Diagnostic Lacunae and Implications of an Automated Implantable Cardioverter Defibrillator Implantation in a Child with Type 3 Long QT (LQT3) Syndrome

A diagnosis of congenital long QT interval syndrome based on history and electrocardiogram was made in a child in the absence of readily available genetic testing. A genotype 3 (LQT3) was suspected after exclusion of other variants as the child was non?responsive to beta?blocker and sodium channel blocker medication. As the child continues to show episodic bradycardia, polymorphic ventricular ectopy, and T?wave alternans, a single?chamber automated implantable cardioverter?defibrillator implantation was done successfully. This report highlights how the diagnosis of LQT3 was arrived at as well as the anesthetic challenges in the management of patients with LQTS.

Ablação por Cateter é Superior a Drogas Antiarrítmicas como Tratamento de primeira linha para Fibrilação Atrial: uma Revisão Sistemática e Metanálise / Catheter Ablation is Superior to Antiarrhythmic Drugs as First-Line Treatment for Atrial Fibrillation: a Systematic Review and Meta-Analysis

Resumo Fundamento A ablação por cateter é uma terapia bem estabelecida para controle do ritmo cardíaco em pacientes refratários ou intolerantes a drogas antiarrítmicas (DAA). Porém, a eficácia desse procedimento comparada à de DAA como estratégia de primeira linha no controle do ritmo cardíaco na fibrilação atrial é menos conhecida. Objetivos Conduzir uma revisão sistemática e metanálise da ablação por cateter vs. DAA em pacientes sem nenhum tratamento prévio para controle do ritmo. Métodos Buscamos, nos bancos de dados do PubMed, EMBASE, e Cochrane, ensaios randomizados controlados que compararam ablação por cateter com DAA para controle do ritmo cardíaco em pacientes com FA sintomática e descreveram os seguintes desfechos: (1) recorrência de taquiarritmia atrial (TA); (2) FA sintomática; (3) internações hospitalares; e (4) bradicardia sintomática. A heterogeneidade foi avaliada por estatística I2. Valores de p menores que 0,05 foram considerados estatisticamente significativos. Resultados Incluímos cinco ensaios com 994 pacientes, dos quais 502 (50,5%) foram submetidos à ablação por cateter. O período médio de acompanhamento foi de um a cinco anos. Recorrências de TA (OR 0,36; IC95% 0,25-0,52; p<0,001) e de FA sintomática (OR 0,32; IC95% 0,18-0,57; p<0,001), e internações hospitalares (OR 0,25; IC95% 0,15-0,42; p<0,001) foram menos frequentes nos pacientes tratados com ablação por cateter que naqueles tratados com DAA. Bradicardia sintomática não foi diferente entre os grupos (OR 0,55; IC95% 0,18-1,65; p=0,28). Derrame ou tamponamento pericárdico significativo ocorreu em oito dos 464 (1,7%) pacientes no grupo submetido à ablação. Conclusão Esses achados sugerem maior eficácia da ablação por cateter que das DAA como estratégia inicial de controle do ritmo cardíaco em pacientes com DA sintomática.

Abstract Background Catheter ablation is a well-established therapy for rhythm control in patients who are refractory or intolerant to anti-arrhythmic drugs (AAD). Less is known about the efficacy of catheter ablation compared with AAD as a first-line strategy for rhythm control in atrial fibrillation (AF). Objectives We aimed to perform a systematic review and meta-analysis of catheter ablation vs. AAD in patients naïve to prior rhythm control therapies. Methods PubMed, EMBASE, and Cochrane databases were searched for randomized controlled trials that compared catheter ablation to AAD for initial rhythm control in symptomatic AF and reported the outcomes of (1) recurrent atrial tachyarrhythmias (ATs); (2) symptomatic AF; (3) hospitalizations; and (4) symptomatic bradycardia. Heterogeneity was examined with I2statistics. P values of < 0.05 were considered statistically significant. Results We included five trials with 994 patients, of whom 502 (50.5%) underwent catheter ablation. Mean follow-up ranged from one to five years. Recurrences of AT (OR 0.36; 95% CI 0.25-0.52; p<0.001) and symptomatic AF (OR 0.32; 95% CI 0.18-0.57; p<0.001), and hospitalizations (OR 0.25; 95% CI 0.15-0.42; p<0.001) were significantly less frequent in patients treated with catheter ablation compared with AAD. Symptomatic bradycardia was not significantly different between groups (OR 0.55; 95% CI 0.18-1.65; p=0.28). Significant pericardial effusions or tamponade occurred in eight of 464 (1.7%) patients in the catheter ablation group. Conclusion These findings suggest that catheter ablation has superior efficacy to AAD as an initial rhythm control strategy in patients with symptomatic AF.

