POPDC1 Variants Cause Atrioventricular Node Dysfunction and Arrhythmogenic Changes in Cardiac Electrophysiology and Intracellular Calcium Handling in Zebrafish.

Popeye domain-containing (POPDC) proteins selectively bind cAMP and mediate cellular responses to sympathetic nervous system (SNS) stimulation. The first discovered human genetic variant (POPDC1S201F) is associated with atrioventricular (AV) block, which is exacerbated by increased SNS activity. Zebrafish carrying the homologous mutation (popdc1S191F) display a similar phenotype to humans. To investigate the impact of POPDC1 dysfunction on cardiac electrophysiology and intracellular calcium handling, homozygous popdc1S191F and popdc1 knock-out (popdc1KO) zebrafish larvae and adult isolated popdc1S191F hearts were studied by functional fluorescent analysis. It was found that in popdc1S191F and popdc1KO larvae, heart rate (HR), AV delay, action potential (AP) and calcium transient (CaT) upstroke speed, and AP duration were less than in wild-type larvae, whereas CaT duration was greater. SNS stress by ß-adrenergic receptor stimulation with isoproterenol increased HR, lengthened AV delay, slowed AP and CaT upstroke speed, and shortened AP and CaT duration, yet did not result in arrhythmias. In adult popdc1S191F zebrafish hearts, there was a higher incidence of AV block, slower AP upstroke speed, and longer AP duration compared to wild-type hearts, with no differences in CaT. SNS stress increased AV delay and led to further AV block in popdc1S191F hearts while decreasing AP and CaT duration. Overall, we have revealed that arrhythmogenic effects of POPDC1 dysfunction on cardiac electrophysiology and intracellular calcium handling in zebrafish are varied, but already present in early development, and that AV node dysfunction may underlie SNS-induced arrhythmogenesis associated with popdc1 mutation in adults.

Pembrolizumab-induced myocarditis with complete atrioventricular block and concomitant myositis in a metastatic bladder cancer patient: a case report and review of the literature.

BACKGROUND: The cardiovascular system is among the least systems affected by immune-related adverse events. We report a rare life-threatening case of pembrolizumab-induced myocarditis with complete atrioventricular block and concomitant myositis in a metastatic bladder cancer patient. CASE PRESENTATION: An 82-year-old Caucasian female with invasive urothelial carcinoma, started on first-line pembrolizumab, was admitted four days after receiving her second dose for severe asthenia, diffuse muscle aches, neck pain, and lethargy. In the emergency department, she had several episodes of bradycardia reaching 40 beats per minute associated with general discomfort and fatigue. Electrocardiography showed a third-degree atrioventricular heart block, while the patient remained normotensive. Cardiac damage parameters were altered with elevated levels of creatine phosphokinase of 8930 U/L, suggestive of immune checkpoint inhibitor-induced myositis, and troponin T of 1.060 ng/mL. Transthoracic echocardiography showed a preserved ejection fraction. Pembrolizumab-induced myocarditis was suspected. Therefore, treatment was initiated with high-dose glucocorticoids for 5 days, followed by a long oral steroid taper. A pacemaker was also implanted. Treatment resulted in the resolution of heart block and a decrease in creatine phosphokinase to the normal range. CONCLUSION: Life-threatening cardiac adverse events in the form of myocarditis may occur with pembrolizumab use, warranting vigilant cardiac monitoring. Troponin monitoring in high-risk patients, along with baseline echocardiography may help identify this complication promptly to prevent life-threatening consequences.

Diagnosis and treatment of recurrent syncope in a middle-aged women.

A 50-year-old female patient, presented with repeated syncope for more than 2 years. Prior assessments were conducted at different hospitals, but no definite abnormalities were found. The patient's fear and anxiety about possible future attacks were escalating. Through a Head-up tilt test, the cause was finally identified as vasovagal syncope. Following a 5-min administration of nitroglycerin, the patient reported palpitations, nausea, and deep, rapid breathing. The electrocardiogram initially showed a first-degree atrioventricular block, progressing swiftly to a second-degree type I atrioventricular block-high atrioventricular block. Immediate intervention was undertaken, but blood pressure was not instantly ascertainable, coinciding with an abrupt loss of consciousness. Subsequent electrocardiographic findings included paroxysmal third-degree atrioventricular block, sinus arrest, and complete cardiac arrest, prompting the initiation of external cardiac compressions. The longest recorded ventricular arrest approximated 15 s, with sinus rhythm resuming post 10 s of cardiac compressions and the patient regaining consciousness. The patient underwent vagal ablation and no longer experienced syncope.

