Dec 26, 2017 - Ian Crozier, Daly Matthew, Melton Iain, Graham Roper, and Lim Gary. Christchurch, New Zealand. Introduction: Radiofrequency ablation (RFA) ...
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HIGH-RESOLUTION INFRARED THERMOGRAPHY REVEALS ESOPHAGEAL TEMPERATURE DYNAMICS DURING ABLATION OF ATRIAL FIBRILLATION
COMPARISON OF THE RELATIVE RADIATION REDUCTION ASSESSED BY DOSIMETRY OF RADIATION PADS AND COLLIMATION USED IN THE ELECTROPHYSIOLOGY LAB
Ian Crozier, Daly Matthew, Melton Iain, Graham Roper, and Lim Gary
Scott Pollak, George Monir, and Julie Pepe
Christchurch, New Zealand
Orlando, USA
Introduction: Radiofrequency ablation (RFA) for pulmonary vein isolation (PVI) is known to cause thermal injury to structures adjacent to the heart, most notably the esophagus. Esophageal temperature monitoring during RFA is common, however, recommended temperature thresholds are implausibly low reflecting the inadequate characteristics of discrete temperature sensors rather than the biology of thermal injury. To address these limitations, we investigated the use of a high-resolution, intra-body, infrared thermography (IRT) catheter to continuously map instantaneous surface temperatures within the esophagus during PVI. Methods: We studied 16 paroxysmal atrial fibrillation patients undergoing first-time PVI. A flexible, 9F IRT catheter was inserted nasally (N ¼ 8), or orally (N ¼ 8) into the esophagus posterior to the left atrium. Throughout each case IRT captured surface temperatures from .7600 points per second circumferentially over a 6 cm length of esophagus. Physician-operators (N ¼ 3) were blinded to temperature. Endoscopy was performed within 24 hours to assess thermal injury. Results: Device insertion was well tolerated. Thermal mapping with IRT documented that most patients (63%) experienced thermal events where peak esophageal temperature was above 4088 C. Peak esophageal temperature differential above core body temperature (DTpeak) was often significantly elevated by conventional standards. In 11 of 16 patients DTpeak was between 288 -1588 C, but this DTpeak range was not associated with esophageal injury. Endoscopy identified thermal ulcerations in 2 of 3 patients with DTpeak .1588 C. Conclusions: Infrared thermography provided dynamic, high-resolution temperature mapping of the esophagus during cardiac ablation. Esophageal temperature changes are common during RFA. In this pilot study esophageal injury was only observed for DTpeak .1588 C. Further studies are warranted to determine the complex relationship between thermal parameters and esophageal injury risk. Conflict of interest: none
Introduction: Use of x-ray is still prevalent although there is recognition that any radiation may be associated with cancer risk. Recent new technology allows real-time assessment of radiation dose exposure at a given location. The purpose of this study was to assess the relative value of two different radiation reduction methods in the EP lab (collimation and radiation pads) compared to an open configuration using real- time radiation dose monitoring. Methods: A phantom acrylic model was used in order to allow serial measurements using the same parameters with the x-ray system. Radiation real-time detectors (RaySafeTM ) were used to measure radiation dose around the phantom in three different configurations (open, collimation, and radiation pads) with three different camera angulations. The open configuration consisted of x-ray exposures without radiation reduction methods. Collimation tests were conducted by moving collimators to the border of the saline/contrast phantom. The radiation pad configuration used radiation pads placed along the operator side of the table extending from the acrylic block at the heart level to the block at groin level. Results: The parameters analyzed for radiation dose were measured in millirem by real-time radiation detectors. The parameters obtained from the x-ray system labeled patient measurements were total mGy and cGy-cm2. Collimation resulted in this phantom simulation in a significant decrease ( p , 0.01) of approximately 50% in