Cardiology Flashcards
True or false; echocardiography is used to detect CHF signs such as pulmonary edema
False. Echo utility: Structural defects Pericardial effusions FS% Blood Flow Pressure gradients (severity)
What can you assess with 2-dimensional mode of echo?
Valve structure, chamber structure
M-mode assesses what?
Heart movement over time
What do neither M-mode or 2-D mode assess?
Blood flow
What does doppler echo do and what is crucial for correct blood flow accuracy?
Evaluates direction and speed (spectral) and flow (color) of blood.
Alignment needs to be parallel to blood flow for accuracy
What are the two 2-D views we can look at the heart on echo?
Long (sagittal) and Short (transverse) axis
If we have a mushroom what view are we in?
Short axis LV view
Where are M-mode images obtained?
Short axis at the level of the LA (base), MV, LV
What can M-mode tell you?
Wall thickness, quality of contraction, fractional shortening (accurate measurements of systolic contraction) dilation, MV view can assess mitral valve motion and LV diastolic function
What is Fractional shortening %?
Difference between the Diastolic and Systolic dimensions, taken from the internal wall
LVDD-LVDS/LVDDx100
What is the normal Fractional shortening range in dogs? Cats?
Dogs: 25-40%
Cats: 35-50%
What does it mean if the FS% is small?
Poor systolic function
Doppler echo has two types: which is qualitative and which is quantitative?
Color flow- turbulence (qualitative)
Spectral- flow/speed (quantitative)
on color doppler echo, what does blue, red, green/yellow mean?
Blue: flow away from probe
Red: flow towards probe
Green/yellow: turbulence and high velocity
What can spectral doppler assess?
pressure gradient across a stenotic valve or shunt
calculate chamber pressures
- Modified Bernoulli Equation (4xvsquared)
-velocity is never overestimated (commonly underestimated if not parallel)
What is a normal aortic valve velocity?
1.5 m/sec
What is the normal pulmonic arterial velocity?
1.5 m/sec
Normal RA pressures?
2 - 8
Normal RV pressures?
(S) 15 - 30 / 2-8 (D)
What does the Bernoulli equation calculate?
chamber pressures difference, it can tell you severity of stenosis
E.g. PA vs RV pressures
Normal PA pressures?
(S) 15-30/4-12 (D)
Normal LA pressures?
2-10
Normal LV pressures?
(S) 100 - 140 / 3-12 (D)
Normal Aortic pressures?
(S) 100 - 140 / 60 - 90 (D)
What is the heart’s response to Diastolic dysfunction?
Concentric hypertrophy
What is the heart’s response to Pressure overload?
Concentric hypertrophy
What is the heart’s response to Systolic dysfunction?
Eccentric hypertrophy
What is the heart’s response to Volume overload?
Eccentric hypertrophy
What are two causes of primary systolic dysfunction?
Dilated Cardiomyopathy
Arrhythmogenic Right ventricular cardiomyopathy
What are 5 causes of secondary systolic dysfunction?
Toxin/drug Dietary deficiency Tachycardia-induced Hypothyroidism Inflammation
How does hypothyroid cause secondary systolic dysfunction?
Decreased production of T4 and T3 -> Decreased metabolic rate (indirect) and decreased inotropy + chronotropy (direct)
What do you see with tachycardia-induced cardiomyopathy?
Supraventricular arrhythmias which can lead to atrial fibrillation (the heart gets tired!)
Treatment for Tachy-induced CM?
Slow the heart (beta blockers, Digoxin)
What are some dietary deficiencies that can lead to Systolic dysfunction?
Taurine (cats, cocker spaniels)
L-carnitine (cockers, goldens, boxers)
Which dietary deficiency can you only confirm with heart muscle biopsy?
L-carnitine
What is the name of the chemotherapeutic agent that is cardio toxic?
Doxorubicin (Adriamycin)
Who gets DCM?
Adult large dogs
Tx for primary DCM?
B1: monitor
B2: Pimo +/- ACE
C: Furos, Pimo, ACE, +/- spiro, +/- antiarrhythmics
Arrhythmogenic RVCM also known as boxer cardiomyopathy etiology?
