The distribution of relaxation times (DRT) method allows the direct interpretation of electrochemical impedance data, yielding an increased resolution in the frequency domain. Calculating the DRT ...from experimental impedance spectra, however, is an intrinsically ill‐posed problem requiring special mathematical treatments such as, for example, the Tikhonov regularization. In this study, we propose a new approach for finding optimal regularization parameters in the Tikhonov regularization. The new test function is based on repetitive impedance measurements and a simple data resampling with a subsequent variance investigation. Furthermore, our new approach is combined with already published procedures considering the determination of best regularization parameters. Here, the combination of several tests enables a clear assignment of an upper and a lower boundary for suitable regularization parameters. Finally, both tests were applied to simulated as well as to experimental impedance data for validation. To analyze the sensitivity of the approach, varying error extent was generated to the synthetic and experimental measurements.
Relax, test does it: A new test procedure is proposed for identifying optimal regularization parameters in the distribution of relaxation times method. Based on repetitive measurements and simple data resampling, the error structure of the investigated impedance data is revealed and the regularization parameter can be adjusted accordingly.
Despite the advent of non-fluoroscopic technology, fluoroscopy remains the cornerstone of imaging in most interventional electrophysiological procedures, from diagnostic studies over ablation ...interventions to device implantation. Moreover, many patients receive additional X-ray imaging, such as cardiac computed tomography and others. More and more complex procedures have the risk to increase the radiation exposure, both for the patients and the operators. The professional lifetime attributable excess cancer risk may be around 1 in 100 for the operators, the same as for a patient undergoing repetitive complex procedures. Moreover, recent reports have also hinted at an excess risk of brain tumours among interventional cardiologists. Apart from evaluating the need for and justifying the use of radiation to assist their procedures, physicians have to continuously explore ways to reduce the radiation exposure. After an introduction on how to quantify the radiation exposure and defining its current magnitude in electrophysiology compared with the other sources of radiation, this position paper wants to offer some very practical advice on how to reduce exposure to patients and staff. The text describes how customization of the X-ray system, workflow adaptations, and shielding measures can be implemented in the cath lab. The potential and the pitfalls of different non-fluoroscopic guiding technologies are discussed. Finally, we suggest further improvements that can be implemented by both the physicians and the industry in the future. We are confident that these suggestions are able to reduce patient and operator exposure by more than an order of magnitude, and therefore think that these recommendations are worth reading and implementing by any electrophysiological operator in the field.
Non-invasive electrocardiogram (ECG) mapping allows the activation of the entire atrial epicardium to be recorded simultaneously, potentially identifying mechanisms critical for atrial fibrillation ...(AF) persistence. We sought to evaluate the utility of ECG mapping as a practical tool prior to ablation of persistent AF (PsAF) in centres with no practical experience of the system.
A total of 118 patients with continuous AF duration <1 year were prospectively studied at 8 European centres. Patients were on a median of 1 antiarrhythmic drug (AAD) that had failed to restore sinus rhythm. Electrocardiogram mapping (ECVUE™, CardioInsight, USA) was performed prior to ablation to map AF drivers (local re-entrant circuits or focal breakthroughs). Ablation targeted drivers depicted by the system, followed by pulmonary vein (PV) isolation, and finally left atrial linear ablation if AF persisted. The primary endpoint was AF termination. Totally, 4.9 ± 1.0 driver sites were mapped per patient with a cumulative mapping time of 16 ± 2 s. Of these, 53% of drivers were located in the left atrium, 27% in the right atrium, and 20% in the anterior interatrial groove. Driver-only ablation resulted in AF termination in 75 of the 118 patients (64%) with a mean radiofrequency (RF) duration of 46 ± 28 min. Acute termination rates were not significantly different amongst all 8 centres (P = 0.672). Ten additional patients terminated with PV isolation and lines resulting in a total AF termination rate of 72%. Total RF duration was 75 ± 27 min. At 1-year follow-up, 78% of the patients were off AADs and 77% of the patients were free from AF recurrence. Of the patients with no AF recurrence, 49% experienced at least one episode of atrial tachycardia (AT) which required either continued AAD therapy, cardioversion, or repeat ablation.
Non-invasive mapping identifies biatrial drivers that are critical in PsAF. This is validated by successful AF termination in the majority of patients treated in centres with no experience of the system. Ablation targeting these drivers results in favourable AF-free survival at 1 year, albeit with a significant rate of AT recurrence requiring further management.
