General Medicine Syncope

Front 1

What is the definition of syncope?

Back 1

Sudden, transient loss or depression of consciousness w/ spontaneous recovery
-often results from decreased oxygen delivery to the brain (~10 s loss of cerebral blood flow)

Front 2

What are 3 clinical signs that occur pre-syncope?

Back 2

Ataxia, paresis, collapse

Front 3

What are 3 cardiac causes of syncope?

Back 3

Electrical, structural, cyanotic heart disease

Front 4

What are 4 extracardiac causes of syncope?

Back 4

1) Metabolic
-hyperglycemia, addisons
2) Respiratory
-tussive/ cough
3) Neurologic
4) Indeterminate

Front 5

How can coughing cause syncope?

Back 5

Increased pressure causes decreased venous return and decreased cardiac output OR increased intracranial pressure decreases cerebral blood flow

Front 6

What are the 2 ways that structural cardiac/ lung disease results in syncope?

Back 6

1) Outflow obstruction
2) Low cardiac output

Front 7

What are 2 arrhythmias that can result in syncope?

Back 7

Bradyarrhythmias
Tachyarrhythmias

Front 8

What are 2 causes of bradyarrhythmias?

Back 8

1) > 6-8 s pause in the heart's electrical activity
-SA node dysfunction
2) heart rate cannot increase in response to physiologic stress
-3rd degree AV block
-Atrial standstill

Front 9

What is the definition of an tachyarrhythmia?

Back 9

May occur when the heart rate is >300 bpm for > 6 s

Front 10

How does tachycardia result in syncope?

Back 10

-HR increases--> decreases diastolic filling--> decreased cardiac output

Front 11

What is occurring in the heart with a high grade AV block? How does it lead to syncope?

Back 11

Bradyarrhythmia: atria (sinus) firing but have escape beats taking over bc sinus node's signal doesn't get through to AV node, then run and get excited--> syncope

Front 12

What is sick sinus syndrome (sinus node dysfunction)?

Back 12

Constellation of arrythmias:
-sinus arrest (results in long pauses), sinus bradycardia/ tachycardia
-Paroxysms of supraventricular tachycardia

Front 13

What is the treatment for sick sinus syndrome?

Back 13

Put in a pacemaker

Front 14

What are the results of atrial standstill? Describe the rhythm.

Back 14

Supraventricular escape rhythm
-no evidence of atrial activity= no p wave, just escape beats along the way

Front 15

What causes atrial standstill?

Back 15

-Hyperkalemia (blocked cats, addisonian crisis)
-Atrial fibrosis

Front 16

What are the 2 types of tachyarrhythmias? Why is it important to distinguish the two?

Back 16

1) Supraventricular
2) Ventricular
*differentiate b/w the two because different treatments

Front 17

When do you normally see syncope due to obstruction to flow or low output? Why?

Back 17

With exercise bc fixed obstruction + exercise-induced vasodilation = hypotension & syncope
-pressure and flow through stenosis increase w/ exercise --> inability to meet metabolic demands

Front 18

How is obstruction to flow or low output result in arrhythmogenic?

Back 18

Results in a hypertrophied ventricle, which is prone to arrhythmias

Front 19

What are 2 conditions that obstruct blood flow and can therefore result in syncope?

Back 19

1) Pulmonic valve stenosis
2) Subaortic stenosis

Front 20

What are 2 examples of conditions that result in low cardiac output and therefore syncope?

Back 20

1) Dilated cardiomyopathy
-poor systolic function +/- arrhythmias
2) Severe mitral regurgitation
-degenerative valve dz common

Front 21

What is an example of cyanotic heart disease?

Back 21

Tetralogy of fallot: right to left PDA (NOT L to R)

Front 22

What are the 4 defects in animals with tetralogy of fallot?

Back 22

1) Overriding aorta
2) Ventricular hypertrophy
3) Pulmonic stenosis
4) Ventricular septal defect

Front 23

How does tetralogy of fallot result in hypoxemia?

Back 23

Mixing of arterial & venous blood, body responds bc kidney sees decreased O2 content resulting in increased EPO--> polycythemia

Front 24

History is important to differentiate syncopal events from _________ and ________.

Back 24

Seizures & collapse

Front 25

What are the 5 main focuses of questioning when you are trying to differentiate syncope from seizure and collapse?

Back 25

1) activities leading up tot he event
2) duration of the episode
3) Activities during the event
4) Activities after the event
5) Current meds?
-esp drugs that slow AV nodal conduction or reduce inotropy

Front 26

How are seizures different from syncope?

Back 26

seizures= longer duration overall and hypersalivation and involuntary motor activity, tonicity
Seizures have a pre- or post-ictal period

Front 27

What are the "historical" findings of a patient that experienced syncope?

