What is the definition and cause of syncope?
- Transient LOC with rapid recovery
- Syncope is characterized by a temporary reduction in cerebral blood flow.
What percentage of all syncopes are classified as reflex?
65%
Reflex syncope includes vasovagal syncope and other triggers.
What are common causes for reflex syncope?
- Vasovagal - Prodromal stressor (e.g. Postural (prolonged standing)
- Situational (straining, peeing, sneezing, blood)
- Carotid hypersensitivity
An example of carotid hypersensitivity is a necktie being too tight.
What percentage of syncopes are classified as orthostatic?
15%
Common in populations such as the elderly and diabetics.
What are possible diagnoses for orthostatic syncope?
- Orthostatic hypotension
- POTS
Patients may have a history of lightheadedness when standing and poor oral intake.
What percentage of syncopes are classified as cardiogenic?
10%
Cardiogenic syncope is considered dangerous.
There are 5
Characteristics of cardiogenic syncope
- Hx of sudden LOC
- No prodromal symptoms
- Exertional/supine syncope
- Chest pain/palpitations
- PMHx of sudden cardiac death
What are red flags in ECG related to syncope? (ABCDE Left Right)
- A - AV blocks
- B - Brugada syndrome
- C - Corrected QT (QTc)
- D - Delta wave
- E - Epsilon wave
- Left - LVH
- Right - Right ventricular strain pattern (PE)
These red flags help identify potential causes of syncope.
What is a significant concern with AV blocks?
Second and third degree heart block due to slow ventricular rate = haemodynamic instability
A trick to differentiate Mobitz type II and 3rd degree is if the P wave is tucked inside a QRS complex, indicating 3rd degree.
What is Brugada syndrome?
Cardiac abnormality with a high incidence of sudden death in patients with structurally normal hearts
It can cause VF or VT usually at times of increased vagal tone.
What ECG finding is characteristic of Brugada sign?
Coved STE (shark fin appearance) in V1-2 with T wave inversion
There are 4
What is the clinical criteria for Brugada syndrome
- Any documented VF or polymorphic VT (Torsades De Pointes)
- Hx of sudden cardiac death in family
- Nocturnal agonal respirations
- Coved ECG type family members
What does QTc standardize?
QT interval regardless of heart rate
Red flag QTc interval
> 500ms
What is the R on T phenomenon?
R wave jumps on top of proceeding T wave = can cause VF or Torsades de pointes
It is associated with prolonged QT intervals.
What does a delta wave indicate and what does it look like?
- Wolf Parkinson White syndrome (SVT)
- Short PR interval with upward sloping into QRS. Only seen in sinus rhythm
Only needs to be seen in one lead
What is an epsilon wave?
Small deflection buried in the end of QRS complex
It is characteristic in patients with arrhythmogenic right ventricular dysplasia (ARVD).
What is left ventricular hypertrophy?
Abnormal thickening of left ventricle
It is the number one cause of sudden cardiac death in young people.
3
What are the ECG findings for left ventricular hypertrophy?
- High voltage QRS complexes
- Narrow and deep Q waves in lateral and inferior leads
- LV strain pattern - ST depression and T wave inversion in lateral leads
Sokolow-Lyon criteria can be used to assess LVH.
What does a right ventricular strain pattern suggest?
Changes that may suggest a PE
It includes sinus tachycardia and T wave inversion in V1-4 and inferior leads.
