Module 7: Vascular and Myocardial Disease (C26) Flashcards
C26: Vascular control
C26: Vascular control
CO = BP/SVR
Flow (Cardiac Output) = Change in pressure/ resistance
-> CO = stroke volume x Heart Rate
Stabilize BP in the face of changing CO
Baroreceptor arcs
MAP (Mean arterial pressure) = 1/3 pulse pressure + diastolic pressure
pulse pressure = difference between systolic and diastolic pressure
(T/F) MAP > 60 mm HG = organ perfusion
True
Measurement: non-invasive (or non-direct)
Doppler is more accurate and will only read …
systolic pressure
In _________ mostly invasive measurement are used although routine clinical monitoring can be performed
Large animals
What if your blood pressure cuff is too BIG?
It will underestimate the blood pressure
Definition:
Abnormally low blood pressure
- Mean blood pressure (< 60 mm Hg)
Hypotension
Clinically
- Often measure the systolic (not mean)
- Consider hypotensive if systolic BP < 90 mm HG
- And clinically dull
Hypotension:
- Decreased Inotropy
- Decreased HR
- Severe heart failure
- Decreased Plasma volume
Decreased CO
Hypotension:
- drugs/anesthetics
- sepsis
- acidosis
Excessive vasodilation (Vascular resistance)
Treatment for Hypotension:
- decreased CO
- decreased Inotropy
Pimobendan (Vetmedin)
- Oral calcium sensitizer
- Indicated for CHF
Dobutamine CRI
- Beta-1 adrenergic receptor agonist
- Indicated for cardiogenic shock
Treatment for Hypotension:
- decreased CO
- decreased HR
- Anticholinergics (Atropine)
- Pacemaker
Treatment for Hypotension:
- decreased CO
- decreased Stroke Volume
- Severe Congestive Heart Failure NO FLUIDS
- Decreased Plasma Volume: FLUIDS!
- hemorrhage
- dehydration
- hypoadrenocorticism
Term:
is a loop diuretic (water pill) that prevents your body from absorbing too much salt. This allows the salt to instead be passed into your urine.
Lasix
- Excitement/stress, exercise, hyperthyroidism
- Typically transient (baroreceptor reflexes “auto-corrects”)
Hypertension
- Excessive Cardiac Output (CO)
- Vascular disease, hormonal imbalances, RAAS activation
Hypertension
- Increased vascular resistance
If they are hypertension, most of the time it is secondary to some other condition:
- Kidney disease
- Endocrinopathies
Drug side effects, Idiopathic (or primary or “essential”), Obesity is NOT a cause
Target Organ Damage:
Eyes
Heart (thickening of the left ventricle)
Brain (Vascular)
Kidneys (tricky)
Treatment for Hypertension:
- Reduce the likelihood and risk of target organ damage
- Gradually reduce BP over a couple of weeks
ACE-Inhibitors (ACE-I) (FIRST LINE TX IN DOGS)
- Enalapril, benazepril
Calcium channel blocker (CCB)
- Amlodipine (FIRST LINE TX IN CATS)
Combination therapy (ACE-I + CCB)
Angiotensin receptor blockers (ARB)
- Telmisartan
Hypertension: General Tx Approach
- If BP < 180 mm HG (and no TOD)
- ACE-I alone
- If BP > 180 mm Hg
- ACE-I + Amlodipine
Dogs
Hypertension: General Tx Approach
- If BP < 200 mm Hg
- Amlodipine 0.625 mg/CAT q24h
- If BP > 200 mm Hg
- Amlodipine 1.25 mg/CAT q24h + ACE-I (or other)
Cats
(T/F) Do not give an ACE-I if Dehydrated
True
Definition:
A marked increase in BP with ongoing acute organ damage (TOD)
Hypertensive Crisis
- Aggressive therapy
- Gradual reduction
You are screening for high blood pressure in an anxious 11 YO miniature poodle with degenerative mitral valve disease. You get a systolic blood pressure reading of 165 mm Hg. There is no obvious evidence of target organ damage. What should your next steps be?
Recheck the blood pressure in about 1-2 weeks in a less-stressful environment and look for target organ damage again
A 10 YO Doberman is presented to you after a collapsing episode. On presentation, the patient is in respiratory distress. You suspect the patient is in left-sided congestive heart failure. You check your blood pressure and get a systolic blood pressure reading of 70 mm Hg. What should your next step be?
