Double atrial potentials as a marker for isthmus block during ablation of atrial flutter

ABSTRACT

Assessment of success is an integral part in atrial flutter ablation. This work is concerned with evaluating the added value of recording double potentials along the ablation line induced to interrupt the macro-reentrant circuit of atrial flutter. Atrial flutter was ablated in 24 consecutive patients, 7 males and 7 females, their ages ranged from 10-65 years, with mean age of 37 +/- 12.5 years. The ablation was done through burning a continuous line across the cavo-tricuspid right atrial isthmus. In all patients pace-mapping indicated complete bidirectional isthmus block, we tried to record double potentials along the ablation line during pacing from the coronary sinus ostium. The patients were followed up for 6 months, recurrent cases were reablated. the acute success rate was 100% in both the initial and the second procedures. Nine recurrences [37.5%] occurred during the period of follow up, which were reablated; none of the reablated cases had any recurrence during six months of follow up, with overall late recurrences of nine patients out of 33 procedures [27%]. Whenever double atrial potentials were recorded along the ablation lines, there was no recurrence [specificity of 100%], but in cases in which these potentials were not recorded, it did not predict recurrence except in 40% of cases [sensitivity 60%]. Predictors of late recurrence, in this study, were age of the patient and Duration of symptoms. We compared between 4 and 8 mm tip ablation catheters, it turned to be that the recurrence and the procedure duration was lower with the use of 8 mm tip catheters. Patient with structural heart disease in this study were older, with more duration of symptoms and their procedures were longer. In conclusion, there was an added value of recording double atrial potentials to the conventional mapping technique used to identify bidirectional isthmus block in patients with atrial flutter. In addition, 8 mm tip catheters were considered safe and effective in the term of reducing the time of the procedure and recurrence rate specially when combined with SVC approach. Abbreviations SVC superior vena cava