Idiopathic, histology shows fibro-fatty replacement of myocytes
What are the three main functions of the heart?
- conduct electricity
- systole
- diastole
Boxer CM Dx, Tx?
Dx: Holter monitor and echo Tx: If they just have the arrhythmia no CHF yet: Antiarrhythmics (oral) -Mexiletine -Sotalol If in CHF -Furosemide -Pimobendan -Ace inhibitor -+/- spironolactone Prognosis is guarded either way (sudden death at any time with boxer CM)
Which usually have a better prognosis primary or secondary systolic dysfunction diseases?
secondary
When we have diastolic dysfunction, where does the blood back up to?
Left side most prominent: Overflows from the left ventricle (can’t open to take more blood) , back to the left atrium, back to the pulmonary veins and causes pulmonary edema.
What are causes of primary diastolic dysfunction disease?
Hypertrophic obstructive cardiomyopathy
Hypertrophic cardiomyopathy
Restrictive cardiomyopathy
What are causes of secondary diastolic dysfunction?
Pressure overload
Pericardial diseases
What are the categories of pressure overload?
Hypertension
Stenosis (congenital)
Where is the pressure overload happening if we have pulmonary hypertension?
Right ventricle -> right sided diastolic dysfunction
Where is the pressure overload if we have systemic hypertension?
Left ventricle -> left sided diastolic dysfunction
What type of hypertrophy do we get with pressure overload?
Concentric hypertrophy (can get it with primary diastolic dysfunction as well)
What does blood pressure dictate?
perfusion - goldilocks (not to low or too high for brain and kidneys)
What value is systemic hypertension?
> 160 mmHg (sustained)
What are the most common causes of systemic hypertension in vetmed?
Hyperaldosteronism (both) Pheochromocytoma (Dogs) Acromegaly (both) Medications (both) Diabetes Mellitus (both) Hyperthyroid (Cats) Hypothyroid (Dogs) Cushing's (Dogs) Renal disease (both)
Which diseases CAN skip the systemic hypertension and just give you systemic hypertrophy?
Pheochromocytoma
Cushing’s
Acromegaly
Hyperthyroidism
What are the target organs that are most susceptible to systemic hypertension?
Brain - hemorrhage encephalopathy
Eyes - cats, tortuosity, retinal detach
Heart - vessels outside, myocardial infarct
Kidney - ^GFR, proteinuria, ischemia, KD
Does heart disease cause systemic hypertension?
NO - decreased CO
Can systemic hypertension cause heart disease?
YES - concentric hypertrophy
What drugs lower blood pressure?
Amlodipine Diuretics - not first line (makes kidneys work harder) ACE-inhibitors Beta-blockers Phenoxybenzamine
How do you decide which bp drug to use?
Target underlying disease Amlodipine - general and cats w/renal dz ACE-I - proteinuria Beta-blocker - Hyperthyroidism Phenoxybenzamine (alpha 1 antagonist) - pheochromocytoma
What is a drug that can commonly cause hypertension?
Phenylpropanolamine
What are the goals of hypertension treatment?
get BP to 100 - 160 mmHg
Ameliorate clinical signs
Prevent organ damage (b,e,h,k)
Do animals get primary systemic hypertension?
No, its due to some underlying process
Severe acute arteriolar vasoconstriction would have what affect on the heart
Decrease heart rate (reflex bradycardia)
What is the cushing reflex?
When there is an intercranial bleed, there is a reflex bradycardia from the increased blood pressure to maintain brain perfusion.
brain perfusion = sys. bp - intracranial pressure.
Etiology of HCM?
Genetic - myosin-binding protein C
-Maine Coons
-Ragdolls
Idiopathic
How do you diagnose HCM?
Echocardiogram (wall should be less than 5.5 mm) - rule out secondary causes
- radiographs don’t show concentric hypertrophy.
Treatment for HCM Stage B2?
not a lot of research. Pick what you want. ACE-I, B-blocker, Diltiazem, Spiro, Antithrombotic
What is stage C HCM in a cat?
