Persistent Atrioventricular Block Research Articles

Isolated non-immune-mediated second-degree atrioventricular block in the fetus: natural history and predictive factors for spontaneous recovery.

To determine the clinical course of fetal isolated non-immune-mediated second-degree atrioventricular block (AVB) and the factors associated with spontaneous recovery in these cases. Fetuses with isolated non-immune-mediated second-degree AVB were recruited prospectively between 2014 and 2022. These fetuses were divided into two groups: those which recovered spontaneously and those which did not. Maternal and fetal characteristics and intrauterine and postnatal outcomes were compared between the two groups. The study cohort included 20 fetuses with isolated non-immune-mediated second-degree AVB, diagnosed at a median gestational age of 22.0 (range, 17.0-35.0) weeks. In 12 fetuses, 1:1 atrioventricular conduction was restored spontaneously in utero and there was no recurrence during the postnatal follow-up period. In the remaining eight fetuses, second-degree AVB was maintained and, in six of these, the pregnancy was terminated on parental request. Of the two liveborn children who had persistent second-degree AVB prenatally, one had progressed to complete AVB at the latest follow-up, at the age of 34 months, but was asymptomatic, without heart enlargement or dysfunction. The other child progressed to complete AVB after delivery and was diagnosed with type-2 long QT syndrome. This infant died aged 2 months. Fetuses in the group that recovered spontaneously had earlier gestational age at diagnosis (median, 20.0 (range, 17.0-26.0) vs 24.5 (range, 18.0-35.0) weeks; P = 0.004) and higher atrial rate at diagnosis (median, 147 (range, 130-160) vs 138 (range, 125-149) bpm; P = 0.006) in comparison with the group that did not recover spontaneously. The best cut-off values for prediction of failure to recover spontaneously were 22.5 weeks' gestational age at diagnosis and 144 bpm atrial rate at diagnosis, with sensitivities of 87.5% and 75.0%, respectively, and specificities of 92.0% and 87.5%, respectively. The outcome of 60% of fetuses with isolated non-immune-mediated second-degree AVB was favorable. Earlier gestational age and higher atrial rate at diagnosis were associated with spontaneous reversion to normal sinus rhythm. Prenatal genetic testing should be performed in cases with persistent AVB, to exclude heritable disorders including long QT syndrome. These findings provide important information for clinical management and prenatal counseling in these cases. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Anatomical Ablation of the Atrioventricular Node.

Atrioventricular (AV) conduction ablation has been achieved by targeting the area of penetration of the conduction axis as defined by recording a His bundle potential. Ablation of the His bundle may reduce the possibility of a robust junctional escape rhythm. It was hypothesised that specific AV nodal ablation is feasible and safe. The anatomical position of the AV node in relation to the site of penetration of the conduction axis was identified as described in dissections and histological sections of human hearts. Radiofrequency (RF) ablation was accomplished based on the anatomical criteria. Specific anatomical ablation of the AV node was attempted in 72 patients. Successful AV nodal ablation was accomplished in 63 patients (87.5%), following 60 minutes (IQR 50-70 minutes) of procedure time, 3.4 minutes (IQR 2.4-5.5 minutes) of fluoroscopy time, and delivery of 4 (IQR 3-6) RF lesions. An escape rhythm was present in 45 patients (71%), and the QRS complex was similar to that before ablation in all 45 patients. Atropine was administered in six patients after the 10-min waiting period and did not result in restoration of conduction. In nine patients, AV conduction could not be interrupted, and AV block was achieved with ablation of the His after delivery of 12 (IQR 8-15) RF lesions. No cases of sudden death were encountered, and all patients had persistent AV block during a median 10.5 months (IQR 5-14 months) of follow-up. Anatomical ablation of the AV node is feasible and safe, and results in an escape rhythm similar to that before ablation.

