Pressure waveform analysis for occlusion assessment significantly reduces contrast medium use in cryoballoon pulmonary vein isolation.

BACKGROUND: Pulmonary vein (PV) occlusion is crucial for adequate lesion formation during cryoballoon-guided pulmonary vein isolation (CB-PVI). PV occlusion is usually confirmed by angiographies over the inflated balloon device. The aim of our study was to analyze the safety and efficacy of pressure waveform-based PV occlusion assessment during CB-PVI utilizing a novel fully integrated pressure analysis tool. METHODS: Consecutive patients with symptomatic atrial fibrillation (AF) scheduled for CB-PVI were prospectively enrolled for pressure waveform-based PV occlusion assessment. A patient cohort receiving conventional angiographies served as control group. Patients with common PV ostia were excluded. RESULTS: The study group consisted of 40 patients (16 females, mean age was 64.5 ± 9.7, 45% persistent AF). The control group consisted of 40 matched patients. All 160 PVs in the study group were successfully isolated without the use of additional venograms confirming PV occlusion. The mean procedure duration was 69 ± 12 min in the study group with a mean fluoroscopy duration of 11.5 ± 4.4 min. The mean contrast medium volume was 22 ± 9 ml in the study group and 36 ± 12 ml in the control group (p = 0.0001). Mean procedure duration, mean balloon temperatures, and mean ablation application durations did not differ significantly between the study and the control group. No periprocedural complications occurred. CONCLUSION: CB-PVI utilizing a fully integrated pressure waveform analysis tool to assess PV occlusion is feasible and safe and significantly reduces the amount of contrast medium without impact on procedural parameters and freedom from arrhythmia recurrence.

Atrial fibrillation ablation workflow optimization facilitated by high-power short-duration ablation and high-resolution mapping.

AIMS: Pulmonary vein isolation (PVI) for catheter ablation of atrial fibrillation (AF) is a time-demanding procedure. High-power short-duration (HPSD) ablation protocols and high-density mapping catheters have recently been introduced to clinical practice. We investigated the impact of high-density mapping and HPSD ablation protocols on procedural timing, efficacy, and safety by comparing different standardized set-ups. METHODS AND RESULTS: Three electrophysiology (EP) laboratory set-ups were analysed: (i) circular catheter for mapping and HPSD ablation with 30/35 W guided by an ablation index (AI); (ii) pentaspline catheter for mapping an HPSD ablation with 50 W guided by an AI; and (iii) pentaspline catheter for mapping and HPSD ablation with 90 W over 4 s using a novel ablation catheter. All patients underwent PVI without additional left atrial ablation strategies. Procedural data and operating intervals in the EP laboratory were systematically analysed. Three hundred seven patients were analysed (30/35 W AI: n = 102, 50 W AI: n = 102, 90 W/4 s: n = 103). Skin-to-skin times [105.3 ± 22.7 (30/35 W AI) vs. 81.4 ± 21.3 (50 W AI) vs. 69.5 ± 12.2 (90 W/4 s) min, P ≤ 0.001] and total laboratory times (132.8 ± 42.1 vs. 107.4 ± 25.7 vs. 95.2 ± 14.0 min, P < 0.001) significantly differed among the study groups. Laboratory interval analysis revealed significant shortening of mapping and ablation times. Arrhythmia-free survival after 12 months was not different among the study groups (log-rank P = 0.96). CONCLUSION: The integration of high-density mapping and HPSD protocols into an institutional AF ablation process resulted in reduced procedure times without compromising safety or efficacy.

Pulsed field ablation for atrial fibrillation - Lessons from magnetic resonance imaging.

Pulsed field ablation (PFA) is a promising technology for the treatment of atrial fibrillation (AF). Due to its unique tissue selectivity, PFA potentially bears superior characteristics as compared to established thermal energy sources in AF ablation procedures. Cardiovascular magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE) is an established tool in the analysis of myocardial fibrosis representing atrial cardiomyopathy as well as ablation-induced atrial scar formation following catheter ablation with thermal energy. Mechanisms of atrial lesion formation differ between thermal ablation and electroporation and its impact on results of CMR imaging are not fully understood until now. In this review article, the potential of CMR imaging for PFA lesion assessment and available data are discussed. Further, additional needs to adopt imaging approaches to the cellular mechanisms of electroporation are considered.

Damage to the left descending coronary artery due to radiofrequency ablation in the right ventricular outflow tract: Clinical case series and anatomical considerations.

