Variance in tissue thermodynamics during cryothermal ablation depends on the distance from balloon and peri-balloon blood flow leaks. This information may be useful for successful PVI without severe complications.

Electromagnetic interference produced by medical equipment can interact with implanted cardiac devices such as pacemakers and implantable cardioverter-defibrillators. The most commonly observed interaction is in the operating room with electrosurgery. The risk of interactions can often be mitigated by close communication between the cardiac-device specialist and the anesthesiology/surgical team to develop a patient-specific strategy that accounts for factors such as type of device, type of surgery, and whether the patient is pacemaker dependent. Although magnetic resonance imaging should generally not be used in patients with implanted cardiac devices, several published guidelines provide strategies and recommendations for managing risks if magnetic resonance imaging is required with no suitable diagnostic alternatives. Other common sources of electromagnetic interference in the medical environment are ionizing radiation and left ventricular assist devices.

BackgroundRecently, pulmonary vein isolation (PVI) using the second generation cryoballoon, introduced as a therapy for patients with drug-refractory atrial fibrillation, has shown better outcomes than with the first generation cryoballoon. [1][2][3][4][5] However, some questions about the second generation cryoballoon remain. Several studies in cryobiology have shown that prolongation of freeze duration produces a greater destructive effect in noncardiac tissue. 6,7 However, ablation duration to achieve acute and long-term PVI is still debatable. It is also unclear how different sized balloons (23 and 28 mm) should be used, as the impact of the balloon size on tissue and balloon temperature profiles and ablative lesion size have not been studied. Information on the effects of ablation duration and balloon size is required to achieve high PVI success rates without severe complications using the second generation cryoballoon.The purpose of this study was to investigate the impact of ablation duration and balloon size on tissue and balloon thermodynamics, acute and chronic PVI success rates, complications, and chronic histological changes of the PV and left atrium (LA). Methods GeneralThis study was designed to compare the ablation effect and safety of different ablation durations (3 versus 4 minutes) and different balloon sizes (23 versus 28 mm) in an in vivo model. Twenty-six dogs underwent PVI using second generation cryoballoon. Animal PreparationThe protocol was approved by Mayo Foundation Institutional Animal Care and Use Committee. Dogs (30.3±2.5 kg) were anesthetized with intravenous ketamine and diazepam, intubated, and maintained on 1% to 3% isoflurane. The surface ECG, body temperature, and blood pressure were monitored. Tissue Temperature MonitoringTissue temperatures were monitored by implanted thermocouples, as reported previously. 8,9 All dogs underwent left/right thoracotomy for access to the superior/inferior PVs. The pericardium was opened to © 2015 American Heart Association, Inc. Original Article Circ Arrhythm ElectrophysiolBackground-The differences in ablation characteristics of freezing time and balloon size using second generation cryoballoon are still unknown. Methods and Results-Twenty-six dogs underwent pulmonary vein (PV) isolation. Balloon and tissue temperatures (left atrial-PV junction, phrenic nerve, and internal esophagus) were monitored. The ablation duration was randomized to either 3 or 4 minutes, which did not show significant differences in temperature profiles, PV isolation success rate, complications, or histological changes. Twenty dogs underwent cryoablation using 28-mm cryoballoon, 6 dogs were done using the 23-mm cryoballoon. Positioning of the 23-mm cryoballoon was more distal in the PV, which resulted in better PV occlusion. Temperature profiles showed lower temperatures in the 23-mm cryoballoon than in the 28-mm cryoballoon

The number of patients with cardiovascular implantable electronic devices (CIEDs), such as permanent pacemakers and implantable cardioverter-defibrillators, is dramatically rising due to an aging population and recent clinical trials showing benefits in mortality and morbidity. Coupled with this increase in the number of patients with CIEDs is the proliferation of technology that emits electromagnetic signals, which can potentially interfere with CIED function through electromagnetic interference (EMI). Despite continuous efforts of manufacturers to create ''EMI-proof'' CIEDs, adverse events from EMI still occur. Physicians caring for patients with CIEDs should be aware of potential sources of EMI and appropriate management options. This 2-part review aims to provide a contemporary overview of the current knowledge regarding risks attributable to EMI interactions from the most common nonmedical (Part I) and medical (Part II) sources. Device Responses to Electromagnetic Interference Before discussing EMI from specific sources, it is important to emphasize that the clinical consequences of the interaction will depend on the type of interaction, type of device, and patient characteristics (Table 2). All