Arrhythmic burden in patients with new-onset persistent left bundle branch block after transcatheter aortic valve replacement: 2-year results of the MARE study.

AIMS: We determined the incidence and type of arrhythmias at 2-year follow-up in patients with new-onset persistent left bundle branch block (LBBB) following transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: Multicentre prospective study including 103 consecutive patients with new-onset persistent LBBB post-TAVR (SAPIEN XT/3: 53; CoreValve/Evolut R: 50). An implantable cardiac monitor (Reveal XT, Reveal Linq) was implanted before hospital discharge and patients had continuous monitoring for up to 2 years. Arrhythmic events were adjudicated in a central core lab. 1836 new arrhythmic events (tachyarrhythmias: 1655 and bradyarrhythmias: 181) occurred at 2 years. Of these, 283 (15%) occurred beyond 1 year (tachyarrhythmias 212, bradyarrhythmias 71) in 33 (36%) patients, without differences between valve type. Most late (>1 year) arrhythmic events were asymptomatic (94%) and led to a treatment change in 17 (19%) patients. A total of 71 late bradyarrhythmias [high-degree atrioventricular block (HAVB): 3, severe bradycardia: 68] were detected in 17 (21%) patients. At 2 years, 18 (17%) patients had received a permanent pacemaker (PPM) or implantable cardiac-defibrillator. PPM implantation due to HAVB predominated in the early phase post-TAVR, with only 1 HAVB event requiring PPM implantation after 1 year. CONCLUSION: Patients with new-onset LBBB post-TAVR exhibited a very high burden of arrhythmic events within the 2 years post-procedure. While new tachyarrhythmic events were homogeneously distributed over time, the vast majority of new HAVB episodes leading to PPM implantation occurred early after the procedure. These results should help to guide the management of this challenging group of patients. (clinicaltrials.gov: NCT02153307).

Anatomical targets and expected outcomes of catheter-based ablation of atrial fibrillation in 2020.

Anatomical-based approaches, targeting either pulmonary vein isolation (PVI) or additional extra PV regions, represent the most commonly used ablation treatments in symptomatic patients with atrial fibrillation (AF) recurrences despite antiarrhythmic drug therapy. PVI remains the main anatomical target during catheter-based AF ablation, with the aid of new technological advances as contact force monitoring to increase safety and effective radiofrequency (RF) lesions. Nowadays, cryoballoon ablation has also achieved the same level of scientific evidence in patients with paroxysmal AF undergoing PVI. In parallel, electrical isolation of extra PV targets has progressively increased, which is associated with a steady increase in complex cases undergoing ablation. Several atrial regions as the left atrial posterior wall, the vein of Marshall, the left atrial appendage, or the coronary sinus have been described in different series as locations potentially involved in AF initiation and maintenance. Targeting these regions may be challenging using conventional point-by-point RF delivery, which has opened new opportunities for coadjuvant alternatives as balloon ablation or selective ethanol injection. Although more extensive ablation may increase intraprocedural AF termination and freedom from arrhythmias during the follow-up, some of the targets to achieve such outcomes are not exempt of potential severe complications. Here, we review and discuss current anatomical approaches and the main ablation technologies to target atrial regions associated with AF initiation and maintenance.

Personalized monitoring of electrical remodelling during atrial fibrillation progression via remote transmissions from implantable devices.

AIMS: Atrial electrical remodelling (AER) is a transitional period associated with the progression and long-term maintenance of atrial fibrillation (AF). We aimed to study the progression of AER in individual patients with implantable devices and AF episodes. METHODS AND RESULTS: Observational multicentre study (51 centres) including 4618 patients with implantable cardioverter-defibrillator +/-resynchronization therapy (ICD/CRT-D) and 352 patients (2 centres) with pacemakers (median follow-up: 3.4 years). Atrial activation rate (AAR) was quantified as the frequency of the dominant peak in the signal spectrum of AF episodes with atrial bipolar electrograms. Patients with complete progression of AER, from paroxysmal AF episodes to electrically remodelled persistent AF, were used to depict patient-specific AER slopes. A total of 34 712 AF tracings from 830 patients (87 with pacemakers) were suitable for the study. Complete progression of AER was documented in 216 patients (16 with pacemakers). Patients with persistent AF after completion of AER showed ∼30% faster AAR than patients with paroxysmal AF. The slope of AAR changes during AF progression revealed patient-specific patterns that correlated with the time-to-completion of AER (R2 = 0.85). Pacemaker patients were older than patients with ICD/CRT-Ds (78.3 vs. 67.2 year olds, respectively, P < 0.001) and had a shorter median time-to-completion of AER (24.9 vs. 93.5 days, respectively, P = 0.016). Remote transmissions in patients with ICD/CRT-D devices enabled the estimation of the time-to-completion of AER using the predicted slope of AAR changes from initiation to completion of electrical remodelling (R2 = 0.45). CONCLUSION: The AF progression shows patient-specific patterns of AER, which can be estimated using available remote-monitoring technology.