Abstract 12786: Predictors of Intermediate to Long-Term Ventricular Pacing Requirement Following Transcatheter Aortic Valve Replacement

Objectives: To identify factors associated with persistent atrioventricular (AV) block in patients with permanent pacemaker (PPM) in the peri-transcatheter aortic valve replacement (TAVR) setting. Background: Patients undergoing TAVR may develop AV block requiring pacing. However, whether there are patients who recover AV conduction over time is unknown. Methods: Patients who underwent TAVR and either had pre-existing PPM implanted for sinus node dysfunction or required PPM implantation during the peri-procedural TAVR period were identified from two hospitals in the University of North Carolina Health system. Demographic, electrocardiographic, echocardiographic, and procedural characteristics were abstracted. PPM data was abstracted from remote and in-person PPM interrogations at intermediate (1-12 mo) and long-term (>12 mo) checks. Patients were separated into cohorts with negligible (<1%) or significant (>1%) ventricular pacing burdens. Bivariable and multivariable analyses were performed to identify factors associated with a significant ventricular pacing requirement. Results: The cohort consisted of 159 patients with PPM implanted prior to (n=38) or in the peri-procedural (n=121) TAVR period. Bivariate analyses identified pre-procedural RBBB (17.1% vs 42.9%, p=0.007) and post-procedural RBBB (15.2% and 39.3%, p=0.015) with significant ventricular pacing requirement in the intermediate or long-term period after TAVR. In multivariate analyses, atrial fibrillation (AF) (OR 5, 95% CI 1.78-16.6, p=0.003) and RBBB (OR 11, 95% CI 2.2-100.0, p=.008) in the post-TAVR period were associated with significant ventricular pacing requirements. Patients without AF or RBBB less often required significant ventricular pacing in the intermediate (19.3% vs 80.7%) or long-term periods (19.8% vs 80.2%) after TAVR. Conclusions: Post-procedure RBBB or a history of AF predict long-term persistence of AV block post-TAVR. However, patients without RBBB or AF less often require long-term ventricular pacing and may be candidates for temporary or more basic pacing options (e.g. leadless ventricular devices) as necessary in the peri-op period.

Acute lymphocytic myocarditis presenting as complete heart block in an adult: a case report

BackgroundComplete heart block (CHB) as a first presentation of acute viral myocarditis is a rare occurrence associated with increased morbidity and mortality. In such cases, an endomyocardial biopsy is recommended to make a clear histological diagnosis aiding to differentiate from other possible conditions such as sarcoiditic myocarditis, giant cell myocarditis, and eosinophilic myocarditis. Insertion of a permanent pacemaker may be considered on a case-to-case basis.Case presentationA previously healthy 21-year-old female presented to the emergency department after having suffered two episodes of syncope on a background of a few days’ history of myalgias, chills, and rigors. Electrocardiogram showed high-grade Mobitz II block with intermittent periods of CHB. A bedside echocardiogram upon admission demonstrated normal biventricular systolic function. Given the patient’s unstable haemodynamic status and lack of obvious reversible causes for the CHB, a permanent dual-chamber pacemaker was inserted urgently. Initial blood investigations indicated an ongoing inflammatory process highlighting the possibility of myocarditis as a cause of the CHB. Therefore, a troponin level was taken and was noted to be elevated confirming the suspicion of myocarditis. The left ventricular ejection fraction (LVEF) decreased over the following days to approximately 20%, clinically resulting in pulmonary oedema and acute shortness of breath. The patient required aggressive intravenous diuresis and anti-heart failure medication. An endomyocardial biopsy (EMB) confirmed the diagnosis of lymphocytic myocarditis. The patient’s condition improved secondary to an improvement in LVEF and resolution of the heart block. A cardiac magnetic resonance (CMR) imaging performed 6 weeks from admission reported an improved LVEF of 51% with no late gadolinium enhancement (LGE). Based on the reassuring CMR findings and the resolution of CHB on follow-up pacemaker checks, it was deemed safe to explant the pacemaker.ConclusionsAcute myocarditis may be complicated with high-degree AV block and cardiogenic shock necessitating close observation in a critical care unit. A permanent pacemaker may provide atrio-ventricular synchrony which helps stabilise the patient’s condition and protect from a prolonged period of heart block. Early myocardial fibrosis on EMB and degree of LGE on CMR are indicators of persistent atrioventricular block. Guideline-directed treatment of heart failure is essential.

