Embedded Model Control calls for disturbance modeling and rejection

Robust control design is mainly devoted to guaranteeing the closed-loop stability of a model-based control law in the presence of parametric uncertainties. The control law is usually a static feedback law which is derived from a (nonlinear) model using different methodologies. From this standpoint, stability can only be guaranteed by introducing some ignorance coefficients and restricting the feedback control effort with respect to the model-based design. Embedded Model Control shows that, the model-based control law must and can be kept intact in the case of uncertainty, if, under certain conditions, the controllable dynamics is complemented by suitable disturbance dynamics capable of real-time encoding the different uncertainties affecting the ‘embedded model', i.e. the model which is both the design source and the core of the control unit. To be real-time updated the disturbance state is driven by an unpredictable input vector, the noise, which can only be estimated from the model error. The uncertainty-based (or plant-based) design concerns the noise estimator, so as to prevent the model error from conveying uncertainty components (parametric, cross-coupling, neglected dynamics) which are command-dependent and thus prone to destabilizing the controlled plant, into the embedded model. Separation of the components in the low and high frequency domain by the noise estimator itself allows stability recovery and guarantee, and the rejection of low frequency uncertainty components. Two simple case studies endowed with simulated and experimental runs will help to understand the key assets of the methodolog

Phrenic Nerve Injury During Cryoballoon-Based Pulmonary Vein Isolation: Results of the Worldwide YETI Registry.

BackgroundCryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce.MethodsThe YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible.ResultsA total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was -49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months.ConclusionsThe incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03645577. Graphic Abstract: A graphic abstract is available for this article

withdrawn 2017 hrs ehra ecas aphrs solaece expert consensus statement on catheter and surgical ablation of atrial fibrillation

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Successful cryoablation of left ventricular summit premature ventricular contractions via the coronary sinus

The left ventricular summit (LVS) is a challenging location for catheter-based percutaneous ablation due to its anatomical location. There have been case reports of cryoablations performed in this region, but the technique may be underutilized when radiofrequency ablation fails. A 45-year-old male was found to have 25 000 premature ventricular contractions (PVCs) a day despite previous ablation and a reduced ejection fraction of 40% despite medical therapy. Coronary sinus epicardial mapping revealed the coronary sinus distal region generated activations earlier than the QRS onset by 28 ms. Two separate, 4-minute cryoablations were delivered that suppressed the PVCs within 5 seconds. Alternate energy modalities such as cryo may offer a safer and more viable approach for ablation of LVS in select patients.12 month embargo; published online: 23 May 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Successful cryoablation of left ventricular summit premature ventricular contractions via the coronary sinus

The left ventricular summit (LVS) is a challenging location for catheter-based percutaneous ablation due to its anatomical location. There have been case reports of cryoablations performed in this region, but the technique may be underutilized when radiofrequency ablation fails. A 45-year-old male was found to have 25 000 premature ventricular contractions (PVCs) a day despite previous ablation and a reduced ejection fraction of 40% despite medical therapy. Coronary sinus epicardial mapping revealed the coronary sinus distal region generated activations earlier than the QRS onset by 28 ms. Two separate, 4-minute cryoablations were delivered that suppressed the PVCs within 5 seconds. Alternate energy modalities such as cryo may offer a safer and more viable approach for ablation of LVS in select patients.12 month embargo; published online: 23 May 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

In vivo safety and pulmonary vein isolation performance of a new cryoballoon for the treatment of atrial fibrillation

Background: Cryoablation to achieve pulmonary vein (PV) isolation has become one of the standard approaches for atrial fibrillation (AF) ablation. The Arctic Front series cryoballoon and Achieve circular mapping catheter (Medtronic) inherently possess design defects that have been associated with unfavorite clinical outcomes. Lately, a new cryoablation system (Nordica Cryoablation System, Synaptic Medical) was developed with improved design of the cryoballoon and circular mapping catheter to address the inadequacies of current cryoablation technology. An animal study was conducted to test the efficacy and safety in performing PVI with the Nordica Cryoablation System. Methods: Pulmonary vein isolation with the Nordica Cryoablation System was performed on 12 PVs of six healthy canines. Acute PVI and peri-procedural complications were recorded. All animals underwent a repeat EP study at least 4 weeks after index procedures followed by pathological and histological assessments of the heart and collateral/downstream organs after planned euthanasia. Results: Acute PV isolation was achieved in all targeted PVs with 50% of PVs being isolated with a single cryoablation application. There were no major peri-procedural complications or device malfunction events. All PVs remained isolated after 29–30 days follow-up. Histological examination showed transmural cryo-lesions at treated sites with minimal inflammation, neovascularization, and neointima formation but no significant injury to adjacent tissue or embolization in downstream organs. Conclusion: Acute and durable PVI can be achieved by using the novel Nordica Cryoablation System. Ablation with this new cryoablation system is associated with transmural lesions at targeted myocardium but creates no injury to the collateral tissues or downstream organs.12 month embargo; published 03 June 2024This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]