Implications of bipolar voltage mapping and magnetic resonance imaging resolution in biventricular scar characterization after myocardial infarction.

AIMS: We aimed to study the differences in biventricular scar characterization using bipolar voltage mapping compared with state-of-the-art in vivo delayed gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) imaging and ex vivo T1 mapping. METHODS AND RESULTS: Ten pigs with established myocardial infarction (MI) underwent in vivo scar characterization using LGE-CMR imaging and high-density voltage mapping of both ventricles using a 3.5-mm tip catheter. Ex vivo post-contrast T1 mapping provided a high-resolution reference. Voltage maps were registered onto the left and right ventricular (LV and RV) endocardium, and epicardium of CMR-based geometries to compare voltage-derived scars with surface-projected 3D scars. Voltage-derived scar tissue of the LV endocardium and the epicardium resembled surface projections of 3D in vivo and ex vivo CMR-derived scars using 1-mm of surface projection distance. The thinner wall of the RV was especially sensitive to lower resolution in vivo LGE-CMR images, in which differences between normalized low bipolar voltage areas and CMR-derived scar areas did not decrease below a median of 8.84% [interquartile range (IQR) (3.58, 12.70%)]. Overall, voltage-derived scars and surface scar projections from in vivo LGE-CMR sequences showed larger normalized scar areas than high-resolution ex vivo images [12.87% (4.59, 27.15%), 18.51% (11.25, 24.61%), and 9.30% (3.84, 19.59%), respectively], despite having used optimized surface projection distances. Importantly, 43.02% (36.54, 48.72%) of voltage-derived scar areas from the LV endocardium were classified as non-enhanced healthy myocardium using ex vivo CMR imaging. CONCLUSION: In vivo LGE-CMR sequences and high-density voltage mapping using a conventional linear catheter fail to provide accurate characterization of post-MI scar, limiting the specificity of voltage-based strategies and imaging-guided procedures.

Mapping Technologies for Catheter Ablation of Atrial Fibrillation Beyond Pulmonary Vein Isolation.

Catheter ablation remains the most effective and relatively minimally invasive therapy for rhythm control in patients with AF. Ablation has consistently shown a reduction of arrhythmia-related symptoms and significant improvement in patients' quality of life compared with medical treatment. The ablation strategy relies on a well-established anatomical approach of effective pulmonary vein isolation. Additional anatomical targets have been reported with the aim of increasing procedure success in complex substrates. However, larger ablated areas with uncertainty of targeting relevant regions for AF initiation or maintenance are not exempt from the potential risk of complications and pro-arrhythmia. Recent developments in mapping tools and computational methods for advanced signal processing during AF have reported novel strategies to identify atrial regions associated with AF maintenance. These novel tools - although mainly limited to research series - represent a significant step forward towards the understanding of complex patterns of propagation during AF and the potential achievement of patient-tailored AF ablation strategies for the near future.

Influence of Baseline Physical Activity as a Modifying Factor on COVID-19 Mortality: A Single-Center, Retrospective Study.

INTRODUCTION: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes a severe respiratory disease with a 3% global mortality. In the absence of effective treatment, controlling of risk factors that predispose to severe disease is essential to reduce coronavirus disease 2019 (COVID-19) mortality. Large observational studies suggest that exercise can reduce the risk of all-cause and disease-specific mortality. The aim of this study was to analyze the influence of the baseline physical activity level on COVID-19 mortality METHODS: This is a retrospective cohort study that included patients between 18 and 70 years old, diagnosed with COVID-19 and hospitalized in our center between February 15 and April 15, 2020. After discharge all the patients included in the study were contacted by telephone. Baseline physical activity level was estimated using the Rapid Assessment of Physical Activity Scale questionnaire and patients were divided into two groups for comparison: sedentary patients (group 1) and active patients (group 2). RESULTS: During the study period 552 patients were admitted to our hospital and met the inclusion criteria. Global mortality in group 1 was significantly higher than in group 2 (13.8% vs 1.8%; p < 0.001). Patients with a sedentary lifestyle had increased COVID-19 mortality independently of other risk factors previously described (hazard ratio 5.91 (1.80-19.41); p = 0.003). CONCLUSION: A baseline sedentary lifestyle increases the mortality of hospitalized patients with COVID-19. This finding may be of great utility in the prevention of severe COVID-19 disease.

