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.

Bradicardia sinusal inducida por corticoesteroides en un niño con insuficiencia suprarrenal y septicemia / Corticosteroid-induced sinus bradycardia in a young boy with adrenal insufficiency and sepsis

La bibliografía no incluye frecuentemente alteraciones en el ritmo cardíaco de los pacientes que reciben corticoesteroides; se desconoce su mecanismo exacto. En este artículo, presentamos el caso de un paciente con bradicardia sinusal asociada con una dosis de estrés de corticoesteroides. Se ingresó a un niño de 9 años con antecedentes de panhipopituitarismo con gastroenteritis y neumonía y presentó choque septicémico el día de la hospitalización. El tratamiento con líquidos intravenosos, dosis de estrés de hidrocortisona y antibióticos permitió la recuperación. Sin embargo, luego se documentó bradicardia sinusal con una frecuencia cardíaca de 45 latidos por minuto. Esta se resolvió después de reducir gradualmente la hidrocortisona. La bradicardia sinusal inducida por corticoesteroides es un efecto adverso que suele resolverse tras interrumpir el tratamiento. Se debe considerar el monitoreo hemodinámico en estos casos. Este es el primer informe de bradicardia sinusal posterior al uso de hidrocortisona en niños con insuficiencia suprarrenal

The literature does not commonly describe cardiac rhythm disturbances, including bradycardia, in patients who are receiving corticosteroids, and the exact mechanism of such disturbances remains unknown. Herein, we present a case of sinus bradycardia associated with stress-dose corticosteroid therapy. A nine-year-old boy with a history of panhypopituitarism was admitted with gastroenteritis and pneumonia and developed septic shock on the day of admission. Management using intravenous fluids, stress doses of hydrocortisone, and antibiotics resulted in full recovery. However, within 24 hours following treatment, sinus bradycardia was documented, with a heart rate of 45 beats per minute (BPM). The bradycardia resolved after the dose of hydrocortisone was decreased gradually. Corticosteroidinduced sinus bradycardia is an adverse effect that usually resolves after corticosteroid treatment is discontinued. During stress-dose corticosteroid therapy, hemodynamic monitoring should be considered. To our knowledge, this is the first report of sinus bradycardia following the use of hydrocortisone in children who have adrenal insufficiency.

Research Progress on Pathological Fibrosis of Sinoatrial Node / 法医学杂志

Human heart rhythm is mainly regulated and controlled by the sinoatrial node. Fibrosis plays an important regulating role in adjusting the structural and functional integrity of the sinoatrial node pacemaker complex. In physiological state, the fibrosis degree of sinoatrial node is negatively correlated with heart rate, positively correlated with age and heart size, and can maintain a relatively stable heart rate. Pathological fibrosis of sinoatrial node can induce various types of arrhythmias which can result in sudden death. Determination of the mechanisms related to sinoatrial node pathological fibrosis could provide a target for clinical treatment of sinoatrial node fibrosis and diagnosis basis for forensic pathologists. This paper reviews the main mechanism of sinoatrial node pathological fibrosis, including abnormal activation of cardiac fibroblast cells in sinoatrial node, hyperplasia of epicardial adipose tissue, calcium clock disorder, artery stenosis, etc., introduces the test methods, diagnostic criteria as well as its role in sudden cardiac death and discusses the potential application, to provide reference for relevant research and application.

El nodo sinusal normal: Lo que ahora sabemos / The normal sinus node: What we know now

RESUMEN El nodo sinusal constituye el marcapasos fisiológico del corazón. Diferentes estados fisiopatológicos conducen a una reducción de su función, lo que es llamado en la clínica, disfunción sinusal. Sin embargo, para la mejor comprensión de su estado de enfermedad se requiere dilucidar cómo opera en condiciones normales. Las nuevas evidencias señalan que el automatismo del nodo sinusal se produce por la interacción del reloj de membrana y el reloj de calcio, lo que le confiere un fuerte carácter que lo protege contra fallas de funcionamiento. Se presentan las evidencias actuales sobre la sincronía celular dentro del nodo sinusal, así como la forma de propagación eléctrica y el acoplamiento fuente-sumidero. Además, se describen recientes hallazgos anatómicos e histológicos.

ABSTRACT The sinus node is the physiological pacemaker of the heart. Different pathophysiological conditions lead to a reduction of its function, which is clinically called sinus dysfunction. However, for a better understanding of its disease state, it is necessary to elucidate how it works under normal conditions. New evidences indicate that the automatism of the sinus node is produced by the interaction of the membrane clock and the calcium clock, which gives it a strong character that protects it against malfunctions. Current evidences on cell synchrony within the sinus node are presented, as well as the form of electrical propagation and the source-sink coupling. In addition, recent anatomical and histological findings are described.