Give a dose of IV Lasix and start a dobutamine CRI
A 12 YO cat is presented to you after the owner noticed a dull mentation and the cat bumping into objects at home. Upon exam, you suspect complete or partial blindness and get a systolic blood pressure reading of 200 mm Hg. What should your next steps be?
Hospitalize and start antihypertensive medications
C27: Hypertrophic Cardiomyopathy - CATS
C27: Hypertrophic Cardiomyopathy - CATS
(T/F) Cats usually do not cough with cardiac disease
True
- Heartworm
- Bronchial
CAT INFO
- Gallops and Murmurs are sensitive (murmur) and specific (gallop) of cardiac dz in cats
- Heart rate is not a good indicator of cardiac disease
- Cats tend to have *high sympathetic tone8 during PE
- Medical treatment is technically more difficult in cats
Feline Myocardial Diseases:
Primary Cardiomyopathies:
- Hypertrophic CM
- Dehydration
- Hypertension
- Acromegaly
- Hyperthyroidism
- Restrictive CM
- Dilated CM
- Dietary taurine deficiency
- Tachycardia-induced cardiomyopathy
- Arrhythmogenic RV CM
- Cardiomyopathy of non-specific phenotype
Feline Myocardial Diseases:
Secondary:
- Hyperthyroidism
- Hypertension
- Ischemia
Definition:
A primary, myocardial disease of unknown origin characterized by concentric hypertrophy (pressure overload) and diastolic dysfunction (filling) of the LV and rarely the RV
Feline HCM
- very common
- Maine coon (4-7 years), Ragdolls (early onset (6-24 mo))
- Male»_space; females
A disease of abnormal myocardial growth of (most likely) genetic origin
HCM
- Genetic abnormality
- Mutation – Impaired structure | sarcomere assembly
- Poison peptides or haploinsufficiency
- Mutation – Impaired structure | sarcomere assembly
- Left side has higher pressure
- live a long healthy life
- clinical Heterogeneity
- No signs
- Young - old age
Auscultation finding for Feline HCM:
- Systolic murmur (dynamic auscultation (raise cat up and down)
- Gallop sounds (use bell of stethoscope) = are never normal!
- Arrhythmia
- systolic click
** Abnormal in 90% **
heart murmurs also in about 50% of healthy cats
Feline HCM - Electrocardiography
- Highly variable
-> Increased R amplitude > 0.9 mV
- LV enlargement pattern
-> increased P
- Atrial enlargement pattern
Radiography Findings :
- LV elongation (LVH)
- LA enlargement
Echocardiography:
LV hypertrophy (increased diastolic thickness)
Serum NTpro-BNP:
- Useful as a confirmatory test for cats with murmurs for justification of an echocardiogram
- helpful in the workup of respiratory distress
- normal cats: < 100 pmol/L
- Cats with CHF often Increased
- Many false negative
Genetic testing;
- Only for Maine coon cats, ragdolls, and sphynx cats
LV hypertrophy:
- Systemic hypertension
- Feline Hyperthyroidism
Management:
Acute CHF, FATE - Uniform therapeutic approach
- FONST = Furosemide, Oxygen, Nitroglycerine paste (ear pinnae), Sedation, Tap (pleural effusion)
Treatment Asymptomatic or post-symptomatic cats - Tailored therapy according to key problems or Risks
cat is hypothermia and hypotension -> Cardiogenic shock ->
RUN
- Dobutamine
- Pimobendan is not commonly used in cats, but sometimes if the cat has CHF
not usually a recomendation
Management acute:
What will you consider adding if BP and circulation do not recover?
Dopamin CRI
POST clinical HCM:
Triple Treatment:
- Furosemide
- ACEi - Enalapril
- Plavix +/- Asprin
** DONT USE ATENOLOL **
Preclinical HCM:
Watchful Waiting!
- Severe outflow tract obstruction (Atenolol)
- Mod | sev LA enlargement (Asprin | Plavix)
- Atrial fibrillation (Diltiazem)
- DCM phenotype (Taurine, Pimobendan, Enalapril)
Which of the following statements about feline
HCM is CORRECT?
a. It is always associated with LV systolic dysfunction.
b. Most cats finally die of thromboembolism.
c. If severe it is most commonly treated with pimobendan.
d. It is common in cats with an estimated prevalence in the general cat population of around 50-60%.
e. It is considered a genetic disease predominantly of the cardiac sarcomere.
e. It is considered a genetic disease predominantly of the cardiac sarcomere.
