Ablation of myocardial autonomic ganglion plexus in the treatment of bradyarrhythmia A one-arm interventional study.

OBJECTIVES: To study the complications and effectiveness of the treatment of chronic arrhythmias with cardiac Ganglion Plexus (GP) ablation, and to explore the value of the treatment of chronic arrhythmias with GP ablation. METHODS: This study was a one-arm interventional study of patients from the first hospital of Xinjiang Medical University and the People's Hospital of Xuancheng City admitted (09/2018-08/2021) because of bradyarrhythmia. The left atrium was modeled using the Carto3 mapping system. The ablation endpoint was the absence of a vagal response under anatomically localized and high-frequency stimulation guidance. Postoperative routine follow-up was conducted. Holter data at 3-, 6-, and 12-months were recorded. RESULTS: Fifty patients (25 male, mean age 33.16 ± 7.89 years) were induced vagal response by either LSGP, LIGP, RAGP, or RIGP. The heart rate was stable at 76 bpm, SNRT 1.092s. DC, DR, HR, SDNN, RMSSD values were lower than that before ablation. AC, SSR, TH values were higher than those before ablation, mean heart rate and the slowest heart rate were significantly increased. There were significant differences in follow-up data between the preoperative and postoperative periods (all p < 0.05). All the patients were successfully ablated, and their blood pressure decreased significantly. No complications such as vascular damage, vascular embolism and pericardial effusion occurred. CONCLUSIONS: Left Atrial GP ablation has good long-term clinical results and can be used as a treatment option for patients with bradyarrhythmia.

Cardioneuroablation for the treatment of reflex syncope and functional bradyarrhythmias. a scientific statement of the european heart rhythm association (ehra) of the esc, the heart rhythm society (hrs), the asia pacific heart rhythm society (aphrs) and the latin american heart rhythm society (lahrs)

Cardioneuroablation has emerged as a potential alternative to cardiac pacing in selected cases with vasovagal reflex syncope, extrinsic vagally induced sinus bradycardia-arrest or atrioventricular block. The technique was first introduced decades ago, and its use has risen over the past decade. However, as with any intervention, proper patient selection and technique are a prerequisite for a safe and effective use of cardioneuroablation therapy. This document aims to review and interpret available scientific evidence and provide a summary position on the topic.

Síndrome de QT largo congénito y bradicardia fetal: la importancia del diagnóstico / Congenital long QT syndrome and fetal bradycardia: the importance of the diagnosis

Antecedentes: El síndrome de QT largo es una canalopatía que afecta a la repolarización ventricular y aumenta el riesgo de sufrir arritmias ventriculares graves. Puede ser congénito o adquirido, y es una causa conocida de muerte súbita. Caso clínico: Gestante primigesta, de 28 años, sin antecedentes de interés. En ecografías prenatales se objetivó en el feto bradicardia sinusal mantenida desde la semana 28, sin repercusión hemodinámica, que persistió hasta la finalización de la gestación (semana 37+3). Al nacimiento se realizaron electrocardiogramas seriados que mostraron alteraciones en la repolarización con alargamiento del intervalo QT corregido. Se realizó estudio genético que confirmó síndrome de QT largo tipo 1 y se inició tratamiento oral con beta-bloqueantes, con buena respuesta. Conclusiones: El síndrome de QT largo suele diagnosticarse posnatalmente. Es importante conocer sus características clínicas prenatales para poder establecer un diagnóstico precoz y minimizar así el riesgo de muerte súbita de estos pacientes.

Background: Long QT syndrome is a channelopathy that affects ventricular repolarization and increases the risk of severe ventricular arrhythmias. It can be congenital or acquired, and is a known cause of sudden cardiac death. Case report: A 28-year-old primigravida with no significant medical history. Prenatal ultrasounds revealed sustained fetal sinus bradycardia from week 28, without hemodynamic repercussion, which persisted until the end of gestation (at 37+3 weeks). Serial electrocardiograms were performed after birth, showing repolarization abnormalities with prolonged corrected QT interval. A genetic study confirmed long QT syndrome type 1, and oral treatment with beta-blockers was initiated, showing a positive response. Conclusions: Long QT syndrome is often diagnosed postnatally. It is important to be aware of his prenatal clinical features in order to establish an early diagnosis and minimize the risk of sudden death in these patients.

Apnea, Intermittent Hypoxemia, and Bradycardia Events Predict Late-Onset Sepsis in Infants Born Extremely Preterm.

