Defibrillation-guided radiofrequency ablation of atrial fibrillation secondary to an atrial focus
Chu-Pak Lau, MD, FACC*,
Hung-Fat Tse, MB* and
Gregory M. Ayers, MD, PhD, FACC
* Division of Cardiology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, China
InControl, Redmond, Washington, USA
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Figure 1 Cineangiographic views (A) of catheter layout in a patient undergoing defibrillation-guided mapping and RF ablation of AF secondary to a focus in the right superior pulmonary vein, just inside the orifice (Patient 2). (B) Recording of spontaneous AF reinitiation in a patient with a focus just inside the RSPV (same Patient as in A). At the site of putative focus, the atrial electrogram during sinus rhythm is fragmented. A rapidly discharging focus with fragmented electrograms and a reproducible coupling interval of 200 ms to the sinus beat initiates a nonsustained, then a sustained run of AF. The first beat of the focus (*) is 115 ms (not labeled) ahead of the high right atrial electrogram (RA A9–A10) There was shortening of the cycle length after the first beat of the focus before the onset of AF. Because of the rapidity of the tachycardia, some electrograms appeared to be blocked (second and fourth beat after *). Note a similar activation sequence of the RA, but earlier activation of HIS and RAW electrograms at the first beat of the tachycardia compared to the sinus beat, with advancement of all CS electrograms suggestive of a LA focus. ABL = ablation catheter (at RSPV); CS = coronary sinus (B9, B10 = proximal CS; B1, B2 = distal CS); HIS = His bundle; LAO = left anterior oblique view; RA = right atrium (A9, A10 = high RA; A1, A2 = low RA); RAO = right anterior oblique view; RAW = high right interatrial septum; RV = right ventricular apex; RSPV = right superior pulmonary vein. Each calibration mark on the left represents 1 mV for that and the following recordings until a change in calibration was made.
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Figure 2 Activation of a focus leading to AF in patient 7 from just inside the left superior pulmonary vein (LSPV, HIS potential was of low amplitude). The first beat of the focus (*) was 58 ms (not labeled) ahead of the high RA electrogram. In this patient, decremental conduction occurred from the focus to the rest of the atrium, and advancement of CS electrograms compared to the sinus beat. At the ablation catheter, the atrial electrogram shows an initial rounded then a fast component during sinus rhythm, which appears to reverse and separate at the first beat of tachycardia. Abbreviations as in Figure 1. Each calibration mark on the left represents 1 mV for that and the following recordings until a change in calibration was made.
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Figure 3 Suppression of early reinitiation of AF after RF ablation of a focus in the right superior pulmonary venous orifice (patient 5). (A) Before ablation, AF recurred consistently within 10 s after a 1.2-J transvenous atrial defibrillation shock. (B) After ablation, sinus rhythm remained after restoration of induced AF. Recording artifact occurred during switching from the defibrillation to the recording mode. Abbreviations as in Figure 1.
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