Ablation of atrial tachycardia after Mustard and Senning surgeries for d-transposition of the great arteries ☆ Irina Suman-Horduna, Sabine Ernst ⁎ Cardiology department of the Royal Brompton and Harefield Hospital, United Kingdom abstract article info Keywords: Mustard Senning Atrial tachycardia Remote navigation Various types of cardiac arrhythmias can be encountered in patients with previous Mustard or Senning palliation for dextro transposition of the great arteries. This review focuses on the most frequent presentations with supra- ventricular tachycardias which are amenable to catheter ablation using advanced technologies. In most of the cases, success can be achieved with ablation from the neo-pulmonary venous site, a region no longer directly accessible. Different techniques can be employed to reach the pulmonary side of the circula- tion, depending on the personal experience and the available equipment including remote magnetic naviga- tion. Careful pre- and peri-procedural assessment of the underlying anatomy, possible baffle obstructions or residual leaks is essential. © 2012 Published by Elsevier Ireland Ltd. 1. Introduction Between the early 1960s and mid-1980s, the Mustard and Senning operations [1,2] represented the major surgical palliative procedures to redirect the atrial inflow to the opposite atrioventricular valve in chil- dren with d-transposition of the great arteries (D-TGA). These operations involved re-routing of the venous return towards the opposite ventricle by creating intra-atrial baffles made of either an artificial material or pericardium in the Mustard variant or of the right atrial free wall in the Senning form. The surgical correction also involved longitudinal bisec- tion of the cavo‐tricuspid isthmus and an atrial septectomy. With the advent of the arterial switch operation by the mid-1980s, these procedures have been progressively replaced by the Jatene's an- atomical correction [3] as the standard definitive surgical procedure in patients with D-TGA. This approach has allegedly smaller risk of late occurrence of sinus node dysfunction or atrial tachyarrhythmias. More importantly, the morphologically left ventricle is restored to the systemic circulation, with less risk for developing systemic ventricu- lar failure in the long-term. Nevertheless, some adolescents and most adults today with D-TGA still have Mustard or Senning baffles. Due to extensive atrial modifica- tions and scarring, development of bradyarrhythmias and tachyar- rhythmias is seen in up to 25% cases by 20 years after the surgery [4,5]. 2. The most important arrhythmia after intra-atrial baffle procedures Sudden death is the most common cause of late death after atrial switch procedure for D-TGA with a reported incidence of 4.9 per 1000 patient-years in a population-based study [6]. The clinical pro- file of the patient with previous atrial inflow switch procedure at risk of SD is currently unknown, but it appears that supraventricular arrhythmias are associated with the risk of dying suddenly in this par- ticular population [7,8]. In a case–control study, Kammeraad et al. [7] found that presence of symptoms of arrhythmia or heart failure and presence of documented atrial flutter/atrial fibrillation are the best predictors of SD in patients with previous Mustard or Senning opera- tion. Several mechanisms can account for the possible link between supraventricular arrhythmias and SD: (i) a rapid ventricular response to paroxysmal supraventricular tachycardias can subsequently cause hemodynamic deterioration or trigger fatal ventricular arrhythmias [8]; (ii) the occurrence of atrial flutter or atrial fibrillation in a patient with atrial inflow correction for D-TGA seems to represent a marker of a failing systemic right ventricle [9]. 3. Types of supraventricular arrhythmias The most common types of supraventricular arrhythmias in patients with Mustard or Senning intracardiac baffles are represented by macro‐ reentrant tachycardias in relationship with the previous atriotomy scars or sites of placement of the suture lines for the intracardiac baffles. The most frequently encountered form of macro‐reentry is a circuit which revolves around the tricuspid valve [10–12] (Fig. 1). The cavo‐ tricuspid isthmus (CTI) is divided by the baffle placement within the atria which leads to separation of the caval and tricuspid annular aspects of the CTI on the systemic and pulmonary venous sides of the Progress in Pediatric Cardiology 34 (2012) 75–78 ☆ This study was supported by the NIHR Cardiovascular Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College London. ⁎ Corresponding author at: National Heart and Lung Institute, Imperial College, Royal Brompton and Harefield Hospital, Sydney Street, SW3 6NP, London, United Kingdom. Tel.: +44 207 351 8612; fax: +44 207 351 8629. E-mail address: S.Ernst@rbht.nhs.uk (S. Ernst). 1058-9813/$ – see front matter © 2012 Published by Elsevier Ireland Ltd. http://dx.doi.org/10.1016/j.ppedcard.2012.08.003 Contents lists available at SciVerse ScienceDirect Progress in Pediatric Cardiology journal homepage: www.elsevier.com/locate/ppedcard