OBJECTIVE: The objective of this study was to examine the association of cardiorespiratory events, including apnea, periodic breathing, intermittent hypoxemia (IH), and bradycardia, with late-onset sepsis for extremely preterm infants (<29 weeks of gestational age) on vs off invasive mechanical ventilation. STUDY DESIGN: This is a retrospective analysis of data from infants enrolled in Pre-Vent (ClinicalTrials.gov identifier NCT03174301), an observational study in 5 level IV neonatal intensive care units. Clinical data were analyzed for 737 infants (mean gestational age: 26.4 weeks, SD 1.71). Monitoring data were available and analyzed for 719 infants (47 512 patient-days); of whom, 109 had 123 sepsis events. Using continuous monitoring data, we quantified apnea, periodic breathing, bradycardia, and IH. We analyzed the relationships between these daily measures and late-onset sepsis (positive blood culture >72 hours after birth and ≥5-day antibiotics). RESULTS: For infants not on a ventilator, apnea, periodic breathing, and bradycardia increased before sepsis diagnosis. During times on a ventilator, increased sepsis risk was associated with longer events with oxygen saturation <80% (IH80) and more bradycardia events before sepsis. IH events were associated with higher sepsis risk but did not dynamically increase before sepsis, regardless of ventilator status. A multivariable model including postmenstrual age, cardiorespiratory variables (apnea, periodic breathing, IH80, and bradycardia), and ventilator status predicted sepsis with an area under the receiver operator characteristic curve of 0.783. CONCLUSION: We identified cardiorespiratory signatures of late-onset sepsis. Longer IH events were associated with increased sepsis risk but did not change temporally near diagnosis. Increases in bradycardia, apnea, and periodic breathing preceded the clinical diagnosis of sepsis.

Long-term outcomes of cardioneuroablation with and without extra-cardiac vagal stimulation confirmation in severe cardioinhibitory neurocardiogenic syncope.

BACKGROUND: Cardioneuroablation (CNA) is a novel therapeutic approach for functional bradyarrhythmias, specifically neurocardiogenic syncope or atrial fibrillation, achieved through endocardial radiofrequency catheter ablation of vagal innervation, obviating the need for pacemaker implantation. Originating in the nineties, the first series of CNA procedures was published in 2005. Extra-cardiac vagal stimulation (ECVS) is employed as a direct method for stepwise denervation control during CNA. OBJECTIVE: This study aimed to compare the long-term follow-up outcomes of patients with severe cardioinhibitory syncope undergoing CNA with and without denervation confirmation via ECVS. METHOD: A cohort of 48 patients, predominantly female (56.3%), suffering from recurrent syncope (5.1 ± 2.5 episodes annually) that remained unresponsive to clinical and pharmacological interventions, underwent CNA, divided into two groups: ECVS and NoECVS, consisting of 34 and 14 cases, respectively. ECVS procedures were conducted with and without atrial pacing. RESULTS: Demographic characteristics, left atrial size, and ejection fraction displayed no statistically significant differences between the groups. Follow-up duration was comparable, with 29.1 ± 15 months for the ECVS group and 31.9 ± 20 months for the NoECVS group (p = .24). Notably, syncope recurrence was significantly lower in the ECVS group (two cases vs. four cases, Log Rank p = .04). Moreover, the Hazard ratio revealed a fivefold higher risk of syncope recurrence in the NoECVS group. CONCLUSION: This study demonstrates that concluding CNA with denervation confirmation via ECVS yields a higher success rate and a substantially reduced risk of syncope recurrence compared to procedures without ECVS confirmation.

Sleep bruxism and associated physiological events in children with obstructive sleep apnea: a polysomnographic study.

STUDY OBJECTIVES: The aim of this study was to evaluate the physiological events associated with sleep bruxism (Sleep Bruxism [SB]; presence of mandibular movement activity) and the control window (4 minutes prior to SB event, where no mandibular movement activity was detected) in a polysomnography study in children with mild sleep apnea. METHODS: Polysomnography data from children aged 4 to 9 years old diagnosed with mild sleep apnea were analyzed by 2 trained examiners. The mandibular movement activity (bruxism event; SB) was classified into phasic and tonic. The control window was selected 4 minutes prior to the SB event. All physiological events were recorded in both bruxism and control windows, including sleep phase (N1, N2, N3, and rapid eye movement), arousal, leg movements, tachycardia, bradycardia, oxygen desaturation, and number of obstructive and central sleep apnea events. The moment in which those phenomena occurred when associated with SB was also analyzed (before/after). Data were analyzed using 95% confidence intervals (α = 5%). RESULTS: A total of 661 mandibular movements were analyzed and classified as tonic (n = 372) or phasic (n = 289). The mean apnea-hypopnea index was 1.99 (SD = 1.27) events/h. The frequency of leg movements, microarousal, and tachycardia was increased in SB events when compared with the control window (P < .05). There was an increase in bradycardia frequency in the control window when compared with SB (in both tonic and phasic events). The frequency of obstructive and central apnea during SB was lower when compared with the other physiological phenomena. CONCLUSIONS: There is a difference in the physiological parameters evaluated in children with mild sleep apnea when comparing the 2 windows (SB and control). Sleep bruxism is associated with other physiological phenomena, such as leg movements, tachycardia, and microarousal. The use of a control window (where no mandibular activity was detected) was representative since it did not show activation of the sympathetic nervous system. CITATION: Bonacina CF, Soster LMSFA, Bueno C, et al. Sleep bruxism and associated physiological events in children with obstructive sleep apnea: a polysomnographic study. J Clin Sleep Med. 2024;20(4):565-573.

