A simplified single transseptal puncture approach using high-density 3D voltage mapping for atrial fibrillation ablation: acute complications and long-term results.

Background: An ablation catheter and a circular mapping catheter requiring a double transeptal puncture (TSP) for left atrial access have been conventionally used for atrial fibrillation (AF) ablation. Recently, different operators have combined a single transseptal puncture technique with 3D high-density mapping catheters for pulmonary vein isolation (PVI). Objective: This study aims to compare two strategies, single vs. double TSP, regarding the duration of the procedure, radiation time, complication rates, and outcomes. Methods: Retrospective analysis of a large cohort of consecutive patients that underwent first PVI with radiofrequency energy (RF), using a point-by-point strategy, with a 3D mapping system, either with single or double TSP, according to the operator's choice. Results: 285 patients with a mean age of 59.5 ± 11.6 years (36.5% female, 67.7% paroxysmal AF) underwent a point-by-point catheter ablation with RF between July 2015 and March 2020. The mean CHA2DS2-VASc score was 1.7 ± 1.3. Single TSP was performed in 115 (40.3%) patients and double TSP in 170 (59.6%). The operator's experience (≥5 years of AF ablation procedures) was equally distributed among the two groups. The average procedure time (133 ± 31.7 min vs. 123 ± 35.5 min, for single and double TSP, respectively) did reach a statistical difference between both groups (p = 0.008), but there was a substantial advantage regarding fluoroscopy time (13 ± 6.3 min vs. 19 ± 9.1 min, for single and double TSP, respectively; p < 0.001). Acute major complications present similar rates in both groups (2.6% vs. 2.3%, p = 0.799). At the 2-year follow-up, both groups had a similar sinus rhythm maintenance rate (76.5% vs. 78.8%, p = 0.646). Conclusion: A simplified single-TSP technique using high-density multi-electrode 3D mapping is a safe and highly successful option for AF ablation. This approach yields a substantial reduction in fluoroscopy time, with the potential to avoid acute complications, compared to a conventional double-TSP strategy.

Post-acute exercise cardiovagal modulation in older male adults with and without type 2 diabetes.

PURPOSE: We examined heart rate variability (HRV) and baroreflex sensitivity (BRS) disease- and age-related response at 10-and 60-min after an acute high-intensity interval (HIIE) and moderate continuous exercise (MICE) in older adults with and without type 2 diabetes mellitus (T2DM) and healthy young adults. METHODS: Twelve older male adults with (57-84 years) and without T2DM (57-76 years) and 12 healthy young male adults (20-40 years) completed an isocaloric acute bout of HIIE, MICE, and a non-exercise condition in a randomized order. Time and Wavelets-derived frequency domain indices of HRV and BRS were obtained in a supine position and offline over 2-min time-bins using Matlab. RESULTS: HIIE but not MICE reduced natural logarithm root mean square of successive differences (Ln-RMSSD) (d = - 0.85; 95% CI - 1.15 to - 0.55 ms, p < 0.001), Ln-high-frequency power (d = - 1.60; 95% CI - 2.24 to - 0.97 ms2; p < 0.001), and BRS (d = - 6.32; 95% CI - 9.35 to - 3.29 ms/mmHg, p < 0.001) in adults without T2DM (averaged over young and older adults without T2DM), returning to baseline 60 min into recovery. These indices remained unchanged in older adults with T2DM after HIIE and MICE. Older adults with T2DM had lower resting Ln-RMSSD and BRS than aged-matched controls (Ln-RMSSD, d = - 0.71, 95% CI - 1.16 to - 0.262 ms, p = 0.001; BRS d = - 3.83 ms/mmHg), 95% CI - 6.90 to - 0.76, p = 0.01). CONCLUSIONS: Cardiovagal modulation following acute aerobic exercise is intensity-dependent only in adults without T2DM, and appears age-independent. These findings provide evidence of cardiac autonomic impairments in older adults with T2DM at rest and following aerobic exercise.

Validation of a Heart Failure Risk Score in a Cohort of Cardiac Resynchronization Therapy Patients Under Remote Monitoring: Results from the TriageHF™ Algorithm.