Could be CHF OR Arterial thromboembolism
What does left sided CHF look like in a cat?
Pulmonary edema and/or Pleural effusion -modified transudate -chylous
How on PE could you tell a cat had pulmonary edema vs. pleural effusion?
Pulmonary edema: Crackles, wheezes
Pleural effusion: Decreased ventral heart sounds
Treatment for stage C (CHF) HCM?
Furosemide, ACE-I, Pimo, Spiro, Antiarrhythmics.
Pleural effusion - thoracentesis and then Furosemide to stop re-accumulation of fluid.
Treatment for stage C (Thromboembolism) HCM
Due to blood stasis (left auricle) -> aortic thromboembolism -> infarct at the aortic trifurcation.
Tx: Supportive care (pain mgmt.) Antithrombotics (Asprin, Clopidogrel, LMWH)
What is prognosis for a cat with Arterial thromboembolism?
Guarded to poor
critical period 24 - 72 hrs
reperfusion injury (hyperkalemia)
What are the 4 ECG changes associated with hyperkalemia?
Tented T waves
Decreased amplitude P waves to no P waves
Increased PR intervals
Wide QRS complexes
Treatment for hyperkalemia from reperfusion injury?
Dextrose (drive potassium in) Furosemide Bicarb Calcium IV fluids
What do you use to treat HOCM?
everything as HCM but with Beta-blockers
Restrictive cardiomyopathy differences?
Fibrosis? Cat dz
no thickened walls on echo but diastolic dysfunction
dx of exclusion
Tx: same as HCM but if you have systolic dysfunction add on pimobendin
Prog: worse (6-10 mo)
What is pulse pressure? Why do heart failure animals often have normal pulse pressures?
systolic bp - diastolic bp, the body tries to maintain bp from falling CO by increasing SVR.
Right heart pressure overload causes backup where?
So the pressure is highest in the pulmonary arteries. So volume backs up to the right ventricle and atrium
What is increased pressure in the lungs?
> 30 mmHg systolic
>10 mmHg diastolic
What can cause increased pulmonary venous/LA pressure?
Left-sided heart failure Pulmonary venous obstruction (rare) Hilar lnn enlargement Increased volume within the lungs (cardiac output - horses) Left to right shunt (PDA, VSD, ASD) Increased pulmonary vascular resistance
What can cause increase pulmonary vascular resistance?
Loss of pulmonary vessels: -Pulmonary thromboembolism (Virchow's Triad) --Neoplasia --Cushing's --PLN --Inflammatory disease (IMHA) -- Heartworm dz (endo inj) -- Vasculitis (endo inj) Hypoxemia (pulmonary vasoconstriction) --Primary lung dz (CBr, Ctrach, Pulm fib) -- High altitude
What is Virchow’s Triad?
Blood Stasis
Endothelial injury
Hypercoagulability
How do you diagnose pulmonary hypertension?
Cardiac catheterization (gold standard) Echocardiogram (indirect, regurgitation, modified Bernoulli equation to est. pressures)
How do you treat Pulmonary Hypertension?
- Treat the underlying disease
2. Sildenafil (Viagra) MOA: PDE type V inhibitor (lungs - vasodilation)
Prognosis for pulmonary hypertension?
Guarded, depends on underlying dz
What is the primary function of Wolbachia in heartworm?
Helps them grow and develop and have more babies.
How do you diagnosis heart worm?
Heartworm antigen of the adult female reproductive tract. (takes 6 months to be positive from infection)
Antibody - only exposure
Microfilaria - Knotts test
Classification and staging of heartworm disease?
- Asymptomatic
- Respiratory signs (coughing, tachypnea)
- Cor Polmonale: pulmonary hypertension
- R-sided CHF (from hypertension)
- Caval syndrome (hepatic cong.)
Heartworm comorbidities?
Antigen-Antibody complexes - glomerular deposition - proteinuria - PLN
Thrombocytopenia
Anemia
How do you test for the comorbities?
CBC - anemia, thrombocytopenia
Chem - renal values
UA - proteinuria
Thoracic rads - pulmonary vascular changes
Echo - evaluate for pulmonary hypertension
How do you treat heartworm?
