Automatic identification of ablation targets in persistent atrial fibrillation: Initial experience with a new mapping tool.

INTRODUCTION: Strategies beyond pulmonary vein isolation (PVI) in persistent atrial fibrillation (persAF) are debated. A novel mapping tool provides algorithmic detection of ablation targets based on electrogram (EGM) properties specific to stable localized rotational activations. METHODS: The mapping tool was used on 31 patients (20 de novo). The algorithm was used to optimize PVI line placement and guide additional ablations. Targets were detected by calculating local cycle length (L-CL) and local spread of activation within that L-CL (Duty Cycle; DC) for EGMs with consistent morphology and activation. At least two left atrial (LA) maps (pre-PVI and post-PVI) were acquired in atrial fibrillation (AF) in all patients (except those with AF termination during PVI). Extra-pulmonary vein (PV) targets were compared between the two LA maps in each patient. Follow-up included Holter monitoring every 3 months. RESULTS: Patients had a median of 3 extra-PV drivers/targets. The majority (81%) were localized in the same areas between the two LA maps. All patients had progressive AF organization demonstrated by global activation slowing: histogram peak L-CL increased from 162 to 171 ms (post-PVI; p = .0003) than to 175 ms (posttarget ablation; p = .04). Moreover, L-CL dispersion was reduced by ablation; in 50% their values tended to cluster around two dominant cycles. In de novo patients AF terminated to sinus rhythm or atrial tachycardia (AT) within 48 h postprocedure in 88% of cases, and at 18 months mean follow-up recurrence occurred in only five (25%) patients (three persAF, two AT). There were no complications. CONCLUSION: The algorithmic detection of EGMs consistent with localized reentry during sequential mapping of persAF provided reproducible targets for ablation. This allowed personalized PVI and limited, highly-selective, extra-PV ablation. Results of this initial experience included progressive organization of AF with ablation and a low recurrence rate after a single procedure.

Single-Wire Control and Fault Detection for Automotive Exterior Lighting Systems.

The design of exterior lighting is crucial for automotive manufacturers to ensure the visibility and safety of the driver. This article proposes a new strategy to control and diagnose one or more exterior lighting functions in electric vehicles by maximising the electrical faults that are detected and their transfer over a single-wire. The outcome is a decreased system cost and an additional method for vehicle lighting infrastructure control and diagnosis. Virtual simulation tools are used to explore the correlation between master-slave architecture and the effectiveness of the single-wire approach to comply with safety and regulatory demands. Safety-related and non-safety-related needs are explored to properly assess lighting functions, internal logic, and fault-case scenarios. Furthermore, assessing the viability of minimizing wire harness utilization while retaining the diagnostic capabilities for the controlled lighting sources, thereby simultaneously reducing the vehicle's overall weight. This approach aims to concurrently decrease the overall weight of the vehicle. This work has three main contributions: (1) the development of efficient and reliable lighting systems in electric vehicles, a critical factor for achieving optimal performance, ensuring customer satisfaction, meeting regulatory compliance, and enhancing cost-effectiveness in automotive lighting systems. (2) Framework for future development and implementation of lighting systems in electric vehicles. (3) Simulation of the hardware architecture associated with the system strategy to achieve the desired system strategy for effectively applying the single-wire approach.

Exploring Arylazo-3,5-Bis(trifluoromethyl)pyrazole Switches.

Arylazopyrazoles stand out among the azoheteroarene photoswitches due to their excellent properties in terms of stability of the least stable isomer and conversion between isomers, leading to their use in several interesting applications. We report herein the synthesis of arylazo-trifluoromethyl-substituted pyrazoles and their switching behavior under light irradiation. UV-vis and NMR experiments showed that arylazo-1H-3,5-bis(trifluoromethyl)pyrazoles displayed very long half-lives in DMSO (days), along with reasonable values of other parameters that characterize a photoswitch. Inclusion of naphthyl moieties as aryl counterparts of the arylazopyrazoles is beneficial only in combination with trifluoromethyl groups, while extending the conjugation by grafting the pyrazole moiety with electron-donating or -withdrawing substituents positively affects the photoswitching behavior, in terms of isomerization yield and half-lives of the least stable isomer. The experimental values were correlated with theoretical calculations indicating the valuable influence of the trifluoromethyl groups onto the photoswitching behavior.