The heart failure risk status (HFRS) is a validated dynamic tool for risk score prediction, based on the TriageHF™ algorithm (Medtronic, Minneapolis, MN, USA), for the occurrence of a heart failure (HF) event in the 30 days following a remote monitoring (RM) transmission. The aim of this study was to evaluate the accuracy of the HFRS in predicting an unplanned hospital admission due to HF decompensation in a real-world cohort of patients submitted to cardiac resynchronization therapy (CRT). We conducted a single-center review of a cohort of 40 consecutive HF patients, under RM, with CRT devices using the HFRS of the TriageHF™ algorithm. The correlation of the HFRS with hospital admissions was analyzed. During a mean follow-up of 36 months, a stepwise increase in the HFRS was significantly associated with a higher risk of HF admission (odds ratio, 12.7; 95% confidence interval, 3.2-51.5; P < .001), and the HFRS was demonstrated to have good discrimination for HF hospitalization, with an area under the receiver-operating characteristic curve of 0.812. The TriageHF™ algorithm effectively predicted HF-related hospitalization in a cohort of CRT patients during long-term RM follow-up, providing a novel clinical pathway to optimize the clinical management of this complex population.

Orthostatic Stress and Baroreflex Sensitivity: A Window into Autonomic Dysfunction in Lone Paroxysmal Atrial Fibrillation.

The abnormal neural control of atria has been considered one of the mechanisms of paroxysmal atrial fibrillation (PAF) pathogenesis. The baroreceptor reflex has an important role in cardiovascular regulation and may serve as an index of autonomic function. This study aimed to analyze the baroreceptor reflex's role in heart rate regulation during upright tilt (HUT) in patients with lone PAF. The study included 68 patients with lone PAF and 34 healthy individuals who underwent baroreflex assessment. Parameters such as baroreflex sensitivity (BRS), number of systolic blood pressure (BP) ramps, and the baroreflex effectiveness index (BEI) were evaluated. The study found that PAF patients had comparable resting BPs and heart rates (HRs) to healthy individuals. However, unlike healthy individuals, PAF patients showed a sustained increase in BP with an upright posture followed by the delayed activation of the baroreceptor function with a blunted HR response and lower BEI values. This indicates a pronounced baroreflex impairment in PAF patients, even at rest. Our data suggest that together with BRS, BEI could be used as a marker of autonomic dysfunction in PAF patients, making it important to further investigate its relationship with AF recurrence after ablation and its involvement in cardiovascular autonomic remodeling.

Central Autonomic Network Regions and Hypertension: Unveiling Sympathetic Activation and Genetic Therapeutic Perspectives.

INTRODUCTION: Hypertension, a leading cause of death, was investigated in this study to understand the role of specific brain regions in regulating blood pressure. The lateral parabrachial nucleus (LPBN), Kolliker-fuse nucleus (KF), and periductal grey matter (PAG) were examined for their involvement in hypertension. METHODS: Lentiviral vectors were used to alter the activity of these brain regions in hypertensive rats. Over a 75-day period, blood pressure, heart rate, reflex responses, and heart rate variability were measured. RESULTS: Decreasing the activity in the LPBN resulted in a reduced sympathetic outflow, lowering the blood pressure and heart rate. In the KF, the sympathetic activity decreased and chemoreflex variation was attenuated, without affecting the blood pressure. Silencing the PAG had no significant impact on blood pressure or sympathetic tone, but decreased cardiac baroreflex gain. DISCUSSION: These findings highlight the significant role of the LPBN in hypertension-related sympathetic activation. Additionally, LPBN and KF neurons appear to activate mechanisms that control respiration and sympathetic outflow during chemoreceptor activation. CONCLUSIONS: The study provided insights into the contribution of the midbrain and pontine regions to neurogenic hypertension and offers potential avenues for future genetic interventions and developing novel treatment approaches.

Evaluation of left atrial strain imaging and integrated backscatter as predictors of recurrence in patients with paroxysmal, persistent, and long-standing persistent atrial fibrillation undergoing catheter ablation.