Permanent Pacemaker Implantations after Catheter Ablation in Patients with Atrial Fibrillation Associated with Underlying Sinus Node Dysfunction

BACKGROUND AND OBJECTIVES: The objective of this study was to evaluate the long-term clinical outcomes and the incidence of permanent pacemaker implantation after catheter ablation in patients with of atrial fibrillation (AF) and sinus node dysfunction (SND).METHODS: Among 3,068 total consecutive patients who underwent AF catheter ablation (AFCA), this study included 222 (9.5%; men 53.2%, 63.7±9.2 years of age, 81.5% paroxysmal AF) with underlying SND and a regular rhythm follow-up. We analyzed the rhythm outcomes, changes in the mean heart rate or heart rate variability, and permanent pacemaker implantation rate.RESULTS: During 47.5±28.8 months of follow-up, 25 (11.3%) patients received pacemaker implantations due to symptomatic SND. More than half (56.0%, 14/25) underwent a pacemaker implantation within 3 months of the AFCA, and the annual pacemaker implantation rate was 2.0% afterwards. Both the early (68.0% vs. 31.0%, p<0.001) and clinical AF recurrence (68.0% vs. 32.5%, p=0.001) rates and continuous antiarrhythmic drug use after 3 months (44.0% vs. 24.4%, p=0.036) were significantly higher in patients requiring pacemaker implantations than those that did not. An anterior linear ablation (odds ratio [OR], 9.37 [3.03–28.9]; p<0.001) and the E/Em (OR, 1.15 [1.02–1.28]; p=0.018) were independently associated with permanent pacemaker implantations after AFCA in patients with AF and SND.CONCLUSIONS: After AFCA in patients with AF and SND, 1 of 9 patients needed a pacemaker implantation and half needed implantations within 3 months. The AF recurrence rate was significantly higher in those who required pacemaker implantations after the AFCA.

Catheter Ablation is Effective for Recovery from Sinus Node Dysfunction in Patients with Atrial Fibrillation, But Close Monitoring is Still Needed

No abstract available.

Cardiomiopatia não compactada: doença do nó sinusal como manifestação inicial tratada com marcapasso / Noncompaction cardiomyopathy: sinus node disease as an initial manifestation treated with bicameral pacemaker

A cardiomiopatia não compactada é uma doença congênita, que resulta de falha da compactação do miocárdio na vida embrionária. Nesse processo, há a persistência de trabeculações e recessos profundos, que se comunicam com a cavidade ventricular e geram espessamento do miocárdio em duas camadas distintas. O aspecto clínico dessa doença tanto em crianças como em adultos é muito heterogêneo, variando desde a ausência de sintomas até a tríade composta por insuficiência cardíaca congestiva, arritmias e tromboembolismo sistêmico, porém bradicardias sintomáticas são muito raras. Relatamos o caso de uma paciente com doença do nó sinusal como manifestação inicial de cardiomiopatia não compactada

Noncompaction cardiomyopathy is a congenital disease that results frommyocardial compaction failure in embryonic life. In this process there is the persistence of deep trabeculations and recesses that communicate with the ventricular cavity, resulting in myocardial thickening in two distinct layers. The clinical aspect of this disease in both children and adults is very heterogeneous, ranging from absence of symptomatology to a triad including congestive heart failure, arrhythmias and systemic thromboembolism. However, symptomatic bradycardias are very rare. We report the case of a patient with sinus node disease as the initial manifestation of non-compaction cardiomyopathy

Variação nos tipos de irrigação do nodo sinoatrial em cães de diferentes raças / Variation in irrigation of the sinoatrial node in dogs of different breeds