Hawthorne root (Crataegus mexicana) toxicity.

Here we present the case of a patient who purchased a Hawthorne root (Crataegus mexicana) product, Raiz de Tejocote, for weight loss purposes. She presented with diffuse myalgias, dizziness and a heart rate of 52 beats per minute. At triage and at initial evaluation, the patient denied taking any medications, but on iterative questioning concerning over-the-counter, over-the-internet and herbal medications, she reported taking Hawthorne root tablets in the three days prior to the emergency department (ED) visit for the purpose of weight loss. The product was purchashed through the internet. Her plasma digoxin concentration was 0.4 ng/ml the patient's constellation of symptoms, as well as the detectable plasma digoxin concentration, were consistent with hawthorne root toxicity. Hawthorne root has intrinsic cardiac glycoside activity. In addition, Hawthorne root may cause a range of toxicity. Mild symptoms can include flu-like syndrome with significant myalgias. However, in the more severe exposures the cardiac glycoside effects can result in bradycardia and hemodynamic instability. Symptoms resolved with ED observation. The heart rate normalized. This case reinforces the importance of asking a patient about all medications, including over-the-counter, over-the-internet and herbal medications.

Atropine does not prevent hypoxemia and bradycardia in tracheal intubation in the pediatric emergency department: observational study.

OBJECTIVE: The benefit of atropine in pediatric tracheal intubation is not well established. The objective of this study was to evaluate the effect of atropine on the incidence of hypoxemia and bradycardia during tracheal intubations in the pediatric emergency department. METHODS: This is a single-center observational study in a tertiary pediatric emergency department. Data were collected on all tracheal intubations in patients from 31 days to incomplete 20 years old, performed between January 2016 and September 2020. Procedures were divided into two groups according to the use or not of atropine as a premedication during intubation. Records with missing data, patients with cardiorespiratory arrest, cyanotic congenital heart diseases, and those with chronic lung diseases with baseline hypoxemia were excluded. The primary outcome was hypoxemia (peripheral oxygen saturation ≤88%), while the secondary outcomes were bradycardia (decrease in heart rate >20% between the maximum and minimum values) and critical bradycardia (heart rate <60 bpm) during intubation procedure. RESULTS: A total of 151 tracheal intubations were identified during the study period, of which 126 were eligible. Of those, 77% had complex, chronic underlying diseases. Atropine was administered to 43 (34.1%) patients and was associated with greater odds of hypoxemia in univariable analysis (OR: 2.62; 95%CI 1.15-6.16; p=0.027) but not in multivariable analysis (OR: 2.07; 95%CI 0.42-10.32; p=0.37). Critical bradycardia occurred in only three patients, being two in the atropine group (p=0.26). Bradycardia was analyzed in only 42 procedures. Atropine use was associated with higher odds of bradycardia in multivariable analysis (OR: 11.00; 95%CI 1.3-92.8; p=0.028). CONCLUSIONS: Atropine as a premedication in tracheal intubation did not prevent the occurrence of hypoxemia or bradycardia during intubation procedures in pediatric emergency.

Ten years follow-up of the largest oral Chagas disease outbreak: Cardiological prospective cohort study.