Diagnostic Dilemma of Syncope: Esophageal Hiatal Hernia and High-risk Bundle-branch Block.

We herein report a complicated case of recurrent syncope accompanying bundle branch block and hiatal hernia of the esophagus. An 83-year-old woman presented with syncope. Echocardiography visualized the left atrium compressed by an esophageal hiatal hernia, which had potential to decrease the cardiac output. Although she underwent esophageal repair surgery, two months after the surgery, she presented to the emergency department again with complaints of syncope. At the return visit, her face was pale and her pulse rate was 30 beats per minute. Electrocardiography showed complete atrioventricular block. On reviewing the patient's previous electrocardiography findings, we found a record of trifascicular block. This case illustrates the importance of predicting atrioventricular blocks in patients with high-risk bundle-branch blocks. Keeping in mind high-risk bundle-branch blocks will help clinicians avoid anchoring bias due to a striking image masquerading as the true diagnosis.

Cardiovascular Adverse Events Associated With Second-generation Bruton Tyrosine Kinase Inhibitor Therapy: A Systematic Review and Meta-analysis.

PURPOSE: Cardiovascular adverse events (CVAEs) are common adverse effects of first-generation Bruton tyrosine kinase inhibitors (BTKis) and limit their use considerably. This led to the development of second-generation BTKis-acalabrutinib and zanubrutinib-which are more selective, potent, and presumed to have better safety profiles than the previous group of medications. However, there have been sporadic reports of CVAEs associated with second-generation BTKis in clinical practice. To address this issue, a comprehensive meta-analysis to pool the documented CVAEs was performed, including major hemorrhage, any bleeding, atrioventricular block, atrial fibrillation/flutter, pericardial effusion, pericarditis, heart failure, cardiac arrest, myocardial infarction, hypertension, hypotension, and stroke. This meta-analysis incorporated 8 studies. Among these, 6 were Phase III trials and 2 were Phase II trials. These studies collectively enrolled a total of 2938 patients. METHODS: Multiple databases, including PubMed, MEDLINE, Cochrane Library, Scopus, and EMBASE, were systematically searched for relevant clinical trials from inception through January 14, 2023. The effect measure used was odds ratio (OR) and 95% CI. FINDINGS: Of a total of 1774 studies identified during the initial database search, 8 were included in the meta-analysis. The incidence of overall and cardiovascular mortality was comparable between the 2 groups. There were no significant differences observed for cardiovascular mortality (OR = 0.36; 95% CI, 0.08-1.65; n = 2588; I2 = 45%; P = 0.19). Similar results were found for all-cause mortality (OR = 0.85; 95% CI, 0.67-1.07), any bleeding (OR = 1.90; 95% CI, 0.88-4.09), major bleeding (OR = 1.07; 95% CI, 0.65-1.76), atrioventricular block (OR = 0.74; 95% CI, 0.15-3.68), atrial fibrillation/flutter (OR = 0.74; 95% CI, 0.37-1.50), and other CVAEs associated with second-generation BTKis. IMPLICATIONS: Based on the available evidence, there is no indication of worse cardiovascular outcomes or superiority of second-generation BTKis compared with standard treatments in terms of safety profile. However, additional large-scale controlled trials are needed to provide robust support for the superior tolerability of new-generation BTKis.

Cardiac and renal AL amyloidosis controlled by autologous stem cell transplantation for 17 years accompanying late onset atrial fibrillation and complete atrioventricular block.

Amyloid light chain (AL) amyloidosis is a rare hematologic disease that may involve multiple organs. Amongst the organs, cardiac involvement causes the greatest concern as its treatment is challenging. Diastolic dysfunction rapidly progresses to decompensated heart failure, pulseless electrical activity, and atrial standstill due to electro-mechanical dissociation resulting in death. High-dose melphalan plus autologous stem cell transplantation (HDM-ASCT) is the most radical treatment but its risk is very high and thus only less than 20% of patients can receive this therapy under criteria that can suppress treatment-related mortality. In substantial proportion of patients, levels of M protein remain elevated, and organ response cannot be achieved. Moreover, relapse may occur, making prediction of treatment response and judgement of disease eradication very difficult. Herein we report a case of AL amyloidosis who was treated with HDM-ASCT, resulting in preserved cardiac function and resolution of proteinuria for more than 17 years after HDM-ASCT ensuing atrial fibrillation and complete atrioventricular block required management by catheter ablation and pacemaker implantation 10 years and 12 years after transplantation, respectively.