The purpose of this paper was to highlight the importance of the anatomy of the right ventricular outflow tract (RVOT) and the proximity of the mid segment of the left anterior descending coronary artery (LAD) to the RVOT in the setting of ablation of ventricular arrhythmias in the RVOT. During the period from 2014 till 2017, five patients with injury to the LAD during ablation within RVOT were identified in three centers, in Belgium, Germany and Israel. The clinical characteristics, procedural data and follow up data, where available, are reported. The literature review over coronary artery damage during radiofrequency ablation procedures is provided and the anatomy of the RVOT and the neighboring vascular structures is discussed. We present five patients who underwent radiofrequency ablation of ventricular arrhythmias mapped to the inferior and anterior part of the RVOT, at the insertion of the right ventricular wall to the septum, whereby ablation resulted in occlusion in four and severe stenosis in one, of the mid segment of the LAD coronary artery. All patients underwent percutaneous coronary intervention and stenting, four of them immediately during the same procedure and one 3 days later because of lack of signs and symptoms of acute coronary occlusion. In conclusion, the mid segment of the LAD at the level of the second septal perforator/second diagonal branch runs in very close proximity to the endocardial aspect of the lower part of the RVOT and care should be taken during ablation of ventricular arrhythmias in this region. Additional imaging such as intracardiac echocardiography and coronary angiography may be helpful in avoiding complications.

What can anatomy teach the electrophysiologist for diagnostic procedures?

Even for a basic study, the electrophysiologist needs to have a clear mental picture of cardiac anatomy when positioning the diagnostic catheters. This review highlights some of the features of the four cardiac chambers relevant for translating anatomic knowledge into an understanding of fluoroscopy images and electrograms. Integration of images from real cardiac anatomy into three-dimensional mapping based on electrograms and "virtual" anatomy is crucial for the success and safety of diagnostic and therapeutic electrophysiological procedures.

[Relevant anatomy of epicardial space for the electrophysiologists]. / Relevante Anatomie des epikardialen Raums für Elektrophysiologen.

The arrhythmogenic substrate in patients with Chagas cardiomyopathy, arrhythmogenic dysplasia, postmyocarditis nonischemic dilative cardiomyopathy as well as after extensive posterior or anterior wall myocardial infarction is predominantly located epicardially. This can necessitate epicardial access for an effective, substrate-based catheter ablation of the ventricular tachycardia (VT). Anterior percutaneous epicardial puncture represents the standard approach for epicardial VT ablation. The most important anatomical particularities that must be taken into account when performing an epicardial puncture or epicardial VT ablation are epicardial coronary arteries, left phrenic nerve and epicardial fat. The typical anatomic characteristics of the epicardial structures and resulting considerations for epicardial access are discussed here in detail.

Amplified sinus-P-wave reveals localization and extent of left atrial low-voltage substrate: implications for arrhythmia freedom following pulmonary vein isolation.

AIMS: Presence of arrhythmogenic left atrial (LA) low-voltage substrate (LVS) is associated with reduced arthythmia freedom rates following pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF). We hypothesized that LA-LVS modifies amplified sinus-P-wave (APW) characteristics, enabling identification of patients at risk for arrhythmia recurrences following PVI. METHODS AND RESULTS: Ninety-five patients with persistent AF underwent high-density (>1200 sites) voltage mapping in sinus rhythm. Left atrial low-voltage substrate (<0.5 and <1.0 mV) was quantified in a 10-segment LA model. Amplified sinus-P-wave-morphology and -duration were evaluated using digitized 12-lead electrocardiograms (40-80 mm/mV, 100-200 mm/s). 12-months arrhythmia freedom following circumferential PVI was assessed in 139 patients with persistent AF. Left atrial low-voltage substrate was most frequently (84%) found at the anteroseptal LA. Characteristic changes of APW were related to the localization and extent of LA-LVS. At an early stage, LA-LVS predominantly located to the LA-anteroseptum and was associated with APW-prolongation (≥150 ms). More extensive LA-LVS involved larger areas of LA-anteroseptum, leading to morphological changes of APW (biphasic positive-negative P-waves in inferior leads). Severe LA-LVS involved the LA-anteroseptum, roof and posterior LA, but spared the inferior LA, lateral LA, and LA appendage. In this advanced stage, widespread LVS at the posterior LA abolished the negative portion of P-wave in the inferior leads. The delayed activation of the lateral LA and LA appendage produced the late positive deflections in the anterolateral leads, resulting in the "late-terminal P"-pattern. Structured analysis of APW-duration and -morphology stratified patients to their individual extent of LA-LVS (Grade 1: mean LA-LVS 4.9 cm2 at <1.0 mV; Grade 2: 28.6 cm2; Grade 3: 42.3 cm2; P < 0.01). The diagnostic value of APW-duration for identification of LA-LVS was significantly superior to standard P-wave-amplification (c-statistic 0.945 vs. 0.647). Arrhythmia freedom following PVI differed significantly between APW-predicted grades of LA-LVS-severity [hazard ratio (HR) 2.38, 95% confidence interval (CI) 1.18-4.83; P = 0.015 for Grade 1 vs. Grade 2; HR 1.79, 95% CI 1.00-3.21, P = 0.049 for Grade 2 vs. Grade 3). Arrhythmia freedom 12 months after PVI was 77%, 53%, and 33% in Grades 1, 2 and 3, respectively. CONCLUSION: Localization and extent of LA-LVS modifies APW-morphology and -duration. Analysis of APW allows accurate prediction of LA-LVS and enables rapid and non-invasive estimation of arrhythmia freedom following PVI.

