cardiology unit 2 Flashcards
Why does DCM occur
Decreased LV systolic function
myocardial disease (problem with the muscle itself)
Primary DCM: Genetic/idiopathic: Dobermans PDK4 mutation
Secondary DCM: nutritional deficiency, infectious/inflammatory , tachycardia-induced cariomyopathy, sepsis-induced mycardial dysfunction
Histology from cardiac muscle, what is your diagnosis?
DCM
What ECG changes do you see with DCM and dobermans?
ventricular arrhythmias often precede echo changes in DCM
What ECG changes do you see with DCM and Irish Wolfhounds?
Atrial fibrillation
What dogs are the most common to get DCM ?
Dobermans >6months ~50% of the time
Great danes
Irish Wolfhounds
Cats: taurine deficiency
Male > Female
How is DCM detected?
breeder screenings (especially for dobermans)
Murmurs, or arrhythmias on veterinary screenigns
What do you look for on echocardiography for DCM diagnosis?
Decreased LV systolic function
Increased LV size
What is the ECG Holter scale used for DCM diagnosis?
Used to determine the probability that a Doberman will develop DCM
>100 VPC’s/24hr 100%
>50 VPC’s/24hr or 1 couplet/triplet: 94%
1+ VPC/5 minutes 96.7%
1+ VPC/24hrs 74%
NO VPCs/24 hrs 42%
True or False
The severity of ventricular arrhythmias is correlated with the severity of myocardial dysfunction in relation to DCM
True
What is NT-proBNP
DCM biomarker
What nutritional deficiencies are associated with DCM?
Taurine/carnitine - measure the blood and supplement if it is low
Plasma carnitine does not correlate with myocardial carnitine
What are the complications of DCM?
Left or Right sided CHF
- dyspnea, tachypnea
- cough
- Exercise intolerance/inappetence
- abdominal distension
Syncope-secondary to ventricular arrhythmias
sudden cardiac death
where does the fluid go for a dog with Left sided CHF
Pulmonary edema
where does the fluid go for a Dog with Right-sided CHF
Ascites
occasionally pleural effusion
Where does the fluid go for a cat with left-sided CHF
pulmonary edema
pleural effusion
pericardial effusion
Where does the fluid go for a cat with right-sided CHF
pleural effusion
ascites
pericardial effusion
What is a negative prognostic indicator for DCM
severe ventricular arrhythmias:
poorly controlled atrial fibrillation rate:
younger age of onset;
pleural effusion;
being a Doberman or Great Dane
what is the average time to CHF for a dog with DCM?
2 years with a doberman
2-5 years for other breeds.
following an episode of CHF 6mo-2 year.
What is the cause of death in a patient with DCM?
2/3 of cases end in CHF
1/3 of cases end in sudden cardiac death
What is the treatment protocol for a patient witih DCM?
The goal is to optimize the heart rate.
Pimobendan: prolongs time to CHF
ACE inhibitor: prolongs time to CHF
Atenolol is cardioprotective (do not give to acute CHF patient)
Treat arrhythmias
Ventricular arrhythmias: sotalol, mexiletine
Atrial fibrillation: digoxin, diltiazem
dog with acute DCM treatment
FOPS:
Furosemide
Oxygen
Pimobendan
Sedation (butorphanol)
centesis if pleural effusion/ascites
dobutamine if in cardiogenic shock- poor CO
lidocaine: if life threatening VT
What is the treatment for a dog with Chronic DCM with CHF
“Dogs Are For Special People”
Dietary Na+ restriction
ACEi
Furosemide
Spironolactone
Pimobendan
Diltiazem/Digoxin: rate control in atrial fibrilation
Sotalol/Mexiletine: Ventricular arrhythmias
What is Arrhythmogenic Right ventricular cardiomyopathy ARVC?
a disease of the desmosomes
Ventricular arrhythmias with DCM phenotype
signalment: middle-aged Boxers
clinically present with syncope most of the time.
