- 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;