Late arrhythmias in patients with new-onset persistent left bundle branch block after transcatheter aortic valve replacement using a balloon-expandable valve.

BACKGROUND: The arrhythmic burden after discharge in patients with new-onset left bundle branch block (LBBB) undergoing transcatheter aortic valve replacement (TAVR) with the balloon-expandable SAPIEN 3 (S3) valve remains largely unknown. OBJECTIVE: The purpose of this study was to determine the incidence of late arrhythmias in patients with new-onset LBBB undergoing TAVR with the balloon-expandable S3 valve. METHODS: This was a multicenter, prospective study that included 104 consecutive TAVR patients with new-onset persistent LBBB following TAVR with the S3 valve. An implantable cardiac monitor (Reveal XT, Reveal LINQ) was implanted before discharge. The primary endpoint was the incidence of high-degree atrioventricular block or complete heart block (HAVB/CHB). RESULTS: A total of 40 patients (38.5%) had at least 1 significant arrhythmic event, leading to a treatment change in 17 (42.5%). Significant bradyarrhythmias occurred in 20 of 104 patients (19.2%) (34 HAVB/CHB episodes, 252 severe bradycardia episodes), with 10 of 20 patients (50%) exhibiting at least 1 episode of HAVB/CHB. Most HAVB/CHB episodes (60%) occurred within 4 weeks after discharge. Nine patients (8.7%) underwent permanent pacemaker implantation at 12 months based on the Reveal findings (6 HAVB/CHB, 3 severe bradycardia). CONCLUSION: S3 valve recipients with new-onset LBBB have a high arrhythmic burden, with more than one-third of patients exhibiting at least 1 significant arrhythmic episode within 12 months (HAVB/CHB in 10% of patients). About one-half of bradyarrhythmic events occurred within 4 weeks after discharge. These results should inform future strategies on the use of continuous electrocardiographic monitoring in TAVR S3 patients with new conduction disturbances following the procedure.

Late Electrocardiographic Changes in Patients With New-Onset Left Bundle Branch Block Following Transcatheter Aortic Valve Implantation.

This study sought to determine, in patients with new-onset persistent left bundle branch block (NOP-LBBB) after transcatheter aortic valve implantation (TAVI), the incidence and factors associated with (i) LBBB recovery and (ii) permanent pacemaker implantation (PPI) at 1-year follow-up. This was a multicenter study including 153 patients (mean age: 81 ± 5 years, 56% of women) with NOP-LBBB post-TAVI (balloon-expandable valve in 112 patients). Delta PR (ΔPR) and delta QRS (ΔQRS) were defined as the difference in PR and QRS length between baseline and hospital discharge ECG, and the relative ΔPR and ΔQRS as absolute ΔPR and ΔQRS divided by baseline PR and QRS length, respectively. The patients had a clinical visit and 12-lead ECG at 1-year follow-up. LBBB recovery was observed in 50 patients (33%), and 14 patients (9%) had advanced conduction disturbances requiring PPI during the follow-up period. No clinical or ECG variables were associated with LBBB recovery, including prosthesis type (self- or balloon-expandable valve, p = 0.563), QRS width at baseline/discharge or absolute/relative ΔQRS (p >0.10 for all). The presence of atrial fibrillation at baseline (0.026), a longer PR interval at discharge (0.009), and a longer absolute and relative ΔPR (p = 0.002 and p = 0.004, respectively) were associated with an increased risk of PPI at 1-year follow-up. In conclusion, NOP-LBBB post-TAVI resolved in one-third of patients at 1-year follow-up, but no clinical or ECG variables were associated with LBBB recovery. Conversely, a nonsinus rhythm at baseline and a longer ΔPR were associated with an increased risk of PPI within the year after TAVI.

Lesion Index Titration Using Contact-Force Technology Enables Safe and Effective Radiofrequency Lesion Creation at the Root of the Aorta and Pulmonary Artery.

