Syncope and Murmur Dogs Flashcards
syncope (or cataplexy)
sudden loss of consciousness and postural tone
sudden loss of consciousness and postural tone
syncope (or cataplexy)
what other signs may occur with syncope
-paddling
-loss of bowel/urination
-seizures
these signs are no discriminatory
Pulse deficits may be observed on examination in what arrhythmias
Any arrhythmia with an early beat where the heart contracts before having effective time to fill
1) Premature atrial complexes
2) Premature ventricular complexes
3) Atrial fibrillation
4) Ventricular tachycardia
What is a pulse deficit
when you hear an asucultated beat but you dont appreciate a pulse
usually due to left ventricle contracts but fails to generate enough strength to generate a pulse or fails to open up the aortic valve
occur when an abnormal heart rhythm causes the heart to contract prematurely and close the AV valves (causing a heart sound) but the stroke volume of the early beat may be inadequate to open the aortic valve or to lead to a palpable pulse in a peripheral artery
Pulse deficits
What are your differentials for a fainting event **
1) Seizure
-Epilepsy
-Metabolic: hypoglycemia, hypocalcemia, uremia, HE
-Infectious: Viral, Protozoal, Fungal, Bacterial
-Immune-mediated
-Traumatic
-Neoplastic
-Toxic
2) Syncope
-Cardiac: Tachyarrythmia, Bradyarrhythmia, Low CO
-Neurogenic: Reflex-mediated or situational
-Exertional syncope
-Cyanotic heart disease
-Drug related
-Hyperviscosity
2) Syncope
How might you differentiate seizure from syncope *
seizure: post-ictal period
syncope: acute loss of consciousness and postural tone but then goes back to normal in seconds to minutes
*neuro and cardiac exams
breeds predilections
What are causes of syncope
Cardiac
1) Tachyarrythmia
2) Bradyarrhythmia
3) Low CO
others
4) Neurogenic: Reflex-mediated or situational
5) Exertional syncope
6) Cyanotic heart disease
7) Drug related
8) Hyperviscosity
T/F: sinus bradycardia can cause syncope
True- but it does not cause a pulse deficit
What arrhythmias might cause syncope
1) PVCs
2) PACs
3) Pronounced Sinus Arrhthmia
4) 2nd degree heart block
5) Atrial fibrillation
6) Atrial flutter (with variable conduction)
7) Atrial tachycardia (with variable conduction)
8) Paroxysmal Ventricular tachycardia
What causes a left basilar systolic heart murmur
1) Aortic Stenosis
-Subvalvular
-Valvular
-Mass obstruction
2) Pulmonary valve stenosis: congenital or secondary to increased flow (ASD)
Functional: elevated outflow velocity (athletic heart) , anemia, thyrotoxicosis, pyrexia
murmurs unrelated to structural heart disease
can be secondary to athleticism, excitement
common in the Boxer and other athletic breeds
may reflect a relatively smaller aorta
functional heart murmurs
what breeds might have a functional heart murmur
Boxer and other athletic breeds
What might cause a functional heart murmur
secondary to athleticism and excitement
-elevated outflow velocity, anemia, thyrotoxicosis, pyrexia
(not a structural heart disease)
What should you do for diagnostics for a dog with syncope **
1) Blood pressure
2) Electrocardiogram *** (preferred)
3) Echocardiogram
4) Bloodwork - CBC & Chemistry (+/- cardiac troponin)
5) Splenic ultrasound
6) +/- Holter or Event Monitor
7) +/- Thoracic radiographs
What is a normal systolic blood pressure in a dog
110-160 mmHg
T/F: PVCs have a QRS that is wider
true- and it is much different in appearance than sinus complexes
What are the different patterns of premature ventricular complexes that you can have
1) Single
2) Couplet
3) Triplet
4) Bigeminy
5) trigeminy
What is ventricular bigeminy
VPCs that alternate with normal sinus complexes
What is ventricular trigeminy
VPCS that occur after two normal sinus complexes
How can you tell which ventricles the PVCs are originating from *
Right ventricle: depolarization along lead II will have a positive R
Left ventricle: depolarization direction opposite lead II; negative S
PVC that is postive on lead II originate from the
right ventricle
PVC that is negative on lead II originate from the
left ventricle
What are the differential diagnoses for PVCs **
HEAD
H- heart disease: cardiomyopathy, myocarditis, etc
E- Endocrine / Metabolic: thyroid excess, hypokalemia
A- Autonomic imbalance: elevated sympathetic tone
D- Drugs/toxins: digoxin, cocaine, etc
S- Systemic issues: splenic disease, GDV, sepsis, DIC, etc
What autonomic imbalance can lead to PVCs
elevated sympathetic tone
What drugs/toxins can lead to PVCs
Digoxin
Cocaine
Chocolates
What systemic issues can lead to PVCs
Splenic disease
GDV
sepsis
DIC
unrecogonized splenic masses can cause
ventricular ectopy
worn for 24 to 48 hours in hime environment
allows for objective assessment of treatment efficacy
Holter Monitor
-ambulatory ECG
How many ventricular ectopic beats are normal in 24 hours?