Slow Conduction Corridors and Pivot Sites Characterize the Electrical Remodeling in Atrial Fibrillation.

OBJECTIVES: This study aimed to evaluate the progression of electrophysiological phenomena in a cohort of patients with paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PsAF). BACKGROUND: Electrical remodeling has been conjectured to determine atrial fibrillation (AF) progression. METHODS: High-density electroanatomic maps during sinus rhythm of 20 patients with AF (10 PAF, 10 PsAF) were compared with 5 healthy control subjects (subjects undergoing ablation of a left-sided accessory pathway). A computational postprocessing of electroanatomic maps was performed to identify specific electrophysiological phenomena: slow conductions corridors, defined as discrete areas of conduction velocity <50 cm/s, and pivot points, defined as sites showing high wave-front curvature documented by a curl module >2.5 1/s. RESULTS: A progressive decrease of mean conduction velocity was recorded across the groups (111.6 ± 55.5 cm/s control subjects, 97.1 ± 56.3 cm/s PAF, and 84.7 ± 55.7 cm/s PsAF). The number and density of slow conduction corridors increase in parallel with the progression of AF (8.6 ± 2.2 control subjects, 13.3 ± 3.2 PAF, and 20.5 ± 4.5 PsAF). In PsAF the atrial substrate is characterized by a higher curvature of wave-front propagation (0.86 ± 0.71 1/s PsAF vs 0.74 ± 0.63 1/s PAF; P = 0.003) and higher number of pivot points (25.1 ± 13.8 PsAF vs 9.5 ± 6.7 PAF; P < 0.0001). Slow conductions: corridors were mostly associated with pivot sites tending to cluster around pulmonary veins antra. CONCLUSIONS: The electrical remodeling hinges mainly on corridors of slow conduction and higher curvature of wave-front propagation. Pivot points associated to SC corridors may be the major determinants for functional localized re-entrant circuits creating the substrate for maintenance of AF.

Single-Pass VDD Pacing Lead for Cardiac Resynchronization Therapy: A Reliable Alternative.

(1) Background: Cardiac resynchronization therapy (CRT) systems can be simplified by excluding the atrial lead and using a Ventricular-Dual-Dual (VDD) pacing lead. Possible disadvantages might include atrial undersensing and Ventricular-Ventricular-Inhibition (VVI) pacing. Because literature data concerning these systems are scarce, we analyzed their benefits and technical safety. (2) Methods: this retrospective study compared 50 patients implanted with VDD-CRT systems (group A), mainly because of unfavorable venous anatomy concerning the complication rate, with 103 subjects with Dual-Dual-Dual (DDD)-CRT systems (group B) implanted during 2000-2016 and 49 (group C) during 2016-2020. To analyze the functional parameters of the devices, we selected subgroups of 27 patients (subgroup A) and 47 (subgroup B) patients with VDD-CRT in 2000-2016, and 36 subjects (subgroup C) with DDD-CRT implanted were selected in 2017-2020. (3) Results: There was a trend of a lower complication rate with VDD-CRT systems, especially concerning infections during 2000-2016 (p = 0.0048), but similar results were obtained after rigorous selection of patients and employment of an upgraded design of devices/leads. With a proper device programing, CRT pacing had similar results, atrial undersensing being minimal (p = 0.65). For VDD-systems, VVI pacing was recorded only 1.7 ± 2.24% of the time. (4) Conclusions: In patients with a less favorable venous anatomy, VDD-CRT systems may represent a safe alternative regarding complications rates and functional parameters.

Sequential ultrahigh-density contact mapping of persistent atrial fibrillation: An efficient technique for driver identification.