Translational Approach for Percutaneous Interventions for the Treatment of Cardiac Arrhythmias

Abstract New translational concepts on cellular and tissue substrate of cardiac arrhythmias have been responsible for the development of non-pharmacological interventions, with important achievements compared to the conventional approach with antiarrhythmic drugs. In addition, the increasing knowledge of anatomical and electrophysiological studies, sophisticated mapping methods, special catheters, and controlled clinical trials have favored the progression of ablation of tachyarrhythmias, particularly of ventricular tachyarrhythmias and atrial fibrillation.

Bradycardic and Antiarrhythmic Effects of the D-Limonene in Rats / Efeitos Bradicárdicos e Antiarrítmicos do D-Limoneno em Ratos

Abstract Background: D-limonene (DL) is a monoterpene and is the major component in the essential oil of citrus fruit. It presents antihyperglycemic and vasodilatation activities. Objectives: This study evaluated the cardiovascular effects and potential antiarrhythmic of DL in rats. Methods: Hemodynamic and electrocardiographic (ECG) parameters were measured in male Wistar rats, which under anesthesia had been cannulated in the abdominal aorta and lower vena cava and had electrodes subcutaneously implanted. In the in vitro approach, the heart was removed and perfused using the Langendorff technique. The significance level adopted was 5% (p < 0.05). Results: DL, in doses of 10, 20, and 40 mg/kg (i.v), produced intense and persistent bradycardia associated with hypotension. Bradycardia with prolonged QTc was observed in the ECG in vivo recording. In the in vivo model of arrhythmia induced by Bay K8644, DL (10 mg/kg) decreased the arrhythmia score from 15.33 ± 3.52 to 4.0 ± 2.64 u.a (p < 0.05, n = 4). In isolated perfused hearts, DL (10-3 M) promoted significant reductions in heart rate (from 228.6 ± 8.5 ms to 196.0 ± 9.3 bpm; p < 0.05) and left ventricular development pressure (from 25.2 ± 3.4 to 5.9 ± 1.8 mmHg; n = 5, p < 0.05). Conclusions: DL produces bradycardia and antiarrhythmic activity in rat heart.

Resumo Fundamento: O D-limoneno (DL) é um monoterpeno e o principal componente do óleo essencial de frutas cítricas. Ele apresenta atividades anti-hiperglicêmicas e vasodilatadoras. Objetivos: Este estudo avaliou os efeitos cardiovasculares e antiarrítmicos potenciais do DL em ratos. Métodos: Os parâmetros hemodinâmicos e eletrocardiográficos (ECG) foram mensurados em ratos Wistar machos que, sob anestesia, tiveram a aorta abdominal e a veia cava inferior canuladas e receberam eletrodos implantados subcutaneamente. Na abordagem in vitro, o coração foi removido e perfundido utilizando a técnica de Langendorff. O nível de significância adotado foi de 5% (p < 0,05). Resultados: DL, nas doses de 10, 20 e 40 mg/kg (i.v), produziu bradicardia intensa e persistente associada à hipotensão. A bradicardia com QTc prolongado foi observada no registro in vivo do ECG. No modelo in vivo de arritmia induzida por Bay K8644, DL (10 mg / kg) houve diminuição do escore da arritmia de 15,33 ± 3,52 para 4,0 ± 2,64 u.a (p < 0,05, n = 4). Em corações perfundidos isolados, o DL (10-3 M) promoveu reduções significativas na frequência cardíaca (de 228,6 ± 8,5 ms para 196,0 ± 9,3 bpm; p < 0,05) e na pressão desenvolvida do ventrículo esquerdo (de 25,2 ± 3,4 para 5,9 ± 1,8 mmHg; n = 5, p < 0,05). Conclusões: O DL produz bradicardia e atividade antiarrítmica no coração de ratos.