<50 is normal
What heart conditions do Boxers and Bull dogs typically get
Arrhythmogenic right ventricular cardiomyopathy
what is the pathophysiology of Arrhythmogenic right ventricular cardiomyopathy *
1) Fibrofatty replacement of ventricular myocytes
2) Allows for anatomic substrate for ventricular ectopy
typically in right ventricle, may progress to the left and cause CHF
What breeds commonly get Arrhythmogenic right ventricular cardiomyopathy
Boxers and Bulldogs
What is your preferred emergency therapy for ventricular tachycardia
Iv lidocaine
What do you do therapeutically for ARVC **
1) Intravenous antiarrhthmics: IV lidocaine*, procainamide, amiodarone
2) Oral antiarrhthmics (at home): Sotalol*, Amiodarone, Mexiletine
Describe the EKG features of ventricular tachycardia
premature
wide and normal
quick
All of the following may cause a hyperkinetic pulse except
-Aortic stenosis
-Aortic regurgitation
-PDA
-Anemia
-Arteriovenous fistula
-Bradycardia
What factors influence the intensity of the pulse we feel
1) Pulse pressure (difference between systole and diastole)
2) Vascular tone (old patients with stiff vessels might have intense pulse)
3) Cardiac output
4) Volume of the blood
5) Run off of blood from aorta drops diastolic pressure (Aortic regurgitation, PDA, Arteriovenous fistula)
T/F: bradycardia is associated with a stronger/bounding pulse
True
T/F: anemia is associated with a stronger/bounding pulse
True - increased plasma volume creating more bounding ulse
How does aortic stenosis
narrowing of the outflow, takes longer so the rate of pulse pressure rise is longer
What might cause a truly continuous heart murmur
PDA
AV fistula
Rare defects (AP window)
What might cause a gallop sound?
1) S4 (atrial filling)
-Stiff ventricle
-Hypertension
-HCM
2) S3 (ventricular filling)
-Volume distended LV
-CHF gallop
an extra sound within the heart beat during diastole
Gallop
can be S4 (atrial filling) or ventricular filling
What might cause you to hear a S4 sound
S4 (atrial filling)
-Stiff ventricle
-Hypertension
-HCM
What might cause you to hear a S3 sound
S3 (ventricular filling)
-Volume distended LV
-CHF gallop
closure of the mitral / tricuspid sounds
S1
closure of the semilunar valves
S2
a gallop sound that occurs later in diastole
S4- dub lub dub
a gallop sound that occurs right after S2
S3 -lub dub dub
What might sound like a continuous murmur
Combined systolic and diastolic murmurs
1) VSD and Ao regurgitation
2) Ao stenosis and Ao regurgitation
3) PS and pulmonary regurgitation
What are the top 5 loud systolic murmurs heard in puppies ***
1) Subaortic stenosis
2) Pulmonary valve stenosis
3) Ventircular septal defect
4) Tricuspid valve dysplasia - regurgitation
5) Mitral valve dysplasia- regurgitation
Subaortic stenosis causes what kind of murmur
systolic murmur, heard best over the left heart base, poor femoral pulse
What kind of murmur is heart with pulmonary valve stenosis
systolic murmur, head best over left heart base
T/F: dogs with pulmonary valve stenosis have an abnormal pulse
False
T/F: dogs with subaortic stenosis have an abnormal pulse
True
VSD causes ________ murmurs best heard over the __________
systolic murmurs best heard over the right thorax
Tricuspid valve dysplasia with regurgitation causes a _________ murmur heard best over the ________
systolic murmur heard best over the right apex
Mitral valve dysplasia with regurgitation causes a _________ murmur heard best over the ________
systolic murmur heard best over the left apex
What should you do diagnostically for a puppy with a continuous murmur
Thoracic Rads
Echocardiogram
Blood Pressure
+/- blood work
What is the best diagnostic test to confirm CHF
thoracic rads
T/F: puppies tend to have little lower blood pressures at younger ages
true: ex 95mmHg might be normal