BACKGROUND: Impaired left atrial (LA) strain predicts atrial fibrillation (AF) recurrence after catheter ablation (CA), but currently there is no cut-off to guide patient selection for CA. Integrated backscatter (IBS) is a promising tool for noninvasive quantification of myocardial fibrosis. The aim of this study was to compare LA strain and IBS between paroxysmal, persistent, and long-standing persistent AF and evaluate their association with AF recurrence after CA. METHODS: Analysis of consecutive patients with symptomatic paroxysmal and persistent AF who underwent CA. LA phasic strain, strain rate and IBS were assessed by two-dimensional speckle-tracking at baseline. RESULTS: We analyzed 78 patients, 31% with persistent AF (46% long-standing AF), 65% male, mean age 59 ± 14 years, who underwent CA and were followed-up for 12 months. AF recurrence occurred in 22 (28%) patients. LA phasic strain parameters were significantly impaired in patients with AF recurrence and were independent predictors of AF recurrence in a multivariable analysis. LA reservoir strain (LASr) < 18% predicted AF recurrence with 86% sensitivity and 71% specificity, with a higher predictive power compared to LA volume index (LAVI). LASr < 22% in paroxysmal AF and LASr < 12% in persistent AF correlated with AF recurrence. Increased IBS was a predictor of AF recurrence in patients with paroxysmal AF. CONCLUSION: LA phasic strain parameters were predictors of AF recurrence after CA, independently of LAVI and AF subtype. LASr < 18% showed a higher predictive power compared to LAVI. Further studies are needed to investigate the role of IBS as a predictor of AF recurrence.

Case report: Mutation in NPPA gene as a cause of fibrotic atrial myopathy.

Early-onset atrial fibrillation (AF) can be the manifestation of a genetic atrial myopathy. However, specific genetic identification of a mutation causing atrial fibrosis is rare. We report a case of a young patient with an asymptomatic AF, diagnosed during a routine examination. The cardiac MRI revealed extensive atrial fibrosis and the electrophysiology study showed extensive areas of low voltage. The genetic investigation identified a homozygous pathogenic variant in the NPPA gene in the index case and the presence of the variant in heterozygosity in both parents.

The TANGO2 disease and the therapeutic challenge of acute arrhythmia management: a case report.

Background: TANGO2-related metabolic encephalopathy and arrhythmia are a rare, newly recognized, and likely under-diagnosed condition. First described in 2016, it is characterized by developmental delay and recurrent metabolic crisis. During these episodes, patients may present QTc prolongation and ventricular arrhythmias. Case summary: A 13-year-old female, with developmental delay, presented with severe rhabdomyolysis and an initially normal electrocardiogram (ECG). Due to the worsening of rhabdomyolysis, QTc prolongation was identified (QTc 570 ms) and oral ß-blocker therapy started. A non-sustained ventricular tachycardia developed, initially managed with magnesium and lidocaine. After a short period, an arrhythmic storm of polymorphic ventricular extrasystoles induced Torsade de Pointes (TdP) was triggered. A temporary percutaneous pacing lead was placed and esmolol infusion started. The electrical instability ran in parallel with the increasing severity of rhabdomyolysis and systolic ventricular function decline. Genetic testing identified a pathogenic variant in homozygosity in the TANGO2 gene. A stable sinus rhythm was achieved with metabolic and serum electrolytes optimization. ECG showed normalization of the QTc interval. Discussion: The full TANGO2-related phenotype emerges over time and the prognosis is linked to the appearance of ECG abnormalities. QT interval prolongation can lead to life-threatening ventricular tachycardias. The arrhythmia mechanism seems to be secondary to metabolite build-up in cardiomyocytes, which can explain the cardiac phenotype during the crisis which subsides after their resolution. In these patients, avoiding bradycardia is fundamental, since long QT-related TdP seems to be triggered by bradycardia and short-long-short ventricular premature beats (VPB). During an acute metabolic crisis, the management of arrhythmias relies on metabolic control.

Clinical outcome of a single procedure cryoballoon ablation for the treatment of atrial fibrillation: A real-world multicenter experience in Portugal.