Fast kill method:
Melarsomine - adulticide (retest 6 mo)
Babies - preventative (minimize reinfection)
Wholbocia - doxycycline (kill the friends)
Feline heartworm clinical signs?
They look like asthma cats, false negs common, few worms.
Tx for feline hw?
Steroids, Doxycycline, surgery?
What are two diastolic dysfunction diseases that are pericardial diseases?
Pericardial effusion
Peritoneal-pericardial diaphragmatic hernia
When does a pericardial effusion become a physiological problem?
When the pericardial pressures exceed the right atrial pressures (5 mmHg) = cardiac tamponade
When do you get clinical signs from pericardial effusion?
When you have cardiac tamponade
What is absent on PE with an animal with pericardial effusion?
Precordium (normal vibration of the heart in the chest cavity, fluid absorbs this)
Explain pulsus parodoxus
Arterial blood pressure varies with breathing. During inspiration the intrathoracic pressures are low so smaller right heart so pulse is weak and during expiration your left heart fills better so the pulse is better.
What are the 3 radiographic hallmarks
Enlarged cardiac silhouette (crisp edge)
Small pulmonary vasculature
Distension of caudal vena cava
What are the ECG findings of pericardial effusion?
Decreased QRS amplitude (<1mV)
What is the emergency Tx for pericardial effusion?
Fluids and then pericardiocentesis once client permission.
Most common causes of hemorrhagic pericardial effusion?
Neoplasia
- HSA (right auricle)
- Chemodectoma (Aortic base)
- Ectopic thyroid CA
- LSA
Why do you need lidocaine on hand when doing a pericardiocentesis?
For arrhythmias, if you accidentally poke the heart it will cause VPCs
When you get fluid out during a pericardiocentesis and it looks like blood but doesn’t clot, what does that mean?
The fluid likely came from the pericardial sac, it will clot if you got it out of the ventricle.
If you find an asymptomatic cat has a PPDH what is the treatment?
Just leave them alone. Likely congenital, not causing a problem!
What 4 things can cause a valve to be insufficient?
Endocardiosis
Endocarditis
widening of ventricle (DCM)
Dysplasia (congenital)
What type of murmur do you get with a valve regurgitation?
Systolic plateau
What is endocardiosis?
Myxomatous degeneration of the valve (mainly mitral valve of small breed dogs)
Does the loudness of the murmur correlate with the severity of disease?
Nope
What does the ECG show for mitral endocardiosis?
LA or LV enlargement - tall QRS
Wide P waves
Arrhythmias (likely atrial)
What is the treatment for Stage C CHF with AV valve endocardiosis?
Furosemide (Loop diuretic) Enalapril (ACE - I) Pimobendan (Inodilator) IF atrial tachyarrhythmias/afib: -add digoxin or Diltiazem (ca ch bl) DO NOT give Beta blockers if CHF present
What are the 3 radiographic hallmarks of left heart failure?
Enlarged heart with left atrial backpack
Enlarged pulmonary veins
Pulmonary interstitial edema
What are two complications of endocardiosis that cause acute failure or collapse.
Ruptured chordae tendonae
Left atrial tear
Important facts about endocarditis?
Due to bacterial usually, uncommon (dogs), aortic and mitral valve affected.
Need: damage to valve, virulent bacteremia, immunosuppression.
NO dental link! Systemic signs (fever)
UTI risk! Poorer prognosis
What are the 5 “rules of the heart”
- Know normal circulation (pulmonary artery is deoxygenated blood, etc)
- Heart is a muscle (work out = bigger)
- 3 main functions
- conduct electrical activity
- contraction
- diastole - Blood is lazy (RA5, RV20/5, PA20/8, PC6, PV6, LA6, LV120/6, Ao120/80)
- BP=COxSVR (CO=SVxHR) (SV=pre,after,cont)
- The heart has limited response to disease: Concentric hypertrophy - diastolic dysfunction/pressure overload. Eccentric hypertrophy - Systolic dys/volume overload.
What type of hypertrophy does stenosis cause? Where does this happen in reference to the stenosis?