BACKGROUND: Chagas disease (ChD) is the most important endemy in Latin America. Some patients, develop chronic Chagasic cardiopathy (CCC) years after the acute phase. It is unknown if patients infected by the oral route have higher risk of developing early CCC. METHODS AND FINDINGS: A prospective cohort study was conducted to assess morbidity and mortality during 10 years observation in 106 people simultaneously infected and treated in the largest known orally transmitted ChD outbreak in 2007. A preschooler died during the acute phase, but thereafter was no mortality associated to ChD. All acute phase findings improved in the first-year post-treatment. Each person was evaluated 8.7 times clinically, 6.4 by electrocardiogram (ECG)/Holter, and 1.7 by echocardiogram. Based on prevalence, the number of people who had any abnormalities (excluding repolarization abnormalities and atrial tachycardia which decreased) was higher than 2007, since they were found at least once between 2008-2017. However, when we evaluated incidence, except for clinical bradycardia and dizziness, it was observed that the number of new cases of all clinical and ECG findings decreased at the end of the follow-up. Between 2008-2017 there was not incidence of low voltage complex, 2nd degree AV block, long QT interval, left bundle branch block or left ventricular dysfunction that allowed the diagnosis of CCC. Total improvement prevailed over the persistence of all clinical and ECG/Holter findings, except for sinus bradycardia. Incomplete right bundle branch block, sinus bradycardia and/or T-wave inversion were diagnosed persistently in 9 children. The second treatment did not have significant influence on the incidence of clinical or ECG/Holter findings. CONCLUSIONS: At the end of the 10-year follow-up, there were not clinical or ECG/Holter criteria for classifying patients with CCC. The incidence of arrhythmias and repolarization abnormalities decreased. However, special attention should be paid on findings that not revert as sinus bradycardia, or those diagnosed persistently in all ECG as sinus bradycardia, incomplete right bundle branch block or T-wave inversion. Early diagnosis and treatment may have contributed to the rapid improvement of these patients. In ChD follow-up studies prevalence overestimates the real dimension of abnormalities, the incidence looks as a better indicator.

Long-Term Outcome of Cardiac Denervation Procedures: The Anatomically Guided Septal Approach.

BACKGROUND: Functional bradycardia is a challenging condition that affects a healthy population. Ganglionated plexus ablation has emerged as a therapeutic alternative to avoid a pacemaker. OBJECTIVES: The purpose of this study is to evaluate long-term effects of anatomically guided cardiac denervation. METHODS: This is a prospective longitudinal study that included 36 patients with symptomatic functional bradycardia. Electroanatomic reconstruction of both atria was carried out, and the main septal ganglionated plexi were anatomically located and targeted. RESULTS: Ablation endpoints were: 1) heart rate increment; 2) Wenckebach cycle length shortening; and 3) atrio-Hisian (AH) interval shortening. A sinus node denervation was obtained in all patients with an increment of 21.6% in the mean heart rate. All patients presented a negative atropine test after ablation. Twenty-eight (77.7%) patients presented immediate sings of atrioventricular node denervation, with a shortening of 15.6% of mean Wenckebach cycle length and 15.9% of the mean AH interval. All heart rate variability parameters showed a significant reduction after 12 months, enduring after 18 months. Thirty (83.3%) patients remained free of events after a mean follow-up of 52.1 ± 35.2 months. One patient (2.77%) presented acute sinus node artery occlusion during ablation with persistent sinus dysfunction and had a pacemaker implantation; 3 (8.3%) other patients evolved with sinus tachycardia, and 4 (11.1%) patients presented syncope recurrence during follow-up, 3 (8.3%) of them requiring a pacemaker implantation. No other tachyarrhythmia was observed. CONCLUSIONS: The anatomically guided septal approach is an effective technique for syncope prevention, promoting long-lasting autonomic changes. No significant proarrhythmia effect has been observed during the long-term follow-up.

Treatment results of carotid artery stenting in a developing country.

OBJECTIVE: The purpose of this study was to investigate the details of minor complications of carotid artery stenting in a developing country. METHODS: This was a retrospective, single-center study conducted on the target group consisting of 65 symptomatic patients who underwent carotid artery stenting. We assessed technical success rate, periprocedural complication within 30 days (hypotension, bradycardia, acute kidney injury, vasospasm, a transient ischemic attack, stroke, myocardial infarction, and death), and the differences between groups with and without complications. RESULTS: Minor periprocedural complications occurred in 15 patients. In all, 8 (12.3%) had transient hypotension, 6 (9.2%) had bradycardia, 7 (10.7%) had acute kidney injury, 2 (3.1%) had vasospasm, and 1 (1.5%) had transient ischemic attack. A greater rate of minor complications was observed in women (p=0.051). CONCLUSION: The results of the carotid artery stenting procedures performed in a developing country were acceptable.

Review article: Risk of cardiovascular events in patients with inflammatory bowel disease receiving small molecule drugs.