Considerando a heterogeneidade anatômica e eletrofisiológica do nodo sinoatrial para a geração e propagação do potencial de ação, bem como as particularidades relacionadas a origem da sua irrigação sanguínea, este trabalho teve como objetivo analisar o comportamento das artérias envolvidas na irrigação do nodo sinoatrial em cães realizando uma análise descritiva e comparativa entre diferentes raças estudadas, detalhando a origem, o percurso e a ramescência dos vasos, assim como a eventual ocorrência de anastomoses. Ao todo analisamos resultados obtidos em 240 corações, os quais foram fixados em solução de formalina 10% e submetidos a diafanização de Spalteholz. A irrigação deste ocorre mediante colaterais oriundos do ramo circunflexo direito ou ramo circunflexo esquerdo, mostrando particularidades diferentes para cada raça. Assim, predominantemente, nas raças ora estudadas a irrigação arterial do nodo sinoatrial depende exclusivamente (63,6%), ou de anastomoses de colaterais da artéria coronária direita, havendo também participação dos ramo proximal atrial direito e intermédio atrial direito. Menos frequentemente (15,4%) o suprimento sanguíneo ocorre exclusivamente por conta do ramo proximal atrial esquerdo, oriundo do ramo circunflexo da artéria coronária esquerda. Os dados aqui apresentados sobre a origem da irrigação sanguínea do nodo sinoatrial e a ramescência dos vasos envolvidos nesta tarefa representam conhecimento fundamental para o desenvolvimento da clínica-cirúrgica em cães, da patologia e trabalhos de natureza experimental.(AU)

Considering the anatomical and electrophysiological heterogeneity of the sinoatrial node for generation and propagation of the action potential, as well as the particularities relating to the origin of blood nutrition, this study aimed to analyze the behavior of arteries involved in irrigation of the sinoatrial node in dogs performing a descriptive and comparative analysis between different breeds, with emphasis in the origin, pathway and branching of vessels, as well as the presence of anastomoses. Totally, 240 hearts were fixed in solution of formalin 10% and subjected to Spalteholz diaphanization. The vascularization of the sinoatrial node occurs by the right circumflex branch or left circumflex branch, showing several particularities according to the breed. Thus, predominantly in the studied breeds, the blood supply of the sinoatrial node depends exclusively (63.6%) or from anastomosis of the right coronary artery. There is also participation of right atrial proximal branch and right atrial intermediary branch. Less often (15.4%) the blood supply occurs exclusively from the left atrial proximal branch, which is a branch of the circumflex branch of the left coronary artery. In summary, our results related to the origin of the sinoatrial node blood nutrition and the branching of vessels involved on that represents a fundamental knowledge for the development and improvement of surgery in dogs, as well as for pathology and experimental research.(AU)

Análise da variação do limiar de captura após a realização de cardioversão elétrica em portadores de dispositivos cardíacos eletrônicos implantáveis / Captured threshold variance analysis after electric cardioversion in patients using cardiaca implantable electronic devices

Introdução: Com o aumento da expectativa de vida da população e a consequente maior incidência de arritmias, que podem necessitar de cardioversão elétrica e crescente desenvolvimento e indicação de dispositivos cardíacos eletrônicos implantáveis, torna-se necessária a reavaliação do comportamento desses dispositivos após a aplicação de terapia elétrica, especialmente naqueles pacientes dependentes de estimulação. Este trabalho teve como objetivo avaliar a variação do limiar de captura ventricular após choque terapêutico para tratamento de taquiarritmias supraventriculares, em condições de prá- tica clínica diária. Método: Entre julho de 2009 e maio de 2015, foram avaliados pacientes portadores de dispositivos cardíacos eletrônicos implantáveis, na cidade de Araras (SP, Brasil), que necessitaram de cardioversão elétrica, sendo determinados os limiares de captura ventricular antes e imediatamente após a terapia. A avaliação teve como objetivo analisar a variação desse parâmetro, que reflete item de segurança do dispositivo. Resultados: Foram incluídos 12 pacientes tratados em 13 episódios de taquiarritmias supraventriculares (fibrilação e taquicardia atriais), com média de idade de 71,6 anos, predominantemente do sexo masculino, com tempo variável de implante do dispositivo, não sendo encontrada variação significativa do limiar de captura ventricular antes e após a cardioversão elétrica. Conclusão: Não há variação significativa do limiar de captura ventricular após cardioversão elétrica em pacientes com taquiarritmias supraventriculares

Background: With the increase in the population's life expectancy, a greater incidence of cardiac arrhythmias is observed. These arrhythmias may require treatment with electric cardioversion. Furthermore, with the increase in the development and indications for cardiac implantable electronic devices, the behavior of these devices after electric therapy must be reevaluated, especially in patients who depended on cardiac stimulation. This study aimed to evaluate the ventricular captured threshold variance after therapeutic countershock for the treatment of supraventricular tachyarrhythmias in daily practice conditions. Method: From July 2009 to May 2015, patients with cardiac implantable electronic devices requiring electric cardioversion were evaluated, in Araras (SP, Brazil). Captured threshold variance before and immediately after therapy was determined. The evaluation aimed at analyzing the variance of this parameter, which reflects a safety feature of the device. Results: 12 patients were included, presenting with 13 episodes of supraventricular tachyarrhythmias (atrial tachycardia and fibrillation). Mean age was 71.6 years, with a prevalence of males and variable device implant times. No significant ventricular captured threshold variation was found before and after electric cardioversion. Conclusion: There is no significant variation of ventricular captured threshold variance after electric cardioversion in patients with supraventricular tachyarrhythmias