P196 ENDOCARDITIS MASQUERADING AS STILL‘S DISEASE: WHEN AN ECHOCARDIOGRAM SAVES YOUR LIFE

Abstract A 44–year–old man in apparent good health thus far presented with weight loss and fever preceded by shivers, profuse sweating, and arthralgias. Blood tests documented normal white blood count with slightly altered CRP and ESR. Chest X–rays did not find pleuro– parenchymal lesions with normal cardiac silhouette. Abdomen ultrasounds was regular. Due to the persistence of the symptoms, he was referred to a rheumatologist who diagnosed Adult Still’s disease (AOSD) and recommended therapy with prednisone and sulfasalazine, interleukin–1 inhibitor, with the resolution of the fever. After three months, because of the recrudescence of the fever, he was admitted to the emergency room a total–body CT–scan documented inflammatory–abscess lesions in the brain and hypodense areas in the spleen. ECG showed type 1 second–degree atrioventricular (AV) block. The patient was therefore transferred to the Cardiology Department; echocardiograms documented an endocardic mass on the aortic valve and suspected periannular abscess also infiltrating the interventricular septum. The patient underwent urgent surgery with excision of the aortic valve, opening and draining of the abscessual cavities, reconstruction of the aortic annulus with bovine pericardium patch and aortic valve replacement with bioprosthesis. The patient did not present further febrile episodes after surgery but a pacemaker implantation was necessary due to persistent AV block. Biological material sent for culture was positive for S. gallolyticus. AOSD is one of the most common conditions responsible for fevers of unknown origin. It is characterized by fever, arthritis, evanescent rash, leukocytosis, and multiorgan involvement. Yamaguchi criteria required for the diagnosis of AOSD are as follows: main criteria: Fever >39°C, lasting 1 week or more, Arthralgia or arthritis, lasting 2 weeks or more, Typical rash, Leukocytosis >10,000/mm3; Minor criteria: Sore throat, Recent development of significant lymphadenopathy, Hepatomegaly or splenomegaly, Negative tests for antinuclear antibodies and rheumatoid factor; Exclusion criteria: Infections, Malignancies, Other rheumatic diseases.

Characterization of pathological remodeling in the chronic atrioventricular block cynomolgus monkey heart.

We studied time course of pathological remodeling occurring in the cynomolgus monkey hearts against persistent atrioventricular block condition (n = 10). The atrioventricular block induced the ventricular and atrial dilation followed by the ventricular hypertrophy. Interstitial fibrosis in the ventricle was also observed along with gradual increases in the plasma angiotensin II and aldosterone concentrations. These adaptations were associated with the changes in gene expression profiling reflecting fibrosis and hypertrophy. Atrioventricular block reduced the ventricular rate and cardiac output, but the ejection fraction and stroke volume increased, whereas the cardiac output was gradually restored to its basal level. Systolic/diastolic blood pressure after the atrioventricular block was kept equal to or lower than that before the block, according with lack of increase in the plasma catecholamine levels. Chronic atrioventricular block gradually prolonged the QRS width and JT interval, leading to the QT interval prolongation in conscious state. 10mg/kg of dl-sotalol hydrochloride induced torsade de pointes (TdP) in 6 out of 10 animals by 15months. Animals showing longer QTcF under anesthesia after the atrioventricular block developed dl-sotalol-induced TdP earlier. No marked difference was observed in pharmacokinetics of dl-sotalol between 1 and 7months after the atrioventricular block. Each TdP spontaneously terminated, reflecting a monkey's relatively small "effective size of the heart (=∛(left ventricular weight)/wavelength of reentry)". These fundamental knowledge will help better utilize the chronic atrioventricular block monkeys as an in vivo proarrhythmia model for detecting drug-induced TdP.

PO-717-01 TIME COURSE AND MANAGEMENT OF DELAYED ONSET ATRIOVENTRICULAR BLOCK FOLLOWING SLOW PATHWAY ABLATION

Radiofrequency catheter ablation of the slow pathway of the atrioventricular (AV) node carries a small risk of irreversible AV block from thermal AV nodal injury. As opposed to immediate and persistent AV block which typically requires permanent pacemaker implantation, delayed onset block may be associated with local inflammatory changes and improve with anti-inflammatory therapy.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

Cardioneuroablation for Treatment of Atrioventricular Block.

