Wolff-Parkinson-White Syndrome Associated Syncope After Orthotopic Heart Transplantation

Introduction Orthotopic heart transplantation (OHT) patients may develop a variety of arrhythmias. Accessory pathway (AP) dependent supraventricular tachycardia (SVT), namely Wolff-Parkinson-White (WPW) syndrome is rare in these patients. There is wide variability in how OHT patients manifest symptoms of WPW, ranging from minimal or none to abrupt syncope due to hemodynamic compromise. Case This is a 72-year-old man with a history of OHT two years prior to presentation with preexcitation in donor's heart who presented with 3 episodes of syncope over an hour preceded by lightheadedness. EKG showed normal sinus rhythm 90 beats per minute, delta wave, wide QRS complex with right bundle branch block morphology (Fig. 1). Preexcitation (PE) has been found on EKG since OHT. The donor didn't have manifest PE or history of cardiac arrhythmias. The differential diagnosis of patient's syncope included cardiac arrhythmia, orthostatic hypotension, and neurocardiogenic syncope. The presence of PE on the EKG argued in favor of an arrhythmic etiology and thus an electrophysiology study (EPS) was performed. Baseline EPS revealed presence of a bidirectionally-conducting left-lateral AP. Atrial program stimulation reproducibly induced SVT proven to be orthodromic reciprocating tachycardia (ORT). Of note, systolic blood pressure dropped from 130 mmHg at baseline to 40 mmHg after induction of ORT. Furthermore, a wide complex tachycardia consistent with antidromic reciprocating tachycardia (ART) was also induced with atrial pacing (Fig. 2). Radiofrequency ablation (RFA) was successfully performed after 3D mapping via a transseptal approach. Post-ablation, pacing maneuvers, and administration of adenosine showed no evidence of AP. Neither ORT nor ART could be induced. Postprocedural EKG revealed normal sinus rhythm without delta waves (Fig. 1). At four month follow-up visit, patient denied any recurrent syncope and EKG was without PE. Discussion WPW syndrome after OHT is rare. APs can occasionally manifest only after OHT. Clinical presentation ranges from asymptomatic PE to hemodynamically significant arrhythmia. Electrophysiologic induction of arrhythmia and correlation with signs and symptoms is essential for accurate diagnosis. RFA of the AP is typically curative for OHT patients with symptomatic WPW.