BACKGROUND: In the context of an ageing inflammatory bowel disease (IBD) population, cardiovascular comorbidities become particularly relevant. Novel small molecule drugs (SMDs) for the treatment of moderate-to-severe IBD have been recently approved, including Janus kinase (JAK) inhibitors and sphingosine-1-phosphate receptor (S1P) modulators. Data from rheumatoid arthritis population have raised concerns about the risk of cardiovascular events with the use of tofacitinib, which was extrapolated to other immune-mediated diseases and other JAK inhibitors. S1P receptor modulation has been associated with potential cardiovascular events, especially bradycardia and cardiac conduction abnormalities. AIM: To review the incidence of cardiovascular events with the use of SMDs in patients with IBD and to provide practical recommendations on mitigation strategies. METHODS: Published literature was reviewed; recommendations were synthesised by experts in both cardiovascular diseases and IBD. RESULTS: Evidence from the IBD population does not indicate a higher risk of cardiovascular events with tofacitinib and other JAK inhibitors. The risk is higher in patients with intermediate to high cardiovascular risk. S1P modulators may be associated with a dose-dependent, first-dose effect, transient risk of conduction abnormalities (bradycardia and AV block). Screening and monitoring of cardiovascular risk factors should be done in all patients with IBD. Risk stratification for cardiovascular disease should be performed before starting treatment with SMDs. CONCLUSIONS: Available evidence of both JAK inhibitors and S1P modulators indicates a reassuring safety profile of SMDs from the cardiovascular perspective in the overall IBD population. Efforts should be made to identify patients with IBD at a higher risk of cardiovascular events.

Incidence of bradycardia during noradrenaline or phenylephrine bolus treatment of postspinal hypotension in cesarean delivery: A randomized double-blinded controlled trial.

The treatment of choice for spinal anesthesia-induced hypotension during cesarean section is phenylephrine. As this vasopressor can cause reflex bradycardia, noradrenaline is a suggested alternative. This randomized double-blinded controlled trial included 76 parturients undergoing elective cesarean delivery under spinal anesthesia. Women received noradrenaline in bolus doses of 5 mcg or phenylephrine in bolus doses of 100 mcg. These drugs were used intermittently and therapeutically to maintain systolic blood pressure ≥ 90% of its baseline value. The primary study outcome was bradycardia incidence (<60 bpm) with intermittent bolus administration of these drugs. Secondary outcomes included extreme bradycardia (<40 bpm), number of bradycardia episodes, hypertension (systolic blood pressure > 120% of baseline value), and hypotension (systolic blood pressure < 90% of baseline value and requiring vasopressor use). Neonatal outcomes per the Apgar scale and umbilical cord blood gas analysis were also compared. The incidence of bradycardia in both groups (51.4% and 70.3%, respectively; p = 0.16) were not significantly different. No neonates had umbilical vein or artery pH values below 7.20. The noradrenaline group required more boluses than phenylephrine group (8 vs. 5; p = 0.01). There was no significant intergroup difference in any of the other secondary outcomes. When administered in intermittent bolus doses for the treatment of postspinal hypotension in elective cesarean delivery, noradrenaline, and phenylephrine have a similar incidence of bradycardia. When treating hypotension related to spinal anesthesia in obstetric cases, strong vasopressors are commonly administered, thought these can also have side effects. This trial assessed bradycardia after bolus administration of noradrenaline or phenylephrine, and found no difference in risk for clinically meaningful bradycardia.

Bradycardia in a pediatric population after sugammadex administration: case series

Abstract Sugammadex is a distinctive neuromuscular reversal drug that acts by encapsulating the neuromuscular relaxant molecule and dislodging it from its site of action. Sugammadex has been approved for pediatric patients over 2 years of age. Although arrhythmias have been reported, there is no report of adverse effects in healthy children, such as severe bradycardia requiring intervention. We report two cases of severe bradycardia immediately after the administration of sugammadex in healthy children. Our aim is to alert to the occurrence of one of the most severe adverse effects of sugammadex, in the healthy pediatric population as well.

Cardiovascular effects of hyoscine butylbromide in patients under general anaesthesia.

BACKGROUND: Cardiovascular effects for drugs such as hyoscine butylbromide are poorly documented in the literature, unlike atropine, which is considered the antimuscarinic of choice in the presence of intraoperative bradycardia. AIM: The aim of the study was to describe the dose-related cardiovascular effect of hyoscine butylbromide in patients between 18 and 65 years of age, with low perioperative risk undergoing elective surgery under general anaesthesia on an outpatient basis or hospitalised at our institution between 1 January and 31 May 2019. METHODS: Descriptive, cross-sectional, retrospective study; 28 patients with low perioperative risk who underwent general anaesthesia were selected. Changes in heart rate and blood pressure were analysed during the first 6 minutes after the administration of hyoscine butylbromide. The data obtained was recorded in a Microsoft Excel database and analysed using the Excel analysis tool and IBM SPSS. RESULTS: The average dose of 0.15mg/kg of hyoscine butylbromide achieved an increase in heart rate and mean arterial pressure in 96% and 92.8%, respectively, in the first 6 minutes after the administration. Significant changes in heart rate and blood pressure were obtained during the first 6 minutes at doses between 0.05mg/kg and 0.15mg/kg. CONCLUSION: Hyoscine butylbromide generates positive effects on the heart rate and blood pressure of patients under general anaesthesia, representing a possible alternative in the management of intraoperative bradycardia.

