Easily available ECG and echocardiographic parameters for prediction of left atrial remodeling and atrial fibrillation recurrence after pulmonary vein isolation: A multicenter study.

BACKGROUND: The assessment of noninvasive markers of left atrial (LA) low-voltage substrate (LVS) enables the identification of atrial fibrillation (AF) patients at risk for arrhythmia recurrence after pulmonary vein isolation (PVI). METHODS: In this prospective multicenter study, 292 consecutive AF patients (72% male, 62 ± 11 years, 65% persistent AF) underwent high-density LA voltage mapping in sinus rhythm. LA-LVS (<0.5 mV) was considered as significant at 2 cm2  or above. Preprocedural clinical electrocardiogram and echocardiographic data were assessed to identify predictors of LA-LVS. The role of the identified LA-LVS markers in predicting 1-year arrhythmia freedom after PVI was assessed in 245 patients. RESULTS: Significant LA-LVS was identified in 123 (42%) patients. The amplified sinus P-wave duration (APWD) best predicted LA-LVS, with a 148-ms value providing the best-balanced sensitivity (0.81) and specificity (0.88). An APWD over 160 ms was associated with LA-LVS in 96% of patients, whereas an APWD under 145 ms in 15%. Remaining gray zones improved their accuracy by introduction of systolic pulmonary artery pressure (sPAP) of 35 mmHg or above, age, and sex. According to COX regression, the risk of arrhythmia recurrence 12 months following PVI was twofold and threefold higher in patients with APWD 145-160 and over 160 ms, compared to APWD under 145 ms. Integration of pulmonary hypertension further improved the outcome prediction in the intermediate APWD group: Patients with APWD 145-160 ms and normal sPAP had similar outcome than patients with APWD under 145 ms (hazard ratio [HR] 1.62, p = .14), whereas high sPAP implied worse outcome (HR 2.56, p < .001). CONCLUSIONS: The APWD identifies LA-LVS and risk for arrhythmia recurrence after PVI. Our prediction model becomes optimized by means of integration of the pulmonary artery pressure.

Reduction in new cardiac electronic device implantations in Catalonia during COVID-19.

AIMS: During the COVID-19 pandemic, concern regarding its effect on the management of non-communicable diseases has been raised. However, there are no data on the impact on cardiac implantable electronic devices (CIED) implantation rates. We aimed to determine the impact of SARS-CoV2 on the monthly incidence rates and type of pacemaker (PM) and implantable cardiac defibrillator (ICD) implantations in Catalonia before and after the declaration of the state of alarm in Spain on 14 March 2020. METHODS AND RESULTS: Data on new CIED implantations for 2017-20 were prospectively collected by nine hospitals in Catalonia. A mixed model with random intercepts corrected for time was used to estimate the change in monthly CIED implantations. Compared to the pre-COVID-19 period, an absolute decrease of 56.5% was observed (54.7% in PM and 63.7% in ICD) in CIED implantation rates. Total CIED implantations for 2017-19 and January and February 2020 was 250/month (>195 PM and >55 ICD), decreasing to 207 (161 PM and 46 ICD) in March and 131 (108 PM and 23 ICD) in April 2020. In April 2020, there was a significant fall of 185.25 CIED implantations compared to 2018 [95% confidence interval (CI) 129.6-240.9; P < 0.001] and of 188 CIED compared to 2019 (95% CI 132.3-243.7; P < 0.001). No significant differences in the type of PM or ICD were observed, nor in the indication for primary or secondary prevention. CONCLUSIONS: During the first wave of the COVID-19 pandemic, a substantial decrease in CIED implantations was observed in Catalonia. Our findings call for measures to avoid long-term social impact.

Comparison between endocardial and epicardial cardiac resynchronization in an experimental model of non-ischaemic cardiomyopathy.