Treatment Sotalol
guarded prognosis
What are congenital pericardial diseases?
Absence of pericardium
Peritoneopericardial diaphragmatic hernia PPDH
What are acquired pericardial diseases?
Pericardial effusion and cardiac tamponade
constrictive pericarditis
What are the different types of fluid found in pericardial effusion, and differentials for each
hemorrhagic
- neoplasia (#1 cause in dogs)
- idiopathic (#2 cause in dogs)
- other
Transudate
- RCHF
- Hypoalbuminemia
Exudate
- infectious
- FB/hardware disease (#1 cause in cattle)
- fungal coccidiomycoses
- Sterile
- secondary to systemic inflammation
what type of dysfunction do you get with pericardial diseases?
Diastolic dysfunction
What is cardiac tamponade
the clinical syndrome that occurs when increased intrapericardial pressure interferes with normal cardiac filling
what is the outcome of cardiac tamponade?
sudden death
Compensation
Reduced cardiac filling resulting in low CO and Low BP
What are clinical signs of cardiac tamponade?
collapse, weakness
decreased appetite, vomiting
lethargy
decreased milk production in cattle
polyurea, polydipsia
What are physical examinatino findings of cardiac tamponade cases?
distended jugular veins
pleural effusion
muffled heart sounds
weak femoral arteries
ascites
What is pulsus paradoxus?
Changes in cardiac output based on the breathing cycle.
on inspiration, the negative intrathoracic pressure increases the volume of blood in the heart.
What are the 3 hallmark findings of pericardial effusion on radiographs?
- enlarged rounded cardiac sillhouette
- dilated caudal vena cava
- Small pulmonary arteries and veins
True/ False
During pericardial effusion, you are not able to make out the underlying structures.
True
what are other ECG abnormalities seen with Pericardial effusion
decreased QRS amplitude
Variable R wave heights
what are treatments for pericardial effusion
- if unstable/decreased BP IV fluids.
- if preparing for a pericardiocentesis, administer quarter shock bolus of IV crystalloids
- Pericardiocentesis
Where do you performa pericardiocentesis?
The right side of the chest ICS 3-5
in the intercostal space, go just cranial to the rib to avoid the neurovascular bundle that lies caudal to the rib
What is the pathogenesis of constrictive pericarditis?
inflammation or infectious process
thickened, noncompliant pericardium +/- adhesion to the cardiac muscle prevents relaxation of the heart
Reduced cardiac filling results in low cardiac output and low blood pressure
Same clinical signs exam findings, and radiographic findings EXCEPT the heart can be nromal size.
What is PPDH
this is an abnormal connection from the abdomen tot he pericardium
Cats> dogs
Clinical signs vary depending on organs affected, tachypnea, dyspnea, vomiting, anorexia, weight loss
What does PPDH stand for
peritoneal-pericardial diaphragmatic hernea
What is the normal pulmonary artery pressure and what defines Pulmonary hypertension?
normal: 25mmHg
PHT > 30mmHg
Why does Pulmonary hypertension occur?
- idiopathic -retnetion of fetal pulmonary vascular resistance
- Left sided heart disease -> pulmonary venous hypertension (post capillary disease)
- Chronic pulmonary disease -> hypoxemia and vasoconstriction
- Pulmonary thromboembolic disease
Where is pulmonary hypertension localized?
precapillary
postcapillary
- left sided heart disease
What happens to pulmonary arteries/arterioles in pulmonary hypertension?
medial hypertrophy
Intimal proliferation and fibrosis
“Plexiform” lesions
What happens to the heart with pulmonary hypertension?
high right ventricular afterload
Right ventricular hypertrophy and dilation, main pulmonary artery enlargement, tricuspid regurgitation, pulmonic regurgitation
What are the complications of Pulmonary hypertension?
syncope
dyspnea
exercise intolerance
cough
These are often misdiagnosed as L-CHF secondary to mitral valve disease
How do you diagnose the PA pressure on echocardiography
velocity of blood flow is determined by PRessure Gradient
Estimate PA pressure using velocity of
- Tricuspid regurgitation (systolic)
- Pulmonic regurgitation (diastolic)
How do you diagnose Chronic bronchopulmonary disease as the primary cause of pulmonary hypertension?
thoracic radiographs
fluoroscopy
Bronchoscopy
How do you diagnose pulmonary thromboembolic disease as the primary cause of pulmonary hypertension
thoracic CT-angiography
D-dimers
what medications are for the treatment of pulmonary hypertension in the presence of R-CHF?