Clinical efficacy of anti-anxiety treatment in patients with arrhythmia / 中国基层医药

Objective@#To analyze the relationship between arrhythmias and anxiety, and to evaluate the effect of anti-anxiety treatment in patients with arrhythmias while given conventional treatment.@*Methods@#From February 2015 to February 2017, 111 patients with arrhythmia in the Fourth Hospital of Handan were selected in the study, and they were divided into treatment group(n=62) and control group(n=49) according to the admission to single and double wards.The control group was treated with conventional anti-arrhythmias drugs, while the treatment group was treated with low-dose of anti-anxiety drugs and conventional anti-arrhythmias drugs.The therapeutic effects, symptoms improvement time and adverse reactions were compared between the two groups.@*Results@#The effective rate in the treatment group was 96.8%(60/62), which in the control group was 77.6%(38/49), the difference was statistically significant between the two groups (χ2=9.78, P<0.05). The time of symptoms improvement significantly was (4.7±1.1)d in the treatment group, which in the control group was (6.9±1.3)d, there was statistically significant difference between the two groups(t=7.33, P<0.05). There was no statistically significant difference in side effect between the two groups(P>0.05).@*Conclusion@#Arrhythmia has a certain relationship with anxiety.Anti-anxiety combined with anti-arrhythmic treatment can improve the curative effect of patients with arrhythmia and shorten the time when symptoms begin to improve.

Clinical efficacy of anti－anxiety treatment in patients with arrhythmia / 中国基层医药

Objective To analyze the relationship between arrhythmias and anxiety , and to evaluate the effect of anti －anxiety treatment in patients with arrhythmias while given conventional treatment .Methods From February 2015 to February 2017,111 patients with arrhythmia in the Fourth Hospital of Handan were selected in the study,and they were divided into treatment group (n＝62) and control group (n＝49) according to the admission to single and double wards.The control group was treated with conventional anti －arrhythmias drugs,while the treatment group was treated with low －dose of anti －anxiety drugs and conventional anti －arrhythmias drugs.The therapeutic effects,symptoms improvement time and adverse reactions were compared between the two groups .Results The effective rate in the treatment group was 96.8%(60／62), which in the control group was 77.6%(38／49), the difference was statistically significant between the two groups (χ2 ＝9.78,P＜0.05).The time of symptoms improve－ment significantly was (4.7 ±1.1)d in the treatment group ,which in the control group was (6.9 ±1.3)d,there was statistically significant difference between the two groups (t＝7.33,P＜0.05).There was no statistically significant difference in side effect between the two groups (P＞0.05).Conclusion Arrhythmia has a certain relationship with anxiety.Anti－anxiety combined with anti －arrhythmic treatment can improve the curative effect of patients with arrhythmia and shorten the time when symptoms begin to improve.

Effect and safety of amiodarone in emergency treatment of tachyarrhythmia / 中国基层医药

Objective To analyze the efficacy and safety of amiodarone in the treatment of patients with tachyarrhythmia in emergency department.Methods The clinical data of 112 patients with emergency tachyarrhythmia admitted to the Emergency Department of the First People's Hospital of Jinzhong from March 2017 to March 2018 were analyzed.According to the different treatment plans applied,the patients were divided into two groups,with 56 patients in each group.The control group was given routine emergency treatment,and the observation group was treated with routine emergency treatment and amiodarone.The efficacy,blood pressure,heart rate and safety in the two groups were compared.Results The total effective rate in the observation group was 91.07％,which was higher than that in the control group(69.64％) (x2 =8.145,P ＜ 0.05).The diastolic blood pressure,systolic blood pressure and heart rate in the observation group were (77.40:±:6.21) mmHg,(124.24 ± 6.15) mmHg and (130.18 ± 6.14) beats/min,respectively,which were lower than those in the control group[(93.47 ± 7.40)mmHg,(140.60 ± 7.48)mmHg and (150.35 ± 12.32) bests/main] (x2 =8.145,t =12.448,12.642,10.966,all P ＜ 0.05).The total incidence rate of adverse reactions in the observation group was 3.57％,which was lower than 19.64％ in the control group (x2 =7.049,P ＜0.05).Conclusion For patients with tachyarrhythimia in the emergency department,the application of amiodarone has significant curative effects and high safety,which can help stabilize their blood pressure,heart rate and improve their conditions,and yet incurs less adverse reactions.Therefore,it is of significant value to be popularized in clinical applications.

