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.

A Case of Severe Transient Sinus Bradycardia in Herpes Simplex Infection

@#Herpes simplex virus remains the commonest organism of sporadic encephalitis. Common presentations in herpes simplex encephalitis are seizures and behavioural changes apart from fever, lethargy and headache. Cardiac manifestations, nonetheless, are uncommon in herpes simplex infection. We presented an 8-year-old boy with clinical meningoencephalitis and bradycardia. The initial impression was typhoid meningitis due to severe bradycardia. He was managed in paediatric intensive care unit with transcutaneous cardiac pacemaker and infusion of low dose noradrenaline until the bradycardia resolved. A diagnosis of herpes simplex encephalitis was made based on clinical and specific right temporal and focal radiological findings including right insular ribbon involvement, focal changes over temporal and frontal electroencephalographic (EEG) inference and positive HSV IgM serological confirmation.

Severe Sinus Bradycardia Requiring Cardiac Pacing in a Lupus Patient Who Was Successfully Treated Using Methylprednisolone Pulse Therapy / 대한내과학회지

Symptomatic sinus bradycardia in adults with systemic lupus erythematosus (SLE) is rare. Here, we report a case of severe sinus bradycardia requiring temporary cardiac pacing in a SLE patient successfully treated using methylprednisolone pulse therapy.

Alteraciones electrocardiográficas en anorexia nervosa: revisión crítica de la literatura / Electrocardiographic abnormalities in anorexia nervosa: a critical review of the literature

Introducción: La anorexia nervosa (AN) es un trastorno de la conducta alimentaria y, entre sus causas de mortalidad, las arritmias cardiacas y la muerte súbita son frecuentes, por lo que es indispensable la monitorización electrocardiográfica. Se han descrito muchos hallazgos con resultados contradictorios, por lo que es necesaria una revisión crítica de la literatura científica. Metodología: Revisión de los estudios relevantes sobre cambios electrocardiográficos en AN, consultados en PubMed desde 1974 hasta febrero de 2014, utilizando los términos MeSH: Eating disorders, nervosa anorexia, sinusal bradycardia, QT prolongation, QT dispersion, electrocardiography, EKG, electrocardiogram. Resultados y discusión: Las dos alteraciones más comunes reportadas incluyen la bradicardia sinusal y los cambios en la repolarización evidenciados en prolongación del QT e incremento de su dispersión. Los trastornos electrolíticos parecen ser la causa de estas alteraciones en algunos pacientes, pero otras razones se discuten en detalle, como la desviación del eje del QRS a la derecha, la alteración en variabilidad de la frecuencia cardiaca, R en derivación V6 de bajo voltaje, disminución de la amplitud del QRS y onda T y alargamiento del QRS. La mayoría de los autores hablan de reversibilidad de los cambios después del tratamiento. Conclusiones: Estos resultados siguen apoyando la necesidad de valorar a los pacientes con AN con electrocardiogramas inicial y de seguimiento, para el diagnóstico temprano y tratamiento de alteraciones cardiovasculares relacionadas con alta morbimortalidad. También apoyan la necesidad del uso racional de psicofármacos para no aumentar el riesgo de arritmias cardiacas y muerte súbita.

Background: Anorexia nervosa is an eating disorder in which cardiac arrhythmias and sudden death are frequent causes of mortality, which makes electrocardiographic monitoring indispensable in these patients. There are many suggestive findings but results are contradictory, making a critical review of the scientific literature is necessary. Methods: The most relevant studies on electrocardiographic (EKG) changes in patients with AN, found in PubMed from 1974 to February 2014, were reviewed using the MeSH terms: eating disorders, nervosa anorexia, sinus bradycardia, QT prolongation, QT dispersion, electrocardio graphy, EKG, and electrocardiogram. Findings and discussion: The two most common EKG findings reported in the literature are sinus bradycardia and changes in depolarization, as shown by prolongation and increased dispersion of the QT interval. Electrolyte disturbances seem to be the cause of these disturbances in some patients, but other reasons are also discussed in detail, such as QRS right axis deviation, disturbances of heart rate variability, low R wave voltage in V6, amplitude decrease of the QRS and T wave, and QRS prolongation. The majority of authors report that these changes are reversible after treatment of AN. Conclusions: These findings support the need for initial and follow-up EKGs in patients with AN and for early diagnosis and treatment of cardiovascular disturbances that are associated with morbidity and mortality. They also support the need for the rational use of psychop harmacology, and that does not increase the risk of arrhythmias and sudden death in these patients.

Atropine-induced atrial bigeminy during general anesthesia in a Cocker Spaniel dog / 대한수의학회지

A 12-year-old female Cocker Spaniel (7.5 kg of body weight) was presented for resection of a mammary gland tumor. During surgery, the heart rate was remarkably decreased due to a second-degree type I atrioventricular block. Atropine (0.05 mg/kg) was administered to increase the heart rate. Although the heart rate was elevated, atrial bigeminy occurred and persisted until the dog fully recovered from general anesthesia. These results highlight the possibility of atrial bigeminy caused by atropine administration during anesthesia.

