1. Amiodarone Use in Cardiac Surgical Resuscitation
Jeffrey R. Balser, M.D., Ph.D.
Associate Professor, Anesthesiology and Pharmacology
Associate Dean, Physician Scientist Development
Vanderbilt University School of Medicine
Nashville, TN 37232

2. Ventricular Arrhythmias
Common Substrates
PVCs, nonsustained VT
normal ventricle, periop
Sustained monomorphic VT
prior MI, structural disease
Polymorphic VT with normal QT
acute ischemia, infarction,
idiopathic cardiomyopathy
Ventricular fibrillation
Polymorphic VT with
congenital, prior drugs,
low K, Mg, bradycardia
prolonged QT interval
(torsade de pointes)

3. Most common sustained VT/VF in
cardiac surgery
Normal QT Polymorphic VT
(ischemia, hypothermia, infarction,)
Ventricular Fibrillation (VF)
- Little data on pharmacologic therapy for VT/VF in
surgical patients… however, there are recent data in
nonsurgical patients

4. IV Amiodarone in ICU patients
Recurrent VT/VF refractory to lidocaine, procainamide, and bretylium:
40% arrhythmia-free at 24 hrs
JACC 27:67, 1996
After lidocaine and procainamide failure
efficacy: bretylium = amiodarone
side effects: bretylium > amiodarone
Hypotension: 33% vs. 21%
CHF: 5% vs. 0%
Circ 92:3255, 1995

5. IV Amiodarone in Cardiac Arrest
504 victims of out-of-hospital cardiac arrest in Seattle
IV amiodarone (300 mg) or vehicle control
administered by emergency personnel following
3 defibrillation attempts and 1 mg of epinephrine
while CPR continued.
The likelihood of being resuscitated and being admitted to the hospital was 44% in the treatment group vs. 34% in the placebo arm (p = 0.03)
Kudenchuk et al., N Engl J Med. 1999;341:871-8

6. Recent Recommendations for VT/VF Management in Cardiac Arrest
Airway, Breathing, etc..
Defibrillatory Shocks
If refractory: consider antiarrhythmic drugs
amiodarone (IIb), lidocaine (Indeterminate),
magnesium (IIb if hypomagnesemic state)
procainamide (IIb for intermittent/recurrent VF/VT)
Circulation 2000 (Aug 22), 102:I-147

7. Evidence-based recommendations: Terminology
IIb (Amiodarone, Procainamide)
Consensus review of evidence by experts in the field suggest the intervention is “Fair to Good”
Considered within “standard of care”: reasonably prudent physicians can use.
Considered optional or alternative interventions by majority of experts (versus an intervention of choice for IIa recommendation)
Circulation 2000 (Aug 22), 102:I-147

8. Evidence-based Recommendations: shock-refractory VT/VF
Lidocaine: new recommendation is “Indeterminate”
Lidocaine has not been shown to be effective in treating human cardiac arrest during shock-resistant VF
Circulation 2000 (Aug 22), 102:I-149

9. Unique Features of IV Amiodarone
No known value to combine with other agents
- usually discontinue lidocaine, procainamide, and other antiarrhythmic agents when using IV amiodarone
Loading is empiric
- 150 mg IV (rate as hemodynamically tolerated)
- 2-4 loading doses are often needed
- more are not unheard of….

10. IV Amio in Electrical Storm
Typical Scenario
load IV amio
(150 mg/5-10 min)
Shock VF
VF! (CPR)
VF recurs
(10 sec)
sinus rhythm
6 hrs:  amio
to 0.5 mg/min
(30 sec)
sinus
rhythm
Shocks
VF recurs
sinus rhythm (for now)...
reload IV amio
shock VF
Shock VF
reload IV amio (no agent change)!
sinus rhythm lasting 5-10 min
1 min later:
VF recurs
start amio infusion:
1 mg/min (6 hrs)

11. Features of IV Amiodarone Use
Rarely chemically converts VF -- maintains SR after defibrillatory shocks
- load, shock, SR, VF, load, shock, SR…. Sign of drug “response” may be gradual lengthening of the interval of SR between episodes of VF
Amiodarone and its solvent are both vasodilators
- pressors may be needed to support BP during amiodarone loading (especially in SR)

12. Summary: VT/VF Pharmacologic Strategies in Cardiac Surgery
Nonsustained VT: Usually does not require drug therapy
Sustained VT/VF:
- Drug-induced Long QT, Torsades de Pointes:
Defibrillation, then K+, Mg2+, pacing
- Other VT/VF: No controlled trials in surgical patients
- data in other settings (ICU, out-of-hospital)
support the use of IV amiodarone in preference
to lidocaine