2018 Korean Heart Rhythm Society Guidelines for Antiarrhythmic Drug Therapy in Non-valvular Atrial Fibrillation / 대한내과학회지

Rhythm control therapy is the main strategy for restoring and maintaining sinus rhythm in patients with non-valvular atrial fibrillation (NVAF). Sinus rhythm is better restored and maintained with antiarrhythmic drugs than with placebo treatment. In addition, catheter ablation or combination therapy is more effective than antiarrhythmic drugs for treating NVAF. However, in most clinical trials to date, rhythm control therapy has resulted in neutral clinical outcomes compared with rate control therapy. The decision to undergo rhythm control therapy should be based on age, atrial fibrillation (AF)-related symptoms, type of AF, structural heart disease, and underlying comorbidities. For now, rhythm control therapy is indicated to improve symptoms in patients with NVAF who have refractory symptoms after adequate rate control therapy. The Korean Heart Rhythm Society organized the Korean AF Management Guideline Committee and analyzed all available data, including South Korean patients with NVAF. This review article provides general principles and detailed methodology for rhythm control therapy in South Korean patients with NVAF.

Application of ibutilide in clincal atrial arrhythmia / 中华老年心脑血管病杂志

Objective To study the efficacy and safety of ibutilide for AF and atrial flutter.Methods Thirty-two AF and atrial flutter patients with arrhythmia ≤3 months were randomly divided into ibutilide treatment group (n=17) and amiodarone treatment group (n=15).The patients in ibutilide treatment group were treated with 10 ml 5％ glucose injection containing 1 mg ibutilide,which was repeated after 10 min if it was ineffective and those in amiodarone treatment group were treated with 10 ml 5％ glucose injection containing 150 mg amiodarone,which was repeated after 10 min if it was ineffective.Results The total recovery rate of AF and atrial flutter was significantly higher in ibutilide treatment group than in amiodarone treatment group (64.7％ vs 40.0％,P＜0.05).The mean recovery time of AF and atrial flutter was significantly shorter in ibutilide treatment group than in amiodarone treatment group (29.28±12.57 min vs 70.59±16.83 min,P＜0.01).Conclusion Ibutilide can rapidly recover AF and atrial flutter with a high success rate and a reliable safety.The therapeutic effect of ibutilide is better than that of amiodarone for AF and atrial flutter.

Ablación o drogas en la fibrilación auricular paroxística

Resumen Durante años las drogas antiarrítmicas (DAA) han constituido el tratamiento fundacional para los pacientes con fibrilación auricular paroxística (FAP) en los cuales se desea mantener el ritmo sinusal. Debido a las limitaciones en su eficacia, principalmente a largo plazo, sumado a la gran proporción de pacientes que discontinúan la terapia por efectos adversos, nuevas terapias no farmacológicas han sido desarrolladas con el fin de lograr un adecuado control del ritmo. En la última década la ablación por catéter se ha mostrado como la terapia más efectiva y posiblemente la más segura en aquellos pacientes con falla del tratamiento antiarrítmico. Estudios randomizados y metaanálisis recientemente publicados indican que la ablación podría ser considerada como primera línea de terapia en pacientes seleccionados con FAP en quienes se busca controlar el ritmo. Por lo tanto, en este artículo revisaremos la evidencia actual que avala el uso de DAA o ablación en la FAP.

Management of Aborted Sudden Cardiac Arrest with J Wave Syndrome

We report the case of a 19-year-old male who successfully recovered from sudden cardiac arrest. Careful evaluation did not reveal any electrical or structural abnormalities. He underwent implantable cardioverter defibrillator (ICD) implantation, with a diagnosis of idiopathic ventricular fibrillation (VF). Three months later, VF recurred and was successfully terminated by ICD shock. Electrocardiogram (ECG) revealed a slurred type J point elevation at the inferolateral leads with a horizontal/descending ST segment change, which was not present during the initial hospitalization. Cilostazol was prescribed to prevent further lethal ventricular arrhythmias. Subsequently, no arrhythmic events were reported, and the J wave disappeared at the follow-up ECG. However, recurrent VF episodes with an interval of 1–2 weeks occurred 1 year later, and were terminated by ICD shock. Simultaneous ECG revealed a J point elevation at the inferolateral leads. Cilostazol was replaced by quinidine. Subsequently, no arrhythmic event recurred for over 12 months. Serial follow-up ECG is needed to identify masked inherited primary arrhythmic syndromes in sudden cardiac arrest survivors diagnosed with idiopathic VF. Cilostazol and quinidine might be good therapeutic options to prevent further lethal events in cases where the J wave syndrome is present with recurrent ventricular arrhythmias.

