dog with respiratory distress case Flashcards
Left apical systolic murmurs are nearly always secondary to
mitral regurgitation (MR)
You note a left apical systolic murmur. What might cause mitral regurgitation **
VALVE PROBLEMS
1) Myxomatous (degenerative) mitral valve disease - acquired, very common
2) Infective endocarditis of MV (acquired, rare)
3) Mitral valve dysplasia/malformation (congenital; rare)
CHAMBER REMODELING (FUNCTIONAL MR)
1) Dilated cardiomyopathy (acquired, common)
2) Other causes of LV dilation
Left apical systolic murmurs secondary to DCM tend to be
quieter, usually grade 1 or 2
occasionally 3, rarely 4
never 5 or 6
T/F: dogs tend to get high grade murmurs with DCM
False
You have a 7yo dog with dyspnea, tachypnea, coughing/retching, increased lung sounds, reduced energy, hyporexia, tachycardia, irregular/chaotic cardiac rhythm, variable femoral pulses and a Grade II/VI left apical systolic murmur
What do you do first
ORDER
1) Flow by oxygen and sedation
2) Electrocardiogram (ECG)
3) Place IV (while setting up ECG) - POC blood work
4) Airway exam, thoracic imaging (POCUS)
5) Blood pressure ideal (QAR, hypotensive?)
What are the ECG hallmarks of atrial fibrillation
1) No discernable p waves
2) Chaotic (irregularly irregular) rhythm (R to R intervals differ)
3) Narrow complex/ supraventricular tachycardia
How do you differentiate atrial fibrillation from Ventricular tachycardia
ventricular tachycardia is usually a regular rhythm with a wide complex QRS
both sound similar on ausciltation
Is urgent therapy required for atrial fibrillation or ventricular tachycardia
Ventricular tachycardia - IV lidocaine
T/F: urgent therapy is required for atrial fibrillation
False- it is not urgent but you need to figure out the cause of Afib
Goal is to slow/delay AV node conduction
What two arrhythmias are usually associated with severe cardiac disease when together
Atrial fibrillation + tachycardia
1) Severe atrial enlargement
2) Heart failure in dogs and cats
What is the treatment goal of atrial fibrillation
slow / delay AV node conduction
You notice a grade II/VI left apical systolic murmur. What should you do for diagnostics
-Brief echo/cardiac POCUS
-Thoracic radiogrpahs
-NT-proBNP
What are the echo hallmarks of DCM
LV and LA chamber dilation secondary to overt systolic dysfunction
What will you see on thoracic radiographs that tells you DCM
1) LA enlargement (backpack on lateral, VD- bowlegged cowboy)
2) Left auricular buldge (2-3oclock on VD)
3) Tall heart
+/- pulmonary venous distension
+/- pulmonary edema -> perihilar and caudodorsal interstitial (+/- alveolar) pattern; diffuse distribution
Left sided CHF, edema typically occurs where on radiographs
Perihilar and caudodorsal interstitial +/- alveolar pattern
diffuse distribution when severe
How do you treat acute (in-hospital) congestive heart failure
Goal: alleviate suffering and decrease preload and increase O2 delivery -SPOF
1) Sedation (butorphanol)
2) Pimobendan (increase contractility and vasodilator)
3) Oxygen
4) Furosemide (diuretic to decrease preload / venous pressure)
What two ways does Pimobendan help in CHF tx
1) Increases contractility
2) Vasodilator
What is the purpose of giving furosemide in CHF tx
(diuretic to decrease preload / venous pressure)
Once a patient is stabilized, you begin to treat Atrial fibrillation. How do you treat
You need to slow AV node conduction
Diltiazem +/- digoxin
How does Diltiazem slow AV node conduction in case of atrial fib
Ca2+ channel blocker
AV node is reliable on calcium
How does Digoxin slow AV node conduction in cases of atrial fib
It does increase contractility but it mainly increases parasympathetic toe, which slows the AV node conduction
When should you transition from acute CHF tx to chronic CHF tx
once no longer oxygen dependent
primary myocardial disease is characterized by
Functional impairment and/or electrical abnormalities (tachyarrhthmias) in the absence of any other cardiovascular disease to cause the myocardial abnormality
ex: primary DCM- the pump doesnt work
At what time does DCM usually present
adult onset
How can you clinically recognize DCM in dogs
1) Cardiac auscultation -> usually low grade/soft, gallop sounds, arrhythmia
2) Clinical signs: exercise intolerance, syncope, breathing difficulty, abdominal distension
3) Breed screenings with echo
What are the clinical signs of DCM
Exercise intolerance
Syncope
Breathing difficulty
abdominal distension
Causes of Secondary DCM (DCM phenotype) *
1) Nutritionally mediated (low taurine or L-carnitine)
2) Tachycardia-induced CM (TICM)
3) Myocarditis (infectious, inflammatory, immune-mediated, idiopathic)
4) Cardiotoxicities (Doxorubicin)
5) Ischemic cardiomyopathy (humans)
6) Endocrinopathies (HypoT4 or Addisons) - very unlikely
How can you diagnose primary DCM
1) DCM phenotype
2) Diagnosis of exclusion
-ECG and Holter (TICM)
-CBC, CHEM, troponin, infectious disease testing
-Drug hx
-Diet history (boutique, exotic, grain-free, pulses - lentils, peas, beans) as the main ingredient
3) ECHO **
4) 24h holter monitor
How should you manage preclinical DCM *
Pimobendan * +/- ACEi, spironolactone, betablockers?