A 6mo puppy patient presents with respiratory distress. Upon thoracic rads you see LV enlargement, Ao dilation, pulmonary overcirculation, and perihilar edema with an interstitial lung pattern. What medication do you give
Furosemide
9week old puppy has
-severe LA and LV dilation
-hyperdynamic LV function
-continuous, high velocity flow entering MPA
-Mild mitral regurgitation
-elevated aortic velocity
what is the diagnosis
PDA
How does PDA lead to mitral regurgitation
blood leaves aorta and goes back through to the left atrium and pulls the mitral leafs appart causing regurgitation
Why might a patient with PDA have elevated aortic velocity
Increased venous return to the left heart
In fetal circulation ______ blood goes to pulmonary arteries and then across the ______ to the _____ to end up in the placenta
deoxygenated blood to PA and then across ductus to Ao and back to placenta
in fetal circulation, where does oxygenation occur
placenta, then returns through umbilical vein, across atrial septum to the left heart and body
ductus arteriosus normally closes by
1 week of life and becomes the ligamentum arteriosus
What allows closure of the ductus arteriosus
smooth muscle allows active closure after birth
persistency is a defect in this muscle
the absent muscle limits constriction and closure
Why do you hear a continuous murmur with a PDA
Left to right shunt
What are the 7 sequelae to a PDA *
1) Aortic dilation (ductal bump)
2) Pulmonary overcirculation
3) Increased venous return
4) LA dilation
5) LV eccentric hypertrophy / dilation
6) Continuous murmur from L-R shunt
7) Hyperkinetic shunt
What are the physical findings of PDA
1) Loud, continuous machinery murmur, flow during systole and diastole. Ao pressure is always higher than PA pressure
2) May be left apical murmur of Mitral regurgitation as well
3) Pulmonary crackles if CHF in severe cases
4) Rhythm abnormalities can occur due to cardiac enlargement (atrial arrythmias)
5) Pulse quality is very strong, bounding
What is the pulse of a patient with a PDA
very strong and bounding
-Wide pulse pressures (systolic - diastolic) ex: 132/52
-secondary to diastolic run-off into PA = lower diastolic
leads to pulse being bounding, water hammer, hyperkinetic
What happens to the pulse once the PDA is ligated
the diastolic pressure will increase
How is PDA treated in dogs
Close via interventional occlusion (catherization) or by open surgical ligation
*treat as early as possible
medical management if symptomatic: diuretics, ACE-inhibitors, pimobendan (if in CHF)
Uncorrected PDA may lead to
high probability of premature death
small PDA results
normal lifespan if closed
What are the results of a large PDA
progressive myocardial failure from volume overload leading to CHF
What arrythmia can occur with PDA
atrial fibrillation from LA enlargement
If a patient with a PDA is symptomatic, what medical management should you do
Diuretics
ACE-inhibitors
Pimobendan (if in CHF)
Where is the approach to PDA surgical ligation
L 4th intercostal
retract lungs
double ligature
What is the risk of surgical PDA ligation
Ductal tear
Hemorrhage
What is the most common congenital heart defect in the dog
PDA or Pulmonary Stenosis
Where is a PDA heart murmur heard loudest
continuous (machinery) murmur; heard loudest at the left heart base (craniodorsal)
T/F: if closed PDA carries an excellent prognosis
True
if untreated, they progress to L CHF, and high mortality in year one
Intervention for PDA is either
Surgical or transcatheter to ligate/occlude the ductus
catherization depends on the size of the femoral artery. if you can get a large enough catheter in it then it can be done with catheters
What are the features of an innocent / functional heart murmur
1) No structural changes
2) Soft (grade 1 or 2/6)
3) Systolic
What is the most common form of congenital heart disease in the cat
VSD