Which of the following is NOT a common outcome of HCM?
a. Benign disease with relatively normal longevity
b. Chronic exercise intolerance and weakness
c. Feline arterial thromboembolism
d. Sudden cardiac death
e. Congestive heart failure
b. Chronic exercise intolerance and weakness
All are characteristic histopathologic findings in feline HCM, EXCEPT:
a. Lymphocytic infiltration of the myocardium with myocardial edema
b. Interstitial and replacement fibrosis
c. Myocyte hypertrophy
d. Myofiber disarray
e. Intramural coronary artery narrowing
a. Lymphocytic infiltration of the myocardium with myocardial edema
A cardiac gallop sound heard on auscultation indicates:
a. Presence of severe systolic dysfunction
b. Poor cardiac output
c. Severe diastolic dysfunction
d. Advanced pericardial disease
e. LV outflow tract obstruction
c. Severe diastolic dysfunction
Which statement about the use of circulating cardiac biomarkers in feline HCM is CORRECT?
a. Blood NT-proBNP is an excellent screening test for symptomatic HCM
b. Cats with CHF have very low NT-proBNP due to myocardial exhaustion
c. It is a very useful confirmatory test for cats with heart murmurs to determine the significance of the murmur
d. cTnI can clearly separate normal cats from HCM cats, but not mild HCM from severe HCM
e. Unfortunately, NT-proBNP is also relevantly elevated in most cats with primary lung disease and arrhythmias
c. It is a very useful confirmatory test for cats with heart murmurs to determine the significance of the murmur
Differential diagnoses of LV wall thickening identified on echocardiography include all, EXCEPT?
a. Aortic stenosis
b. Dehydration
c. Hyperthyroidism
d. Myocardial lymphoma
e. Restrictive cardiomyopathy
e. Restrictive cardiomyopathy
C28-29: RCM, ARVC, DCM, and other Feline CM
C28-29: RCM, ARVC, DCM, and other Feline CM
Feline RCM is characterized by …
a. Left ventricular (LV) wall thickening and systolic dysfunction
b. LV outflow tract obstruction with a loud systolic heart murmur
c. Mitral valve thickening and mild to moderate mitral regurgitation
d. Myocardial fibrosis and severe diastolic dysfunction
e. Right ventricular enlargement and supraventricular arrhythmias
d. Myocardial fibrosis and severe diastolic dysfunction
Extra:
- Not very common in cats, tends to happen in older cats
- Rarely murmur
- Loud gallop
- No Hypertrophy
- Severe LA | RA enlarged (Valentine
- Sign of decreased LV compliance | increased filling pressure
- Poor Prognosis
Q3: Felix is a 5-year old DSH cat with lethargy, an irregular heartbeat, distended jugular veins, a gallop sound heard best right parasternal and an enlarged abdomen.
On echocardiography, the right ventricle is very large, and RV systolic function is poor. What is the most likely diagnosis for Felix?
a. ARVC
b. HCM
c. Cardiomyopathy of non-specific phenotype
d. RCM
e. Hyperthyroid heart disease
a. ARVC (Arrhythmogenic Right Ventricular Cardiomyopathy)
Extra:
- Severe RV and RA dilation in a cat
- Triangle of dysplasia (the area where fatty infiltration typically starts)
- Very abnormal and a lot of fat
- Older cats
- Not a common disease
- a lot of ascites
- Poor prognosis
Q4: Which statement about feline cardiomyopathy is CORRECT?
a. RCM is the most common myocardial disease in cats
b. Thoracic radiography can be used to accurately distinguish between the different types of feline heart muscle disease
c. Restrictive LV filling is a Doppler echocardiographic characteristic of early (occult) HCM
d. Hypertensive cardiomyopathy most often leads to sudden death or arterial thromboembolic disease
e. DCM is rare in cats and is characterized by both chamber dilation and poor systolic function
e. DCM is rare in cats and is characterized by both chamber dilation and poor systolic function
Extra:
- Primary myocardial disease characterized by left | right ventricular eccentric hypertrophy (dilatation) and LV systolic dysfunction
- RARE
- Systolic dysfunction is, however, also common secondary to chronic volume overload, ischemic heart disease, myocarditis, and taurine deficiency
- Gallop sounds
- Cardiac enlargement pattern
- Pumpkin shape, severe generalized cardiomegaly
- Low blood pressure
- LV dilatation and systolic dysfunction
- Measure Taurine levels (maybe on an abnormal diet) < 20 nmol/ml -> very bad
- check for Troponin I
- Poor prognosis
Which statement about feline arterial thromboembolism (FATE) is NOT correct?
