Waste Heat Recovery in the EU industry and proposed new technologies

In the European Union (EU), industrial sectors use 26% of the primary energy consumption and are characterized by large amounts of energy losses in the form of waste heat at different temperature levels. Their recovery is a challenge but also an opportunity for science and business. In this study, after a brief description of the conventional Waste Heat Recovery (WHR) approaches, the novel technologies under development within the I-ThERM Horizon 2020 project are presented and assessed from an energy and market perspectives. These technologies are: heat to power conversion systems based on bottoming thermodynamic cycles (Trilateral Flash Cycle for low grade waste heat and Joule-Brayton cycle working with supercritical carbon dioxide for high temperature waste heat sources); heat recovery devices based on heat pipes (flat heat pipe for high grade radiative heat sources and condensing economizer for acidic effluents).European Union’s Horizon 2020 research and innovation programme, the Centre for Sustainable Energy Use in Food Chains (CSEF) and the Engineering and Physical Sciences Research Council (EPSRC) funded project ‘Optimising Energy Management in Industry-OPTEMIN

Occlusion tool software for pulmonary vein occlusion verification in atrial fibrillation cryoballoon ablation

Background: Optimal pulmonary vein (PV) occlusion, usually verified with selective contrast injection, is mandatory to obtain an effective PV isolation during cryoballoon (CB) ablation. Aim of the study: The purpose of this study was to verify the feasibility and the accuracy of a new dielectric sensing system in assessing PV occlusion during CB ablation in patients with atrial fibrillation (AF). Methods: We enrolled 28 consecutive patients with paroxysmal or persistent AF. After transseptal access, a detailed image reconstruction of left atrium and PVs was achieved with an octapolar or decapolar mapping catheter (Achieve catheter, Medtronic Inc.) and KODEX-EPD system (EPD Solutions, a Philips company). The degree of PV occlusion with the inflated Arctic Front Advance Cryoballoon (Medtronic Inc.) was verified using the new “occlusion tool” software module (EPD Solutions, a Philips company) and compared to an angiogram obtained with contrast medium injection in each PV. Results: A total of 105 PV CB occlusion were tested. The new occlusion tool software module showed a 91% sensitivity and 76% specificity in assessing a complete PV occlusion verified with contrast medium injection. The positive predictive value was 80%, and the negative predictive value was 88.6%. Mean procedure time was 81 ± 17 minutes. Mean fluoroscopy time was 6 ± 2 minutes. No 30-day complications were observed. Conclusion: The new dielectric imaging system was able to assess the degree of PV occlusion during a CB ablation with good sensitivity and specificity

Efficacy of cryoballoon ablation in patients with paroxysmal atrial fibrillation without time to pulmonary vein isolation assessment

Background: Real-time visualization of the electrical activity of the pulmonary veins (PV) is not always possible in the setting of atrial fibrillation (AF) cryoballoon ablation. We investigated the relation between the effective documentation of time to PV isolation and the clinical outcome in a cohort of patients with paroxysmal AF who underwent cryoballoon ablation. Methods: One thousand forty two consecutive patients were enrolled. An inner lumen mapping catheter was typically used to visualize real-time electrical activity inside the PVs. Results: Time to PV isolation was documented in all targeted PVs in 391 patients (Group 1), in 651 patients it was not possible to record PV potentials and assess time to PV isolation in at least one PV (Group 2). In Group 1 a longer procedure duration and ablation time were observed, while a longer fluoroscopy time was observed in Group 2. After a mean follow-up of 14 ± 11 months, 209/1042 (20%) patients had an atrial arrhythmia recurrence (20.2% in Group 1, 19.9% in Group 2, p = 0.25). Complications occurred in 54/1042 (5.2%) patients without any difference among the two study groups. Conclusion: In our retrospective analysis, in about two thirds of patients undergoing cryoballoon ablation it was not possible to acutely assess time to PV isolation in all PVs. However, one-year freedom from clinically symptomatic atrial tachyarrhythmia was similar to that of patients in which time to PV isolation was documented in all targeted veins. Clinical Trial Registration: clinicaltrials.gov (NCT01007474)

Long-term reduction of atrial tachyarrhythmia recurrences in patients paced for bradycardia-tachycardia syndrome

Background: Atrial tachyarrhythmias (AT) are considered progressive diseases. Several rhythm control therapies for treatment of AT have been proposed. Objectives: The Italian AT500 Registry was designed to prospectively study long-term AT evolution in patients paced for the brady-tachy form of sinus node disease (BT-SND). Methods: Three hundred forty-six BT-SND patients received an antitachycardia dual-chamber pace-maker and were followed-up for a minimum of 12 months (median 19 months). Prevention and antitachycardia pacing (ATP) features were enabled in all patients. Results: During the observation period, 224 (65%) patients were treated by antiarrhythmic drugs and 45 (13%) patients were cardioverted. Five patients suffered a stroke, 4 transient ischemic attack, 22 permanent AT, and 98 AT recurrences longer than 7 days. AT mean cycle length changed from 246 to 2 70 ms, and the percentage of patients with AT-related hospitalizations significantly decreased with an annual 28% relative reduction. AT burden and the percentage of patients with AT recurrences longer than 2 days remained constant with time in the overall population but decreased significantly in the subgroup of patients who did not develop permanent AT. High ATP efficacy was associated with an increasingly higher prevention of AT recurrences longer than 2 days. Conclusion: In a long-term observation of BT-SND patients, AT-related hospitalizations decreased significantly and mean AT cycle length increased significantly. The data suggest that rhythm control therapies induce inversion of AT progression. © 2005 Heart Rhythm Society. All rights reserved