Abbreviations 3D three‐dimensional AF atrial fibrillation AP accessory pathway ARVC arrhythmogenic right ventricular cardiomyopathy AT atrial tachycardia AVB atrioventricular block AVNRT ...atrioventricular nodal reentrant tachycardia AVRT atrioventricular reentrant tachycardia BBR bundle branch reentry BrS Brugada Syndrome CFAE complex fractionated atrial electrogram CHD congenital heart disease CPVT catecholaminergic polymorphic ventricular tachycardia CT computed tomography DSM dynamic substrate map EP electrophysiology EPS electrophysiology study ER early repolarization syndrome FTI force‐time integral ICD implantable cardioverter defibrillator ICE intracardiac echocardiography ICM ischemic cardiomyopathy IPAS inherited primary arrhythmias syndrome IVF idiopathic ventricular fibrillation LAVA local abnormal ventricular activity LBBB left bundle branch block LQTS long QT syndrome LV left ventricle MB moderator band MRI magnetic resonance imaging NCM noncontact mapping NICM nonischemic cardiomyopathy OT outflow tract PCCD progressive cardiac conduction disturbance PM papillary muscle PSI pixel signal intensity PV pulmonary vein PVC premature ventricular contraction PVI pulmonary vein isolation RBBB right bundle branch block RF radiofrequency RFCA radiofrequency catheter ablation RV right ventricle SQTS short QT syndrome SVT supraventricular tachycardia TEE transesophageal echocardiography VA ventricular arrhythmia VF ventricular fibrillation VT ventricular tachycardia PREAMBLE This document describes the use of three‐dimensional mapping systems and includes recommendations regarding their application in clinical practice based on scientific evidence. ...their availability as well as reimbursement practice varies widely across different countries largely depending on the economic situation. The societies involved in the development of this document recognize the existence of these factors and the significant barriers that these may pose in everyday practice and on the decision to use or not use a three‐dimensional mapping system in a given patient. ...in cases where these useful systems are not available or cannot be used in a wide scale due to financial constraints, electrophysiology procedures should certainly be offered to the patients based on established indications. Good catheter contact, correct interpretation of the colors in the map, appropriate choice of reference electrogram, complete mapping of the correct chamber of interest, and strategies to address catheter tip migration with respiration or change in cardiac rhythm and annotation of complex intracardiac signals are all necessary prerequisites for the success of ablation.
Peer review - Why, when and how Steer, Philip J.; Ernst, Sabine
International journal of cardiology congenital heart disease,
February 2021, 2021-02-00, 2021-02-01, Letnik:
2
Journal Article
Recenzirano
Odprti dostop
Peer review has a key role in ensuring that information published in scientific journals is as truthful, valid and accurate as possible. It relies on the willingness of researchers to give of their ...valuable time to assess submitted papers, not just to validate the work but also to help authors improve its presentation before publication. Referees should allocate adequate time to prepare their review. They should have access to important resources such as PubMed, Scopus, Google Scholar, and the websites of the Committee on Publication Ethics (https://publicationethics.org/) and Equator (https://www.equator-network.org/) which has a useful ‘toolkit’ for reviewing. Comments on the papers are ideally numbered and objective, assessing study design (including sample size), data analysis, interpretation, and strengths and weaknesses. Maintaining confidentiality is essential. Being asked to be a referee is a privilege and has benefits for the reviewer, including exposure to new ideas, staying aware of recent trends, increasing personal knowledge, and learning from good authors how to write better.
Cryo Balloon Pulmonary Vein Isolation Ernst, Sabine, MD
Journal of the American College of Cardiology,
04/2013, Letnik:
61, Številka:
16
Journal Article
Recenzirano
Odprti dostop
Since the seminal observation of an atrial fibrillation (AF)-initiating trigger mostly originating from the pulmonary veins (PVs), techniques to reproducibly achieve electrical PV isolation have been ...investigated (1). The time-consuming, point-by-point radiofrequency ablation technique was challenged by using novel technologies aiming for a tantalizing "single-shot" approach to facilitate and speed up the invasive procedure.