Antiarrhthmics as needed (lidocaine, sotalol)
treat underlying cause, if possible
change the diet if high pulse / nontraditional and supplement taurine if low
What is the long-term prognosis of primary/idiopathic DCM
6-12 months, worse if atrial fib
How do you treat atrial fibrillation
Slow AV node conduction (decrease ventricular rate)
-Diltiazem
-+/- digoxin or beta blocker
How do you treat ventricular tachycardia
Acute: lidocaine IV bolus or CRI
Chronic (oral): sotalol or atenolol
How do you treat atrial standstill
temporary: NaHCO3, Ca2++
permanent: pacemaker
What is the number one cause of mitral regurgitation in old small dogs
Myxomatous (degenerative) mitral valve disease
Loud left apical systolic murmur (grade 5 or 6) in old small dogs often correlate with
clinically significant MMVD
What is your top priority of ruling out when you have a loud left apical systolic murmur in old small dogs with breathing difficulty
Cardiogenic pulmonary edema
Sets:
1) Flow by oxygen +sedation
2) Consider empircial furosemide
3) Place IVC (point of care bloodwork)
4) Airway exam, thoracic imaing (POCUS)
5) Brief echo if possible
6) Thoracic radiographs **
7) Blood pressure ideal but not urgent
What is a normal vertebral heart score in a dog
<10.7
What is a normal vertebral left atrial (VLAS) size in dog
<2.3
Why is getting a systolic arterial pressure important to get in cases of mitral regurgitation
if there is systemic hypertension then it will increase the backflow into the left atrium
Radiographic signs of CHF should be paired with ________ to make a clinical diagnosis of CHF
clincal signs
Dogs with suspected CHF should have moderate to severe radiographic signs of cardiomegaly. How can you make this less subjective
VHS and/or VLAS
T/F: cough is a reliable clinical sign of CHF
false
tachypnea /dyspnea is
What is the most important thing in the treatment plan of dogs with chronic CHF
Furosemide *most important
Pimobendan
Once the patient with CHF is no longer O2 dependent you can discharge and transition to chronic CHF meds. What do you prescribe
DOGS ARE FOR SPECIAL PEOPLE
1) Diet: Low in sodium
2) Angiotensin converting enzyme (ACE) inhibitor
3) Furosemide *
4) Spironolactone
5) Pimobendan *
T/F: spironolactone has a weak diuretic effect
T- it is mainly important for treating chronic CHF because it blocks Aldosterone and RAS
Why is an ACE inhibitor paired with spironolactone when treating chronic CHF
need to block ACE and Aldosterone
RAS= sodium retention, vasoconstriction, and increasing blood volume
also blocks growth factors that promote adverse remodeling (such as scar tissue which can further cause arrhythmias)
______ % of small breed dogs have MMVD by 13 years of age
85%
slowly progressive in asymptomatic small breed dogs
T/F: most dogs with MMVD dont require therapy
True
T/F: large breed dogs also get MMVD
True- has a faster progression, overt myocardial dysfunction, Afib
T/F: tricuspid valve is commonly affected by degernation but it is unimportant
True
How do you predict clinically significant MMVD
Heart size (and rate of change of heart size) = tried and true progression of the progression
1) LA and LV size
2) Echocardiography vs radiography
subclinical MMVD where there is MMVD without cardiac remodeling
needs no treatment, just watchful waiting
Stage B1
sublinical MMVD where there is at risk breed with no current disease
-no treatment, just breed screening
Stage A
clinical MMVD where there is heart failure
-requires treatment for CHF (dogs are for special people)
-up titrate drugs (furosemide) as needed
Stage C
clinical MMVD where there is heart failure and end stage/ refractory to treatment
-requires treatment for CHF (dogs are for special people)
-up titrate drugs (furosemide) as needed
Stage D
subclinical MMVD where there is MMVD with significant cardiac remodeling (specific crtieria defined) without CHF
-Start Pimobendan 0.3mg/kg PO q12h to delay onset of CHF and prolong the survival
Stage B2
approved ace inhibitors for CHF
Benazepril, enalapril, imidapril and ramipril