Bradycardia in a pediatric population after sugammadex administration: case series.

Sugammadex is a distinctive neuromuscular reversal drug that acts by encapsulating the neuromuscular relaxant molecule and dislodging it from its site of action. Sugammadex has been approved for pediatric patients over 2 years of age. Although arrhythmias have been reported, there is no report of adverse effects in healthy children, such as severe bradycardia requiring intervention. We report two cases of severe bradycardia immediately after the administration of sugammadex in healthy children. Our aim is to alert to the occurrence of one of the most severe adverse effects of sugammadex, in the healthy pediatric population as well.

Indicaciones del uso apropiado del marcapasos sin cable: Revisión sistemática y criterios de uso / Indications for the appropriate use of wireless pacemakers: Systematic review and use criteria

INTRODUCCIÓN Se ha demostrado que los marcapasos transvenosos mejoran la calidad de vida y reducen la mortalidad de los pacientes con bradicardia y bloqueos de la conducción cardíaca. Sin embargo, presentan inconvenientes inevitables, ya que tienen una incidencia relativamente alta de complicaciones relacionadas con el cable y el bolsillo del dispositivo. Por ello, los marcapasos sin cable han surgido como una solución para reducir las complicaciones observadas con los marcapasos convencionales. Sin embargo, hasta ahora, no se han publicado recomendaciones de las sociedades nacionales o internacionales para las indicaciones e implantación de los marcapasos sin cables unicamerales. OBJETIVO Desarrollar criterios de uso adecuado para la implantación de los marcapasos sin cables VR en pacientes con fibrilación auricular o en ritmo sinusal, basándonos en la revisión sistemática de la literatura y en la opinión de un grupo de expertos. MATERIAL Y MÉTODO Se utilizó la metodología RAND/UCLA para la creación de los criterios de indicación del uso adecuado del marcapasos sin cables VR. Para ello, se realizó una actualización de un informe previo con una revisión de la literatura (Anexo 1) sobre la efectividad y seguridad del marcapasos sin cables en pacientes con indicación de estimulación ventricular, con el objetivo de facilitársela a los expertos. Posteriormente se elaboró una lista de indicaciones a partir de la bibliografía y de la consulta con especialistas en cardiología. Finalmente, se formó un panel de expertos compuesto por 10 expertos en la materia que puntuaron sobre la adecuación del marcapasos sin cables, haciéndolo en dos rondas de votaciones. Las puntuaciones se analizaron de acuerdo en criterios estadísticos, basados en la mediana de las puntuaciones para cada escenario y el grado de acuerdo entre panelistas. Se realizaron análisis de regresión logística multinomial para determinar el grado en que cada una de las variables analizadas individualmente influían en los juicios de adecuación. Los criterios explícitos desarrollados se resumieron mediante un análisis de árbol de clasificación y regresión. RESULTADOS En la revisión sistemática no se localizaron estudios desde 2017 que evaluaran la efectividad clínica ni la seguridad del marcapasos sin cables de forma comparada con los marcapasos convencionales. En las dos rondas se evaluaron 64 indicaciones o escenarios clínicos en el caso de fibrilación auricular y 192 para el ritmo sinusal. Los resultados obtenidos en segunda ronda para en fibrilación fueron: de los 64 escenarios evaluados el 65,6 % se clasificaron como adecuados (calificándose con acuerdo en el 71,4 %), el 23,4 % dudosos y el 11 % como inadecuados. En el caso del ritmo sinusal, de los 192 escenarios el 46,9 % fue considerado adecuado (se encontró acuerdo en el 75,6 % de los escenarios), el 31,2 % dudoso y el 21,9 % inadecuado. El grado de desacuerdo bajó respecto al obtenido en la primera ronda y solo se mostraron 3 escenarios con desacuerdo en el total de los escenarios (1,2 %). Todas las variables consideradas para la composición de los escenarios del panel en la fibrilación auricular y el ritmo sinusal mostraron una influencia estadísticamente significativa según el modelo de regresión logística. No obstante, la limitación para el acceso vascular a través de la vena cava superior fue la variable con mayor capacidad predictiva. Los árboles de clasificación creados mostraron un resumen de los resultados del panel según las variables clínicas valoradas. CONCLUSIONES La evidencia localizada en la revisión sistemática no demuestra la no inferioridad ni la superioridad de este dispositivo frente al convencional, aunque parece ventajosa frente a los dispositivos convencionales en determinadas situaciones clínicas. Se aplicó el método de consenso RAND/UCLA para desarrollar criterios de uso adecuado para la selección e implantación de marcapasos sin cables VR en pacientes con fibrilación auricular y en ritmo sinusal. De forma general, en los casos en los que se presenta una limitación importante o completa para el acceso vascular a través de la vena cava superior, la implantación del marcapasos sin cables resulta adecuada tanto en pacientes en fibrilación auricular como aquellos en ritmo sinusal, pues en estos casos la alternativa habitual es el implante quirúrgico de un electrodo epicárdico. Los criterios presentados pueden considerarse una ayuda en la toma de decisiones, a tener en cuenta junto con otra información científica y en el contexto de la relación médico-paciente individual. Las recomendaciones presentadas no reemplazan el juicio clínico del profesional, que siempre tiene en cuenta las necesidades particulares de cada situación clínica. Para facilitar la consulta de los resultados íntegros del panel de expertos, se ha diseñado una aplicación informática (disponible en https://www.aetsa.org/). Las preferencias de los pacientes con respecto al tratamiento son un aspecto importante a tener en cuenta y en el futuro es probable que se disponga de un mayor cuerpo de evidencia científica sobre los resultados en salud (mortalidad, morbilidad cardiovascular, riesgo de infección…) a corto y medio plazo del marcapasos sin cable frente al convencional en distintos escenarios clínicos, facilitando la toma de decisiones para su indicación tanto en pacientes en fibrilación auricular como aquellos que estén en ritmo sinusal.

