Master the board step 3

Master the Boards: USMLE Step 3
Torsade de pointes is
ventricular tachycardia with
an undulating amplitude.
Magnesium should always
be given in addition to
medical or electrical
therapy.
Ventricular Fibrillation (V-Fib)
V-fib presents as sudden death.
Diagnostic Testing
You cannot tell what caused the loss of pulse without an EKG.
Treatment
Treatment of V-fib is always with unsynchronized cardioversion first. Do not
answer intubation first. Dead people are never breathing. If you shock them
back to life, they are more likely to breathe!
When to deliver
electricity:
Unsynchronized
At any point in cycle
Synchronized
Not during the T-wave
Indications: V-fib, pulseless VT Everything except V-fib
and pulseless VT
Basic Science Correlate
Mechanism of Need for Synchronization
The T-wave represents the refractory period. An electrical shock delivered
during the T-wave can set off a worse rhythm—specifically, asystole and
ventricular fibrillation are worse than ventricular tachycardia. Do not deliver a
shock during the refractory period.
Unsynchronized cardioversion (defibrillation) is administered as follows:
1. Continue CPR
2. Reattempt defibrillation
3. Administer IV epinephrine or vasopressin
4. Reattempt defibrillation
5. Administer IV amiodarone or lidocaine
6. Reattempt defibrillation
7. Repeat several cycles of CPR between each shock
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