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Pacemaker implantation post congenital heart disease surgical repair: tertiary center experience.

This was a retrospective study documenting all pacemaker implantations (PMIs) secondary to postoperative atrioventricular block. A total of 26 patients were included between 2011 and 2020. The incidence rate was 1.8%, with a median follow-up time of 4.5years. At the time of the initial PMI, the median weight was 5kg, and the median generator longevity was 45months. Mean cardiopulmonary bypass and aortic clamp times were significantly longer among surgeries complicated with PMI (P≤0.05). Trisomy 21 patients were 4 times more likely to need a PMI (95% CI 1.8-9, P < 0.001). The mean Risk Adjustment in Congenital Heart Surgery and Society of Thoracic Surgery scores were higher in patients with PMI. All initial PMIs were epicardial (18 single chamber). Most patients underwent ventricular septal defect closure (isolated or complex), except for 5 patients who underwent left-sided surgery. Pacing-induced dilated cardiomyopathy occurred in 3 patients. All implanted leads were functional except for 2 leads with high thresholds and another biventricular system infection. There was a 31% rate of pacing reintervention.Conclusion: PMI resulted in significant morbidity but without mortality. The highest risk for PMI was left ventricular outflow tract repair, trisomy 21, prolonged cardiopulmonary bypass, and aortic cross times. What is Known: •Incidence rate for postoperative atrioventricular block requiring pacemaker was at 1.8%, similar to previously published reports. •Longer cardiopulmonary bypass and aortic cross-clamp times were associated with higher risk for developing postoperative persistent atrioventricular block. What is New: •Incidence for persistent atrioventricular block requiring pacemaker was highest among left ventricular outflow tract surgery at 8.6%. •Following all intracardiac repair, Down syndrome patients were 4 times more likely to need a pacemaker implantation compared to the non-syndromic group.

Long-term percentage of ventricular pacing in patients requiring pacemaker implantation after transcatheter aortic valve replacement: A multicenter 10-year experience

Recent studies suggest that atrioventricular (AV) conduction may recover after pacemaker (PM) implantation following transcatheter aortic valve replacement (TAVR), but little is known about long-term follow-up of such patients. The purpose of this study was to evaluate the long-term percentage of right ventricular pacing in patients who underwent TAVR and required PM implantation stratified based on the indication for permanent pacing. Retrospective analysis of all consecutive patients who underwent TAVR from February 2008 to August 2019 at 3 centers was performed. Patients already implanted with a PM/implantable cardioverter-defibrillator (ICD) before TAVR, implanted with a cardiac resynchronization therapy device, or implanted >30 days after TAVR were excluded. Eligible patients were divided into 2 groups based on the presence (persistent atrioventricular block [AVB] group) or absence (nonpersistent AVB group) of persistent third-degree AVB after TAVR. A total of 1594 patients underwent TAVR. Two hundred four patients were implanted with a PM or ICD after TAVR and 32 met exclusion criteria, so 172 patients were eligible (median time TAVR-PM implant 4 days) for a total of 352 follow-up visits analyzed. A significant difference in the percentage of ventricular pacing was observed at follow-up performed 7-90 days after implantation (98% persistent AVB group vs 8% nonpersistent AVB group; P <.001). This difference remained significant at follow-up performed 91-270 days (95% vs 3.5%; P <.001), 271-540 days (95.5% vs 3%; P = .006), and 541-900 days (97.4% vs 2.2%; P <.001) after implantation. Patients requiring PM implantation due to persistent third-degree AVB after TAVR were less likely to show AV conduction recovery, whereas patients implanted for other indications showed a low percentage of pacing during follow-up.