INTRODUCTION Transvenous pacemakers have been shown to improve quality of life and reduce mortality in patients with bradycardia and cardiac conduction block. However, they have unavoidable drawbacks, as they have a relatively high incidence of complications related to the lead and the pocket of the device. Therefore, leadless pacemakers have emerged as a solution to reduce the complications seen with conventional pacemakers. However, so far, no recommendations have been published by national or international societies for indications and implantation of single-chamber leadless pacemakers. OBJECTIVE Develop appropriate use criteria for the implantation of VR leadless pacemakers in patients with atrial fibrillation or in sinus rhythm, based on systematic review of the literature and expert panel opinion. MATERIAL AND METHOD The RAND/UCLA methodology was used to create the criteria for the appropriate use of VR leadless pacing. For this purpose, an update of a previous report with a review of the literature on the effectiveness and safety of leadless pacing in patients with an indication for ventricular pacing was performed for the purpose of providing it to the experts. A list of indications was then compiled from the literature and consultation with cardiology specialists. Finally, an expert panel of 10 experts in the field was formed to score the suitability of the leadless pacemaker in two rounds of voting. The scores were analysed according to statistical criteria, based on the median score for each scenario and the degree of agreement between panellists. Multinomial logistic regression analyses were performed to determine the degree to which each of the individually analysed variables influenced judgements of appropriateness. The explicit criteria developed were summarised using a classification and regression tree analysis. RESULTS In the systematic review, no studies were located since 2017 that evaluated the clinical effectiveness or safety of the leadless pacemaker compared to conventional pacemakers. In the two rounds, 64 indications or clinical scenarios were evaluated for atrial fibrillation and 192 for sinus rhythm. The results obtained in the second round for atrial fibrillation were: of the 64 scenarios evaluated, 65.6 % were classified as adequate (71.4 % in agreement), 23.4 % as uncertain and 11 % as inadequate. In the case of sinus rhythm, of the 192 scenarios 46.9 % were considered adequate (agreement was found in 75.6 % of the scenarios), 31.2 % doubtful and 21.9 % inadequate. The degree of disagreement was lower than in the first round, with only 3 scenarios showing disagreement in the total number of scenarios (1.2%). All variables considered for the composition of the panel scenarios in atrial fibrillation and sinus rhythm showed a statistically significant influence according to the logistic regression model. However, limitation for vascular access through the superior vena cava was the variable with the highest predictive ability. The classification trees created showed a summary of the panel results according to the clinical variables assessed. CONCLUSIONS The evidence located in the systematic review does not demonstrate the non-inferiority or superiority of this device over the conventional device, although it seems advantageous over conventional devices in certain clinical situations. The RAND/UCLA consensus method was applied to develop appropriate use criteria for the selection and implantation of VR leadless pacemakers in patients with atrial fibrillation and in sinus rhythm. In general, in cases where there is significant or complete limitation of vascular access through the superior vena cava, leadless pacing is appropriate in both patients in atrial fibrillation and those in sinus rhythm, where the usual alternative is surgical implantation of an epicardial lead. The criteria presented can be considered as a decision aid, to be considered in conjunction with other scientific information and in the context of the individual patient-physician relationship. The recommendations presented do not replace the clinical judgement of the practitioner, which always takes into account the particular needs of each clinical situation. To facilitate consultation of the full results of the panel of experts, a computer application has been designed (available at https://www.aetsa.org/). Patient preferences regarding treatment are an important aspect to be taken into account and in the future it is likely that a greater body of scientific evidence will be available on health outcomes (mortality, cardiovascular morbidity, risk of infection…) in the short and medium term of leadless versus conventional pacing in different clinical scenarios, facilitating decision making for its indication in both patients in atrial fibrillation and those in sinus rhythm.