The drug therapy of cardiac arrhythmias / 天津医药

Cardiac arrhythmias are varied and very common. They are usually classified as bradyarrhythmias and tachyarrhythmias, which are treated according to their own common principle separately. There is no long term effective oral drugs that can be used to treat bradyarrhythmias effectively up to now. Pacemaker is still the only effective treatment for it. Now catheter ablation has already applied to almost every kind of tachyarrhythmias, and which is the first choice for treating supraventricular tachycardia and atrial flutter because of the satisfactory result. Most patients with other types of tachyarrhythmias, especially atrial fibrillation and all kinds of premature beats are still given drug therapy. Amiodarone, propafenone, sotalol and mexiletine are common used antiarrhythmic drugs in our country. This article overviewed the principle and the matters need to attention in the drug therapy of cardiac arrhythmias.

Bioequivalência de cloridrato de propafenona 300mg em comprimido revestido em administração pós-prandial em adultos saudáveis / Bioequivalence of propafenone hydrochloride 300mg film coated tablets in healthy adults

OBJETIVO: Avaliar a bioequivalência de duas formulações de cloridrato de propafenona 300mg em comprimido revestido.MÉTODOS: Estudo randomizado, cruzado, aberto, com dois tratamentos, duas sequências e quatro períodos com 60 participantes sadios de ambos os sexos. Os voluntários foram internados em quatro oportunidades durante 24 horas; em cada período, os sujeitos receberam a formulação teste ou a formulação referência, em regime pós-prandial. Foram coletadas 23 amostras de sangue após administração da droga para determinação plasmática da propafenona. Para quantificação da droga, foi utilizada técnica de cromatografia líquida acoplada à espectrometria de massas sequencial. RESULTADOS: As formulações foram consideradas clinicamente bem toleradas. A concentração máxima e a área sob a curva de zero a 36 horas foram comparadas: a média geométrica da razão entre as formulações teste e referência para concentração máxima foi de 110,16%, com intervalo de confiança de 99,44% a 122,04% e coeficiente de variação de 33,95%. A média geométrica da razão entre as formulações teste e referência para a área sob a curva de zero a 36 horas foi de 107,92%, com intervalo de confiança de 99,58% a 116,96% e coeficiente de variação de 26,39%. A média geométrica da razão entre o medicamento teste e referência para área sob a curva de zero ao infinito foi de 107,12%, com intervalo de confiança de de 99,11% a 115,78% e coeficiente de variação de 25,48%. CONCLUSÃO: As formulações teste e referência foram estatisticamente bioequivalentes, de acordo com sua taxa e extensão de absorção.

OBJECTIVE: To evaluate the bioequivalence of two 300mg profanone hydrochloride coated tablets. METHODS: Randomized, cross-over, openstudy, with two treatments, two sequences, and four periods with 60 healthy participants of both genders. The volunteers were admitted in four opportunities over 24 hours; on each period, the subjects received a test formulation, or a reference formulation, in a postprandial administration. Twenty-three samples of blood were collected after oral administration of the drug for determining plasma level of propafenone. Liquid chromatography-mass spectrometry was used for quantifying propafenone. RESULTS: The formulations were considered clinically well tolerated. The maximum concentration and the area under the curve from zero to 36 hours were compared: the geometric mean of the ratio between the test and reference formulations for maximum concentration was 110.16%, with confidence interval of 99.44% - 122.04%), coefficient of variation of 33.95%. The geometric mean of the ratio between the test and reference formulations for the area under the curve of zero to 36 hours was 107.92%, with confidence interval of 99.58% - 116.96%, and coefficient of variation of 26.39%. The geometric mean of the ratio between the formulations for area under the curve of zero to infinitum as 107.12% with confidence interval of 99.11% - 115.78%),and coefficient of variation of 25.48%. CONCLUSION: According to the rate and extension of absorption, the test and reference formulations are statistically bioequivalent.

