A QUANTITATIVE FLUOROSCOPIC COMPARISON OF THE CORONARY SINUS OSTIUM IN PATIENTS WITH AND WITHOUT AV NODAL REENTRANT TACHYCARDIA

Coronary Sinus Ostium. Introduction: The purpose of this study was to perform a quantitative fluoroscopic analysis of the coronary sinus ost ium and its relationship to the His bundle in patients with and withou t AV nodal reentrant tachycardia. Sites of slow pathway ablation are o ften near the coronary sinus ostium, which can be located within a few millimeters of the His bundle, Whether such close proximity of the co ronary sinus ostium to the His bundle is unique to patients with AV no dal reentrant tachycardia is unknown. Methods and Results: Fifty conse cutive patients (mean age 39 +/- 14 years) with no structural heart di sease underwent electrophysiologic testing and radiofrequency ablation . The study group consisted of 28 patients with inducible AV nodal ree ntrant tachycardia or dual AV nodal physiology and 22 patients in the control group. A coronary sinus venogram was performed in each patient . The coronary sinus ostium was similar in size in the study group (11 .4 +/- 4.5 mm) and in the control group (10.5 +/- 3.6 mm, P = 0.2). Th e coronary sinus ostium was funnel shaped in half of the study patient s and in half of the control patients (P = 1.0). The mean distance fro m the upper lip of the coronary sinus ostium to the tip of the His bun dle catheter was 9.7 +/- 5.5 mm in the study group and 10.4 +/- 5.1 mm in the control group (P = 0.7). The mean distance from the lower lip of the coronary sinus ostium to the tip of the His-bundle catheter in the study group was 20.1 +/- 6.1 mm and 19.5 +/- 5.6 mm in the control group (P = 0.7). Conclusion: This study demonstrates a wide range of normal coronary sinus ostium diameters, morphology, and anatomic relat ionships with surrounding structures, with no demonstrable correlation to the presence or absence of dual AV node physiology or AV nodal ree ntrant tachycardia.