Aims: Pacing from the left ventricular (LV) endocardium might increase the likelihood of response to cardiac resynchronization therapy. However, experimental and clinical data supporting this assumption are limited and controversial. The aim of this study was to compare the acute response of biventricular pacing from the LV epicardium and endocardium in a swine non-ischaemic cardiomyopathy (NICM) model of dyssynchrony. Methods and results: A NICM was induced in six swine by 3 weeks of rapid ventricular pacing. Biventricular stimulation was performed from 16 paired locations in the LV (8 epicardial and 8 endocardial) with two different atrioventricular (80 and 110 ms) intervals and three interventricular (0, +30, -30 ms) delays. The acute response of the aortic blood flow, LV and right ventricular (RV) pressures, LVdP/dtmax and LVdP/dtmin and QRS complex width and QT duration induced by biventricular stimulation were analysed. The haemodynamic and electrical beneficial responses to either LV endocardial or epicardial biventricular pacing were similar (ΔLVdP/dtmax: +7.8 ± 2.2% ENDO vs. +7.3 ± 1.5% EPI, and ΔQRS width: -16.8 ± 1.3% ENDO vs. -17.1 ± 1.9% EPI; P = ns). Pacing from LV basal regions either from the epicardium or endocardium produced better haemodynamic responses as compared with mid or apical LV regions (P < 0.05). The LV regions producing the maximum QRS complex shortening did not correspond to those inducing the best haemodynamic responses (EPI: r2 = 0.013, P = ns; ENDO: r2 = 0.002, P = ns). Conclusion: Endocardial LV pacing induced similar haemodynamic changes than pacing from the epicardium. The response to endocardial LV pacing is region dependent as observed in epicardial pacing.

Effects of open-irrigated radiofrequency ablation catheter design on lesion formation and complications: in vitro comparison of 6 different devices.

INTRODUCTION: Open-irrigated radiofrequency ablation catheters with slight differences in tip architecture are widely used, although limited comparative data are available. The purpose of this study was to compare the lesion size and potential complications produced by commercially available open-irrigated catheters in an in vitro porcine heart model. METHODS AND RESULTS: Six catheters were tested (Biosense Webster Thermocool, Boston Scientific Open irrigated, St. Jude CoolPath, St. Jude CoolPath Duo, Biosense Webster Thermocool SF, St. Jude Cool Flex) at 20 and 35 W power-control, under 2 different blood flows (0.1 and 0.5 m/s) and at 2 target durations (30 and 60 seconds). A total of 601 lesions were made in 26 in vitro preparations. The tip temperature profile showed significant differences between the catheters (P < 0.001) with the Thermocool SF registering the lowest. Only the surface diameter and the depth at maximum diameter of the lesion were influenced by the design of the ablation electrode. The lesion volume did not show significant differences between catheters for any power, application duration or blood flow condition. Char and pops occurred more often at 35 W with only slight differences between the catheters. CONCLUSIONS: Tip design of the 6 different irrigated catheters does not affect the lesion total volume, although a slight difference in lesion geometry in terms of surface diameter and depth at maximum diameter is present. The catheters show a slight different in vitro safety profile.

Reassessment of the electrical connection between the pulmonary veins and the left atrium: A study to determine the different contributions of myocardial fibers along the standard ablation circumference.

Background: Circumferential ablation around the ipsilateral pulmonary veins (PVs) is the standard strategy for atrial fibrillation ablation. The present study seeks to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection. Methods: A total of 41 patients were included under a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference, between the equatorial line of the superior and the inferior ipsilateral PVs, were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, on the basis of the earliest atrial activation recorded during pacing from inside the PV. Complete PV isolation and the length of the areas not requiring ablation (ANRA) at the time of electrical isolation were evaluated. Results: Ablation of the anterior and posterior segments of the standard circumference led to the isolation of 77% left-PV pairs and 51% right-PV pairs (p = 0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with a median ANRA of 36.9 (IQR: 30.9-42.1) mm in the left PVs [16.0 (IQR: 12.0-19.0) mm superior and 18.8 (IQR: 16.1-24.9) mm inferior, p < 0.01] and 36.9 (IQR: 30.2-41.0) mm in the right PVs [15.1 (IQR: 10.7-19.1) mm superior and 20.6 (IQR: 16.9-23.3) mm inferior, p < 0.01]. Conclusions: The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the pulmonary veins and the left atrium. Ablation of these regions results in PV isolation in the majority of patients.

Influence of sex on intracellular calcium homoeostasis in patients with atrial fibrillation.