Development of a sheep model of atrioventricular block for the application of novel therapies

IntroductionSheep have been adopted as a pre-clinical large animal for scientific research as they are good models of cardiac anatomy and physiology, and allow for investigation of pathophysiological processes which occur in the large mammalian heart. There is, however, no defined model of atrioventricular block in sheep to allow for pre-clinical assessment of new cardiac treatment options. We therefore aimed to develop an adult sheep model of atrioventricular block with the focus on future novel applications.Methods and resultsWe utilized six sheep to undergo two procedures each. The first procedure involved implantation of a single chamber pacemaker into the right ventricular apex, for baseline assessment over four weeks. The second procedure involved creating atrioventricular block by radiofrequency ablation of the His bundle, before holding for a further four weeks. Interrogation of pacemakers and electrocardiograms determined the persistence of atrioventricular block during the follow up period. Pacemakers were inserted, and atrioventricular block created in 6 animals using a conventional approach. One animal died following ablation of the His bundle, due to procedural complications. Four unablated sheep were assessed for baseline data over four weeks and showed 5.53 ± 1.28% pacing reliance. Five sheep were assessed over four weeks following His bundle ablation and showed continuous (98.89 ± 0.81%) ventricular pacing attributable to persistent atrioventricular block, with no major complications.ConclusionWe have successfully developed, characterized and validated a large animal model of atrioventricular block that is stable and technically feasible in adult sheep. This model will allow for the advancement of novel therapies, including the development of cell and gene-based therapies.

High-grade atrioventricular block requiring pacemaker implantation after cardiac transplantation: An unusual complication

Self-limited bradyarrhythmias are commonly seen in postorthotopic heart transplantation patients. The most common cause of such bradyarrhythmias is sinus node dysfunction. Atrioventricular (AV) nodal blocks requiring pacemaker implantation remain distinctly uncommon. After ruling out reversible causes including dyselectrolytemia and drug toxicity, prolonged ischemia time of donor heart and transplant rejection should be considered as possible causes. The present case describes an uncommon occurrence of persistent high-grade AV block in postheart transplantation period ultimately requiring permanent pacemaker implantation.

Long-term progression of rhythm and conduction disturbances in pacemaker recipients: findings from the Pacemaker Expert Programming study.

Knowledge of the long-term progression of rhythm disorders requiring pacemaker implantation could have significant implications for the choice of device and its management during follow-up. Accordingly, we conducted an observational study to analyse the long-term progression of rhythm disorders requiring pacemaker implantation. This multicentre, observational study enrolled 1810 pacemaker patients (age 71.6 ± 13.3 years, men 53.8%) consecutively evaluated during scheduled pacemaker follow-up visits. To evaluate the long-term progression of rhythm disorders, we analysed the patient's rhythm disorders at the time of device implantation and during follow-up. After pacemaker implantation, the rhythm disorders were reassessed and recorded at each scheduled pacemaker follow-up visit, and the spontaneous rhythm was analysed during pacemaker interrogation. During a median follow-up of 61.6 months, we observed a progression of the primary rhythm disorder in 295 patients (16.3%; worsening of the preexisting rhythm disorder in 7.7%; occurrence of a new rhythm disorder added to the preexisting one in 8.6%). Specifically, the cumulative per-year risks of developing the following disorders were: atrioventricular block (AVB) in patients implanted for sinus node disease (SND), 0.3%; permanent atrial fibrillation in SND patients, 2.9%; SND in AVB patients, 0.7%; and persistent AVB in patients implanted for chronic bifascicular block 3.0%. Our results revealed that rhythm disorders requiring pacemaker implantation show long-term progression in a significant number of cases. In many cases, the progression is substantial and may require a change in pacing mode.

