Background <p>Fascicular ventricular tachycardia (VT) is an uncommon idiopathic VT affecting primarily young patients without structural heart disease. It typically involves a reentry mechanism within the Purkinje system, particularly the posterior fascicle, and appears on ECG with a right bundle branch block and left anterior fascicular block pattern. Although generally benign, symptoms such as palpitations or syncope can affect the quality of life. Catheter ablation is the treatment of choice for patients who are refractory to or prefer not to use medical therapy. To our knowledge, a novel 48-electrode paddle-shaped catheter (Optrell) has never been used for mapping fascicular VT.</p> Case summary <p>A 34-year-old competitive athlete with recurrent posterior fascicular VT underwent a second ablation after failed initial procedure and partial response to beta-blockers and verapamil. High-density electroanatomic mapping using the 48-electrode paddle-shaped catheter during tachycardia allowed identification of the abnormal Purkinje potentials (P1 and P2) and the critical fusion point of the reentry circuit at the mid-septum. Radiofrequency energy was delivered at this site, resulting in prompt termination of the arrhythmia. No recurrences were observed during the post-procedural observation period or at follow-up (6&#xa0;months).</p> Conclusions <p>This case demonstrates the safety and efficacy of high-resolution mapping using a novel 48-electrode catheter to facilitate ablation of fascicular VT.</p>