R-CHF: furosemide, Pimobendan, enalapril
Pulmonary vasodilatior: Sildenafil
What is the treatment if pulmonary hypertension is due to chronic bronchopulmonary disease?
Bronchodilators (theophyline)
cough suppressants (hydrocodone)
antibiotics (doxycycline
Steroids (prednisone)
Treatment of pulmonary hypertension that is due to Left sided heart disease
enalapril, pimobendan, furosemide, spironolactone
How do you treat pulmonary hypertension due to pulmonary thromboembolic disease
Clopidogrel
Aspirin
Treatment of PLE/PLN/Cushing’s
How do you traet pulmonary hypertension due to heartworm disease?
heartworm preventative
doxycycline
Melarsomine protocol
What is cTnl?
protein attached to actin/tropomyosin cardiac sarcomere
This is a leakage protein that is released when myocytes are damaged
Sensitive and specific for myocardial injury
this cannot specify what caused the injury
What are differentials for increased cTnl?
myocarditis
thoracic/cardiac trauma
Cardiotoxicity
cardiac hemangiosarcoma in dogs
DCM in dobermans
CHF
Chronic kidney disease
What is the clinical utility of cTnl?
when might you use this test?
- patients with a clinical suspicion of myocarditis
- fever, arrhythmias, echo abnormalities
- Dogs with pericardial effusion
- Asymptomatic Dobermans normal vs. occult DCM
- Dyspneic cat: CHF vs respiratory disease
- NT-proBNP is better in this situation
- Cats with HCM
What is NT-proBNP
hormone synthesized and released from the ventricles in response to myocardial stretch
Causes diuresis, naturesis, vasodilation (natural “anti-RAAS”) causes vasodilation and excretion of water and Na, this will be elevated in cardiac disease
C-BNP is the active form NT-proBNP is the inactive form
What causes NT-proBNP elevation?
incresed with cardiac disease such as: Mitral valve disease, DCM, HCM, CHF
Magnitude fo increase correlates with severity of heart disease
Increased wtih some non cardiac diseases such as day-to-day variations, chronic kidney disease, critical illness, pulmonary hypertension
What is the clinical utility of NTproBNP?
When woul dyou use this
- Asymptomatic cats with murmurs: occult HCM?
- high sensitivity/specificity
- Dyspneic cats: CHF vs respiratory disease
- Dogs with CHF
Dr. Ward almost never runs this test.
What happens if the RAAS system is activated Long Term?
cardiac fibrosis
Renal damage
Cytokine activation
what activates RAAS system?
Juxtaglomerular apparatus releases renin in response to low BP, low renal blood flow, or sodium or high sympathetic nervous system tone
What is the outcome of RAAS activation
increased volume by causing Na and water retention.
aldosterone release to cause Na and water retention
ADH release increasese thirst
Increased vascular resistance due to ADH
Where is Angiotensinogen produced?
The liver Constitutively produces it
in the presence of renin, it is converted to Angiotensin I
What are the negative effects on the heart due to Angiotensin II?
high vascular resistance (increased afterload)
excessive volume retention may lead to CHF in a diseased heart
ATII and aldosterone are cardio-toxic and cause cardiac fibrosis, vascular smooth muscle proliferation leading to systemic hypertension and cytokines and free radical formation that lead to cardiomyocyte death
Renal and arteriolar sclerosis leading to renal damage
How can you intervene with the RAAS system?
improve pumping functoin
Stop or counteract the RAAS activation/actions with ACE inhibitors
Antihypertensives
Cardioprotective agents.