Bradicardia em atleta adolescente de alto rendimento. A importância da avaliação eletrocardiográfica e funcional / Bradycardia in a high-performance adolescent athlete. The importance of electrocardiographic and functional evaluation

INTRODUÇÃO E/OU FUNDAMENTOS: A presença de bradicardia durante o repouso é um achado comum em atletas de alto rendimento. Entretanto a avaliação funcional clínica pura e simples não é sinal de um atleta saudável. No mesmo cenário episódios de síncope podem ocorrer em até 20% dos adolescentes com coração normal. A avaliação clínica pré-participação avalia atletas e esportistas, antes de iniciar atividades de moderada à alta intensidade, com o objetivo de identificar doenças cardiovasculares e a detectar precocemente doenças causadoras de morte súbita cardíaca que possam contraindicar a realização do mesmo. OBJETIVO: Descrever o caso de uma atleta adolescente com bradicardia em repouso e pré sincope com diagnóstico diferencial entre over training e espectro de BAV congênito. RELATO DO CASO: Paciente de 12 anos, sexo feminino, previamente hígida, atleta competitiva. Admitida em nosso serviço após episódios de pré sincope, sem fatores desencadeantes. Na admissão identificado bradicardia com estabilidade hemodinâmica, FC de 43 batimentos por minuto (bpm) e eletrocardiograma (ECG), com diagnóstico de ritmo juncional ativo. Realizado, teste ergométrico com ritmo juncional ativo e períodos de ritmo sinusal com wenckebach (no pico do esforço) e déficit cronotrópico. Teste cardiopulmonar máximo com VO2 pico = 48,5ml.kg, 131% do valor predito para a idade, com presença de distúrbio cardiocirculatório pelo cronotropismo deprimido e ritmo cardíaco basal. Presença associada de doença do nó sinusal e comprometimento da condução atrioventricular no espectro clinico de BAVT congênito. Excluído miocardite ativa, com sorologias negativas, cintilografia cardíaca com gálio e ressonância magnética de coração. Por fim, paciente mantendo estabilidade hemodinâmica sem novos sintomas. Orientamos a suspensão das atividades físicas competitivas e instalação de monitorização prolongada para indicação precoce de marcapasso. CONCLUSÕES: Conclusão: 1) A realização do ECG associado à avaliação clínica (a amnésia e exame físico) é extremamente importante na triagem pré-participação esportiva. 2) Existem alterações eletrocardiográficas no coração de atleta que são variantes da normalidade para a condição como BAV de segundo grau do tipo I (Wenckebach) no repouso mas não no esforço. 3) O descondicionamento físico e a monitorização clínica é eletrocardiográfica prolongada pode evidenciar novas nuances para manutenção do seguimento clínico e esportivo mas também auxilia na indicação adequada do marcapasso.

Changes in gap junction proteins Connexin30. 2 and Connexin40 expression in the sinoatrial node of rats with dexmedetomidine-induced sinus bradycardia

Abstract Background Dexmedetomidine (Dex) is widely used, and its most common side effect is bradycardia. The complete mechanism through which Dex induces bradycardia has not been elucidated. This research investigates the expression of gap junction proteins Connexin30.2 (Cx30.2) and Connexin40 (Cx40) within the sinoatrial node of rats with Dex-induced sinus bradycardia. Methods Eighty rats were randomly assigned to five groups. Saline was administered to rats in Group C. In the other four groups, the rats were administered Dex to induce bradycardia. In groups D1and D2, the rats were administered Dex at a loading dose of 30 μg.kg−1 and 100 μg.kg−1 for 10 min, then at 15 μg.kg−1.h−1 and 50 μg.kg−1.h−1 for 120 min separately. The rats in group D1A and D2A were administered Dex in the same way as in group D1and D2; however, immediately after the administration of the loading dose, 0.5 mg atropine was administered intravenously, and then at 0.5 mg.kg−1.h−1 for 120 min. The sinoatrial node was acquired after intravenous infusion was completed. Quantitative real-time polymerase chain reaction and western blot analyses were performed to measure mRNA and protein expression of Cx30.2 and Cx40, respectively. Results The expression of Cx30.2 increased, whereas the expression of Cx40 decreased within the sinoatrial node of rats with Dex-induced sinus bradycardia. Atropine reversed the effects of Dex on the expression of gap junction proteins. Conclusion Dex possibly altered the expression of gap junction proteins to slow down cardiac conduction velocity in the sinoatrial node.