Clinically oriented device programming in bradycardia patients: part 2 (atrioventricular blocks and neurally mediated syncope). Proposals from AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

: The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features. In part 2, criteria for pacemaker choice and programming in atrioventricular blocks and neurally mediate syncope are proposed. The atrioventricular blocks can be paroxysmal or persistent, isolated or associated with sinus node disease. Neurally mediated syncope can be related to carotid sinus syndrome or cardioinhibitory vasovagal syncope. In sinus rhythm, with persistent atrioventricular block, we considered appropriate the activation of mode-switch algorithms, and algorithms for auto-adaptive management of the ventricular pacing output. If the atrioventricular block is paroxysmal, in addition to algorithms mentioned above, algorithms to maximize intrinsic atrioventricular conduction should be activated. When sinus node disease is associated with atrioventricular block, the activation of rate-responsive function in patients with chronotropic incompetence is appropriate. In permanent atrial fibrillation with atrioventricular block, algorithms for auto-adaptive management of the ventricular pacing output should be activated. If the atrioventricular block is persistent, the activation of rate-responsive function is appropriate. In carotid sinus syndrome, adequate rate hysteresis should be programmed. In vasovagal syncope, specialized sensing and pacing algorithms designed for reflex syncope prevention should be activated.

Safety and efficacy of cryoablation vs. radiofrequency ablation of septal accessory pathways: systematic review of the literature and meta-analyses.

Radiofrequency ablation (RFA) of septal accessory pathways (APs) is associated with a significant rate of first procedure failures and complications. Cryoablation is an alternative energy source but there are no studies comparing both ablation techniques. We aimed to systematically review the literature and compare the efficacy and safety of cryoablation vs. RFA of septal APs. We conducted two separate meta-analysis of cryoablation and RFA of septal APs and calculated the global estimates of the efficacy and safety. Sixty-four articles were included: 38 articles reporting RFA and 27 articles reporting cryoablation procedures. Additionally, we included the previously non-published cryoablation registry of septal APs performed at our institution. Overall, 4244 septal APs constitute our study population, 3495 in the RFA cohort and 749 in the cryoablation cohort. Acute procedural success rate of cryoablation was 86.0% (95% CI 81.6-89.4%) and RFA 89.0% (95% CI 86.8-91.0%). Recurrence rate of cryoablation was 18.1% (95% CI 14.8-21.8%) and RFA 9.9% (95% CI 8.2-12.0%). Long-term success rate after multiple ablation procedures of cryoablation was 75.9% (95% CI 68.2-82.3%) and RFA 88.4% (95% CI 84.7-91.3%). There were no reported cases of persistent atrioventricular block (AVB) with cryoablation and 2.7% (95% CI 2.2-3.4%) with RFA. Studies of RFA for treatment of septal APs report higher efficacy rates than do studies using cryoablation, but a significantly higher rate of AVB.

Clinically guided pacemaker choice and setting: pacemaker expert programming study.

The aim of this multicentre, observational, transversal study was to evaluate pacemaker (PM) choice and setting in a large number of patients, in order to understand their relationship with the patients' clinical characteristics. The study enrolled a total of 1858 patients (71 ± 14 years, 54% male), consecutively evaluated during scheduled PM follow-up visits in 7 Italian cardiac arrhythmia centres. To evaluate the appropriateness of PM choice in relation to the patients' clinical characteristics, we analysed their rhythm disorders at the time of device implantation and the characteristics of the devices implanted. To evaluate the appropriateness of device setting, current rhythm disorders and device setting at the time of enrolment were analysed. In the overall study population, 64.3% of the patients received a PM with all of the features required for their rhythm disorder [80.8% in persistent atrioventricular (AV) block, 76.5% in atrial fibrillation needing pacing, 71.0% in sinus node disease, 58.7% in non-persistent atrioventricular block (AVB), 52.7% in neuro-mediated syncope]. The most frequent cause of inappropriate PM choice was the lack of an algorithm to promote intrinsic AV conduction in non-persistent AVB patients (38.1%). In 76.2% of the patients with an appropriate PM (n = 1301), the PM was optimally set for their rhythm disorder. In the present 'real-world' registry, a large number of patients (35.7%) did not receive an optimal PM for their rhythm disorders. Moreover, one-fourth of appropriate PMs were not programmed according to the patients' clinical characteristics.

Cardiac Safety Profile of First Dose of Fingolimod for Relapsing-Remitting Multiple Sclerosis in Real-World Settings: Data from a German Prospective Multi-Center Observational Study.