Patients with Ebstein's anomaly of the tricuspid valve (EA) are at risk of tachyarrhythmia, congestive heart failure and sudden cardiac death. We sought to determine the value of cardiovascular ...magnetic resonance (CMR) for predicting these outcomes.
Seventy-nine consecutive adult patients (aged 37±15 years) with unrepaired EA underwent CMR and were followed prospectively for a median 3.4 (range 0.4-10.9) years for clinical outcomes, namely major adverse cardiovascular events (MACEs: sustained ventricular tachycardia/heart failure hospital admission/cardiac transplantation/death) and first-onset atrial tachyarrhythmia (AT).
CMR-derived variables associated with MACE (n=6) were right ventricular (RV) or left ventricular (LV) ejection fraction (EF) (HR 2.06, 95% CI 1.168 to 3.623, p=0.012 and HR 2.35, 95% CI 1.348 to 4.082, p=0.003, respectively), LV stroke volume index (HR 2.82, 95% CI 1.212 to 7.092, p=0.028) and cardiac index (HR 1.71, 95% CI 1.002 to 1.366, p=0.037); all remained significant when tested solely for mortality. History of AT (HR 11.16, 95% CI 1.30 to 95.81, p=0.028) and New York Heart Association class >2 (HR 7.66, 95% CI 1.54 to 38.20, p=0.013) were also associated with MACE; AT preceded all but one MACE, suggesting its potential role as an early marker of adverse outcome (p=0.011).CMR variables associated with first-onset AT (n=17; 21.5%) included RVEF (HR 1.55, 95% CI 1.103 to 2.160, p=0.011), total R/L volume index (HR 1.18, 95% CI 1.06 to 1.32, p=0.002), RV/LV end diastolic volume ratio (HR 1.55, 95% CI 1.14 to 2.10, p=0.005) and apical septal leaflet displacement/total LV septal length (HR 1.03, 95% CI 1.00 to 1.07, p=0.041); the latter two combined enhanced risk prediction (HR 6.12, 95% CI 1.67 to 22.56, p=0.007).
CMR-derived indices carry prognostic information regarding MACE and first-onset AT among adults with unrepaired EA. CMR may be included in the periodic surveillance of these patients.
Noninvasive cardiac imaging is crucial for the characterization of patients who are candidates for cardiac ablations, for both procedure planning and long-term management. Multimodality cardiac ...imaging can provide not only anatomical parameters but even more importantly functional information that may allow a better risk stratification of cardiac patients. Moreover, fusion of anatomical and functional data derived from noninvasive cardiac imaging with the results of endocavitary mapping may possibly allow a better identification of the ablation substrate and also avoid peri-procedural complications. As a result, imaging-guided electrophysiological procedures are associated with an improved outcome than traditional ablation procedures, with a consistently lower recurrence rate.
Supraventricular tachycardia (SVT) is one of the most frequent complications in adult patients with congenital heart disease (CHD). Limited experience exists for successful ablation in complex CHD ...patients with prior Damus-Kaye-Stansel (DKS) surgery.
All patient files of a single-center were screened retrospectively to identify CHD patients with prior DKS surgery throughout a time-interval from 1998 to 2020. These were analysed with focus on SVT, treatment and outcome of catheter ablation (CA).
Overall, 13 patients with prior DKS surgery were identified (median age 22.0 years (IQR 20.5–25.5 years), 76.9% male, 92.3% NYHA Class I, median systemic ventricular ejection fraction 58.5% (IQR 53.0–65.5), 69.2% extra cardiac tunnel). Seven patients (53.8%) presented with symptomatic SVT (median cycle length 440 ms (IQR 360–517 ms)). Of these, five patients underwent CA using remote magnetic navigation. The majority of procedures were performed through a retrograde access using three-dimensional image integration. Median procedure time was 180.5 min (IQR 160.8–274.5 min), median fluoroscopy time 1.5 min (IQR 0.5–4.7 min) and radiofrequency time 851 s (265–2005 s). No peri- or postinterventional complications were observed. After a mean of 1.5 procedures, all patients were complaint-free without documentation of tachycardia recurrence throughout a median follow-up of 13 months (IQR 5.8–17.5 months).
In complex univentricular situations after Damus-Kaye-Stansel surgery, ablation for supraventricular tachycardia can be achieved safely and successfully. Techniques such as remote magnetic navigation and three-dimensional image integration may aid for successful procedure results.
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