BACKGROUND: Cryoballoon ablation (CBA) for pulmonary vein isolation (PVI) has been growing as an alternative technique, not only in patients with paroxysmal atrial fibrillation (PAF) but also in persistent atrial fibrillation (AF). Cryoballoon ablation has demonstrated encouraging acute and mid-term results. However, data on long-term follow-up of CB-based PVI are scarce. OBJECTIVE: We sought to examine efficacy, safety, and long-term outcomes of CBA in PAF and persistent AF in four Portuguese centers. METHODS: All patients that were treated with the cryoballoon catheter according to routine practices with a second-generation 28-mm CB in four centers were included. This was a retrospective, non-randomized analysis. Patients were followed-up for >12 months and freedom from atrial arrhythmias (AA) was evaluated at the end of follow-up. RESULTS: Four hundred and six patients (57.7±12.4 years, 66% men) participated. AF was paroxysmal in 326 patients (80.2%) and persistent in 80 (19.7%). The mean procedure time duration was 107.7±50.9 min, and the fluoroscopy time was 19.5±9.7 min. Procedural/periprocedural complications occurred in 30 cases (7.3%), being transient phrenic nerve palsy the most frequent incident (2 out of 3 complications). Anatomic variations of the PV were present in 16.1% of cases. At a mean follow-up of 22.0±15.0 months, 310 patients (76.3%) remained in stable sinus rhythm, with at least one AF episode recurrence documented in 98 cases (24.1%). The recurrence rate was 20.5% in the PAF group and 37.8% in the persistent AF group. CONCLUSION: In this multicenter experience, a single CBA procedure resulted in 75.9% freedom from AF at a 22-month follow-up. This technique was demonstrated to be a safe and effective option in experienced centers for the treatment of PAF and PersAF.

The atrial fibrillation burden during the blanking period is predictive of time to recurrence after catheter ablation.

Objective: This study aimed to assess whether atrial fibrillation (AF) occurrence or its corresponding daily mean burden (in minutes/day) during the mid to late blanking period after pulmonary vein isolation (PVI), predicts AF recurrence. Methods: Analysis of consecutive first PVI ablation patients undergoing prolonged electrocardiogram (ECG) monitoring during the second and third months after PVI. The clinical variables, total AF burden, and their relationship with time to recurrence were studied. Results: 477 patients with a mean age of 56.9 (SD = 12.3) years (63.7 % male; 71.7 % paroxysmal AF), from which 317 (66.5 %) had an external event recorder between 30 and 90 days after ablation. Median follow-up of 16.0 (P 25:12.0: P 75:33.0) months, 177 (37 %) patients had an AF recurrence, with 106 (22.2 %) having the first episode after 12 months of follow-up. In the group of patients with an event recorder, 80 (25.2 %) had AF documented during the blanking period. Multivariable analysis showed that AF during the blanking period was associated with a 4-fold higher risk of recurrence (HR: 3.98; 95 %CI: 2.95-5.37), and, compared to patients in sinus rhythm, those with an AF burden ≥ 23 min/day had an approximately 7-fold higher risk of recurrence (HR estimate: 6.79; 95 %CI: 4.56-10.10). Conclusions: The probability of experiencing AF recurrence can be predicted by atrial tachyarrhythmia episodes during the second and third months after PVI. Atrial arrhythmias burden > 23 min/day has a high predictive ability for recurrence.

The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates.

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.

Cardiovagal Modulation in Young and Older Male Adults Following Acute Aerobic Exercise.

We compared response patterns of cardiovagal modulation through heart-rate variability (HRV) and baroreflex sensitivity (BRS) indices at 10 and 60 min after an acute bout of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in active young and older adults. Twelve young (aged 20-40 years) and older (aged 57-76 years) healthy and active male adults performed an isocaloric acute bout of HIIE, MICE, or a non-exercise condition in a randomized order. HRV and BRS indices were analyzed offline with R-R intervals obtained from a supine position. HIIE decreased natural logarithm (Ln) standard deviation of NN intervals (d=-0.53; 95% CI: -0.77 to -0.30 ms, p<0.001), Ln-root mean square of successive differences (d=-0.85; 95% CI: -1.09 to -0.61 ms, p<0.001), Ln-high-frequency power (d=-1.60; 95% CI: -2.11 to -1.10 ms2; p<0.001), and BRS (d=-6.28; 95% CI: -8.91 to -3.64 ms/mmHg, p<0.001) after exercise in young and older adults, whereas MICE did not. Indices returned to baseline after 60 min. We found no evidence of age-associated response patterns in HRV or BRS to a single bout HIIE or MICE in active participants. HIIE reduced cardiovagal modulation in active young and older adults, returning to baseline values 60 min into recovery.

Protocol-based cardiotoxicity monitoring in hydroxychloroquine medicated COVID-19 pediatric patients.

