title: Electrogram patterns predictive of successful radiofrequency catheter ablation of accessory pathways.
abstract: We assessed anterograde conduction electrogram parameters at successful ablation sites according to accessory pathway (AP) location and compared them to the most favorable electrograms at unsuccessful sites. A median of three radiofrequency energy impulses was applied to ablate 97% of 136 APs versus four impulses to ablate 90% of 65 concealed APs. Electrograms at successful sites showed variable A/V ratio (0.04-7), and a QS pattern of unipolar ventricular wave in 90%. Electrograms were different in right versus left AP: AV time 29 +/- 7 versus 38 +/- 10; and timing of ventricular deflection: 17 +/- 9 versus 2 +/- 9 msec, respectively. Analysis in each patient of the mapping parameters at successful versus "most favorable" unsuccessful sites showed an improvement in at least one parameter in 55%, no apparent change in all parameter values in 30%, and even less favorable parameters in 15% of patients. In patients with manifest AP, overall comparison of electrograms at successful versus unsuccessful sites showed no difference in A/V ratio (1.3 +/- 1.5 vs 1.2 +/- 1.6), unipolar pattern distribution, and AV time (34 +/- 10 vs 35 +/- 9), but earlier bipolar main ventricular potential (-4 +/- 12 vs -1.5 +/- 10 msec) and unipolar intrinsic deflection timings (-5.2 +/- 11 vs -1.8 +/- 10 msec). In patients with concealed AP, a retrograde continuous electrical activity was recorded in 72% of successful versus 38% of unsuccessful sites (P = 0.03).
  
  
  CONCLUSIONS
  Electrogram characteristics at successful radiofrequency ablation are different in right and left manifest AP.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D014927:Wolff-Parkinson-White Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*