Efeitos da lidocaína vs. ropivacaína durante anestesia local para implantes de marcapasso / Effects of lidocaine vs. ropivacaine during local anesthesia for pacemaker implants

Introdução: A lidocaína é o anestésico local mais amplamente utilizado durante os procedimentos de implante de marcapasso, principalmente pelo seu perfil seguro e baixo custo. Atualmente, nosso grupo vem utilizando a ropivacaína no lugar da lidocaína. Essa substância é um anestésico local do tipo amida de longa duração com efeitos anestésico e analgésico, proporcionando, assim, maior conforto aos pacientes. Método: O presente estudo transversal foi realizado em 1.178 pacientes que necessitavam de implante de marcapasso dupla-câmara. Durante o implante do dispositivo eletrônico implantável, 450 pacientes foram submetidos a anestesia do músculo peitoral (direito ou esquerdo) com 20 ml de lidocaína 2% sem vasoconstritor, enquanto 728 pacientes foram submetidos a anestesia local na mesma região com 20 ml de ropivacaína 7,5%. Avaliamos o tempo de ausência da sensação dolorosa após o implante do marcapasso e a segurança relacionada ao uso de lidocaína vs. ropivacaína. Resultados: A ausência de dor após o implante avaliada em horas demonstrou que a ropivacaína promove efeito anestésico de 6,5 ± 0,4 horas ao término do procedimento, enquanto a lidocaína só foi capaz de aliviar a dor durante 2,3 ± 0,6 horas (P < 0,0001). Em relação à segurança dos fármacos, a taxa de complicação anestésica foi muito semelhante: 15 pacientes (2,03%) com utilização de ropivacaína e 12 pacientes (2,67%) com uso de lidocaína (P = 0,5482). Conclusão: A ropivacaína parece ser tão segura e mais eficaz que a lidocaína durante a anestesia local, tendo efeitos analgésicos mais prolongados após implante de dispositivos cardíacos eletrônicos implantáveis

Background: Lidocaine is the most widely used local anesthetic during pacemaker implantation procedures, mainly because of its safe profile and low cost. Currently, our group has been using ropivacaine instead of lidocaine. This substance is a long-acting amide-type local anesthetic with anesthetic and analgesic effects, thus providing greater patient comfort. Method: The present cross-sectional study was performed in 1,178 patients who required a dual-chamber pacemaker implantation. During implantation of the implantable electronic device 450 patients underwent right or left pectoral muscle anesthesia with 20 mL of 2% lidocaine without vasoconstrictor, while 728 patients underwent local anesthesia in the same region with 20 mL of 7.5% ropivacaine. We evaluated the time of absence of the pain after the implantation of the pacemaker and the safety of the use of lidocaine vs. ropivacaine. Results: The absence of post-implant pain evaluated in hours showed that ropivacaine promotes an anesthetic effect of 6.5 ± 0.4 hours at the end of the procedure, whereas lidocaine was only able to relieve pain for 2.3 ± 0.6 hours (P < 0.0001). Regarding drug safety, the rate of anesthetic complication was very similar: 15 patients (2.03%) with ropivacaine and 12 patients (2.67%) with lidocaine (P = 0.5482). Conclusion: Ropivacaine seems to be as safe and effective as lidocaine during local anesthesia and has longer analgesic effects after the implantation of implantable electronic cardiac devices

P wave

The electrical impulses of atrium arise from the sinus node, subsequently pass through the right and left atrium, and finally arrive at the atrioventricular node. The P wave is the summation of the electrical current generated by depolarization due to its passage through the atrial conduction pathway. It provides many clinical clues that may be useful for diagnosis of atrial, ventricular, or valvular heart diseases. This review article briefly describes the clinical implications, mechanism of genesis, and normal and pathologic features of the P wave.