Third-degree atrioventricular block secondary to infiltrative cardiac hemangiosarcoma in a dog.

A nine-year-old male, castrated Pembroke Welsh Corgi presented with a two-month history of lethargy, hyporexia, and occasional vomiting. There was also a two-week history of exercise intolerance; no syncopal episodes were reported. Auscultation revealed bradycardia with an irregular rhythm and otherwise normal heart and lung sounds. Third-degree atrioventricular block was diagnosed. Two-dimensional transthoracic echocardiography revealed a soft tissue structure arising from the atrioventricular junction and interatrial septum. There was scant abdominal effusion. Pacemaker implantation was offered, but the owner elected humane euthanasia due to the unknown prognosis. Necropsy was consistent with cardiac hemangiosarcoma infiltrating the interatrial and interventricular septum.

High-grade idiopathic atrioventricular block in childhood: Case report and literature review. / High-grade idiopathic atrioventricular block in childhood: Case report and literature review.

Atrioventricular blocks are chronotropic abnormalities produced by multifactorial alterations in the cardiac innervation system, specifically between the internodal pathways between the sinus node and the atrioventricular node. These bradyarrhythmias represent 2.3% of cardiac alterations in intrauterine life, registering one case for every 20 000 to 25 000 live births. However, its occurrence in childhood and adolescence is unknown. Likewise, the percentage of idiopathic atrioventricular blocks in this group in Colombia is unknown to date. Among the possible etiol-ogies, congenital and acquired causes have been documented. Some examples are isolated cases found in pregnancies with maternal isoimmunization, from carriers with lupus, and in coexis-tence with structural alterations, such as anomalies of the interventricular septum due to cardiac tumors and defects in the ostium and septation of the cardiac chambers. Atrioventricular blocks are also associated with respiratory syncytial virus infection and concomitant viral myocarditis and with cardiomyopathies of immune, rheumatic, infectious, tumoral, and structural origin, in addition to mitochondrial diseases such as Kearns Sayre syndrome, presenting with multi- organ involvement. These etiologies lead to chronic inflammation with fibrotic repair in the cardiac conduction system, which alters the transmission of the action potential and bradycardia with atrioventricular asynchrony. Idiopathic causes described in the onset of primary dysautonomia have also been reported. We present the case of an 11- year- old patient with a headache crisis and paroxysmal vegetative symptoms associated with repeated fainting, with subsequent studies where no structural alterations or autoimmune findings were identified. The patient was diag-nosed with idiopathic complete atrioventricular block and received expectant management by the electrophysiology service.

Los bloqueos auriculoventriculares son aberraciones cronotrópicas producidas por alteraciones de índole multifactorial en el sistema de inervación cardíaco. Específicamente se localizan entre las vías internodales que conducen el potencial de acción desde el nodo sinusal hasta el nodo auriculoventricular. Estos representan el 2,3% de las alteraciones cardíacas en la vida intrauterina, registrándose un caso por cada 20 000 a 25 000 nacidos vivos. Sin embargo, su ocurrencia en la infancia temprana y la edad escolar es desconocida. Asimismo, el porcentaje de causas idiopáticas de bloqueos auriculoventriculares en esta etapa de la vida es desconocido hasta el momento en Colombia. Dentro de las posibles etiologías se han documentado causas congénitas y adquiridas. Algunos ejemplos son casos aislados producto de isoinmunización materna, en hijo de madre lúpica o en coexistencia con alteraciones estructurales como anomalías del septo interventricular de índole neoplásico, defectos relacionados al ostium y la tabicación de las cámaras cardíacas. También se han descrito casos secundarios a infección por virus sincitial respiratorio y miocarditis vírica concomitante, incluyendo cardiomiopatías de origen inmune, reumático, infeccioso, tumoral, estructural, además de aquellas con compromiso mitocondrial en el cardiomiocito (síndrome de Kearns Sayre) con presentación más tardía con afectación multiorgánica. Todas ellas destacan por un fenómeno en común a nivel celular, referente a la inflamación crónica con reparación fibrótica en el sistema de conducción cardíaco, que conlleva alteraciones de la transmisión del potencial de acción y bradicardia con asíncrona auriculoventricular. También se han reportado causas idiopáticas descritas en el debut de una disautonomía primaria. Se presenta el caso de una paciente de 11 años con crisis de cefalea y síntomas vegetativos paroxísticos asociados a lipotimias a repetición, con posteriores estudios de extensión sin identificación de alteraciones estructurales ni hallazgos autoinmunes. A la niña se le diagnosticó bloqueo auriculoventricular completo, idiopático por lo que recibió manejo expectante por parte del servicio de electrofisiología.