Concentric hypertrophy in the chamber behind the stenosis (where the pressure builds up)
Which is worse, a stenotic valve or a hypoplastic pulmonary artery?
hypoplastic pulmonary artery, it is harder to fix.
What kind of murmur would you hear with pulmonic stenosis? What kind of murmur can you get secondarily the concentric hypertrophy?
PS: Left basilar systolic ejection murmur
Secondary tricuspid regurg: right apex systolic plateau murmur
What will the femoral pulses feel like with pulmonic stenosis vs. subaortic stenosis?
PS: normal
SAS: weak femoral pulse
What will the jugular pressure be like with PS vs SAS?
PS: Jugular pulse
SAS: Normal
What does the velocity on echo tell you about pulmonic stenosis?
Estimates pressure through the modified Bernoulli equation which tells us about the severity. Small hole = high pressure = most severe.
What are treatments for pulmonic stenosis?
Balloon valvuloplasty
Medical: Beta blockers
What breeds are more likely to get pulmonic stenosis?
Terriers, small breed dogs
What breeds are more likely to get Subaortic stenosis?
Large breed dogs
Where would you hear a subaortic stenosis murmur?
Left basilar systolic ejection murmur (similar to pulmonic stenosis)
Additional murmurs you may here with a subaortic stenosis?
SAS radiation out to Carotid arteries (even on head) Aortic regurgitation (left base DIASTOLIC decrescendo murmur)
What is the treatment for subaortic stenosis?
Beta-blockers are really the only treatment
What is the prognosis for a dog with subaortic stenosis?
Depends on severity
At risk for endocarditis
WAY WORSE if they have an arrhythmia = sudden death at any time.
What are the three most common congenital dog cardiac defects?
Pulmonic stenosis
Patent Ductus Arteriosus
Subaortic stenosis
What would the murmur from a PDA be like?
Left basilar continuous murmur
Other PE findings for a dog with PDA?
Femoral pulses: normal to hypertkinetic
Possible arrhythmias - pulse deficits
NO jugular distention/pulse
Why do we get bounding pulses in a PDA?
Their diastolic pressures are much lower (run off) causing a bigger difference in the pulse pressure a thus a bounding pulse.
Where does blood flow starting at the cranial vena cava to the aorta in a PDA?
Cranial vena cava, RA, RV, MPA, Lungs, PV, LA, LV Aorta - ductus, MPA, Lungs, PV, LA, LV Aorta etc.
What are the radiographic findings for a PDA?
LV enlargement (tall) Aortic enlargement (at the arch) MPA enlargement Enlarged pulmonary arteries and veins Left atrial enlargement (backpack)
Severity for PDA is different than congenital stenosis why?
The larger the hole is worse!
When would surgery not be indicated to correct a PDA?
When the hole is so large that the shunt shifts from Right to left! (from pulmonary hypertension)
Where would you hear a VSD?
Right base or apex Systolic ejection quality murmur
What additional murmurs might you hear with a VSD and why?
If the defect is close enough to the base that the aortic valve flaps open and causes aortic regurgitation: Left base DIASTOLIC decrescendo murmur
What components of the heart would be enlarged in a VSD?
The ones where the blood runs though multiple times: Left atrium Left ventricle Pulmonary artery and veins NO MPA or aortic (like in PDA)
What is shunt reversal?
VSD and PDAs normally shunt from L to R but if the pressures change they can shift from R to L (which will be bad, bypass the lungs)
Pathophysiology of polycythemia with VSD or PDAs?
R->L shunting –> Deoxygenated blood to systemic circulation –> Hypoxia –> increase EPO release from kidneys –> Polycythemia –> Hyperviscosity
On PE what would be different about the distribution of cyanosis for a R->L PDA vs. a R->L VSD?
PDA: lower limbs more cyanotic (skips the cephalic trunk)
VSD: head and limbs (everywhere cyanotic)
Which AV valve dysplasia would cause weak femoral pulses? Which would cause a Jugular distention/pulse?
Mitral: normal to weak femoral pulse
Tricuspid: Jugular distention/pulse