Intraoperative management of critical arrhythmia / 대한마취과학회지

The incidence of intraoperative arrhythmia is extremely high, and some arrhythmias require clinical attention. Therefore, it is essential for the anesthesiologist to evaluate risk factors for arrhythmia and understand their etiology, electrophysiology, diagnosis, and treatment. Anesthetic agents reportedly affect normal cardiac electrical activity. In the normal cardiac cycle, the sinoatrial node initiates cardiac electrical activity through intrinsic autonomous pacemaker activity. Sequential atrial and ventricular contractions result in an effective cardiac pumping mechanism. Arrhythmia occurs due to various causes, and the cardiac pumping mechanism may be affected. A severe case may result in hemodynamic instability. In this situation, the anesthesiologist should eliminate the possible causes of arrhythmia and manage the condition, creating hemodynamic stability under proper electrocardiographic monitoring.

Registro de arritmias em pacientes com marcapassos e doença renal crônica de leve a moderada (RYCKE): resultados de um estudo de coorte observacional / Register of arrhythmias in patients with pacemakers and mild to moderate chronic kidney disease (RYCKE): results from an observational cohort study

O presente estudo examinou pacientes submetidos a implante de marcapasso dupla-câmara em decorrência de doença do nó sinusal ou bloqueio atrioventricular de 3o ou 2o graus do tipo 2 na doençarenal crônica em estágios 2, 3 e 4. O estudo teve como objetivo registrar os eventos arrítmicos durante 12 mesesde acompanhamento e comparar a incidência e a gravidade deles nas diferentes fases da doença renal crônica.Método: No total, 305 pacientes foram avaliados a cada 4 meses até 12 meses de acompanhamento. Os eventosarrítmicos foram avaliados em cada visita de acompanhamento. Resultados: Dentro do mesmo grupo de estágio da doença renal crônica não houve diferença entre as causas doença do nó sinusal e bloqueio atrioventricular, a respeito da ocorrência de qualquer arritmia. No entanto, menor incidência de taquicardia atrial/fibrilação atrial foi observada para todas as comparações entre todos os pacientes e os mesmos subgrupos em pacientes no estágio 2 (total: 58%; doença do nó sinusal: 63%; bloqueio atrioventricular: 51%), comparativamente aos estágios 3 (total:87%, P < 0,0001; doença do nó sinusal: 89%, P = 0,0020; bloqueio atrioventricular: 84%, P = 0,0019) e 4 (total: 85%, P < 0,0001; doença do nó sinusal: 81%, P = 0,0409; bloqueio atrioventricular: 90%, P < 0,0001). Em relação à taquicardia ventricular não sustentada/taquicardia ventricular sustentada, foi observada incidência mais elevada para todas as comparações entre todos os pacientes e os mesmos subgrupos em pacientes no estágio 4 (total: 32%; doença do nó sinusal: 16%; bloqueio atrioventricular: 16%), comparativamente aos estágios 3 (total: 11%, P = 0,0007; doença do nó sinusal: 9%, P = 0,0110; bloqueio atrioventricular: 14%, P = 0,0441) e 2 (total: 3%, P < 0,0001; doença do nó sinusal: 3%, P < 0,0001; bloqueio atrioventricular: 4%, P < 0,0001). Conclusão: Nossos resultados sugerem que quanto mais avançado o estágio da doença renal crônica maior a incidência de arritmias malignas...

The present study evaluated patients who had received a dual chamber pacemaker implant due to sinus node disease or 3rd/2nd degree type 2 atrioventricular block in chronic kidney disease stages 2, 3 and 4. The study was aimed at registering arrhythmic events for 12 months of follow-up and comparing their incidence and severity in different stages of chronic kidney disease. Method: Three hundred and five patients were evaluated every 4 months up to 12 months of follow-up. Arrhythmic events were assessed at each follow-up visit. Results: Within the same chronic kidney disease stage group there was no difference between the causes ofsinus node disease and atrioventricular block for the occurrence of any arrhythmia. However, a lower incidence of atrial fibrillation/tachycardia was observed for all comparisons among all patients and the same subgroups in stage 2 patients (total: 58%; sinus node disease: 63%; atrioventricular block: 51%) compared to stages 3 (total: 87%,P < 0.0001; sinus node disease: 89%, P = 0.0020; atrioventricular block: 84%, P = 0.0019) and 4 (total: 85%,P < 0.0001; sinus node disease: 81%, P = 0.0409; atrioventricular block: 90%, P < 0.0001). Regarding nonsustained/ sustained ventricular tachycardia, a higher incidence was observed for all comparisons among all patients and the same subgroups in stage 4 patients (total: 32%; sinus node disease: 16%; atrioventricular block: 16%) compared to stages 3 (total: 11%, P = 0.0007; sinus node disease: 9%, P = 0.0110; atrioventricular block: 14%, P = 0.0441) and 2 (total: 3%, P < 0.0001; sinus node disease: 3%, P < 0.0001; atrioventricular block: 4%,P < 0.0001). Conclusion: Our findings suggest that the more advanced the stage of chronic kidney disease, thegreater the incidence of malignant arrhythmias...