Bloqueo auriculoventricular de alto grado idiopático en la infancia: reporte de caso y revisión de literatura / High-grade idiopathic atrioventricular block in childhood: case report and literature review

Los bloqueos auriculoventriculares son aberraciones cronotrópicas producidas por alteraciones de índole multifactorial en el sistema de inervación cardíaco. Específicamente se localizan entre las vías internodales que conducen el potencial de acción desde el nodo sinusal hasta el nodo auriculoventricular. Estos representan el 2,3% de las alteraciones cardíacas en la vida intrauterina, registrándose un caso por cada 20 000 a 25 000 nacidos vivos. Sin embargo, su ocurrencia en la infancia temprana y la edad escolar es desconocida. Asimismo, el porcentaje de causas idiopáticas de bloqueos auriculoventriculares en esta etapa de la vida es desconocido hasta el momento en Colombia. Dentro de las posibles etiologías se han documentado causas congénitas y adquiridas. Algunos ejemplos son casos aislados producto de isoinmunización materna, en hijo de madre lúpica o en coexistencia con alteraciones estructurales como anomalías del septo interventricular de índole neoplásico, defectos relacionados al ostium y la tabicación de las cámaras cardíacas. También se han descrito casos secundarios a infección por virus sincitial respiratorio y miocarditis vírica concomitante, incluyendo cardiomiopatías de origen inmune, reumático, infeccioso, tumoral, estructural, además de aquellas con compromiso mitocondrial en el cardiomiocito (síndrome de Kearns Sayre) con presentación más tardía con afectación multiorgánica. Todas ellas destacan por un fenómeno en común a nivel celular, referente a la inflamación crónica con reparación fibrótica en el sistema de conducción cardíaco, que conlleva alteraciones de la transmisión del potencial de acción y bradicardia con asíncrona auriculoventricular. También se han reportado causas idiopáticas descritas en el debut de una disautonomía primaria. Se presenta el caso de una paciente de 11 años con crisis de cefalea y síntomas vegetativos paroxísticos asociados a lipotimias a repetición, con posteriores estudios de extensión sin identificación de alteraciones estructurales ni hallazgos autoinmunes. A la niña se le diagnosticó bloqueo auriculoventricular completo, idiopático por lo que recibió manejo expectante por parte del servicio de electrofisiología.

Atrioventricular blocks are chronotropic abnormalities produced by multifactorial alterations in the cardiac innervation system, specifically between the internodal pathways between the sinus node and the atrioventricular node. These bradyarrhythmias represent 2.3% of cardiac alterations in intrauterine life, registering one case for every 20 000 to 25 000 live births. However, its occurrence in childhood and adolescence is unknown. Likewise, the percentage of idiopathic atrioventricular blocks in this group in Colombia is unknown to date. Among the possible etiol-ogies, congenital and acquired causes have been documented. Some examples are isolated cases found in pregnancies with maternal isoimmunization, from carriers with lupus, and in coexis-tence with structural alterations, such as anomalies of the interventricular septum due to cardiac tumors and defects in the ostium and septation of the cardiac chambers. Atrioventricular blocks are also associated with respiratory syncytial virus infection and concomitant viral myocarditis and with cardiomyopathies of immune, rheumatic, infectious, tumoral, and structural origin, in addition to mitochondrial diseases such as Kearns Sayre syndrome, presenting with multi- organ involvement. These etiologies lead to chronic inflammation with fibrotic repair in the cardiac conduction system, which alters the transmission of the action potential and bradycardia with atrioventricular asynchrony. Idiopathic causes described in the onset of primary dysautonomia have also been reported. We present the case of an 11- year- old patient with a headache crisis and paroxysmal vegetative symptoms associated with repeated fainting, with subsequent studies where no structural alterations or autoimmune findings were identified. The patient was diag-nosed with idiopathic complete atrioventricular block and received expectant management by the electrophysiology service.

A case of complete atrioventricular block associated with primary cardiac lymphoma reversed without cardiac pacemaker implantation.