INTRODUCTION: Literature supports the existence of drivers as maintainers of atrial fibrillation (AF). Whether ultrahigh density (UHD) contact mapping may detect them is unknown. METHODS: We sequentially mapped the left atrial (LA) activation during spontaneous persistent AF and performed circumferential pulmonary vein isolation (CPVI), followed by remapping and ablation of potential drivers (rotational and focal propagation sites) with Rhythmia™ in 90 patients. The time reference was an LA appendage (LAA) electrogram (EGM). Regions with uniform color were defined as "organized." Only patients (51) with no previous ablation were considered for acute results and follow-up reporting. RESULTS: LA maps (175 ± 28 ml, 43578 ± 18013 EGM) were acquired in 23 ± 7 min. In all post-CPVI maps potential drivers (7.3 ± 3.2/patient) were visualized: 85% with rotational propagation and continuous low voltage in the center; the remaining with focal propagation and an organized EGM at the site of earliest activation. The RF delivery time for extra-PV driver ablation was 12.2 ± 7.9 min. There was a progressive increase of AF organization: the LAA cycle length prolonged, the number of potential drivers decreased, and the organized LA surface in AF increased from 14 ± 6% to 28 ± 16% (p = .0007). Termination of AF without cardioversion was obtained in 67%. AF recurrence rate at 15 ± 7.3 months was 17.6% after the first procedure. CONCLUSIONS: Sequential UHD contact activation mapping of persistent AF allows visualization of potential drivers. A sequential strategy of CPVI followed by ablation of potential drivers with limited RF time resulted in an increasing organization of AF and good acute and long-term results.

Assessing the safety of implantable cardioverter-defibrillator reuse-A retrospective case-control study.

AIMS: The safety of pacemaker reuse has been proven by numerous studies in the last two decades. With the exception of one research paper, the safety of reuse of implantable cardioverter-defibrillators has not been properly investigated. Our aim was to establish whether resterilized implantable cardioverter-defibrillators are as safe as new devices in relation to functionality and infection rates. METHODS: All the patients (n = 271) implanted with a new or a donated, used implantable cardioverter-defibrillator (ICD) at the Institute of Cardiovascular Disease Timisoara Romania between January 2001 and December 2012 were included in the study. The patients had class I indication for ICD implantation. One hundred fifty-seven patients received reused ICDs and 114 patients received new ICDs. Complications were defined as infections that required reintervention, device malfunction, and replacements due to untimely or unexpected battery depletion. RESULTS: Complications occurred in 4.38% of the patients in the new ICD group and in 1.91% of the reused ICD group. The difference was not considered statistically significant (odds ratio 0.28, 95% confidence interval 0.04-1.82, P = .18). CONCLUSION: According to our data, properly verified and resterilized ICDs are as safe as new devices, when risk of infection or malfunction rates are assessed. Due to the high costs of new ICDs, their safe reuse has profound humanitarian and financial implications.

Electrocardiographic modifications induced by breast implants.

BACKGROUND: Echocardiography realization can be challenging in the presence of breasts implants (BI). It is less known if electrocardiograms (ECG) may be modified in the presence of BI. METHODS: ECG from women with BI (and without any known cardiac structural disease) were sent and analyzed by two experienced electrophysiologists (EP1 and EP2) who were blinded and completely unaware of the context of the patients (Group 1). ECG from a control matched-group of female women without BI (Group 2) were also blindly sent for analysis. RESULTS: ECG were collected from 28 women with BI (42 ± 8 years) without any acute medical condition. A proportion of 42% of the ECG were considered abnormal by EP1 and 46% by EP2. The abnormalities were for EP1: negative T waves (5), ST depression in inferolateral leads (2), absence of R wave progression from V1 to V4 (4), left ventricular (LV) hypertrophy (1), long QT(1), early repolarization (1), short PR (1); For EP2: negative T waves (6), ST depression in inferolateral leads (2), absence of R wave progression from V1 to V4 (4), LV hypertrophy(3), long QT (1), early repolarization (1). ECG from group 2 were considered abnormal in only 1 patient (5%) for EP1, and normal in all for EP2 (P = 0.0002 between the groups). CONCLUSIONS: ECG from women with BI were considered abnormal in 42% to 46% of the cases by expert readers. ECG interpretation can thus be misleading in these women.

Scar identification, quantification, and characterization in complex atrial tachycardia: a path to targeted ablation?

Successful catheter ablation of scar-related atrial tachycardia depends on correct identification of the critical isthmus. Often, this is a represented by a small bundle of viable conducting tissue within a low-voltage area. It's identification depends on the magnitude of the signal/noise ratio. Ultra-high density mapping, multipolar catheters with small (eventually unidirectional) and closely-spaced electrodes improves low-voltage electrogram detection. Background noise limitation is also of major importance for improving the signal/noise ratio. Electrophysiological properties of the critical isthmus and the characteristics of the local bipolar electrograms have been recently demonstrated as hallmarks of successful ablation sites in the setting of scar-related atrial tachycardia.

