Cardioversion: Topics and Technique of


- Discussion: 
- certain rhythms are very sensitive to cardioversion, & low energy levels are likely to bring about conversion: (e.g. A. Flutter and V. Tach); 
- A. Fib & V. Fib are more resistant to cardioversion & require higher energy levels; 
- Pre-Medication: 
- anticoagulants may be administered prior to the procedure; 
- sedation is induced w/ diazepam or other sedative; 
- pts w/ A. Fib or Flutter, quinidine or procainamide should be started 1-2 days before cardio-conversion; 
- pts treated w/ Digoxin, serum levels are recommended prior to cardioversion to rule out toxicity; 
- w/ toxic levels, conversion may produce V. Fib
- w/ ventricular arrhythmias, a 50-100 bolus of lidocaine is administered if procedure is to be continued; 
- if Bradycardia is noted, Atropine, 0.6-1.0 mg IV is generally helpful; 
- Energy Levels: 
- Synchronized energy settings begins at: 
- 25 J for atrial flutter
- 50 J for SVT and VT, and 100 J for atrial fib
- sequential increases to 100, 200, 300 and 360 J may be necessary; 
- Nonsynchronized discharge of 200-300 J is recommended for VF
- nonsynchronized discharge may convert other rhythms to V. Fib, esp if discharge occurs on T wave
- nonsynchronized discharge may be acceptable in V. Tach if QRS and T waves cannot be identified. 
- if cardiac rhythm cannot be determined, consider asynchronous conversion; 
- General Technique: 
- paddles are coated w/ electrode paste (or defibrillation pads)
- position first paddle to the right of sternum at the level of 3rd or 4th ICS; 
- position second paddle just outside cardiac apex or posteriorly at left infrascapular region; 
- apply firm pressure to the paddles and discharge paddles; 
- do not remove the anterior paddle prematurely; 
- Adverse Effects: 
- conversion may produce VF, Asystole;
- muscle soreness, w/ rise in muscle enzymes, and irritation of skin at paddle site are common; 
- increases in CPK-MB is related to amount of energy delivered




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, December 19, 2011 2:09 pm