a. Endothelial injury, blood stasis, and coagulopathy are factors favoring intracardiac clot formation
b. The distal aortic trifurcation is the most common location of clot lodging in FATE
c. The six “S’s” can be used to clinically describe FATE: sudden, severe, strong, simultaneous, silent, subclinical
d. Pain relief, inhibition of platelet aggregation, and prevention of thrombus expansion are the mainstay of acute therapy of FATE
e. Clopidogrel is most often used in the chronic oral prophylaxis of FATE
c. The six “S’s” can be used to clinically describe FATE: sudden, severe, strong, simultaneous, silent, subclinical
Extra:
- Cats are screaming in pain
- Can’t move much (pelvic limbs)
- Dependent on location, degree of occlusion, duration, collateral circulation
- Occlusion of the distal aorta
- Peracute in animals previously been healthy
- Six P’s = Peracute, Pain, paresis, pulselessness, pallor, polar
- Pin relief!
- No “gold standard” for the treatment of FATE
- PLAVIX (preferred), Clopidogrel may not work in all cats
- Myocardial disease that does not fit the characteristics of HCM, RCM, DCM, and ARVC
- LA | RA enlargement
- LV diastolic dysfunction
NCM (Non-specific Phenotype)
Arterial Thromboembolism: a common problem in feline CM + LA enlargement
1. Endothelial Injury
2. Blood Stasis
3. Coagulopathy
VIRCHOW’s Triad
IM injection of Depot Medrol can lead to …
Steroid-induced CHF
- Possibly related to hyperglycemia and secondary fluid shift from interstitial to intravascular space
- Signs of I-CHF
- Likely myocarditis w/ myocardial edema and cell infiltration
- Recently described the phenomenon in young cats (< 5yrs)
- Often severe, symmetrical LV wall thickening on echo (major differential: HCM)
Transient Myocardial Thickening
C30: Canine Myocardial Diseases
C30: Canine Myocardial Diseases
What is common in dogs and represents an advanced stage of different insults to the myocardium?
DCM
- here are breed-specific differences with regard to history, signs, ECG findings, progression, prognosis, and response to therapy in dogs
Definition:
Is an early event in DCM and a major contributor to disease progression
Abnormal neurohormonal activation
List what is included in remodeling of the ventricles:
- Hypertrophy
- Fibrosis
- Dilatation
- Increased chamber sphericity
What is the diagnostic method of choice with dilatation and systolic dysfunction being the most specific of DCM?
Echocardiography
List the Mainstay of therapy of DCM:
- Load reduction
- Inotropic support
- Antiarrhythmics
- Cardio-protective treatments
(T/F) Prognosis of DCM is worst in Dobermans and best in Cocker Spaniels and Irish wolfhounds
True
(T/F) ARVC is common in Boxer dogs
True, Boxer Cardiomyopathy
Definition:
Is primarily a disease associated with rhythm abnormalities leading to sudden cardiac death
ARVC
(T/F) Most boxer dogs with ARVC have abnormal echocardiograms
False, they have normal echos
List treatment of ARVC:
- Symptomatic
- Antiarrhythmics
- CHF drugs
Definition:
- Is a disease associated with atrial myocarditis, atrial destruction, and persistent atrial standstill
- Poor Prognosis
- Most often seen in Springer spaniels
Atrial cardiomyopathy
What may be a reason that Myocarditis seems rare in dogs?
May be under-diagnosed
What has been observed in very young dogs and is likely of genetic origin?
Juvenile DCM
- At this age, tachycardia-induced cardiomyopathy is an important differential
Causes of DCM include all of the following, EXCEPT?
a. Bacterial infections
b. Viral myocarditis
c. Metabolic abnormalities
d. Familial/genetic
e. Nutritional
a. Bacterial infections
Which of the following matches regarding heart muscle disease in dogs is CORRECT?
a. Doberman Pinscher - RCM
b. Congestive heart failure - S4 gallop
c. DCM - Concentric LV hypertrophy
d. Systolic dysfunction - Therapy with atenolol
e. Boxer cardiomyopathy - Ventricular ectopy
e. Boxer cardiomyopathy - Ventricular ectopy
- ventricular ectopy is found as initial abnormalities suggestive of DCM
Echocardiographic findings in advanced canine DCM include all of the following, EXCEPT?
