Anesthetic Implications of Wolff-Parkinson-White Syndrome: AC ase

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					Anesthetic Implications of Wolff-Parkinson-White Syndrome: A Case Report

Maria Defante, M.D. and Donald M. Voltz, M.D.

Wolff-Parkinson-White syndrome (WPW) is a condition in which supraventricular tachyarrythmias can
occur as a result of an abnormal pathway, the accessory bundle of Kent that directly connects the atria and
ventricles bypassing the AV-node1. The resulting supraventricular tachyarrythmias (SVT) that occur in
WPW are the result of either decreased conduction through the atrioventricular (AV) node or an increased
conduction along the accessory bundle of Kent. Treatment of WPW includes medical management and
radiofrequency or surgical ablation of the offending accessory pathway to restore normal conduction
through the AV node. WPW is not a frequent occurrence for anesthesiologists due to a high rate of ablation
of the accessory pathway in symptomatic patients. We present a case report of an asymptomatic patient
who presented with WPW for an aorto-bifemoral vascular bypass to highlight the anesthetic implications of
this disease.

W.A. is a 64 year-old male who presented for an elective aortic bypass operation. His past medical history
is significant for CAD, HTN, and PVD. His preoperative EKG demonstrated a normal sinus rhythm, a rate
of 71 bpm, and a slurring of the QRS upstroke (δ wave) without a shortened P-R interval. The patient
received midazolam (2 mg) and was taken to the OR. Standard monitors were placed and denitrogenation
completed. To decrease the risk of tachycardia with induction, the patient received 5 mg of metoprolol.
Induction consisted of propofol, lidocaine, and vecuronium. During induction and intubation, the patient’s
heart rate remained stable in the 70’s /min. Placement of an invasive blood pressure monitor and pulmonary
artery catheter occurred following intubation. Maintenance of anesthesia was accomplished with isoflurane,
an admixture of O2 : Air, fentanyl, and vecuronium. Throughout the surgical procedure, including
reperfusion of the lower extremities, the patient’s heart rate remained controlled between 70-80 bpm.
Following an uneventful revascularization of his lower extremities, A.W. was extubated in the OR and had
an uneventful postoperative course being discharged home on postoperative day #4.

The presence of an accessory conduction pathway by itself does not carry any increased anesthetic risks,
but the management of supraventricular tachyarrythmias that can result, have the potential for devastating
outcomes. Management of WPW includes controlling the sympathetic nervous system in an attempt to
avoid a hyperadrenergic state that may predispose these patients to SVT. Common medications used to
control the heart rate in SVT may be detrimental in patients with WPW. Calcium-channel blockers such as
verapamil or diltiazem, digoxin, and adenosine all slow conduction through the AV node2. These
medications also may enhance conduction along the accessory bundle or at the very least do not slow
conduction along this abnormal tissue, resulting in rapid ventricular rates. Once rapid conduction along the
accessory bundle takes hold, a rapid ventricular response can deteriorate into ventricular fibrillation. The
use β–blockers in patients with WPW may be useful in slowing re-entry tachyarrythmias through the
accessory bundle1 as well as decreasing the sympathetic activation of the normal cardiac conduction
pathways. Medications that directly increase circulating levels of catecholamines and the heart rate should
be used with caution in patients with WPW. Management of these patients in the postoperative period
continues to be crucial. Adequate pain results in decreased adrenergic output thereby lowering the
possibility for tachydysrhythmia.

Albeit, the incidence of WPW in the operating room is low, the potential for mismanaging the
tachyarrythmias that can result are high and have the potential for devastating consequences.

References:

1.   Gaita F, Giustetto C, Riccardi R, Brusca A. Wolff-Parkinson-White syndrome. Identification and
     management. Drugs.1992 Feb;43(2):185-200.
2.   German LD, Gallagher JJ. Functional properties of accessory atrioventricular pathways in Wolff-
     Parkinson-White syndrome. Clinical implications. Am J Med.1984 Jun;76(6):1079-86.

				
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posted:3/10/2012
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