BACKGROUND: Ablation of some myocardial substrates requires catheter-based radiofrequency delivery at the root of a great artery. We studied the safety and efficacy parameters associated with catheter-based radiofrequency delivery at the root of the aorta and pulmonary artery. METHODS: Thirty-six pigs underwent in-vivo catheter-based ablation under continuous contact-force and lesion index (power, contact-force, and time) monitoring during 60-s radiofrequency delivery with an open-irrigated tip catheter. Twenty-eight animals were allocated to groups receiving 40 W (n=9), 50 W (n=10), or 60 W (n=9) radiofrequency energy, and acute (n=22) and chronic (n=6) arterial wall damage was quantified by multiphoton microscopy in ex vivo samples. Adjacent myocardial lesions were quantified in parallel samples. The remaining 8 pigs were used to validate safety and efficacy parameters. RESULTS: Acute collagen and elastin alterations were significantly associated with radiofrequency power, although chronic assessment revealed vascular wall recovery in lesions without steam pop. The main parameters associated with steam pops were median peak temperature >42°C and impedance falls >23 ohms. Unlike other parameters, lesion index values of 9.1 units (interquartile range, 8.7-9.8) were associated with the presence of adjacent myocardial lesions in both univariate ( P=0.03) and multivariate analyses ( P=0.049; odds ratio, 1.99; 95% CI, 1.02-3.98). In the validation group, lesion index values using 40 W over a range of contact-forces correlated with the size of radiofrequency lesions (R2=0.57; P=0.03), with no angiographic or histopathologic signs of coronary artery damage. CONCLUSIONS: Lesion index values obtained during 40 W radiofrequency applications reliably monitor safe and effective lesion creation at the root of the great arteries.

Genetic mutations in young patients admitted to an emergency department for syncope during sport practice. / Mutaciones genéticas en los pacientes jóvenes atendidos en un servicio de urgencias por síncope durante la práctica de deporte.

BACKGROUND AND OBJECTIVES: To study the frequency of genetic mutations related to genetic heart disease among young patients admitted for syncope during sport practice. PATIENTS AND METHODS: A case series study that included patients≤45 years admitted for syncope during sport practice during 2010-2011. We collected demographic and clinical variables, genetic tests mutations and final clinical diagnosis. RESULTS: A genetic test was performed in 46 (76.7%) of 60 patients evaluated. The genetic test was positive in 12 (26%; 95% CI 15.6-40.3) patients; 10 (21.7%) had PKP2 mutation related to arrhythmogenic right ventricular dysplasia mutation, one (2.2%) KCNQ1 mutation and one (2.2%) SCN5A mutation related to channelopathies. The genetic test was positive in 11 (35.5%) cases of undetermined syncope and one (50%) case of cardiac syncope, being negative in all cases with neuromediated syncopes (P=.037). CONCLUSIONS: Gene mutations are common in young patients suffering from syncope during sports, especially in those with cardiac or undetermined aetiology.

Arrhythmic Burden as Determined by Ambulatory Continuous Cardiac Monitoring in Patients With New-Onset Persistent Left Bundle Branch Block Following Transcatheter Aortic Valve Replacement: The MARE Study.

OBJECTIVES: The authors sought to determine: 1) the global arrhythmic burden; 2) the rate of arrhythmias leading to a treatment change; and 3) the incidence of high-degree atrioventricular block (HAVB) at 12-month follow-up in patients with new-onset persistent left bundle branch block (LBBB) following transcatheter aortic valve replacement (TAVR). BACKGROUND: Controversial data exist on the occurrence of significant arrhythmias in patients with LBBB post-TAVR. METHODS: This was a multicenter prospective study including 103 consecutive patients with new-onset persistent LBBB post-TAVR with the balloon-expandable SAPIEN XT/3 valve (n = 53), or the self-expanding CoreValve/Evolut R system (n = 50). An implantable cardiac monitor (Reveal XT, Reveal Linq) was implanted at 4 (3 to 6) days post-TAVR, and patients had continuous electrocardiogram monitoring for 12 months. All arrhythmic events were adjudicated in a central electrocardiography core lab. Primary endpoints were the incidence of arrhythmias leading to a treatment change, and the incidence of HAVB at 12-month follow-up. RESULTS: A total of 1,553 new arrhythmic events were detected in 44 patients (1,443 episodes of tachyarrhythmia in 26 patients [atrial fibrillation/flutter/atrial tachycardia: 1,427, ventricular tachycardia 16]; 110 episodes of bradyarrhythmia in 21 patients [HAVB 54, severe bradycardia 56]). All arrhythmic events were silent in 34 patients (77%), the arrhythmic event led to a treatment change in 19 patients (18%), and 11 patients (11%) required pacemaker or implantable cardioverter-defibrillator implantation (due to HAVB, severe bradycardia, or ventricular tachycardia episodes in 9, 1, and 1 patient, respectively). A total of 12 patients died at 1-year follow-up, 1 from sudden death. CONCLUSIONS: A high incidence of arrhythmic events was observed at 1-year follow-up in close to one-half of the patients with LBBB post-TAVR. Significant bradyarrhythmias occurred in one-fifth of the patients, and PPM was required in nearly one-half of them. These data support the use of a cardiac monitoring device for close follow-up and expediting the initiation of treatment in this challenging group of patients. (Ambulatory Electrocardiographic Monitoring for the Detection of High-Degree Atrio-Ventricular Block in Patients With New-onset PeRsistent LEft Bundle Branch Block After Transcatheter Aortic Valve Implantation [MARE study]: NCT02153307).