a. Severe mitral valve thickening & regurgitation
b. LV dilation
c. LV systolic dysfunction
d. Mild secondary mitral regurgitation
e. LV wall thinning
a. Severe mitral valve thickening & regurgitation
“Rally” is a 4-year old asymptomatic Doberman Pinscher that is examined during an annual health check. A soft (1-2/6) left apical systolic heart murmur is identified, the cardiac rhythm is slightly irregular, the rate of respiration is 22/min (N: <30), NT-proBNP is within the normal range, left heart size is increased, and LV shortening fraction is 14% (N: 25-45). How would you manage this dog?
a. Start cardio-protective medications including atenolol and spironolactone
b. Place a 24-hour Holter monitor on the dog to fully evaluate the arrhythmia
c. Recommend strict exercise restriction and recheck every 3 months
d. Start dog on pimobendan and enalapril
e. Change the dog’s diet and reduce left cardiac size with a combination of furosemide and spironolactone
f. Answers ‘b’ and ‘d’
g. Answers ‘a’ and ‘d
- Place a 24-hour Holter monitor on the dog to fully evaluate the arrhythmia
- Start dog on pimobendan and enalapril
What is ‘lone’ atrial fibrillation?
a. A fast supraventricular tachycardia in a lonely dog
b. Atrial fibrillation without structural and functional heart disease
c. Atrial fibrillation at a very low heart rate (40-70 bpm)
d. An irregularly irregular heart rhythm with frequent, but isolated ventricular premature beats
e. A type of supraventricular tachycardia that most often leads to sudden cardiac death
b. Atrial fibrillation without structural and functional heart disease
All of the following statements about boxer cardiomyopathy are correct, EXCEPT:
a. It is commonly associated with LV and LA dilation, thin LV walls, and LV systolic dysfunction
b. Boxer cardiomyopathy is associated with fibrofatty infiltration of the RV walls
c. Mutations in the striatin gene seem to have causative importance
d. On echocardiography, boxer cardiomyopathy is commonly characterized by normal chamber size and function
e. Right ventricular ectopy is a hallmark of the disease
f. Therapy is most often with sotalol, fish oil, and exercise restriction
a. It is commonly associated with LV and LA dilation, thin LV walls, and LV systolic dysfunction
C32: PH & Cor Pulmonale
C32: PH & Cor Pulmonale
(T/F) Pulmonary Hypertension (PH) is common in small animals
True
Definition:
Is the morphologic and functional consequence of chronic right-sided pressure overload due to PH characterized by RV dilatation, hypertrophy and dysfunction
Cor pulmonale
(T/F) PH is not always secondary to an underlying disease process
False, it is always
- Non-specific management of PH includes treatment of the primary disease process
- Specific management uses drugs such as Sidenafil and L-Arginine for moderate and severe PH
List the typical conditions associated with Pulmonary Hypertension:
- Heartworm disease
- Interstitial lung disease
- Thromboembolic disease
- Congenital heart disease
- Left-sided heart failure
(T/F) There is no specific, pathognomonic clinical sign of PH
True
What is a common clinical consequence of moderate and severe PH?
Syncope
What is the method of choice in the clinical diagnosis of PH?
Echocardiography
What is used to estimate systolic Pulmonary artery pressure?
Peak velocity of tricuspid regurgitation
What would be the prognosis of severe PH?
GRAVE
Which of the following statements about the
pulmonary vasculature is CORRECT?
a. Pulmonary artery pressure is 2/3 (two-thirds) of systemic blood pressure
b. Alveolar hypoxia is a strong trigger for pulmonary vasoconstriction
c. R (resistance) = (8 x vessel width x viscosity) / pie x length^4
d. Moderate (but not mild) exercise will lead to a clinically relevant increase of pulmonary artery pressure
e. A 20% reduction of overall blood vessel cross-sectional area is needed for pulmonary hypertension to occur
b. Alveolar hypoxia is a strong trigger for pulmonary vasoconstriction
The sequence of the pulmonary vascular response pattern to injury is as follows (select the most appropriate answer):
a. Formation of plexiform lesions -> medial hypertrophy -> reactive vasoconstriction
b. Exudative inflammation -> fibrinoid necrosis -> vasoconstriction -> plaque formation
c. Intimal proliferation -> plaque formation -> medial hypertrophy
d. Thrombosis -> intimal fibrosis -> plexiform lesions -> vasoconstriction
e. Reactive vasoconstriction -> medial hypertrophy -> fibrinoid necrosis -> plexiform lesions
e. Reactive vasoconstriction -> medial hypertrophy -> fibrinoid necrosis -> plexiform lesions
Which statement about pulmonary hypertension
(PH) is CORRECT?
