Ventricular Depolarization Potential-Guided Ablation on the Atrial Side near the Tricuspid Annulus of a Right Free-Wall Accessory Pathway Presenting with Late-Onset Intermittent Preexcitation and Antidromic-Only Slow Conduction

Wolff–Parkinson–White syndrome is characterised by ventricular pre-excitation on a 12-lead electrocardiogram (ECG) due to an accessory pathway (AP).1 Although APs may be identified at any age, their clinical manifestations can only occasionally be detected in childhood,2 adolescence,3, 4 and adulthood.1, 3, 5 Here, we present a case of wide-QRS tachycardia associated with atrial flutter (AFL) in a 78-year-old patient with late-onset right free-wall atrioventricular (AV) AP with intermittent preexcitation and antidromic-only, slow, adenosine-nonsensitive, nondecremental conduction, undetected during prior atrial fibrillation (AF) ablation and successfully ablated on the right atrial (RA) side, guided by ventricular depolarization potentials (VDPs).