7 year old boy Drugrefractory episodes of tachycardia

7 year old boy Drug-refractory episodes of tachycardia, 150 -220/min, since 2 years Normal Echo Comments from Chandrashekhar and Deep Chandh Raja

Tachycardia mechanism? Sinus tachycardia on the left with tall P waves in inferior leads. There is gradual transition to the WCT - LB with normal axis @ 145/min. Fusion complexes at the start and VA dissociation during tachycardia suggest VT. Abnormal automaticity is the probable mechanism.

AV relationship? 1 to 1 VA conduction during the WCT. While the AA intervals appear similar, they are in fact a bit shorter during the narrow QRS complexes. And the atrial activation sequence in RFD and RFP are also different. And the unipolar atrial electrogram shows the most striking difference, from rss’ to r. S. Early ventricular activation signals noted at the His catheter suggesting the focus could be in the vicinity

Rapid atrial pacing- comment. With atrial pacing the WCT disappears and every paced atrial beat is conducted to the ventricle. Once the atrial pacing is stopped the WC rhythm gradually takes over with VA conduction. The His potential is coincident with the QRS onset during the WCT.

1 st RF energy- likely site? Posterior RVOT septum- supra. His, adjacent regions could be RCS or junction of R/L coronary sinus After ablation Programmed Ventricular ES at VANERP and intact antegrade AV conduction

RAO 30 RF site AP LAO 40 1 month follow-up: No arrhythmias noted, no symptoms