radiation exposure for the operator compared to the open configuration for all locations. A non-significant radiation reduction (6-11%) was observed for radiation pads compared to the open configuration. Collimation resulted in a significant reduction ( p , 0.01) of 23-31% in the exit dose of radiation from the phantom, but a significant increase ( p , 0.01) of 54% of the air kerma (AK) measured in mGy for all locations compared to the open configuration. Conclusion: This study showed a significant benefit of collimation compared to an open configuration or radiation pads to reduce radiation exposure. Despite the fact the AK measurement increases significantly with collimation compared to an open configuration, the radiation dose actually decreases as assessed by the dosimetry exit dose from the phantom. Conflict of interest: Honoraria: Biosense Webster
136-13 CAREFUL SETTING OF THE FLUOROSCOPY LEADS TO SIGNIFICANT REDUCTION IN X-RAY EXPOSURE DURING CATHETER ABLATION: A PROSPECTIVE STUDY IN PATIENTS WITH ATRIAL FIBRILLATION Michele Brunelli, Tanja Da¨hne, Markus Frommhold, Anett Grosse, Antonio Madaffari, Santi Raffa, and J. Christoph Geller Bad Berka, Germany Introduction: techniques aiming at reducing X-Ray exposure in patients undergoing catheter ablation (CA) are of great importance. Aim of this study was to compare the dose area product (DAP, microgray, mGy/m2) and the equivalent dose (ED, milliSieverts, mSv) during CA of paroxysmal or persistent atrial fibrillation (AF) before and after the meticulous implementation of measures to reduce XRay exposure (especially careful use of collimation and frame rate reduction). Methods: X-ray exposure, procedural and parameters were compared in the 2 groups of consecutive patients with paroxysmal and persistent AF undergoing CA with the use of a 3D-Mapping System before (High Dose) and after (Low Dose, since 11/2012) the introduction of a strict radiation reduction protocol. Results: between 01/2010 and 10/2015, 870 patients [62 (55,69) years old, 352 (40%) female, 405 (46%) paroxysmal AF, 261 (30%) recurrent AF after previous procedure] underwent CA with the Ensite Velocity (739, 85%) or Carto3 (131, 15%) 3D-Mapping Systems. Slightly larger left atrial volumes were observed in the “low dose” group, other clinical and procedural characteristics were well matched between groups. The dose area product and equivalent were significantly (P ¼ .0000) reduced by 60% for both paroxysmal (DAP 1549 (1032, 2814) vs. 4195 (2521, 6687) mGy/m2 and ED 3.1 (2.1, 5.6) vs. 8.4 (5.0, 13.4) mSv) and persistent (DAP 2300 (1481, 3434) vs. 5605 (3563, 9160) mGy/m2 and ED 4.6 (2.9, 6.9) vs.11.2 (7.1, 18.3) mSv) with careful setting of the fluoroscopy. Conclusion: Careful use of collimation and frame rate reduction leads to a significant decrease in X-Ray exposure during CA for AF.
Age (years) BMI AF Duration (months) LA Diameter (mm) PV Isolation Any LA Linear Abl. CFAEs Abl. CTI Ablation SCV Isolatio Non-PV Foci Procedure Time (min) RF Time (min) X-Ray Time (min) Dose Area Product (mGym2) Equivalent Dose (mSv)
Paroxysmal AF – low Dose (305 patients)
Paroxysmal AF – high Dose (100 patients)
61 + 11 28 + 5 54 (18, 105) 38 (35, 41) 294 (96%) 39 (13%) 23 (8%) 94 (31%) 12 (4%) 17 (6%) 243 (207, 282) 63 (45, 84) 17 (12, 23) 1549 (1032, 2814) 3.1 (2.1, 5.6)
61 + 10 29 + 4 52 (23, 95) 38 (35, 42) 97 (97%) 16 (16%) 5 (5%) 44 (44%) 4 (4%) 9 (9%) 274 (206, 322) 69 (48, 101) 23 (15, 35) 4195 (2521, 6687) 8.4 (5.0, 13.4)
P
.82 .08 .97 .56 .77 .42 .37 .0171 .98 .24 .0108 .0472 < .0001 .0000 .0000
Conflict of interest: none
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Persistent AF- low Dose (288 patients)
Persistent AF – high Dose (177 patients)
62 + 10 29 + 5 57 (24, 108) 41 (38,43) 243 (84%) 198 (69%) 47 (16%) 172 (60%) 18 (6%) 49 (17%) 270 (229, 330) 76 (49, 111) 21 (15, 29) 2300 (1481, 3434) 4.6 (2.9, 6.9)
61 + 10 29 + 4 54 (26, 105) 41 (38,44) 160 (90%) 133 (75%) 16 (9%) 131 (74%) 4 (2%) 21 (12%) 328 (266, 382) 97 (66, 130) 30 (20, 40) 5605 (3563, 9160) 11.2 (7.1, 18.3)
P
.15 .98 .98 .17 .06 .14 .0224 .0015 .0382 .13 < .0001 < .0001 < .0001 .0000 .0000
