Radiofrequency linear ablation using an 8-mm tip electrode catheter achieved a higher complete isthmus block rate than a 4-mm tip catheter (92% vs 67%, P<0.05).
RCT (n=104)
randomly assigned
Does an 8-mm tip electrode catheter improve complete isthmus block rate compared to a 4-mm tip electrode catheter in patients undergoing radiofrequency linear ablation for typical atrial flutter?
Using an 8-mm tip electrode catheter for radiofrequency ablation of typical atrial flutter significantly improves the rate of complete isthmus block and reduces procedure time compared to a standard 4-mm tip catheter.
Absolute Event Rate: 92% vs 67%
p-value: p=<0.05
BACKGROUND: The prospective, randomized study comparing 4- with 8-mm tip electrodes for radiofrequency linear ablation of typical atrial flutter is not available. METHODS AND RESULTS: A total of 104 consecutive patients with typical atrial flutter were randomly assigned to undergo radiofrequency linear ablation using a 4- (Group I, n=54) or 8-mm tip electrode (Group II, n=50) catheter (temperature-control model, preset 70 degrees C). If complete bidirectional isthmus block could not be achieved after 5 pulses, the ablation catheter was changed to the other type; the maximal radiofrequency pulse number was limited to <10 pulses. Complete or incomplete isthmus conduction block was assessed by activation sequence in a multielectrode Halo catheter during low lateral right atrial and proximal coronary sinus pacing. Before shifting to the other catheter type, the 8-mm electrode catheter achieved higher complete isthmus block rate (92% versus 67%, P<0.05) with fewer pulses (2+/-1 versus 3+/-1, P<0.05), shorter procedure time (24+/-15 versus 31+/-12 minutes, P<0.05), and shorter fluoroscopic time (14+/-10 versus 23+/-15 minutes, P<0.05). After 5 failed ablation pulses, 12 (67%) of 18 patients in group I attained complete isthmus block by using an 8-mm tip catheter, but none of 4 patients in group II achieved complete block by changing to a 4-mm tip catheter. CONCLUSIONS: The 8-mm tip electrodes are more effective than the standard 4-mm length electrodes in linear ablation for typical atrial flutter. This clinical benefit may be of particular value for some patients with broad and/or thick isthmus.
Tsai et al. (Tue,) conducted a rct in typical atrial flutter (n=104). 8-mm tip electrode catheter vs. 4-mm tip electrode catheter was evaluated on complete isthmus block rate before shifting to the other catheter type (p=<0.05). Radiofrequency linear ablation using an 8-mm tip electrode catheter achieved a higher complete isthmus block rate than a 4-mm tip catheter (92% vs 67%, P<0.05).