Patients may remain asymptomatic. Episodes of
paroxysmal palpitation (atrial flutter, supraventricular tachycardia) may be
associated with shortness of breath, signs of ventricular failure, and
syncope. Investigations include ECG and electrophysiologic studies to define
the site of accessory conducting tissue and the individual mechanism for
tachycardia generation. The tachycardia is usually a narrow complex, but
functional right bundle or left bundle branch block may cause a wide complex
tachycardia. Several drugs may be used in the management of the condition,
including adenosine (acutely), verapamil, beta blocker, procainamide,
amiodarone, or digitalis. However, verapamil and digoxin are contraindicated
for treatment of atrial fibrillation or flutter in these patients because
they might accelerate conduction through the bypass tract and induce
ventricular fibrillation. Surgical or catheter pathway ablation or
pacemakers (overdrive pacing) may be used.