AIMS: Atrial fibrillation (AF) has been associated with intracellular calcium disturbances in human atrial myocytes, but little is known about the potential influence of sex and we here aimed to address this issue. METHODS AND RESULTS: Alterations in calcium regulatory mechanisms were assessed in human atrial myocytes from patients without AF or with long-standing persistent or permanent AF. Patch-clamp measurements revealed that L-type calcium current (ICa) density was significantly smaller in males with than without AF (-1.15 ± 0.37 vs. -2.06 ± 0.29 pA/pF) but not in females with AF (-1.88 ± 0.40 vs. -2.21 ± 0.0.30 pA/pF). In contrast, transient inward currents (ITi) were more frequent in females with than without AF (1.92 ± 0.36 vs. 1.10 ± 0.19 events/min) but not in males with AF. Moreover, confocal calcium imaging showed that females with AF had more calcium spark sites than those without AF (9.8 ± 1.8 vs. 2.2 ± 1.9 sites/µm2) and sparks were wider (3.0 ± 0.3 vs. 2.2 ± 0.3 µm) and lasted longer (79 ± 6 vs. 55 ± 8 ms), favouring their fusion into calcium waves that triggers ITIs and afterdepolarizations. This was linked to higher ryanodine receptor phosphorylation at s2808 in women with AF, and inhibition of adenosine A2A or beta-adrenergic receptors that modulate s2808 phosphorylation was able to reduce the higher incidence of ITI in women with AF. CONCLUSION: Perturbations of the calcium homoeostasis in AF is sex-dependent, concurring with increased spontaneous SR calcium release-induced electrical activity in women but not in men, and with diminished ICa density in men only.

Determinants of fibrotic atrial cardiomyopathy in atrial fibrillation. A multicenter observational study of the RETAC (reseau européen de traîtement d'arrhythmies cardiaques)-group.

AIMS: Despite advances in interventional treatment strategies, atrial fibrillation (AF) remains associated with significant morbidity and mortality. Fibrotic atrial myopathy (FAM) is a main factor for adverse outcomes of AF-ablation, but complex to diagnose using current methods. We aimed to derive a scoring system based entirely on easily available clinical parameters to predict FAM and ablation-success in everyday care. METHODS: In this multicenter, prospective study, a new risk stratification model termed AF-SCORE was derived in 220 patients undergoing high-density left-atrial(LA) voltage-mapping to quantify FAM. AF-SCORE was validated for FAM in an external mapping-validation cohort (n = 220) and for success following pulmonary vein isolation (PVI)-only (without adjunctive left- or right atrial ablations) in an external outcome-validation cohort (n = 518). RESULTS: FAM was rare in patients < 60 years (5.4%), but increased with ageing and affected 40.4% (59/146) of patients ≥ 60 years. Sex and AF-phenotype had additional predictive value in older patients and remained associated with FAM in multivariate models (odds ratio [OR] 6.194, p < 0.0001 for ≥ 60 years; OR 2.863, p < 0.0001 for female sex; OR 41.309, p < 0.0001 for AF-persistency). Additional clinical or diagnostic variables did not improve the model. AF-SCORE (+ 1 point for age ≥ 60 years and additional points for female sex [+ 1] and AF-persistency [+ 2]) showed good discrimination to detect FAM (c-statistic 0.792) and predicted arrhythmia-freedom following PVI (74.3%, 54.7% and 45.5% for AF-SCORE ≤ 2, 3 and 4, respectively, and hazard ratio [HR] 1.994 for AF-SCORE = 3 and HR 2.866 for AF-SCORE = 4, p < 0.001). CONCLUSIONS: Age, sex and AF-phenotype are the main determinants for the development of FAM. A low AF-SCORE ≤ 2 is found in paroxysmal AF-patients of any age and younger patients with persistent AF irrespective of sex, and associated with favorable outcomes of PVI-only. Freedom from arrhythmia remains unsatisfactory with AF-SCORE ≥ 3 as found in older patients, particularly females, with persistent AF, and future studies investigating adjunctive atrial ablations to PVI-only should focus on these groups of patients.

Remote monitoring in a patient with multiple leadless pacemakers.

We describe through a clinical case some of the challenges we can face when remotely monitoring a patient with two devices. The case describes a patient with two leadless pacemaker in which data transmission by remote monitoring has been achieved.

Atrial Fibrillation Originating in the Inferior Vena Cava: A Typical Presentation of an Atypical Location.

Recurrence of atrial fibrillation (AF) despite successful isolation of the pulmonary veins (PVs) represents a great challenge. We present a patient with recurrent episodes of paroxysmal AF despite PV isolation in which a non-PV trigger was identified in the inferior vena cava. (Level of Difficulty: Intermediate.).

Integration of late-enhanced MRI and electroanatomical mapping for substrate ablation of poorly tolerated ventricular tachycardia.

We describe the case of a patient with a poorly tolerated ventricular tachycardia (VT) in which a substrate ablation was performed. The ablation was guided by the integrated images of the scar obtained by MRI and electro-anatomical mapping. This combined technique can make substrate ablation more accurate and may have a role in the ablation of unmappable VT.

Performance of the Micra cardiac pacemaker in nonagenarians.

