Search

Introduction: Wolf-Parkinson-White (WPW) syndrome is characterized by the presence of one or several atrioventricular accessory pathways which can generate symptomatic arrhythmias, commonly atrioventricular reentry tachycardia (AVRT). It often exists alongside atrial fibrillation (AF), which leads to rapid ventricular rates via an accessory pathway, known as pre-excited AF, a potentially malignant type of arrhythmia. Case Report: A 55- year-old male patient was admitted to the emergency department with recent gastrointestinal symptoms. The 12- lead electrocardiogram revealed a regular wide QRS (145ms) tachycardia (225 beats/min), right QRS axis deviation, right bundle branch block morphology (Rr'), without evidence of atrioventricular dissociation, fusion nor capture beats, hemodynamically stable. Intravenous administration of Amiodarone resulted in the conversion to sinus rhythm, revealing a short PR interval, with positive delta wave in DII, DIII, aVF, V4-V5, intermittent R wave > S wave in V1, biphasic T wave in DII, DIII, aVF, V5-V6. Therefore, suspicion of antidromic AVRT secondary to a left free-wall accessory pathway. No pathological findings were revealed after a complete blood count was carried out; transthoracic echocardiogram showed a slightly left atrial enlargement. During the hospitalization, the patient developed an asymptomatic and hemodynamically stable episode of irregular wide-complex tachycardia (F.B.I), with different grades of fusions, revealing the concertina-like phenomenon secondary to AF mediated by accessory pathway, with spontaneous conversion to sinus rhythm. An electrophysiological study was performed, revealing the left free wall accessory pathway, with the induction of antidromic and orthodromic AVRT, with a SPERRI (shortest pre-excited RR interval) of 250ms. Successful radiofrequency catheter ablation was performed. Discussions : The identification of pre-excited AF is an infrequent manifestation of WPW syndrome. Nonetheless, certain individuals may remain asymptomatic despite evident pre-excitation on electrocardiographic recordings. The pronounced irregular RR intervals accompanied by diverse QRS morphology is a sign of pre-excited AF conducted through the accessory pathway. In such circumstances, the administration of intravenous Amiodarone or other agents aimed at AV nodal blockade may attenuate the intrinsic inhibition of orthodromic conduction, potentially fostering the onset of ventricular tachycardia (VT) or ventricular fibrillation (VF). A SPERRI of less than 250ms increases the risk of sudden death. Conclusions: The presence of irregular wide-complex tachycardia necessitates careful consideration for pre-excitation, highlighting the importance of vigilant evaluation and management in such cases. It is imperative to acknowledge the potential risk of sudden death, particularly in instances where SPERRI measures <250ms. [ABSTRACT FROM AUTHOR]