Intraluminal Esophageal Temperature Monitoring Using the Circa S-Cath™ Temperature Probe to Guide Left Atrial Ablation in Patients with Atrial Fibrillation.

INTRODUCTION: Radiofrequency catheter ablation is a common treatment for atrial fibrillation (AF), during which thermal esophageal injury may rarely occur and lead to an atrio-esophageal fistula. Therefore, we studied the utility of the Circa S-Cath™ multi-sensor luminal esophageal temperature (LET) probe to prevent esophageal thermal injury. METHODS AND RESULTS: Thirty-six patients, enrolled prospectively, underwent circumferential or segmental pulmonary vein isolation for treatment of AF. A maximum ablation electrode temperature of 42ºC was programmed for automatic power delivery cutoff. In addition, energy delivery was manually discontinued when the maximum LET on any sensor of the probe rose abruptly (i.e. ˃0.2ºC) or exceeded 39º C. Esophagoscopy was performed immediately after ablation in 18 patients (with the temperature probe still in place) and at approximately 24 hours after ablation in 18 patients. Esophageal lesions were classified as likely traumatic or thermally related. Of the 36 patients enrolled in the study, 21 had persistent and 15 had paroxysmal AF, average LVEF 57±16% and CHA2DS2VASc score 1.6±1.2 (range 0-4). Average maximum LET was 37.8±1.4ºC, power delivery 31.1±8 watts and ablation electrode temperature 36.4±4.1ºC. Average maximum contact force was 44.5±20.5 grams where measured. Only 1 patient (<3%) had an esophageal lesion that could potentially represent thermal injury and 4 patients (11.1%) had minor traumatic mechanical injury. CONCLUSIONS: LET guided titration of power and duration of energy application, using an insulated multi-sensor esophageal temperature probe, is associated with a low risk of esophageal thermal injury during AF ablation. In only rare cases, LET monitoring resulted in the need to manipulate the esophagus to avoid unacceptable temperature rises, that could not be achieved by adjustment of power and duration of energy application.

Identification of pulmonary vein potentials by differential site atrial pacing in patients with paroxysmal atrial fibrillation: enhanced detection by pulmonary vein pacing.

INTRODUCTION: Pulmonary vein (PV) isolation may cure paroxysmal atrial fibrillation (PAF); however, identification of PV potentials may be difficult in sinus rhythm. Studies have suggested that atrial pacing may improve the identification of PV potentials. METHODS AND RESULTS: In 25 consecutive patients who underwent PV isolation for PAF, the results of pacing from the distal PV, distal and proximal coronary sinus, and high right atrium compared to sinus rhythm were analyzed to determine the most effective pacing site for identification of PV potentials. The percentage of confirmed PV potentials and the longest interval between atrial and PV potentials in each PV were compared during differential site pacing and sinus rhythm. PV potentials were confirmed in 63 (82%) of 77 PVs that could be mapped during the complete pacing protocol and during sinus rhythm. Distal PV pacing identified significantly more PV potentials (left upper pulmonary vein [LUPV] 100%, left lower pulmonary vein [LLPV] 84%, right upper pulmonary vein [RUPV] 80%, right lower pulmonary vein [RLPV] 53%) compared to other pacing sites and sinus rhythm. Among atrial pacing sites, those ipsilateral to the PV being mapped were the most effective for identifying PV potentials. The intervals between atrial and PV potentials were significantly longer during distal PV pacing than pacing at other sites (LUPV 81.6 +/- 26.2 ms, LLPV 61.4 +/- 26.1 ms, RUPV 59.7 +/- 33.2 ms, RLPV 39.7 +/- 26.7 ms). CONCLUSION: (1) Distal PV pacing was most effective for identifying PV potentials. (2) The interval between atrial and PV potentials was longest during distal PV pacing.