Coronary Sinus Activation and ECG Characteristics of Roof-Dependent Left Atrial Flutter After Pulmonary Vein Isolation.

BACKGROUND: The electrocardiographic and intracardiac activation features of left atrial roof-dependent macroreentrant flutter have been incompletely characterized. METHODS: Patients post-pulmonary vein (PV) isolation with roof-dependent atrial flutter based on activation and entrainment mapping were included. ECG and coronary sinus activation were compared with mitral annular (MA) flutter. RESULTS: The roof-dependent left atrial flutter circled the right PVs in 32 of 33 cases. Two forms of roof flutters were identified, posteroanterior, ascendant on posterior wall and descendant on anterior wall (n=24); and anteroposterior, ascendant on the anterior wall and descendent on the posterior wall (n=9). Both forms had positive large amplitude P waves in V1 through V2 with decreasing amplitude in V3 through V6. Posteroanterior roof flutters had positive P wave in the inferior and negative P wave in leads I and aVL similar to counterclockwise MA flutter, but coronary sinus activation was simultaneous for roof and proximal to distal for counterclockwise. Anteroposterior roof flutters were similar to clockwise MA flutter with negative P in inferior leads and transition to flat or negative P in V3 through V6. Coronary sinus activation time ≤39 ms identified roof versus MA flutter (sensitivity: 100% and specificity: 97%). CONCLUSIONS: Roof-dependent flutter around right PVs is more common than around left PVs. The ECG pattern for roof-dependent flutter around right PVs is similar to MA flutter with frontal plane axis dictated by septal activation. Roof-dependent flutter can be distinguished from MA flutter by more simultaneous rather than sequential coronary sinus activation.

Endocardial left ventricular pacing after accidental aortic wall perforation.

Inadvertent endocardial placement of a pacing lead in the left ventricle through the aortic valve is a rare complication with an unknown incidence because of inadequate reporting. Reported cases are usually the result of lead insertion via the subclavian artery. A possible but very unusual situation is endocardial lead insertion in the left ventricle after aortic arch perforation. We report the case of a 72-year-old woman in whom a screw-in pacing lead accidentally perforated the aortic arch and continued its way through the ascending aorta, aortic valve and left ventricle, after insertion through the left subclavian vein. We describe how this complication was diagnosed, the predisposing factors, the risks it carries and the ways in which devastating consequences have so far been avoided, as the patient refused any surgical intervention including lead removal.

Safety and feasibility of biventricular devices reuse in general and elderly population--a single-center retrospective cohort study.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is known to have very important beneficial effects on heart failure patients. Unfortunately, biventricular implantable cardiac devices (CRT devices), through which this therapy is implemented, are very expensive and sometimes hard to achieve, especially in underdeveloped/developing economies, making this an important problem of public health. As a possible solution, CRT reuse is of great interest nowadays, but unlike simple devices, data in the literature are scarce about biventricular device reuse. AIM: To address safety concerns, we aimed to analyze infection burden in the general and elderly population and also early battery depletion and generator malfunction of resterilized biventricular devices compared to new devices. METHODS: A cohort of 261 CRT patients (286 devices), who underwent implantation between 2000 and 2014, was retrospectively analyzed. The study group included 115 patients and 127 resterilized devices, that was divided into a subgroup of 69 elderly patients (≥60 years) and 74 devices and a subgroup of 47 younger patients (<60 years) and 53 devices, and the control group included 146 patients and 159 new devices. The groups were compared using a multivariate logistic regression model. RESULTS: A number of 12 (4.2%) infectious complications were encountered, five (3.9%) in the study group and seven (4.4%) in the control group (odds ratio, 2.83 [0.59-13.44], P=0.189), one (1.3%) in the elderly and four (7.5%) in the younger subgroup (odds ratio, 3.80 [0.36-40.30], P=0.266), with no statistically significant difference between them. There was only one case of early battery depletion, after 17 months, in one study group patient. No generator malfunction was detected. CONCLUSION: Reuse of biventricular cardiac implantable electronics seems feasible and safe in both the general population and the elderly population, and it could be a promising alternative when new devices cannot be obtained in a safe period of time.