Design of a Front-end Device of Heart Rate Variability Analysis System Based on Photoplethysmography / 生物医学工程学杂志

Heart rate variability (HRV) is the difference between the successive changes in the heartbeat cycle, and it is produced in the autonomic nervous system modulation of the sinus node of the heart. The HRV is a valuable indicator in predicting the sudden cardiac death and arrhythmic events. Traditional analysis of HRV is based on a multielectrocardiogram (ECG), but the ECG signal acquisition is complex, so we have designed an HRV analysis system based on photoplethysmography (PPG). PPG signal is collected by a microcontroller from human's finger, and it is sent to the terminal via USB-Serial module. The terminal software not only collects the data and plot waveforms, but also stores the data for future HRV analysis. The system is small in size, low in power consumption, and easy for operation. It is suitable for daily care no matter whether it is used at home or in a hospital.

Sinus Tachyarrhythmia

Sinus tachycardia is an accelerated rhythm in which the rate of impulses arising from the sinoatrial node is elevated. Uncontrolled sinus tachycardia may result in a poor prognosis, particularly in patients with cardiovascular disease, because of a hemodynamic disturbance arising from the tachycardia itself. When sinus tachycardia is specifically triggered by anemia, shock, or fever, it is referred to as physiological sinus tachycardia. Physiological sinus tachycardia should resolve with correction of the underlying cause. Inappropriate sinus tachycardia (IST) is unexplained by physiological demand. Palpitation is the most frequent symptom in IST patients. Even though treatment of IST has insufficient efficacy and a relatively high recurrence rate, several treatment strategies such as use of a β-blocker, ivabradine, and radiofrequency catheter ablation can be used for IST patients.

Sinus Node Dysfunction with Pulmonary Edema Associated with Hyponatremia / 대한내과학회지

Hyponatremia is the most common electrolyte abnormality in hospitalized patients and often presents no symptoms. The association between sinus node dysfunction and hyponatremia has rarely been reported. We describe a 77-year-old woman who developed reversible sinus node dysfunction accompanied by pulmonary edema that was associated with hyponatremia.

«Las otras¼ bradicardias / Those "other" bradycardias

La bradicardia es un hallazgo frecuente en el contexto de pacientes hospitalizados. Algunas veces se detecta de manera incidental y se minimizan sus implicaciones clínicas. No obstante, en ocasiones se asocia con la presencia de síntomas o compromiso hemodinámico en los pacientes que ameritan una intervención adicional. La etiología de la bradicardia no siempre es fácil de determinar y no es extraño que se inicien múltiples estudios con el fin de aclarar el porqué de la situación. Los clínicos estamos familiarizados con el efecto farmacológico y los efectos adversos de variados medicamentos que usamos cotidianamente. A pesar de esto, existen múltiples medicamentos con potencial para desarrollar la bradicardia como respuesta a una propiedad farmacológica menos conocida o en relación con efectos adversos infrecuentes, pero sin duda significativos. El objetivo de la presente revisión es repasar las propiedades farmacológicas y el impacto clínico de algunas sustancias que se han relacionado con la bradicardia, más allá de los que todos conocemos, con el fin de orientar las intervenciones a realizar en los pacientes con causas farmacológicas y reversibles de la bradicardia.

Bradycardia is a common finding in the context of hospitalized patients. Sometimes it is incidentally detected and its clinical implications are minimized. But sometimes it is associated with the presence of symptoms or hemodynamic compromise in patients who warrant further intervention. The etiology of the bradycardia is not always easy to determine and it is not surprising that many studies are initiated in order to clarify the reason for the situation. Clinicians are familiar with the pharmacological and adverse effects of various drugs we use every day. Despite this, there are many drugs with potential to develop bradycardia in response to a less known pharmacological properties or effects related to rare but certainly significant effects. The aim of this review is to explain the pharmacological properties and clinical impact of some substances that have been associated with bradycardia, beyond which we all know, in order to target interventions to be performed in patients with pharmacological and reversible causes of bradycardia.