Cardiac Rhythm Disturbances (General Approach to Tachydysrhythmias)

Question 1

How are tachydysrhythmias categorized?

Answer 1

Narrow or Wide
Regular or Irregular

Question 2

Where do supraventricular tachydysrhythmias originate?

Answer 2

Within or above AV node

Generally narrow

Question 3

Where to ventricular tachycardias originate?

Answer 3

Below AV node

Generally Wide

Question 4

Wide complex tachycardias can occur in supraventricular rhythm in which cases?

Answer 4

Bundle branch block
WPW (ventricular preexcitation syndrome)
Toxic metabolic condition

Question 5

Common narrow complex tachycardias (4)

Answer 5

1. Sinus tachy
2. Afib
3. Atrial flutter
4. Paroxysmal SVT

Less common: Multifocal atrial tachycardia, Atrial tachycardia, preexcited tachycardia (WPW)

Question 6

Classification of wide ventricular tachycardia (2)

Answer 6

1. Vtach
2. Supraventricular tachycardia with aberrant construction

Question 7

Characterize torsades de pointes

Answer 7

1. Polymorphic vtach
2. Sequential and recurring QRS complex amplitude increase and decrease
3. QTc prolongation (>450ms)

Question 8

What tachy rhythms require medical + vagal + cardioversion?

Answer 8

afib/flutter

AV nodal reentrant tachycardia

AV reentrant tachycardia

sinus tachycardia and multifocal atrial tachycardia are best managed by treating underlying cause

Question 9

Enumerate 4 vagal maneuvers

Answer 9

1. Carotid sinus massage
2. Valsalva maneuver
3. Modified valsalva maneuver
4. Diving reflex

Question 10

Steps for modified valsalva

Answer 10

Patient at 45 degrees

Blow into 10cc syringe for 15 seconds

passive leg raise at 45deg for 15 seconds

lay flat for 45 seconds

Question 11

MOA of Valsalva maneuver

Answer 11

Heightens parasympathetic tone and slow electrical conduction

Abolishes sustained entry

Converts WPW and paroxysmal SVT if applied early

Question 12

Diving reflex

Answer 12

Place a bag of ice and water on face for 15-30s

more effective in infants

Question 13

Adenosine
Dose and MOA

Answer 13

Dose: 6mg TIV then 12mg TIV 2nd dose

MOA: Blocks condcution through AV node; Interrupts sustained entry

Terminating narrow QRS complex reentrant tachycardia: Verapamil, Diltiazem, Esmolol, Metoprolol, Propanolol, Adenosine

Question 14

Esmolol
Dose and MOA

Answer 14

500micrograms/kg IV over 1 min bolus then IV infusion at 50micrograms/kg/min

beta blocker