QRS duration reflects underlying changes in conduction velocity during increased intraventricular pressure and heart failure.

Pressure overload and heart failure electrophysiological remodeling (HF-ER) in pigs are associated with decreased conduction velocity (CV) and dispersion of repolarization, which lead to higher risk of ventricular arrhythmia. This work aimed to establish the correlation between QRS complex duration and underlying changes in CV during increased intraventricular pressure (IVP) and/or HF-ER ex-vivo, and to determine whether QRS duration could be sensitive to an acute increase in left ventricular (LV) afterload in-vivo. HF-ER was induced in 7 pigs by high-rate ventricular pacing. Seven weight-matched animals were used as controls. Isolated Langendorff-perfused hearts underwent programmed ventricular stimulation to study QRS complex duration and CV under low/high IVP, using volume-conducted ECG and epicardial optical mapping, respectively. Four additional pigs underwent open-chest surgery to increase LV afterload by partially clamping the ascending aorta, while measuring QRS complex duration during sinus rhythm (SR). In 13 hearts included for analysis, both HF-ER and increased IVP showed significantly slower epicardial CV (-40% and -15%, p < 0.001 and p = 0.004, respectively), which correlated with similar widening of the QRS complex (+41% and +17%, p = 0.005 and p < 0.001, respectively). HF-ER hearts shower larger prolongation of the QRS complex than controls upon increasing the IVP (+21% vs. +12%, respectively. HF-ER*IVP interaction: p = 0.004). QRS complex widened after increasing LV afterload in-vivo (n=3), with correlation between QRS duration and aortic diastolic pressures (R = 0.58, p < 0.001). In conclusion, high IVP and/or HF-ER significantly decrease CV, which correlates with QRS widening on the ECG during ventricular pacing. Increased myocardial wall stress also widens the QRS complex during SR in-vivo.

Safety threshold of R-wave amplitudes in patients with implantable cardioverter defibrillator.

OBJECTIVE: A safety threshold for baseline rhythm R-wave amplitudes during follow-up of implantable cardioverter defibrillators (ICD) has not been established. We aimed to analyse the amplitude distribution and undersensing rate during spontaneous episodes of ventricular fibrillation (VF), and define a safety amplitude threshold for baseline R-waves. METHODS: Data were obtained from an observational multicentre registry conducted at 48 centres in Spain. Baseline R-wave amplitudes and VF events were prospectively registered by remote monitoring. Signal processing algorithms were used to compare amplitudes of baseline R-waves with VF R-waves. All undersensed R-waves after the blanking period (120 ms) were manually marked. RESULTS: We studied 2507 patients from August 2011 to September 2014, which yielded 229 VF episodes (cycle length 189.6±29.1 ms) from 83 patients that were suitable for R-wave comparisons (follow-up 2.7±2.6 years). The majority (77.6%) of VF R-waves (n=13953) showed lower amplitudes than the reference baseline R-wave. The decrease in VF amplitude was progressively attenuated among subgroups of baseline R-wave amplitude (≥17; ≥12 to <17; ≥7 to <12; ≥2.2 to <7 mV) from the highest to the lowest: median deviations -51.2% to +22.4%, respectively (p=0.027). There were no significant differences in undersensing rates of VF R-waves among subgroups. Both the normalised histogram distribution and the undersensing risk function obtained from the ≥2.2 to <7 mV subgroup enabled the prediction that baseline R-wave amplitudes ≤2.5 mV (interquartile range: 2.3-2.8 mV) may lead to ≥25% of undersensed VF R-waves. CONCLUSIONS: Baseline R-wave amplitudes ≤2.5 mV during follow-up of patients with ICDs may lead to high risk of delayed detection of VF. TRIAL REGISTRATION NUMBER: NCT01561144; results.

ECG de enero de 2019 / ECG, January 2019

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Respuesta al ECG de enero de 2019 / Response to ECG, January 2019

No disponible