Masateru Takigawa1, Nicolas Derval2, Claire A Martin3, Konstantinos Vlachos2, Arnaud Denis2, Takeshi Kitamura2, Ghassen Cheniti2, Felix Bourier2, Anna Lam2, Ruairidh Martin4, Antonio Frontera2, Nathaniel Thompson2, Grégoire Massoullié2, Michael Wolf2, Josselin Duchateau2, Nicolas Klotz2, Thomas Pambrun2, Frederic Sacher2, Hubert Cochet2, Mélèze Hocini2, Michel Haïssaguerre2, Pierre Jaïs2. 1. Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France; Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan. Electronic address: teru.takigawa@gmail.com. 2. Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France. 3. Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France; Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom. 4. Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France; Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
Abstract
BACKGROUND: Ablation of complex atrial tachycardias (ATs) is difficult. OBJECTIVE: The purpose of this study was to elucidate a mechanism underlying the behavior of ATs during ablation and to create an algorithm to predict it. METHODS: An algorithm predicting termination/conversion of AT and the second AT circuit associated with the ablation site was developed from 52 index reentrant AT high-resolution activation maps in 45 patients (retrospective phase). First, the wavefront collision site was identified. Then, the N or N-1 beat was defined for each collision associated with the ablation site. When the AT involved wavefront collision solely between N-1/N-1 (N/N) beats, the AT would terminate during ablation. Conversely, when the AT included wavefront collision between N/N-1 beats, the index AT would convert to a second AT. The algorithm was then prospectively tested in 172 patients with 194 ATs (127 anatomic macroreentrant ATs [AMATs], 44 non-AMATs, 23 multiple-loop ATs). RESULTS: Accuracy in predicting AT termination/conversion and the second AT circuit was 95.9% overall, 96.1% in AMATs, 95.5% in non-AMATs, and 95.7% in multiple-loop ATs. Median (25th-75th percentile) absolute variation between predicted and actually observed cycle length of the second AT was 6 (4-9) ms. Prediction failure occurred in 8 ATs; either the second AT used an unmapped chamber or structure in the index map (n = 7) or a line of block was misinterpreted as very slow conduction in the index map (n = 1). CONCLUSION: A simple mechanism underlies the behavior of ATs during ablation, even in complex ATs. With a simple algorithm using high-resolution mapping, AT termination/conversion and the second AT circuit and cycle length may be predicted from the index activation map.
BACKGROUND: Ablation of complex atrial tachycardias (ATs) is difficult. OBJECTIVE: The purpose of this study was to elucidate a mechanism underlying the behavior of ATs during ablation and to create an algorithm to predict it. METHODS: An algorithm predicting termination/conversion of AT and the second AT circuit associated with the ablation site was developed from 52 index reentrant AT high-resolution activation maps in 45 patients (retrospective phase). First, the wavefront collision site was identified. Then, the N or N-1 beat was defined for each collision associated with the ablation site. When the AT involved wavefront collision solely between N-1/N-1 (N/N) beats, the AT would terminate during ablation. Conversely, when the AT included wavefront collision between N/N-1 beats, the index AT would convert to a second AT. The algorithm was then prospectively tested in 172 patients with 194 ATs (127 anatomic macroreentrant ATs [AMATs], 44 non-AMATs, 23 multiple-loop ATs). RESULTS: Accuracy in predicting AT termination/conversion and the second AT circuit was 95.9% overall, 96.1% in AMATs, 95.5% in non-AMATs, and 95.7% in multiple-loop ATs. Median (25th-75th percentile) absolute variation between predicted and actually observed cycle length of the second AT was 6 (4-9) ms. Prediction failure occurred in 8 ATs; either the second AT used an unmapped chamber or structure in the index map (n = 7) or a line of block was misinterpreted as very slow conduction in the index map (n = 1). CONCLUSION: A simple mechanism underlies the behavior of ATs during ablation, even in complex ATs. With a simple algorithm using high-resolution mapping, AT termination/conversion and the second AT circuit and cycle length may be predicted from the index activation map.