Clinical Importance of Koch's Triangle Size in Children: A Study Using 3-Dimensional Electroanatomical Mapping

Background Catheter ablation inside the Koch's triangle has a risk for complete atrioventricular block. Methods and Results The anatomic size of the coronary sinus (CS) and His bundle (HB) in children and the distance between them was studied using a 3-dimensional electroanatomical mapping system (CARTO). Fifty-three children (mean age, 11.8±3.7 years) without congenital heart disease (ie, 24 with atrioventricular re-entrant tachycardia, 18 with atrioventricular nodal re-entrant tachycardia, 7 with atrial tachycardia, 2 with ventricular tachycardia and 2 with atrial flutter) were studied. The size of the HB recording area was 148±97 mm2 and the size of the CS was 66±44 mm2. The size of the CS and the distance between the HB and CS (18±7 mm) were proportional to body weight, body length and body surface area. All patients underwent catheter ablation, including 25 ablations inside Koch's triangle. Catheter ablation was successful in 52 patients without any atrioventricular nodal injury. Conclusions The CS size and the distance between the HB and CS increased proportionally with children's growth. To know the distance from the HB to the ablation point is useful in avoiding atrioventricular node injury, and information about the length of Koch's triangle may provide supportive information when applying radiofrequency energy inside Koch's triangle without needing to use the CARTO system in children, but this merits further investigation. (Circ J 2007; 71: 1918 - 1921)