Primary cardiac lymphoma (PCL) is a rare malignant lymphoma that is characteristically confined to the heart and/or pericardium. Here, the case of a 70-year-old male patient with complete atrioventricular block (AVB) associated with PCL is presented. The patient had a 10-month history of palpitation and electrocardiogram (ECG) showed a complete AVB. Additionally, transthoracic echocardiography indicated pericardial effusion where atypical lymphoid cells were identified by pericardiocentesis. Subsequent mediastinal lymph node biopsy revealed non-germinal centre diffuse large B-cell lymphoma. Therefore, a diagnosis of PCL was confirmed. As the patient's vital signs were stable, he was prescribed chemotherapy without pacemaker implantation. After chemotherapy, the patient achieved remission and dynamic ECG demonstrated no recurrence of AVB. The present case demonstrates that although PCL initially manifesting as complete AVB is rare, this possibility should not be ignored when a new AVB without definite aetiology is encountered. In addition, if the vital signs of the patient are stable, pacemaker implantation may be postponed until the treatment effect of chemotherapy has been assessed.

Management of IMRT in a gastric cancer patient with pacemaker: A case report and review of the literature.

Due to the prolongation of a lifetime, more cancer patients with cardiac implantable electronic devices are treated by radiotherapy. However, radiation may cause permanent or temporary malfunctions on these devices, and new-generation devices are more sensitive to radiation. Besides, radiotherapy techniques and image guidance methods that may cause different interactions with the functions of the devices have been changed significantly recently. Here, we reported our clinical experience in a patient with a pacemaker who underwent radiotherapy with intensity-modulated radiation therapy (IMRT) due to gastric cancer and reviewed the literature.

Severe myocardial bridge presenting as paroxysmal atrioventricular block.

Chest pain complicated with electrocardiographic changes is not an uncommon scenario in emergency departments, which should be examined cautiously. We describe a 51-years-old man with a myocardial bridge of coronary artery presenting with simultaneous Mobitz type I atrioventricular block on electrocardiography. Echocardiography excluded valvular abnormality and systolic/diastolic dysfunction. Coronary angiography confirmed the diagnosis of a myocardial bridge at the middle segment of the left anterior descending artery, involving the most dominant septal perforator branch with marked systolic compression. The patient underwent coronary artery bypass grafting surgery and was followed up uneventfully at the outpatient department with medical treatment of diltiazem and clopidogrel. The present case is being reported to highlight that clinicians should be alert to such a congenital abnormality as a potential cause of repeated myocardial infarction and conduction abnormality.

Successful 2-Stage Pacemaker Implantation for Atrioventricular Block in a Low-Birth-Weight Infant with Congenital Heart Disease: Case Report.

Congenital heart block is a potentially life-threatening condition with high morbidity and mortality, especially in the presence of congenital heart disease. We present the case of a low-body-weight premature infant with complex single ventricle congenital heart disease and high-grade atrioventricular block. A 2-staged pacing approach provided atrio-ventricular synchrony and allowed her to grow until a permanent dual-chamber pacemaker system could be implanted.

Syncope in Patients With Severe Aortic Stenosis: More Than Just an Obstruction Issue.

BACKGROUND: Severe aortic stenosis (AoS) is considered a primary cause of syncope. However, other mechanisms may be present in these patients and accurate diagnosis can have important clinical implications. The aim of this study is to assess the different etiologies of syncope in patients with severe AoS and the impact on prognosis of attaining a certain or highly probable diagnosis for the syncope. METHODS: Out of a cohort of 331 patients with AoS and syncope, 61 had severe AoS and were included in the study. Main cause of syncope and adverse cardiac events were assessed. RESULTS: In 40 patients (65.6%), we reached a certain or highly probable diagnosis of the main cause of the syncope. AoS was considered the primary cause of the syncope in only 7 patients (17.5% of the patients with known etiology). Atrioventricular block (14 patients, 35.0%) and vasovagal syncope (6 patients, 15.0%) were the most frequently diagnosed causes. The presence of a known cause for syncope during the admission was not associated with a lower incidence of recurrence during follow-up (hazard ratio [HR] 0.69, 95% confidence interval [CI] 0.20-2.40). Syncope of unknown etiology was independently associated with greater mortality during 1-year follow-up (HR 5.4, 95% CI 1.3-21.6) and 3-year follow-up (HR 3.5, 95% CI 1.2-10.3). CONCLUSIONS: In a high proportion of patients with severe AoS admitted for syncope, the valvulopathy was not the main cause of the syncope. Syncope in two-thirds of this population was caused by either bradyarrhythmia or reflex causes. Syncope of unknown cause was associated with increased short- and medium-term mortality, independently from treatment of the valve disease. An exhaustive work-up should be conducted to determine the main cause for syncope.