New Proposal for Adlt's Normal Sinus Heart Rates

BACKGROUND: The normal sinus heart rate standard of 60 to 100 beats per minute was set by the NYHA(New York Heart Association) in 1928. It has long been accepted to physicians, but clinical studies and experience suggest that both these limits are too high. Thus we reexamined to define operationally normal sinus heart rate that are scientifically and clinically acceptable. METHODS: Total 1,930 subjects(aged 20 to 92 years) were analyzed and evaluated for age, sex, body mass index(BMI), systolic blood pressure, diastolic blood pressure, and resting heart rates by electrocardiogram. We used Pearson's correlation test and t-test to analyze these data. RESULTS: Among 1930 subjects, 982 cases were male(51%) and 948 cases were female (49%), whose mean age was 48 years in male and 51 years in female. For the entire sample, mean heart rate and standard deviation was 68 +/- 11 beats/min. There was statistically significant difference between male(67+/-11 beats/min) and female(68+/-10 beats/min)(P<0,05). The prevalence of sinus tachycardia and bradycardia, calculated by current normal standard of 60 to 100 beats/min, was 22.0% (424 cases) and 0.9% (18 cases). Mean +/- two standard deviation yields rounded extremes of 46 to 89 beats/min for normal sinus heart rate. A positive correlations between resting heart rate and age(r=0.11), systolic blood pressure(r =0.17), diastolic blood pressure(r=0.12) were found(P<0.01). CONCLUSIONS: Two extremes of the normal sinus heart rate standard of 60 to 100 beats/min are set too high. They result in lower sensitivity for tachycardia and lower specificity for bradycardia. We propose that normal range for sinus heart rate should be 50 to 90 beats/min which is statistically justified, more realistic for clinical investigation.

Critérios para o diagnóstico eletrocardiográfico de vagotonia: existe consenso na opiniäo de especialistas? / Diagnostic Criteria for Vagotonia in the Standard 12-Lead Electrocardiogram. Is there a Consensus in the Opinion of Specialists ?

Objetivo - Identificar os critérios mais valorizados par ao diagnóstico eletrocardiográfico de vagotomia na opiniäo de cardiologistas. Métodos - Questionário distribuído a 40 cardiologistas durante o 9§ Congresso brasileiro de Arritmias Cardíacas (Säo José do Rio Preto, SP). A amostra representou cerca de 15 por cento dos participantes e foi propositalmente viesada para incluir 70 por cento dos palestrantes e apresentadores de temas-livres, e excluir profissionais näo-médicos, a fim de aumentar a validade de conteúdo das respostas. Foi dividido em duas partes: 1ª de resposta espontânea, preenchida sem conhecimento da seguinte; e 2ª, de resposta induzida, onde foram apresentados, em ordem randômica, critérios de eletrocardiograma (ECG) da literatura. Nas duas partes, foi solicitado que as respostas seguissem uma escala decrescente de importância. Resultados - Na 1ª arte. 35 diferentes critérios foram apontados, mas somente 3 foram citados por mais de 25 por cento dos entrevistados: bradicardia sinusal (95 por cento), presença de onda T apiculada (30 por cento) e repolarizaçäo precoce (27,5 por cento). Na 2ª parte, o critério melhor classificado foi a bradicardia sinusal, seguido pelo supradesnível do ponto J e pelo supradesnível do segmento ST. Conclusäo. Entre cardiologistas com interesse em eletrocardiografia e arritmias cardíacas, com exceçäo da bradicardia sinusal, näo existe um claro consenso quanto ao grupo de critérios a serem valorizados para a identificaçäo vagotonia no ECG. Estudos adicionais säo necessários para validar objetivamente os critérios mais comuns identificados nesta pesquisa

A Case Report of Ventricular Dysrhythmia in a Patient with Sinus Bradycardia and Low Blood Pressure / 대한마취과학회지

Sinus Bradycardia per se does not necessitate therapy. In fact, its presence often implies good health or a good prognosis. A 56-year-old patient, whose pulse rate was about 35 beats per minute and blood pressure was 80/50 mmHg, underwent total gastrectomy under general anesthesia. Ventricular dysrhythmia occurred after the second dose of gallamine managed with lidocaine, and after the administration of atropine and ephednne managed with hydralazine. Authors report this case with the evaluation of references.

A Case Report of Ventricular Dysrhythmia in a Patient with Sinus Bradycardia and Low Blood Pressure / 대한마취과학회지

Sinus Bradycardia per se does not necessitate therapy. In fact, its presence often implies good health or a good prognosis. A 56-year-old patient, whose pulse rate was about 35 beats per minute and blood pressure was 80/50 mmHg, underwent total gastrectomy under general anesthesia. Ventricular dysrhythmia occurred after the second dose of gallamine managed with lidocaine, and after the administration of atropine and ephednne managed with hydralazine. Authors report this case with the evaluation of references.