TRANSESOPHAGEAL ECHO PHASE IMAGING FOR LOCALIZING ACCESSORY PATHWAYS DURING ADENOSINE-INDUCED PREEXCITATION IN PATIENTS WITH THE WOLFF-PARKINSON-WHITE SYNDROME

Transesophageal phase images and precordial electrocardiography (ECG) were used to localize accessory pathways during adenosine-induced pree xcitation in 30 patients (18 men, mean age +/- SD 33 +/- 14 years) und ergoing endocardial mapping for suspected Wolff-Parkinson-White syndro me, Digitized 2-dimensional echocardiographic cine loops were mathemat ically transformed using a first harmonic Fourier algorithm before and after catheter ablation, Endocardial mapping found single accessory p athways with anterograde conduction in 20 patients, concealed pathways in 7, and atrioventricutar reentry circuits in 3 patients, At baselin e, precordial ECG correctly localized 8 pathways (40%) with anterograd e conduction and predicted 5 adjacent locations (25%), but findings we re normal in 7 patients (35%), Phase imaging correctly identified only 3 pathway locations (15%), findings were normal in 15 (75%), and coul d not be obtained in 2 patients (10%). Adenosine augmented manifest bu t minimal preexcitation in 9 patients and unmasked latent preexcitatio n in 7, In 4 patients, preexcitation was already maximal at baseline, During adenosine-augmented preexcitation, ECG correctly identified 13 locations (65%), but still predicted 7 adjacent locations (35%), Howev er, phase imaging correctly identified 15 locations (75%) and predicte d only 3 adjacent locations (15%). All midseptal (n = 2) and anterosep tal (n = 2) locations were correctly identified by phase imaging, but none by ECG. On follow-up studies in 16 patients, successful catheter ablation (n = 13) was equally well confirmed by ECG and phase imaging, Therefore, transesophageal echocardiographic phase imaging during ade nosine-induced preexcitation is a readily available and safe procedure that appears clinically most useful for identifying septal pathways.