Prevalencia de potenciales interacciones farmacológicas de Azitromicina en Colombia, 2012-2013 / Prevalence of potential drug interactions with azithromycin in Colombia, 2012-2013

Objetivos Determinar la prevalencia de potenciales interacciones farmacológicas entre azitromicina y diferentes antiarrítmicos del grupo IA y III en una base de datos de prescripción de medicamentos a nivel nacional durante el año 2012-2013. Métodos Estudio retrospectivo a partir de una base de datos poblacional de dispensación de medicamentos. Se extrajeron datos de los pacientes que recibieron azitromicina desde 1 de enero de 2012 a 30 junio de 2013, al igual que pacientes que recibieron este antibiótico en combinación a otros medicamentos con demostrado riesgo de provocar arritmias cardíacas al usarse concomitantemente. Se establecieron frecuencias y proporciones. Resultados Se identificaron 13 859 pacientes que recibieron azitromicina sola o en combinación con otros medicamentos. El tiempo promedio de uso fue 4,5±0,9 días; Un total de 702 pacientes (5,1 %) recibieron azitromicina más otros 19 fármacos de potencial riesgo. Los más frecuentemente asociados fueron: loratadina (77,1 %), difenhidramina (16,5 %) y amitriptilina (8,1 %). Las combinaciones con un solo medicamento fueron las más frecuentes (n=533, 75,9 %), con predominio de azitromicina+loratadina. El máximo número de fármacos combinados fue seis (n=2, 0,3 %). Conclusiones La identificación mediante bases de datos poblacionales la prescripción de medicamentos, es una manera eficaz de encontrar potenciales interacciones entre estos. La frecuencia de potenciales interacciones entre azitromicina y otros fármacos es común en pacientes colombianos. Se debe estimar el riesgo de ocurrencia de eventos cardiacos adversos.(AU)

Objective To determine the prevalence of potential drug interactions between azithromycin and different IA and III antiarrhythmic groups in a national database of drug prescriptions in 2012-2013. Methods Retrospective study based on a population database of medicine dispensation. Data from patients who received azithromycin between January 1, 2012 and June 30, 2013 were extracted along with data from patients who received azithromycin in combination with other medications shown to cause heart arrhythmias when used concomitantly. Frequencies and proportions were established. Results 13 859 patients receiving azithromycin alone or in combination with other drugs were identified. The average time of use was 4.5 ± 0.9 days. A total of 702 patients (5.1 %) received azithromycin plus 19 other potentially risky drugs. The most frequently associated were loratadine (77.1 %), diphenhydramine (16.5 %) and amitriptyline (8.1 %). Combinations with a single drug were the most frequent (n=533, 75.9 %), predominantly azithromycin+loratadine. The maximum number of combined drugs was six (n=2, 0.3 %). Conclusions Identification of drug prescriptions through population databases is an effective way to find potential drug interactions. The frequency of potential interactions between azithromycin and other drugs is common in Colombian patients. Future research should assess the risk of occurrence of adverse cardiac events.(AU)

Comparison of landiolol and esmolol for treatment of intraoperative arrhythmia in dogs / 中华麻醉学杂志

Objective To compare landiolol and esmolol for treatment of intraoperative arrhythmia in dogs.Methods Experiment Ⅰ Eighty-eight KM mice (44 males, 44 females) , aged 4-6 weeks, were studied.The median lethal dose (LD50) and median effective dose (ED50) of landiolol and esmolol were determined using the sequential method.Treatment index (TI) was calculated.Experiment Ⅱ Eighteen dogs (9 males, 9 females), aged 8-12 months, weighing 7-10 kg, were equally and randomly divided into 3 groups: model group (group M) , landiolol group (group L) and esmolol group (group E).Intraoperative arrhythmia model was established by using gastrointestinal surgery combined with epinephrine.When sustained ventricular arrhythmias occurred, normal saline 0.5 ml/kg, landiolol 8.3 mg/kg and esmolol 10.0 mg/kg were given intravenously in C, L and E groups, respectively.The duration of arrhythmias was recorded.If bradycardia occurred (decrease in heart rate [HR] ≥ 25％ of the baseline value) , isoprenaline 0.05 mg/kg and atropine 0.03 mg/kg were injected intravenously.The occurrence of bradycardia after the initial administration of landiolol and esmolol, and the accumulated dose of landiolol and esmolol consumed when bradycardia occurred were recorded.Isoprenaline and atropine-induced improvement in bradycardia was recorded.Results Compared with esmolol, the LD50 and TI of landiolol were significantly increased (P＜0.01), and no significant change was found in ED50 of landiolol (P＞0.05).The duration of arrhythmias was significantly shorter in L and E groups than in group C, and in group L than in group E (P＜0.01).After the initial administration of landiolol and esmolol, the incidence of bradycardia was 0 and 100％, respectively, and the accumulated dose of landiolol and esmolol consumed when bradycardia occurred was (30± 13) mg/kg.Atropine could not effectively treat bradycardia, while isoprenaline could treat bradycardia.Compared with group L, the time for HR to rise and the duration for HR returning to the baseline value were significantly prolonged in group E (P＜0.05).Conclusion Compared with esmolol, landiolol provides faster improvement in intraoperative arrhythmia, weaker negative chronotropic effect, and higher safety;isoproterenol produces better efficacy in treating landiololinduced bradycardia in dogs.

