Wolff-Parkinson-White Syndrome
Anesthetic Considerations
-
Potential for perioperative SVT or atrial fibrillation:
-
Consider crash cart, defbrillator pads, invasive arterial access, emergency drugs (procainamide, amiodarone)
-
Avoid AV nodal blockers if atrial fibrillation
-
-
Avoid sympathetic stimulation: pain, anxiety, hypovolemia, ketamine
Goals
-
Identify patients with WPW
-
Minimize sympathetic stimulation & drugs (adenosine, beta blockers, calcium channel blockers, digoxin) that could enhance anterograde conduction of cardiac impulses through the accessory pathways
-
Reduce anxiety which may precipitate tachycardia
Arrhythmia Treatments
-
Acute termination of orthodromic AVRT (approach is same as the usual patient with SVT):
-
1st line: vagal maneouvers, verapamil (5mg IV q3min up to 15mg), adenosine (6-12mg IV bolus with flush)
-
2nd line: procainamide, beta blockers, digoxin, amiodarone (prolongs the refractoriness of all cardiac tissues)
-
-
Acute termination of antidromic AVRT:
-
If unstable, must cardiovert
-
Avoid AV nodal blocking agents
-
If stable: IV drug of choice for acute treatment to terminate known antidromic AVRT is procainamide.
-
Procainamide is typically infused intravenously at 20 to 50 mg/minute given while monitoring the blood pressure closely every 5 to 10 minutes until the arrhythmia terminates, hypotension ensues, the QRS is prolonged by more than 50 percent, or a total of 17 mg/kg (1.2 g for a 70 kg patient) has been given
-
-
-
Acute termination of atrial fibrillation with pre-excitation:
-
AV nodal blocking drugs (adenosine, verapamil, beta blockers, & digoxin) should be avoided in patients with preexcited atrial fibrillation since blocking the AV node will promote conduction down the accessory pathway & may sometimes directly enhance the rate of conduction over the accessory pathway
-
The goals of acute drug therapy for preexcited AF are prompt control of the ventricular response & ideally, termination of atrial fibrillation
-
If unstable, must cardiovert
-
If stable, careful trial of IV drugs (no clear 1st line drug):
-
Procainamide (Class IA): 20-50mg/min until arrhythmia suppressed, hypotension ensues, QRS prolonged by 50% of original duration or total fo 17mg/kg has been given
-
Amiodarone (Class III): first dose 150mg over 10min, then 1mg/min for 6hrs, then 0.5mg/min for 18hrs
-
Ibutilide (Class III): if patient <60kg, 0.01mg/kg over 10min; if >60kg, 1mg over 10min
-
-
ECG Features
-
Short PR, wide QRS, delta wave