What are common underlying causes of systemic hypertension in dogs
Hyperadrenocorticism
Chronic kidney disease
What are common underlying causes of systemic hypertension in cats
Hyperthyroidism
Chronic kidney disease
Why is systemic hypertension bad?
Kidney- progression of CKD and proteinuria
Eye- retinal hemorrhage and detachment
Brain- hemorrhagic: stroke
Heart: left ventricular hypertrophy
Blood vessels: hemorrhave
what is the “normal” systolic blood pressure?
120-130
When is blood pressuer considered hypertensive?
Above 140
Hypertensive 160-179
Severe >180
What patients should be screened for systemic hypertension?
- patients with evidence of target organ damage
- patients with diseases that cause secondary systemic hypertension
- Patients receiving vasodilatory therapy
- Patients with a disease that can be worsened by systemic hypertension
Routine screening recommended for pets >9 y.o
When you have a patient that presents with No evidence of target organ disease and a BP greater than 160mmHG, how do you choose to proceed?
Repeat the BP twice within 8 weeks.
If it is less than 160mmHg recheck in 3-6months
If greater than 160mmHg Treat!
How is systemic hypertension treated?
The goal is to control the blood pressure.
- Enalapril, benazepril are ACE inhibitors that decrease the BP by 10-15 mmHg
- This decreases glomerular hypertension and proteinuria
- Inhibits RAAS system
- Telmisartan- decreases BP by 20-25mmHg, and inhibits RAAS system
- Amlodipine is a calcium channel blocker that decreases BP by 30-60mmHg. no effect on renal efferent arteriole
- Activates the RAAS system
When should blood pressure be rechecked after antihypertensive medications have been started?
Recheck 7-10 days after starting the antihypertensive. If the BP is > 140 mmHg, increase the dose or add a second agent.
Why does HCM occur?
this is a disease of the sarcomere.
Genetic mutations in MyBPC
Impaired LV myocardial relaxation = DIastolic dysfunction (not enough relaxation/filling)
concentric hypertrophy
What is the difference betwween HCM and HOCM?
The outflow track is obstructed in HOCM
What animals are prone to getting H(O)CM?
Cats
Breeds: Maine Coons, Ragdolls
Males have ~75% of acquiring it
How is HOCM detected?
breeder screening through echocardiogram or genetic testing
Veterinary screeing: Murmur, arrhythmia, cardiac biomarkers
Definitively diagnosed using an Echocardiography and see LV hypertrophy and LV diastolic dysfunction
what causes a heart murmur in H(O) CM ?
dynamic LVOT obstruction. HOCM Is easier to diagnose than HCM
1 in 7 cats have HCM of those 1 in 2 has a murmur
What are complications of HOCM?
CHF with dyspnea, tachypnea, inappetence ADR hiding
Arterial thromboembolism -> acute paresis/pain bilateral hindlimb is more common
Sudden cardiac death
What are negative prognostic indicators for a patient with H(O)CM?
left atrial enlargement, Severe LV hypertrophy, older age.
Asymptomatic cats have an average surgival rate of ~5 years
following left atrial enlargement: 3-6 months
What medications are known to decrease the chance of thrombosis?
Clopidogrel
Aspirin
Heparin
tPA
What medications are used to treat Stage B HCM patients
- Atenolol- LVOT obstruction, severe sinus tachycardia (more likely with HOCM) used to decrease the heart rate and potentially get rid of the outflow blockage
- Ace inhibitors - Severe LV/LA remodeling and fibrosis
- Clopidogrel (moderate-severe LA enlargement) decrease the chacne of thrombus formation
What medications are used to treat Stage C CHF with HOCM?