Nebivolol in preventing atrial fibrillation following coronary surgery in patients over 60 years of age / Nebivolol na prevenção da fibrilação atrial após a cirurgia coronária em pacientes acima de 60 anos de idade

Objective: Postoperative atrial fibrillation is a common complication after cardiac surgery, with an incidence as high as 20-50%. Increased age is associated with a significant increase in postoperative atrial fibrillation risk. This common complication is associated with higher morbidity and mortality rates. The aim of this study was to assess the efficacy of nebivolol in preventing atrial fibrillation following coronary artery bypass surgery in patients over 60 years of age. Methods: In this prospective randomized study, 200 patients who were candidates for elective coronary artery bypass surgery were divided into two groups. The first group was administered with nebivolol and the second group was administered with metoprolol. Treatment was initiated four days prior to surgery, and patients were monitored for atrial fibrillation until discharge. Forty-one patients recieved 50 mg metoprolol succinate daily, which was initiated minimum 4 days before surgery. Results: Demographic data were similar in both groups. The incidence of postoperative atrial fibrillation in both groups was similar, with no significant difference being identified [n=20 (20%); n=18 (18%), P=0.718; respectively]. There were not any mortality at both groups during study. Inotropic agent requirement at ICU was similar for both groups [n=12 (12%), n=18 (18%), P=0.32]. Conclusion: We compared the effectiveness of nebivolol and metoprolol in decreasing the incidence of postoperative atrial fibrillation, and determined that nebivolol was as effective as metoprolol in preventing postoperative atrial fibrillation at patients. Nebivolol may be the drug of choice due to its effects, especially after elective coronary artery bypass surgery. .

Objetivo: Pós-operatório fibrilação atrial é uma complicação comum após a cirurgia cardíaca, com uma incidência tão elevada quanto 20-50%. O aumento da idade está associado com elevação significativa no risco de pós-operatório da fibrilação atrial. Esta complicação comum é associada com taxas de morbidade e mortalidade. O objetivo deste estudo foi avaliar a eficácia do nebivolol na prevenção da fibrilação atrial após cirurgia de revascularização do miocárdio de pacientes acima de 60 anos de idade. Métodos: Neste estudo prospectivo e randomizado, duzentos pacientes candidatos à cirurgia de revascularização do miocárdio foram divididos em dois grupos. O primeiro grupo foi administrado com nebivolol e o segundo grupo, com metoprolol. O tratamento foi iniciado quatro dias antes da cirurgia, e os pacientes foram monitorados para fibrilação atrial até a alta. Quarenta e um pacientes receberam 50 mg de sucinato de metoprolol diário, que foi iniciado, no mínimo, 4 dias antes da cirurgia. Resultados: Os dados demográficos foram semelhantes nos dois grupos. A incidência de fibrilação atrial pós-operatória em ambos os grupos foi semelhante, com nenhuma diferença significativa sendo identificado [n=20 (20%); n=18 (18%), P=0,718; respectivamente]. Não houve mortalidade em ambos os grupos durante o estudo. A necessidade de agente inotrópico em UTI foi semelhante nos dois grupos [n=12 pessoas (12%), n=18 (18%), P=0,32]. Conclusão: Nós comparamos a eficácia do nebivolol e metoprolol na diminuição da incidência de fibrilação atrial no pós-operatório, e verificamos que nebivolol foi tão eficaz como metoprolol na prevenção de fibrilação atrial no pós-operatório em pacientes. Nebivolol pode ser a droga de escolha devido aos seus efeitos, especialmente depois da cirurgia revascularização do miocárdio. .