INTRODUCTION/OBJECTIVES: By May 2020, SARS-CoV-2 had caused more than 400 000 deaths worldwide. Initially, hydroxychloroquine was a treatment option for COVID-19. More recent studies have questioned its safety and efficacy and, until stronger evidence is available, it was suspended from therapy protocols. We describe our experience treating COVID-19 Portuguese pediatric patients with hydroxychloroquine, having applied a protocol for monitoring cardiac toxicity. METHODS: An observational retrospective study of COVID-19 pediatric patients, admitted from March to April 2020 and treated with hydroxychloroquine. Cardiotoxicity was assessed using ECG recordings and corrected QT-time (QTc). Patients were classified into risk-groups depending on QTc value: normal, slightly elevated or severely elevated (>500 ms). RESULTS: Total of 14 patients, with a median age of 10 years [four months; 17 years], treated with hydroxychloroquine for a median of five days. Hydroxychloroquine was used in monotherapy in six patients (mainly mild disease with comorbidities), and in association with lopinavir/ritonavir (3) and azithromycin (5) in moderate to severe disease. Other QT-prolonging therapies were used in five patients: oseltamivir (3), omeprazole (1), morphine (1) and ketamine (1). At 48 hours of treatment, two patients temporarily suspended hydroxychloroquine due to QTc prolongation (>500 ms). All patients completed the whole treatment. No other side effects or deaths occurred. CONCLUSION: Clinical trials are evolving to define hydroxychloroquine effectivity and safety. Our considerable pediatric population supports the need for cardiotoxicity monitoring during therapy but suggest its use seems to be safe in COVID-19 pediatric patients, even in association with other QT-prolonging therapies.

INTRODUÇÃO/OBJETIVO: A hidroxicloroquina foi inicialmente uma das opções terapêuticas na Covid-19. Descreve-se o tratamento com hidroxicloroquina em doentes Covid-19 pediátricos, tendo aplicado um protocolo de monitoração cardíaca pelo seu potencial arritmogénico. MÉTODOS: Estudo observacional retrospetivo de doentes pediátricos com Covid-19, internados de março a abril 2020, medicados com hidroxicloroquina. A monitoração cardíaca foi realizada por eletrocardiogramas regulares e cálculo do intervalo QT corrigido durante o tratamento. Os doentes foram classificados consoante o valor de QTc: normal, moderadamente aumentado ou muito aumentado (>500 msg). RESULTADOS: Total de 14 doentes, com mediana de 10 anos [4 meses; 17 anos], medicados com HCQ durante uma mediana de 5 dias em doentes com pneumonia ou comorbilidades. A monoterapia foi realizada em 6 doentes, 4 com fatores de risco, e em associação com lopinavir/ritonavir (3) e azitromicina (5) na doença grave e moderada. Foram ainda usados fármacos capazes de prolongar o intervalo QT: oseltamivir (3), omeprazol (1), cetamina e morfina (1) em 5 doentes. Após 48 horas de terapêutica, dois doentes apresentaram intervalo QTc muito aumentado, condicionando suspensão temporária do fármaco. Todos os doentes concluíram o tratamento sem outros efeitos adversos. CONCLUSÃO: A HCQ permanece em ensaios clínicos para avaliação da sua efetividade e segurança. A nossa amostra considerável em doentes pediátricos apoia a necessidade de monitoração de toxicidade cardíaca, mas sugere na população estudada, mesmo na associação com outros fármacos que prolongam o intervalo QT, a segurança de sua utilização.

Lockdown measures for COVID-19 outbreak and variation in physical activity in patients with heart failure and cardiac implantable devices.

AIMS: The present study analysed the patterns of physical activity pre-, during and post-lockdown measures for COVID-19 pandemic in patients with chronic heart failure (CHF) and cardiac implantable electronic devices (CIED) under remote monitoring (RM), and assessed the physical activity patterns during these periods. METHODS: The raw data from 95 patients with CHF (age 67,7 ± 15,1 years, 71,5% male) corresponding to 2238 RM transmissions of the Medtronic Carelink™ network platform was obtained. The physical exercise profiles and the impact of the lockdown measures on the physical behaviour during and after the measures were analysed. According to the level of activity duration in the pre-lockdown, lockdown and post-lockdown periods, the patterns of behaviour were identified (non-recoverees, incomplete recoverees, recoverees and full-recoverees). CONCLUSION: RM of CHF patients with CIED using the Carelink™ network is useful for close follow-up and identification of heart failure risk status variations. After relieving the confinement measures there were two groups of patients that did not recover the previous physical activity levels. Physical inactivity in patients with CHF can have a significant impact on outcomes.

