Bradyarrhythmias & life threatening causes of syncope

Question 1

Serious signs and symptoms of bradydysrhythmias

Answer 1

CHAPS
Chest pain, SOB
AMS
Giddiness
Hypotension (SBP < 90)
Syncope

*Stokes-Adams attack

Question 2

What is bradycardia

Answer 2

Heart rate < 60 bpm

Question 3

Approach to bradycardia (<60bpm)

Answer 3

Bradycardia identified
Ask yourself: where does the problem lie?
- Absent P waves: think SA node
- P waves present: think sinus brady or AV nodal block

LOOK AT LEAD II

Question 4

Causes of bradycardia:
Where does the problem lie?

Answer 4

1. SA node
2. AV node
3. Slow conduction due to drugs and electrolytes

Question 5

Types of AV blocks

Answer 5

1st degree AV block
2nd degree AV block (Mobitz 1: Wenkebach)
2nd degree AV block (Mobitz 2)
2nd degree high grade AV block
3rd degree AV block (complete heart block)

Question 6

ECG features: 1st degree AV block

Answer 6

Prolonged PR interval > 0.2s (1 big square) and constant
Every P wave is associated with a QRS complex

P-P interval: regular
P-R interval: regular
R-R interval: regular

Question 7

ECG features:
2nd degree AV block, Mobitz 1 (Wenckebach)

Answer 7

Progressive lengthening of PR interval followed by a dropped QRS (by right it’s p wave not conducted)

P-P interval: regular
P-R interval: irregular
*P-R longest before the dropped beat
R-R interval: irregular

Question 8

ECG features:
2nd degree AV block, Mobitz 2

Answer 8

Dropped QRS every 3 or more P
- P QRS P QRS P DROP

P-P interval: regular
P-R interval: regular
R-R interval: depends on ratio

Question 9

ECG features:
High grade block (2:1, 3:1)

Answer 9

Conducted beats every 2 or more beats
eg.
2:1 = 1 dropped QRS (aka 1 solo P wave) followed by 1 conducted P+QRS
3:1 = 2 dropped beats (aka 2 solo P waves) followed by 1 conducted P+QRS

P-P interval: regular
P-R interval: regular
R-R interval: depends on ratio

Question 10

ECG features:
3rd degree AV block

Answer 10

Every beat is NOT conducted

AV dissociation (P and QRS. are independent rhythms)

P-P interval: regular
P-R interval: irregular
R-R interval: regular (escape rhythm)

Question 11

Causes of AV block

Answer 11

1. Ischemia: ACS
2. Electrolytes:
   - Hyper or hypoK+
   - Hypomagnesium
   - Hypo or hyperCal
3. Drugs:
   - BB
   - CCB
   - Digoxin
4. Infection: Myocarditis
5. Others

Question 12

Management of bradycardia

Answer 12

1. Identify rhythm
2. Determine possible cause of heart block and treat reversible cause
3. Look for serious signs and symptoms (CHAPS)
   - CP, SOB
   - SBP < 90
   - AMS
   - HF (pul edema)
   - Shock
4. If present -> Unstable

Initiate treatment
1st line: IV atropine 0.6mg every 3-5mins
2nd line: IV dopamine or adrenaline
IV fluid resus
Transcutaneous pacing, then transvenous pacing
Permanent pacemaker

If stable
- BP > 90/60 AND NO symptoms
Monitor - no need intervention
If Mobitz 2 or 3rd degree block, close monitoring + prepare for pacing

Question 13

ECG features: Sinus bradycardia

Answer 13

Any HR < 60bpm
Every P wave is associated with QRS complex

Question 14

ECG features: Sinus node dysfunction aka sick sinus syndrome

Answer 14

• Absence of P waves
• Prolonged sinus pause / sinus arrest
• Tachy-brady syndrome (sinus arrest interspersed with A FIB)

Question 15

What syndrome can be seen in SSS

Answer 15

Tachy-brady syndrome
- sinus arrest interspersed with A FIB

Question 16

What is the definitive treatment for SSS

Answer 16

Permanent pacemaker for sinus pause
Anticoagulation

Question 17

ECG features:
Hyperkalemia

Answer 17

A: Tall peaked T waves (Eiffel Tower)
B: Prolonged P-R
C: Flattened P wave
D: Widened QRS
E: Sine wave (serious)

Question 18

HyperK+ management

Answer 18

Stop any K+ infusion if any

1. IV calcium gluconate 10% 10mls over 10 mins (repeat multiple doses if sine waves)
2. IV 50% dextrose 40mls + 10units of insulin
3. Oral resonium 15g
4. +/- Neb Salbutamol
5. Urgent hemodialysis if got sine waves

Question 19

How to tell QT prolongation?

Answer 19

If QT is > than 1/2 of RR interval, QT is likely to be prolonged

Question 20

Implication of prolong QT syndrome

Answer 20

Sudden cardiac death from ventricular arrhythmia

Question 21

Definitive treatment in familial QT syndrome

Answer 21

Automatic Implantable Cardioverter Defibrillator

Question 22

ECG feature: Brugada syndrome

Answer 22

Cove shaped ST in V1-2

Question 23

Risk of Brugada syndrome

Answer 23

Sudden cardiac death from ventricular arrhythmia

Question 24

Criteria for brugada syndrome

Answer 24

ECG pattern pattern +ve
Syncope OR
Fam hx of SCD OR
Fam hx of PPM/AICD
Genetic testing

Question 25

Definitive treatment in Brugada syndrome

Answer 25

Automatic Implantable Cardioverter Defibrillator

Question 26

Massive PE management

Answer 26

Reperfusion
1. 1st line: IV thrombolytic rTPA 100mg over 2h
2. Percutaenous embolectomy
3. Open embolectomy

Bridging therapy
- ECMO

Question 27

Syncope causes

Answer 27

Hyperkalemia
Brugada
QT prolongation
VFIB