INTRODUCTION AND OBJECTIVES: The Micra transcatheter pacing system has shown high effectiveness and a lower complication rate than conventional transvenous pacemakers. However, the benefit of the device is unknown in the very old population (≥ 90 years). The aim of this study was to evaluate the safety and effectiveness of Micra in patients ≥ 90 years. METHODS: We present a prospective observational study with consecutive patients aged >70 years who underwent implantation of a Micra pacemaker system. Patients were divided into 2 groups: ≥ 90 and<90 years. RESULTS: The Micra system was implanted in 129 patients, of whom 41 were aged ≥ 90 years and 88<90 years. The device was successfully implanted in 40 (97.6%) patients ≥ 90 years and in 87 (98.9%) patients<90 years (P=.58). An adequate position was achieved with need for ≤ 2 repositions in 97.5% and 91.9% of patients, respectively (P=.32). Procedure time (26.1 ±11.6 vs 30.3 ±14.2minutes; P=.11) and fluoroscopy time (6.4 ±4.7 vs 7.2 ±4.9minutes; P=0.41) were similar in the 2 groups. There were 3 major complications (2.3%), all in the group aged<90 years: 1 cardiac perforation, 1 femoral hematoma, and 1 femoral pseudoaneurysm. Thirteen patients aged ≥ 90 years (31.7%) and 16 patients aged <90 years (18.2%) died during a mean follow-up of 230±233 days and 394±285 days, respectively. There were no device-related deaths. No infection, dislocation or migration of Micra were observed. The electrical performance was optimal at follow-up. CONCLUSIONS: The Micra leadless pacing system seems to be safe and effective in patients older than 90 years. It may be considered a reasonable alternative to conventional transvenous pacing in this population.

From High-Density Mapping to Low-Density Mapping: Outlining the Active Circuit in Complex Atrial Re-Entrant Tachycardias.

OBJECTIVES: The aim of this study was to describe a mapping approach for ablation of complex atrial re-entrant tachycardias (ARTs) in which high-density activation maps are transformed into low-density activation maps displaying only the active part of the tachycardia circuit. BACKGROUND: High-density activation maps during complex ARTs are challenging to interpret because they include the activation patterns of active and passive circuits. Entrainment mapping provides the identification of the active tachycardia circuit. However, current electroanatomic mapping systems are not capable of color-coding the information obtained from entrainment maneuvers. METHODS: Seventeen consecutive patients with atypical atrial flutter were included. A high-density activation map was acquired during index tachycardia. Subsequently, entrainment maneuvers were performed to generate a low-density activation map in which only the activation of the atria directly involved in the flutter circuit was displayed. RESULTS: Of all patients included, 82% were men, and their mean age was 62 ± 7 years. Structural heart disease was present in 59%, and 53% had undergone prior left atrial ablation procedures. Low-density activation maps were successfully generated from an average of 14 ± 3 entrainment points. Twenty circuits (95%) were identified in the left atrium and 1 (5%) in the right atrium. Ablation guided by low-density mapping successfully terminated all ARTs in 267 ± 353 s of radiofrequency application. CONCLUSIONS: Low-density mapping based on entrainment maneuvers provides a precise delineation of the active circuit during complex ARTs and resulted in successful arrhythmia termination. This approach can be easily incorporated into clinical practice.

[Spanish Catheter Ablation Registry. Fifth official report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2005)]. / Registro Español de Ablación con Catéter. V Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2005).

INTRODUCTION AND OBJECTIVES: The findings (i.e., success and complication rates) of the 2005 Spanish Catheter Ablation Registry, as prepared by the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias, are presented. METHODS: As in previous years, data were collected in two ways: retrospectively using a standardized questionnaire sent to electrophysiology laboratories by the Working Group on Electrophysiology and Arrhythmias, and prospectively from a central database. Each participating center selected its own preferred method of data collection. RESULTS: Forty-seven centers contributed data to the registry. A total of 6162 ablation procedures were analyzed, averaging 131 (88) per center. As in previous reports, the three main conditions treated were atrioventricular nodal reentrant tachycardia (n=1795, 29%), accessory pathways (n=1591, 26%), and typical atrial flutter (n=1378, 22%). Atrial fibrillation was the fourth most common condition treated (n=480, 8%). The overall success rate was 93%, major complications occurred in 1.05%, and the mortality rate was 0.03%. CONCLUSIONS: With more than 6000 ablation procedures recorded and with the participation of a greater number of centers throughout the country, the Spanish Catheter Ablation Registry is becoming increasingly representative and is consolidating its value as a point of reference. The number of catheter ablations carried out for atrial fibrillation in Spain is continuing to grow.