IntroductionFingolimod was the first oral therapy approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Due to its action on cardiac sphingosine 1-phosphate receptors, fingolimod is leading to a transient decrease in heart rate (HR) and the occurrence of rare and asymptomatic self-limited atrioventricular (AV) blocks. This German non-interventional clinical study aimed to assess the cardiac safety profile in RRMS patients during at least 6 h after the initial treatment or restart after interruption of fingolimod in real-world settings.MethodsThe GoCARD study (German National Health Authorities, BfArM, CFTY720DDE18, NIS334) was a prospective, multi-center non-interventional study which was conducted in neurological and other medical practices or hospitals, qualified to routinely assess electrocardiogram (ECG) findings. Data were collected through interviews, clinical evaluations (notably ECGs), and laboratory tests. Medical history, vital signs, and a 12-lead ECG were assessed before fingolimod administration. After the first dose, a 6 h ECG was performed and vital signs (blood pressure and HR) were measured hourly. The occurrence of bradycardia (HR ≤45 beats per minute [BPM]), AV blocks (2nd degree Mobitz type I or higher), and corrected QT interval (QTc) intervals was also documented.ResultsMore than 95% of physicians adhered to the cardiac monitoring recommendations. The observation of 217 patients in 42 study centers showed that while 35.9% of the patients had any cardiac risk profile, none of them experienced a bradycardia during the 6 h post-dose observation. Overall, only 1.8% of all patients displayed bradycardia (HR ≤45 BPM) during 6 h after treatment initiation. Moreover, in this cohort, none of the patients showed a new or persistent onset AV block (2nd degree Mobitz type I or higher) or QTc ≥500 ms.ConclusionAltogether, these data confirm that the first-dose observation after fingolimod initiation is usually uneventful (even in patients with pre-existing cardiovascular risk factors of this cohort) and that the rarely observed events remained asymptomatic and self-limited.FundingNovartis Pharma GmbH, Nürnberg, Germany.

Radiofrequency catheter ablation can be performed with high success rates and very low complication rates in children and adolescents

Radiofrequency catheter ablation is a standard treatment for tachyarrhythmia in children. Recently, several centres using cryoenergy for ablation have reported high success and low complication rates, but an increased risk of recurrence of arrhythmia. The aim of this study was to report success, complications and recurrence rates for radiofrequency catheter ablation in children under current conditions. A retrospective cohort study of 333 consecutive children undergoing radiofrequency catheter ablation over the last two decades. Radiofrequency catheter ablation was performed successfully in 96.7% of patients, but was significantly less successful in patients with a right anterior or right anterolateral accessory pathway (81.8%). Overall mortality was 0%; there was only one (0.3%) major complication, a pericardial haemorrhage, and only 2.8% of the patients developed minor vascular complications at the puncture site. None of the patients developed a persistent atrioventricular block. Over a median observation time of 4.3 years (0.1; 17.8), recurrence of arrhythmia occurred in 9.3% of all patients, but 50% of children with right lateral accessory pathways. Radiofrequency catheter ablation can be performed with high success and very low complication rates in children. Recurrence rates are substantially lower than those reported for cryoablation in the literature.

Postoperative Arrhythmias after Cardiac Surgery: Incidence, Risk Factors, and Therapeutic Management

Arrhythmias are a known complication after cardiac surgery and represent a major cause of morbidity, increased length of hospital stay, and economic costs. However, little is known about incidence, risk factors, and treatment of early postoperative arrhythmias. Both tachyarrhythmias and bradyarrhythmias can present in the postoperative period. In this setting, atrial fibrillation is the most common heart rhythm disorder. Postoperative atrial fibrillation is often self-limiting, but it may require anticoagulation therapy and either a rate or rhythm control strategy. However, ventricular arrhythmias and conduction disturbances can also occur. Sustained ventricular arrhythmias in the recovery period after cardiac surgery may warrant acute treatment and long-term preventive strategy in the absence of reversible causes. Transient bradyarrhythmias may be managed with temporary pacing wires placed at surgery, but significant and persistent atrioventricular block or sinus node dysfunction can occur with the need for permanent pacing. We provide a complete and updated review about mechanisms, risk factors, and treatment strategies for the main postoperative arrhythmias.