Complete Atrioventricular Block and Cardiopulmonary Involvement in Rapidly Progressive Systemic Sclerosis

Abstract The heart and lung are target organs in systemic sclerosis (SSc) and similar symptoms (dyspnea and cough) may make the differential diagnosis between the two lesions difficult. In addition, complete atrioventricular block (CAVB) is a rare complication of this disease. This case report is about a patient with SSc and pulmonary fibrosis who was admitted to the emergency room with CAVB, heart failure (HF) and progressive worsening of the underlying disease.

[Third degree atrio-ventricular blockade during a myocarditis occurring under anti-PD1 : Case report and literature review]. / Bloc atrio-ventriculaire de grade III compliquant une myocardite au décours d'un traitement par anti-PD1 : observation d'un cas et revue de la littérature.

INTRODUCTION: Immune Checkpoint Inhibitor (ICI) therapy is now a standard of care in numerous cancers with very promising results. Nevertheless, adverse events, and especially immune-related adverse events (irAEs) not reported during clinical trials, are emerging and can be life-threatening. OBSERVATION: We report here a teachable case of a 80 year-old man, of third-degree atrioventricular block consecutive to myocarditis associated with the administration of nivolumab (anti-PD1) monotherapy. CONCLUSION: Myocarditis occurring during ICI treatment is a rare but potentially lethal event. Daily serum troponin level seems to predict ICI-related myocarditis but interpretation could be difficult in the context of associated myositis. Echocardiography and cardiac MRI are also useful but can remain negative. Electrocardiogram is a cornerstone of myocarditis diagnosis. In case of cardiac involvement, continuous heart rhythm monitoring should be performed in addition to the administration of high-dose corticosteroids therapy and the cessation of ICI therapy. Add-on treatments should be discussed with a well-trained multidisciplinary team.

Bloqueio atrioventricular total congênito - características de 34 pacientes submetidos a implante ou troca de marcapasso definitivo / Congenital complete heart block - characteristics of 34 patients submitted to definitive pacemaker implant or replacement

Objetivos: Descrever as características de pacientes menores de 18 anos com bloqueio atrioventricular total congênito submetidos a implante ou troca de marcapasso definitivo. Métodos: Foram analisados retrospectivamente 34 pacientes que foram submetidos a implante ou troca de marcapasso entre janeiro de 2011 e maio de 2017 em um único centro. Os pacientes foram divididos em 2 grupos (grupo I: implante e grupo II: troca) e avaliados de acordo com o sexo, idade, cardiopatia congênita, indicação do implante, técnica utilizada, complicações e mortalidade. Resultados: 47,1% eram do sexo feminino. A mediana para idade no momento do implante foi de 2 anos e 6 meses e para peso foi de 17,5Kg. Cardiopatia congênita teve prevalência de 52,9% nos pacientes. As indicações para implante de marcapasso definitivo foram: frequência cardíaca menor que 70 bpm com cardiopatia ou disfunção (44,1%), frequência cardíaca menor que 55 bpm sem cardiopatia (26,5%), sinais e sintomas de baixo débito cardíaco (20,6%) e disfunção ventricular (8,8%). A técnica epicárdica foi realizada em 73,5% e a endocárdica em 26,5% dos pacientes. Foi implantado marcapasso bicameral em 53% e monocameral em 47% deles. Complicações foram observadas em 23,5% e a mortalidade foi de 8,8%. Conclusões: A criteriosa avaliação desses pacientes permite uma adequada escolha do sistema e da técnica de implante. Pouco mais da metade dos pacientes tinham cardiopatia congênita, a técnica epicárdica foi a mais realizada, a maioria recebeu marcapasso bicameral, e as complicações e a mortalidade foram semelhantes as encontradas na da literatura

