathy (DCM) – Fibro-Fatty Type Aortic Stenosis Atrial Septal Defect Supraventricular Tachycardia VPD’s ==> Bigeminy, Trigeminy Endocarditis Carnitine deficiency
What heart problems are specific to Doberman’s?
Dilated Cardiomyopathy – Fibro-fatty Type & Familial
What heart problems are specific to bulldogs?
Pulmonic Stenosis
Ventricular Septal Defect
What heart problems are found in Giant/Large breeds?
Dilated Cardiomyopathy – Wavy Type
AV-Valve Insufficiency
Endocarditis
What heart problems are specific to German shepards?
Inherited Ventricular Arrhythmias (puppies)
PDA (F3:M1)
Endocarditis
Pericardial Effusion (Hemangiosarcoma)
What heart problems are found in Brachycephalic breeds?
Pericardial effusion - paraganglioma
What heart problems are found in cats?
Hypertrophic Cardiomyopathy (HCM) Ventricular Septal Defect Tetrology of Fallot AV Valve insufficiency PRAA – 4th in kittens & Megaesphagus
What heart problems are found in Asian cats?
Endocardial Fibroelastosis
What are some diuretics that inactivate the RAAS system and are useful when furosemide dose has gotten too high in conjunction with ACE Inhibitors?
**Thiazides (synergistic effect w/ furosemide)
**Spironolactone (aldosterone antagonist)
Why are ACE inhibitors so useful in slowing the progression of HF?
**They allow the dose of furosemide to be reduced which helps prevent azotemia from occuring.
**Block potent vasoconstrictor effects of angiotensin II & myocardial remodeling effects and fibrosis induced by aldosterone
Why do we try to maximize ACE inhibitor dose and minimize furosemide dose?
Want to increase volume in animal to increase CO ==> increased GFR and less chance of causing dehydration, azotemia, and electrolyte imbalances
PDA murmur type, sound, pulse type?
- L==>R shunt
* Systolic and Diastolic murmur
* Machinery murmur
* waterhammer pulse - R==>L shunt
* Systolic to absent murmur
Will an EKG detect a PDA?
NOOOOO
Only way to directly cause vasodilation of pulmonary artery?
Oxygen and Sildenafil (useful for reducing amount needed to shunt in PDA)
Aortic Stenosis type of murmur and pulse?
**Systolic & Diastolic murmur
**Weak peripheral pulse but very strong at apex
Holosystolic (still hear heart sounds)
When the aorta outflow is obstructed what happens?
Pressure overload = CONCENTRIC hypertrophy
3 main conditions almost always occur with Aortic Stenosis?
- Synchope
- Weakness
- Sudden death
Why do dogs rarely develop signs of LCHF with aortic stenosis?
Few make it to LHF because DECREASED CO from lack of peripheral blood flow + arrhythmias (VPD & VTach) = sudden death
In Pulmonary Stenotic dogs where sx is not possible, what drug may improve Diastolic fxn and arrhythmias?
Atenolol b/c it is B1 selective and has less effect on the lungs
ASD murmur type?
May be murmur over base of heart due to relative pulmonic stenosis (systolic murmur),
relative tricuspid stenosis (diastolic murmur), and maybe splitting of S2
How can you determine the difference between Aortic Stenosis and ASD?
Only way is ultrasound
A bounding hyperkinetic pulse is indicative of what?
Aortic insufficiency
