Figure 3. 7-year old patient referred after two failed
cryoablations and frequent episodes of tachycardia despite bi-therapy
with antiarrhythmics drugs. During the electrophysiology study, a
bidirectional antero-septal accessory pathway with easily inducible
orthodromic tachycardia was identified. After meticulous mapping of the
septal region and identification of the earliest signals in the His
region and unsuccessful ablation at close proximity of this site, aortic
root mapping was performed. The earliest ventricular signal on the
ablation catheter was identified in the right coronary cusp. Aortic root
angiogram was performed and a distance of 10mm was measured between the
right coronary artery orifice and the target site. A radiofrequency
ablation was performed using an energy of 20 Watts with temperature of
50°C, with immediate and definitive termination of the accessory pathway
conduction within 4 seconds. The left and right panels show the
electro-anatomical reconstruction of the right ventricle, right outflow
tract, tricuspid annulus (brown dots), and aortic root with an
activation map of the accessory pathway earliest signals on the
ventricular insertion (red area). The yellow dots show the areas where
His potentials were recorded; the red dots show the successful ablation
site located 7.9 mm from the site where mechanical AV block was induced
with high contact force (> 20 grams) at the tip of the
ablation catheter (blue dots). Within the non-coronary cusp (NCC brown
dot) we identified large atrial electrograms. The middle panel shows the
surface ECG and intracardiac EGMs recorded on the successful ablation
site in the right coronary cusp (RCC) during sinus rhythm, with a clear
sharp accessory pathway signal on the distal ablation catheter.
Figure 4. Repeated ablation of a bidirectional accessory
pathway within the neck of a diverticulum of the coronary sinus in a
9-year-old patient presenting with pre-excited atrial fibrillation.