Ablation of Persistent Atrial Fibrillation Using Multielectrode Catheters and Duty-Cycled Radiofrequency Energy
Christoph Scharf, MD*,*,
Lucas Boersma, MD ,
Wyn Davies, MD ,
Prapa Kanagaratnam, PhD,
Nicholas S. Peters, MD,
Vince Paul, MD ,
Edward Rowland, MD,
Andrew Grace, MD||,
Simon Fynn, MD||,
Lam Dang, PhD*,
Hakan Oral, MD¶ and
Fred Morady, MD¶
* Cardiovascular Center, Clinic im Park, Zurich, Switzerland
St. Antonius Hospital, Nieuwegein, the Netherlands
St. Mary's Hospital, Imperial College, London, United Kingdom
St. George's Hospital, London, United Kingdom
|| Papworth Hospital, Cambridge, United Kingdom
¶ University of Michigan, Ann Arbor, Michigan
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Figure 1 PVAC
The pulmonary vein ablation catheter (PVAC) is a decapolar, circular, over-the-wire mapping and ablation catheter designed for pulmonary vein (PV) isolation. Stability is provided by the guiding wire advanced into the pulmonary vein (PV), whereas the catheter itself is positioned at different aspects of the PV antrum for mapping and ablation. Note the noise created by the phasing of radiofrequency (RF) energy through the ablation electrodes and the marked circumferential electrogram voltage reduction after 1 min of RF ablation. CS = decapolar coronary sinus electrode with proximal and distal pairs.
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Figure 2 MASC
The multiarray septal catheter (MASC) has 3 arms with 4 electrodes each on the backside and is applied by pullback through the transseptal puncture to the left atrial septum. The electrodes have cooling fins to prevent heating during 1:1 unipolar/bipolar duty-cycled RF delivery. Note the noise created by the phasing of RF energy through the ablation electrodes and the marked electrogram voltage reduction after 1 min of RF ablation. Abbreviations as in Figure 1.
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Figure 3 MAAC
The multiarray atrial ablation catheter (MAAC) has 2 electrodes on each of 4 arms, which are designed to prevent perforation and to ablate complex fractionated atrial electrograms in the atrium. Cooling fins prevent overheating. Note the noise created by the phasing of RF energy through the ablation electrodes and the marked electrogram voltage reduction after 1 min of RF ablation on the chosen channels 1, 2, and 4. MAAC3 was not chosen for ablation, because electrograms were not present on this pair of electrodes due to lack of contact. Abbreviations as in Figure 1.
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Figure 4 Power Output and Current Density of Multipolar Electrodes in Comparison With Standard 4-mm Tip Electrode
Technical details of multielectrodes delivering duty-cycled RF in comparison with a standard 4-mm tip unipolar electrode. Despite lower power output, the calculated current densities are comparable because of the lower surface area of the smaller electrodes. Note also the cooling fins on the backside of the smaller multielectrodes (MASC and MAAC). Abbreviations as in Figures 1, 2, and 3.
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