Back 27

- by definition, syncope is short and transient
-acute collapse w/ altered or loss of consciousness
-exercise, excitement, or coughing pay precipitate the event
+/- clonic movements, involuntary urination or defecation
-Recovery *complete and rapid

Front 28

What are 2 ways a breed can be predisposed to syncope?

Back 28

Those w/ structural heart disease or cardiac arrhythmias

Front 29

What are 4 structural heart diseases that certain breeds are predisposed to?

Back 29

1) DCM
2) Arrhythmogenic RV cardiomyopathy: boxers
3) Chronic degenerative valve disease: older, small breed dogs
4) Subaortic stenosis: boxers, goldens, german sheps, newfoundlands

Front 30

What breeds are predisposed to DCM?

Back 30

dobermans, giant breed dogs

Front 31

What breeds are predisposed to arrhythmogenic RV cardiomyopathy?

Back 31

Boxers

Front 32

What dogs are predisposed to chronic degenerative valve disease?

Back 32

Older, small breed dogs

Front 33

What dogs are predisposed to subaortic stenosis?

Back 33

Boxers, german shepherds, goldens, newfoundlands

Front 34

What are 5 cardiac arrhythmias animals can be predisposed to?

Back 34

1) Sick sinus syndrome
2) AV block
3) Supraventricular tachycardia
4) Ventricular tachycardia
5) Atrial standstill

Front 35

What dogs are predisposed to sick sinus syndrome?

Back 35

Miniature schnauzers
Dachshund
Westies

Front 36

What dogs are predisposed to AV block?

Back 36

Labs and many breeds

Front 37

What animals are predisposed to supraventricular tachycardia?

Back 37

Labs

Front 38

What animals are predisposed to ventricular tachycardia?

Back 38

Dobermans, boxers

Front 39

What animals are predisposed to atrial standstill?

Back 39

English springer spaniels

Front 40

What are 5 clinical exam findings of cardiac disease that can result in syncope?

Back 40

1) Murmur
2) arrhythmia
3) Altered pulse character or quality
4) Cyanosis
5) Evidence of heart failure

Front 41

What What are some physical exam findings that could indicate a neurologic cause of syncope?

Back 41

Abnormal cranial nerve exam, altered reflexes, proprioceptive deficits, altered mentation
-if neuro then maybe really seizures

Front 42

What are the 6 diagnostics that are useful in diagnosing the cause of syncope?

Back 42

1) History
2) Physical exam
-neuro exam
3) CBC, chem panel, uA
4) ECG
5) Echocardiogram
6) thoracic radiographs
-lung parenchyma, airway dz

Front 43

What are 3 types of secondary (more specialized) diagnostics used for syncope?

Back 43

1) Holter monitor (24-48 hours)
-portable ECG patient wears, good for when syncope happens daily
2) Event monitor
-worn longer time, ECG that records b4 and after event
3) implantable loop recorder
-in SQ near L apex, remove activating stores info

Front 44

What is the treatment for a dog that has syncope due to bradyarrhythmia? Tachyarrhythmia?

Back 44

Bradyarrhythmia: Artificial pacemaker
Medications: sympathomimetics, vagolytics
Tachyarrhythmias: anti-arrhythmic drugs

Front 45

What is the treatment strategy of drugs used to treat tachycardia?

Back 45

Goal is to decrease rate of spontaneous depolarization

Front 46

How do you treat syncope due to outflow obstruction?

Back 46

medial or surgical management
-e.g. balloon valvuloplasty for pulmonic stenosis

Front 47

What is the treatment for syncope caused by low cardiac output?

Back 47

-medical therapy: positive inotrope medications, beta blockade (cats with HOCM)
-exercise restrictions

Front 48

What is the treatment for tussive or "cough drop" syncope?

Back 48

Antitussive medications: hydrocodone, butorphanol

Front 49

What are the 4 general ways that cardiac diseases cause syncope?

Back 49

1) Arrhythmias
2) Obstruction to flow/ reduced ejection
3) Cardiac underfilling
4) Cyanotic heart disease

Front 50

What are 3 ways that metabolic disorders cause syncope?

Back 50

1) Abrupt decrease in oxygen or nutrient deliver i.e. glucose
2) severe anemia
3) hyperviscosity

Front 51

What are the 2 ways that neurologic disease can cause syncope?

Back 51

1) Reduced cerebral perfusion
2) Neurocardiogenic (formerly vasovagal)

Front 52

What are 2 ways that the tussive/ cough causes syncope?

Back 52

1) Reduced venous return
2) stimulation of vagal efferents producing bradycardia and vasodilation