Ivabradine Improves Heart Rate Variability in Patients with Nonischemic Dilated Cardiomyopathy / Ivabradina Melhora a Variabilidade da Frequência Cardíaca em Pacientes com Cardiomiopatia Dilatada Não Isquêmica

Background: Ivabradine is a novel specific heart rate (HR)-lowering agent that improves event-free survival in patients with heart failure (HF). Objectives: We aimed to evaluate the effect of ivabradine on time domain indices of heart rate variability (HRV) in patients with HF. Methods: Forty-eight patients with compensated HF of nonischemic origin were included. Ivabradine treatment was initiated according to the latest HF guidelines. For HRV analysis, 24-h Holter recording was obtained from each patient before and after 8 weeks of treatment with ivabradine. Results: The mean RR interval, standard deviation of all normal to normal RR intervals (SDNN), the standard deviation of 5-min mean RR intervals (SDANN), the mean of the standard deviation of all normal-to-normal RR intervals for all 5-min segments (SDNN index), the percentage of successive normal RR intervals exceeding 50 ms (pNN50), and the square root of the mean of the squares of the differences between successive normal to normal RR intervals (RMSSD) were low at baseline before treatment with ivabradine. After 8 weeks of treatment with ivabradine, the mean HR (83.6 ± 8.0 and 64.6 ± 5.8, p < 0.0001), mean RR interval (713 ± 74 and 943 ± 101 ms, p < 0.0001), SDNN (56.2 ± 15.7 and 87.9 ± 19.4 ms, p < 0.0001), SDANN (49.5 ± 14.7 and 76.4 ± 19.5 ms, p < 0.0001), SDNN index (24.7 ± 8.8 and 38.3 ± 13.1 ms, p < 0.0001), pNN50 (2.4 ± 1.6 and 3.2 ± 2.2 %, p < 0.0001), and RMSSD (13.5 ± 4.6 and 17.8 ± 5.4 ms, p < 0.0001) substantially improved, which sustained during both when awake and while asleep. Conclusion: Our findings suggest that treatment with ivabradine improves HRV in nonischemic patients with HF. .

Fundamento: A ivabradina é um novo agente redutor específico da frequência cardíaca (FC) que melhora a sobrevida livre de eventos de pacientes com insuficiência cardíaca (IC). Objetivo: Avaliar o efeito da ivabradina nos índices temporais da variabilidade da frequência cardíaca (VFC) em pacientes com IC. Métodos: Quarenta e oito pacientes com IC compensada de etiologia não-isquêmica foram incluídos no estudo. O tratamento com ivabradina foi iniciado de acordo com as recomendações mais recentes para a IC. O Holter de 24 horas foi utilizado para analisar os índices da VFC em cada paciente antes e após 8 semanas de tratamento com ivabradina. Resultados: Todos os índices da VFC, o intervalo RR médio, o desvio padrão de todos os intervalos RR normais (DPNN), o desvio padrão de intervalos RR médios de 5 minutos (DPNNM), a média do desvio padrão de todos os intervalos RR normais para todos os segmentos de 5 minutos (índice DPNN), porcentagem de intervalos RR normais sucessivos superiores a 50 milissegundos (pNN50), e a raiz quadrada da média dos quadrados das diferenças entre intervalos RR sucessivos (RMQQD) apresentaram redução no ínicio do estudo, antes do tratamento com ivabradina. Após 8 semanas de tratamento com ivabradina, as médias das FC (83,6 ± 8,0 e 64,6 ± 5,8, p < 0,0001) e todos os índices da VFC, médias dos intervalos RR (713 ± 74 e 943 ± 101 ms, p < 0,0001), DPNN (56,2 ± 15,7 e 87,9 ± 19,4 ms, p < 0,0001), DPNNM (49,5 ± 14,7 e 76,4 ± 19,5 ms, p < 0,0001), índice DPNN (24,7 ± 8,8 e 38,3 ± 13,1 ms, p < 0,0001), pNN50 (2,4 ± 1,6 e 3,2 ± 2,2%, p < 0,0001) e RMQQD (13,5 ± 4,6 e 17,8 ± 5,4 ms , p < 0,0001), foram substancialmente melhorados, e permaneceram nestas ...