Lack of efficacy of radiofrequency catheter ablation in Andersen–Tawil syndrome: are we targeting the right spot?

Andersen–Tawil syndrome (ATS) is associated with a high arrhythmic burden as demonstrated recently by Delannoy et al.¹ in this Journal. Almost all subjects (91%) had very frequent ventricular arrhythmias [>10 000 premature ventricular contractions (PVCs)/day] including episodes of bigeminy and non-sustained ventricular tachycardia. As in other hereditary sudden cardiac death syndromes, it seems appropriate to eliminate these arrhythmias by means of radiofrequency catheter ablation (RFCA). To our knowledge, there is no publication of a successful RFCA in ATS. Delannoy et al.¹ reported that RFCA was unsuccessful in the five patients in which it was attempted. In our Institution, during the follow-up of a large family with a genetically confirmed diagnosis of ATS,² one of them became symptomatic (syncope), and an implantable cardioverter-defibrillator (ICD) was implanted in 2005 due to inducibility of ventricular fibrillation in an electrophysiological study. Intracavitary electrograms from the ICD showed frequent PVCs initiating the episode of ventricular fibrillation. Radiofrequency catheter ablation was attempted in 2006 and 2007 due to appropriate discharges of the ICD. In the first procedure, two ectopic sites in the left ventricle were targeted (anteroseptal and anterolateral) guided by electroanatomical mapping, also, ablation of both Purkinje bundles was added. In the following year, she was submitted to a second procedure after a recurrent appropriate discharge of the ICD. In this time, RFCA was delivered in the posteroseptal and apical zones, without elimination of the PVCs.

These apparently large areas of arrhythmogenicity could be the basis for the suggestion expressed by Dr Wilde³ in an accompanying Editorial, that the arrhythmogenic substrate could be present throughout both ventricles thus explaining the lack of efficacy of RFCA. An alternative consideration is that we are not targeting the right spot. Delannoy et al.¹ states that ‘Initial attempts to map ventricular ectopy in patients with ATS reveal that ectopic beats originate from different parts of left Purkinje network’. It could be interesting to study the possibility of uncommon ventricular substrates, like the posterior papillary muscles, recently described as a distinct clinical entity.⁴ These could be considered in future attempts of RFCA of ectopic beats in this group of patients because off the similarities in the morphology of the PVCs.

Conflict of interest: none declared.

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