Aims: Describe the characteristics of 34 patients under 18, with congenital complete heart block submitted for definitive pacemaker implant or replacement. Methods: We retrospectively analyzed patients who underwent pacemaker implant or replacement between January 2011 and May 2017 at a single center. The patients were divided into 2 groups (group I: implant and group II: replacement) and evaluated according to gender, age, congenital heart disease, implant indication, technique used, complications and mortality. Results: Thirty-four patients underwent definitive pacemaker implant or replacement, 47.1% of which were female. The median age at the time of implantation was 2 years and 6 months and median weight was 17.5 kg. Congenital heart disease was found in 52.9% of the patients. The indications for definitive pacemaker implant were heart rate lower than 70 bpm with heart disease or dysfunction (44.1%), heart rate less than 55 bpm without heart disease (26.5%), signs and symptoms of low cardiac output (20.6%) and ventricular dysfunction (8.8%). The epicardial technique was performed in 73.5% and the endocardial technique in 26.5% of the patients. A bicameral pacemaker was implanted in 53% and monocameral ventricular pacemaker in 47% of the patients. Complications were observed in 23.5%, with a mortality of 8.8% of the patients. Conclusions: The careful evaluation of the characteristics of these patients allows an adequate choice of the system and the implant technique. Just over half of the patients had congenital heart disease, the epicardial technique was the most performed, most received bicameral pacemaker, and complications and mortality were similar to the literature

Arritmias cardíacas na sala de emergência e UTI. Bradicardias: como identificar e tratar o paciente com baixa perfusão / Cardiac arrhythmias in the emergency room and ICU. Bradyarrhythmias: how to identify and treat the patient with low perfusion

O sistema cardiovascular é responsável pelo fluxo circulatório adequado, o qual depende do volume sistólico e frequência cardíaca (FC). Quando insuficientes, causa hipofluxo cerebral e incapacidade de realizar atividades. A bradicardia é causada por: a) disfunção sinusal, manifestada por FC inapropriadas, pausas ou síndrome de taqui-bradicardia, síncopes, tonturas e intolerância aos esforços, sem risco à vida; b) distúrbio da condução atrioventricular (bloqueios atrioventriculares - BAV): de primeiro, segundo (Mobitz I, Mobitz II e avançado) e terceiro grau (Total) . O BAV de primeiro grau e do tipo Mobitz I tem bom prognóstico. O BAV Mobitz II, avançado e total, mesmo oligossintomático ou transitório, sem causas removíveis, tem maior morbimortalidade; c) distúrbios neuromediados e a síncope reflexa são desencadeados por posição ortostática ou exposição à estresse emocional e a síndrome do seio carotídeo associada à estimulação da carótida. A FC baixa pode estar associada a um maior risco, sendo que os sinais e sintomas indicam gravidade. Na urgência, deve-se tratar as causas subjacentes assegurar o bom funcionamento das vias aéreas administrar O2 monitorar ritmo, FC, pressão arterial, e, também, o acesso venoso. É importante analisar o ritmo, exame físico e histórico, além de pesquisar e tratar os fatores contribuintes. Caso haja sinais de baixa perfusão, deve-se administrar atropina. A estimulação por marcapasso transcutâneo é indicada, caso a atropina seja ineficaz. Além disso, deve-se considerar a adrenalina ou dopamina e estimulação transvenosa

The cardiovascular system is responsible for adequate circulatory flow, which depends on systolic volume and heart rate (HR). When insufficient, it causes cerebral hypoflow and inability to perform activities. Bradycardia is caused by: a) sinus dysfunction, manifested by inappropriate HR, pauses or tachycardia-bradycardia syndrome, syncope, dizziness and intolerance to exertion, without risk to life; b) atrioventricular conduction disorder (atrioventricular (AV) blocks): first, second (Mobitz type I, Mobitz type II and advanced) and third degree (complete). First-degree and Mobitz type I AV block both have good prognosis. Mobitz type II, advanced and complete AV block, even oligosymptomatic or transient, without removable causes, have higher morbidity and mortality; c) neuromediated disorders and reflex syncope are triggered by orthostatic position or exposure to emotional stress and carotid sinus syndrome, associated with carotid stimulation. Low HR may be associated with increased risk, and signs and symptoms indicate severity. In emergency conditions the underlying causes should be treated to ensure good functioning of the airways; administer O2; monitor cardiac rhythm, HR, blood pressure, and venous access. It is important to analyze rhythm, and conduct a physical examination and clinical history, and to check for and treat contributing factors. If there are signs of low perfusion, atropine should be administered. Simulation by transcutaneous pacemaker is indicated if atropine is ineffective. Epinephrine or dopamine and transvenous stimulation should also be considered