Acute: O@ supplementation +/- thoracocentesis
Furosemide
Ace inhibitors
pimobendan (may be a concern with HOCM cats)
Spironolactone
What medications are used to treat arterial thromboembolism
Analgesia
Clopidogrel
Heparin/low molecular weight heparin
Thrombolysis
the goal is to decrease additional thrombus formation
What are innocent murmurs?
physiological murmurs.
Soft grade I-III/VI
Left sided
Early or mid-systolic
disappear by 4-6 months
What are the most common congenital heart disease in puppies?
PDA
Pulmonic stenosis
subaortic stenosis
PDA
failure of closure of ductus arteriosis
Consequences L-R shunt causing L CHF
signalment: poodles yorkies, shelties especially females
Murmurs: continuous “washing-machine” murmur @ left heart base
What are treatments for PDA?
interventional catheterization
Surgical ligation (thoracotomy)
treatment dramatically improves prognosis
Pulmonic stenosis
congenital narrowing/thickening of the pulmonic valve
Consequences: RV pressure overload -> RCHF, syncope, arrhythmias
Signalment: Beagle, Boxer, Bulldog
Murmur: systolic ejection murmur @ left heart base
Pronosis: guarded with no treatment, good with balloon vulvoplasty
what is the treatment for pulmonic stensosi
mild/moderate: atenolol
Severe : balloon valvuloplasty
True/ False
It is harmful to wait >6mo. for a referral if the murmur is initially soft
False.
there is no harm in waiting
Subaortic stenosis
congenital ridge/narrowing below the aortic valve. Lesion continues to progress throughout growth
L-ventricular pressure overload ->L CHF, endocarditis
Signalment: Larger breeds (Newfoundland, Boxer, GSD, Golden, Rottweilers)
Murmur: systolic ejection murmur at left heart base
Treatment for Subaortic stenosis
Atenolol if moderate/severe
No good procedure: baloon valvuloplasty is not effective
What monitoring recommenations do you have for owners with a pet that has Subaortic stenosis
Disease progresses until the dog is fully grown. i fth emurmur is soft, you must recheck the echocardiograpm as adult to know the disease severity
What are other congenital heart diseases in dogs (less common)
VSD- right-sided murmur
Tricuspid valve dysplasia
Cyanotic heart defects (right to left shunting)
when should you refer a pupy with a murmur?
- refer any murmur that is continuous, diastolic or right sided
- refer a left-sided systolic murmur if you can heart it on both sides of the chest
- Refer any murmur still heard after 6 months
What are the most common congenital heart diseases in kittens?
Ventricular septal defects
AV valve dysplasia (mitral/tricuspid)
Ventricular septal defect
abnormal communication between left and right ventricles
Consequences: L-R shunting -> L-CHF
Murmur: Systolic plateau or decreschendo murmur @ right side
Prognosis is dependent on the size of the defect
What are treatment methods for a VSD in cats?
small restrictive (loud murmur) no treatment required
Large/unrestrictive (softer murmur) treat CHF when it occurs. there is no corrective procedure in cats.
Mitral and tricuspid valve dysplasia
abnormal development and leakage/stenosis of mitral and/or tricuspid valves
consequences: LV or RV volume overload resulting in R or L CHF
Murmur: systolic plateau/regurgitant murmur @ left or right apex
How do you treat Mitral and tricuspid valve dysplasia in cats?
you treat when CHF occurs
No corrective procedure is available
when should you refere a kitten with a murmur?
refera a murmur that is continuous, diastolic or right-sided
Refer a left-sided systolic murmur if you can hear it on both sides fo the chest. Refer any murmur still heard after 6 months
There are fewer surgical/treatment options for cats
How do you distinguish “innocent” murmurs vs murmurs due to congenital heart disease
What congenital heart diseases are associated with volume overload?
Left side: congenital VDA, VSD, MV dysplasia
Right side: congenital:tricuspid dysplasia
what congenital heart diseases are associated with too much afterload (pressure overload)
Left: Congenital Subaortic stenosis
Right: Congenital Pulmonic stenosis