a. Dogs, but not cats, most often have primary (idiopathic) pulmonary arterial hypertension
b. Resistive PH is most commonly related to left heart disease
c. Flow-related (hyperkinetic) PH is a common consequence of severe mitral regurgitation
d. Congestive PH is often observed with severe right-sided heart failure
e. Resistive PH is related to reactive (vasoconstriction) or obstructive/obliterative pulmonary vascular disease
e. Resistive PH is related to reactive (vasoconstriction) or obstructive/obliterative pulmonary vascular disease
Which of the following is NOT a potential clinical sign of severe PH?
a. Cyanosis
b. Syncope
c. Jugular vein distension
d. Shortness of breath
e. Intermittent hind limb weakness
e. Intermittent hind limb weakness
In a dog with severe pre-capillary PH, all of the following radiographic signs would be expected, EXCEPT:
a. Severe LV enlargement
b. Tortuous pulmonary arteries
c. RA enlargement
d. Dilated pulmonary trunk
e. Severe RV enlargement
a. Severe LV enlargement
Which statement about the treatment of PH is CORRECT:
a. Treatment should immediately aim at direct pressure reduction rather than addressing the underlying condition.
b. cGMP-donors are commonly used.
c. Sildenafil is a selective pulmonary artery vasodilator most often used for the treatment of pre-capillary PH.
d. Pimobendan is a very effective PDE-V inhibitor most commonly used.
e. In animals with PH and low-normal hematocrit, blood transfusions are used to increase the oxygen-carrying capacity of the body and thus improve (reduce) pulmonary vasoconstriction.
c. Sildenafil is a selective pulmonary artery vasodilator most often used for the treatment of pre-capillary PH.
C33/C34: Heartworm Disease
C33/C34: Heartworm Disease
(T/F) Canine heartworm the disease is easy to detect and prevent
True
(T/F) The heartworm lifecycle and treatment strategy are complicated
True
Which is true regarding the heartworm life cycle:
A. Larvae must develop into the infective L3 stage within the dog prior to being ingested by a mosquito.
B. The life span of adult heartworm is shorter in cats as compared to dogs
C. Microfilaria are produced within the mosquito.
D. In dogs, it takes ~3 months from the time of first infection to the development of adult worms.
E. Puppies should be tested for heartworm disease at the 8-week vaccine appointment.
B. The life span of adult heartworm is shorter in cats as compared to dogs
- Usually MF-
- Ag testing is not very useful
- Antibody testing = exposure
- Echo Dx
- do NOT give adulticide
Cats
What would be prevention?
Macrocyclic lactones
What is the treatment for adults (hw)?
2-stage approach (3 injections) with 2 month lag
What can make the treatment of HWs more effective?
Doxycycline
(T/F) Resistance strains of HW exist
True
With what are you testing annually in dogs?
AG test (+ MF test)
Which is true regarding the diagnosis of heartworm (HW) infection?
A. In cats, a negative HW antigen test rules out HW infection.
B. The HW antibody test is the first screening test that should be performed in dogs.
C. The HW antigen test should always be repeated in dogs prior to initiating therapy of adult HW.
D. Cats with positive antibody tests often have positive microfilaria tests.
E. Developing larvae in the circulatory phase are detected by HW antigen tests.
C. The HW antigen test should always be repeated in dogs prior to initiating therapy of adult HW.
Which is true regarding heartworm treatment?
A. L3 and L4 larvae are susceptible to melarsomine.
B. Doxycycline is only recommended when dogs are showing respiratory signs.
C. Cats should be stabilized with prednisolone prior to melarsomine.
D. Heartworm preventatives should only be given after the 2-month lag period between diagnosis and melarsomine.
E. A 2-stage, 3-injection protocol is recommended for the treatment of adult heartworms in dogs.
E. A 2-stage, 3-injection protocol is recommended for the treatment of adult heartworms in dogs.
All of the following are examples of heartworm preventatives except:
A. moxidectin
B. ivermectin
C. milbemycin oxime
D. melarsomine
E. selamectin
D. melarsomine