Characterization of Atrial Propagation Patterns and Fibrotic Substrate With a Modified Omnipolar Electrogram Strategy in Multi-Electrode Arrays.

Introduction: The omnipolar electrogram method was recently proposed to try to generate orientation-independent electrograms. It estimates the electric field from the bipolar electrograms of a clique, under the assumption of locally plane and homogeneous propagation. The local electric field evolution over time describes a loop trajectory from which omnipolar signals in the propagation direction, substrate and propagation features, are derived. In this work, we propose substrate and conduction velocity mapping modalities based on a modified version of the omnipolar electrogram method, which aims to reduce orientation-dependent residual components in the standard approach. Methods: A simulated electrical propagation in 2D, with a tissue including a circular patch of diffuse fibrosis, was used for validation. Unipolar electrograms were calculated in a multi-electrode array, also deriving bipolar electrograms along the two main directions of the grid. Simulated bipolar electrograms were also contaminated with real noise, to assess the robustness of the mapping strategies against noise. The performance of the maps in identifying fibrosis and in reproducing unipolar reference voltage maps was evaluated. Bipolar voltage maps were also considered for performance comparison. Results: Results show that the modified omnipolar mapping strategies are more accurate and robust against noise than bipolar and standard omnipolar maps in fibrosis detection (accuracies higher than 85 vs. 80% and 70%, respectively). They present better correlation with unipolar reference voltage maps than bipolar and original omnipolar maps (Pearson's correlations higher than 0.75 vs. 0.60 and 0.70, respectively). Conclusion: The modified omnipolar method improves fibrosis detection, characterization of substrate and propagation, also reducing the residual sensitivity to directionality over the standard approach and improving robustness against noise. Nevertheless, studies with real electrograms will elucidate its impact in catheter ablation interventions.

Amiodarone-induced thyrotoxicosis in a pediatric patient: A rare and demanding clinical case.

Thyroid dysfunction is one of the most common adverse effects of amiodarone therapy, ranging from subclinical changes to overt clinical thyrotoxicosis (AIT) and/or hypothyroidism. Due to its heterogeneity, AIT lasts as a defiant entity, leading to a thorny treatment course, particularly in pediatrics. AIT can be classified as either type 1, type 2 or mixed form based on its pathophysiology. Differentiating between the main AIT subtypes is quite relevant, since there is specific treatment for both, however, this distinction may be difficult in clinical practice. We describe a rare case of AIT in a pediatric patient, with an uncommon congenital cardiac malformation, that started amiodarone therapy due to paroxysmal supraventricular tachycardia. AIT was reported 26 months after drug onset, with a sudden and explosive emerging. This case highlights the current AIT management challenges on the highdemanding pediatric field pursuing, ultimately, an enhanced patient´s care.

Long-term follow-up of adult patients with congenital heart disease and an implantable cardioverter defibrillator.

OBJECTIVE: Sudden cardiac death is common in the adult congenital heart disease (ACHD) population. Knowledge and experience about the use of implantable cardioverter defibrillators (ICD) in ACHD patients is very limited. We aimed to characterize a cohort of patients with ACHD and ICDs. DESIGN: Thirty consecutive ACHD patients submitted to an ICD implantation in a single tertiary center were evaluated. Data on baseline clinical features, heart defect, indication for ICD, type of device, appropriate therapies, ICD-related complication, and mortality during follow-up were collected. RESULTS: Of the 30 patients, 56.7% received appropriate therapies due to ventricular tachycardia (VT) or ventricular fibrillation (VF). The rate of inappropriate therapies and device-related complications was 33.3%. Secondary prevention and primary prevention patients with class I indications for ICD had more appropriate therapies than complication, but this relationship was reversed for patients with class II indications. Remote monitoring played an important role in diagnosing new atrial arrhythmias before scheduled visits in 46.2% of patients, leading to a change in medication. VT/VF episodes were associated with a composite of death, cardiac transplantation, and hospital admission (OR 13.0; 95% CI: 2.1-81.5). CONCLUSION: ICDs are not only useful in preventing SCD, but also have a major role in diagnosing atrial tachyarrhythmias ahead of scheduled visits. Although improvements in ICD technology might reduce complications and inappropriate therapies, adequate selection of candidates for primary prevention still remains difficult because of the lack of clear indications.