Does monitoring local electrogram amplitude during radiofrequency application predict efficacy of tissue heating in patients with common atrial flutter?
The decrease in local electrogram amplitude during RF ablation is a reliable marker for tissue heating efficacy and may serve as an endpoint for individual RF applications in atrial flutter.
Recent studies have suggested that the attenuation of the local electrogram amplitude recorded from the ablation electrode during radiofrequency (RF) application predicts lesion growth. This study examined the time course of local electrogram amplitude during ongoing RF delivery in patients with common atrial flutter (AFl). In 71 patients with AFl, RF energy was applied to the anatomical isthmus. Termination of AFl was noted during 68 of 625 applications of RF energy. The changes in local atrial electrogram amplitude observed at all successful sites were analyzed. With increasing duration of the RF delivery, the electrogram amplitude decreased exponentially to reach a steady state within a mean duration of 17±3 sec, which was significantly longer than that of the steady-state temperature. The average decrease in the amplitude was 67±13%. In 16 patients in whom an increase in the power of RF energy had resulted in AFl termination, there was a dose-response relationship between the power and the amplitude decrease. The decrease in local electrogram amplitude appears to be a reliable marker for the efficacy of tissue heating and may be useful as an endpoint for individual applications. Local electrogram monitoring may offer an optimal energy strategy in AFl ablation. (Jpn Circ J 1998; 62: 559 - 564)
Azegami et al. (Thu,) studied this question.
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