Overview of the current electrophysiology (EP) state of affairs in Russia.

Russia is the largest country in the world based on the landmass, covering more than one-eighth of the earth's inhabited area. Russia faces challenges in electrophysiology (EP) care including insufficient and uneven financing, complicated system for identifying optimal treatment for individual patients, relative paucity of reasonable educational and certification scope for electrophysiologists, suboptimal national statistical data gathering regarding heart rhythm disorders and EP devices in use, and weak networking of medical information. In comparison with the average level of EP utilization in ESC countries, Russia utilizes around 50% in pacemaker; 10% in ICD; 8% in cardiac resynchronization therapy; 55% in ablations; and 45% in AF ablations. As projected, Russia has the biggest unmet demand in EP procedures, so-called developmental potential in the European region. Nearly 37% of implanted single-chamber and 63% dual-chamber devices are manufactured outside of Russia. The price of the Russian devices is slightly (by 10-20%) lower than the one imported and they are readily provided for patients by the Russian Ministry of Health. Based on the analysis of the data available, we suggest some strategies for the improvement of the EP care in Russia. Solutions include the institution of formal EP education and standardization of it, development of international educational, and scientific collaboration; implementation quality-assessment tools for professional knowledge and skills; wide application of national medical databases and collection of heart rhythm disorders' statistics; growth of financial support of electrophysiology and transparent distribution of financing between state/municipal and private medical centers; enhancement of medical care accessibility countrywide; development of technologies for local EP devices production; and collection of data regarding usage and effectiveness of it.

Mechanisms of sex differences in atrial fibrillation: role of hormones and differences in electrophysiology, structure, function, and remodelling.

Atrial fibrillation (AF) is the clinically most prevalent rhythm disorder with large impact on quality of life and increased risk for hospitalizations and mortality in both men and women. In recent years, knowledge regarding epidemiology, risk factors, and patho-physiological mechanisms of AF has greatly increased. Sex differences have been identified in the prevalence, clinical presentation, associated comorbidities, and therapy outcomes of AF. Although it is known that age-related prevalence of AF is lower in women than in men, women have worse and often atypical symptoms and worse quality of life as well as a higher risk for adverse events such as stroke and death associated with AF. In this review, we evaluate what is known about sex differences in AF mechanisms-covering structural, electrophysiological, and hormonal factors-and underscore areas of knowledge gaps for future studies. Increasing our understanding of mechanisms accounting for these sex differences in AF is important both for prognostic purposes and the optimization of (targeted, mechanism-based, and sex-specific) therapeutic approaches.

Distributed Cognition and Process Management Enabling Individualized Translational Research: The NIH Undiagnosed Diseases Program Experience.

The National Institutes of Health Undiagnosed Diseases Program (NIH UDP) applies translational research systematically to diagnose patients with undiagnosed diseases. The challenge is to implement an information system enabling scalable translational research. The authors hypothesized that similar complex problems are resolvable through process management and the distributed cognition of communities. The team, therefore, built the NIH UDP integrated collaboration system (UDPICS) to form virtual collaborative multidisciplinary research networks or communities. UDPICS supports these communities through integrated process management, ontology-based phenotyping, biospecimen management, cloud-based genomic analysis, and an electronic laboratory notebook. UDPICS provided a mechanism for efficient, transparent, and scalable translational research and thereby addressed many of the complex and diverse research and logistical problems of the NIH UDP. Full definition of the strengths and deficiencies of UDPICS will require formal qualitative and quantitative usability and process improvement measurement.