Using a duty-cycled, phased RF ablation system is safe and effective to isolate PVs. No Eso alteration was documented after ablation when LET was not monitored. This suggests that the LET probe may contribute to the thermal effect. Whether the documented increments in LET are due to direct tissue heating or possible interaction between the LET probe requires further investigation.

Recently, a novel radiofrequency (RF) ablation system has been developed to perform pulmonary vein (PV) isolation. The system consists of a decapolar, steerable, over-the-wire mapping and ablation catheter combined with a multichannel RF generator that delivers energy in a temperature-controlled, power-limited fashion in both uni- and bi-polar modes. Using this technique, long continuous ablation lesions can be created within the left atrial antrum around the PV ostium. Electrical disconnection of PVs can be achieved in 93% of targeted PVs. Medium-term success is reported as 79.5% of patients with paroxysmal atrial fibrillation (no atrial fibrillation episodes detected during intensive holter monitoring). Ablation procedures using the novel technique are reported to be short (mean procedure duration: 84-201 min), including RF application duration of up to 40 min. Procedure-related complications are rare (1.8%) but the included total patient numbers are small and further studies on larger patient populations are needed.

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