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The positive chronotropic action induced by 6-nitrodopamine (6-ND) is selectively blocked by ß1-adrenoceptor antagonists at concentrations that do not affect the positive chronotropic effect induced by dopamine, noradrenaline, and adrenaline. Here, the effects of ( ±)-propranolol, ( ±)-4-NO2-propranolol, and ( ±)-7-NO2-propranolol were investigated in the rat isolated right atrium. The atrium was mounted in glass chambers containing gassed (95%O2:5%CO2) and warmed (37 °C) Krebs-Henseleit's solution, and the isometric tension registered (PowerLab system). ( ±)-Propranolol, ( ±)-4-NO2-propranolol, and ( ±)-7-NO2-propranolol caused concentration-dependent falls in the spontaneous atrial frequency (pIC50: 4.80 ± 0.10, 4.64 ± 0.10, and 4.95 ± 0.10, respectively). The calculated pA2 values for ( ±)-propranolol, ( ±)-4-NO2-propranolol, and ( ±)-7-NO2-propranol on noradrenaline-induced positive chronotropism were 8.44 ± 0.08, 6.41 ± 0.07, and 9.21 ± 0.29, respectively. The positive chronotropism induced by 6-ND (10 pM) was blocked by ( ±)-propranolol (1 µM) and ( ±)-4-NO2-propranolol (30 nM), whereas ( ±)-7-NO2-propranolol (1 µM) had no effect on 6-ND-induced responses. The pIC50 of ( ±)-propranolol, ( ±)-4-NO2-propranolol, and ( ±)-7-NO2-propranolol were significantly shifted to the right in L-NAME-treated atria. The discrepancy between pA2 values of ( ±)-propranolol and its respective pIC50 indicates that the falls in atrial rate induced by ( ±)-propranolol should not be attributed to b-adrenergic antagonism. The reduced chronotropism by ( ±)-propranolol was unaffected by the sodium channel inhibitors tetrodotoxin and lidocaine but that was abolished in atria pre-treated with ( ±)-4-NO2-propranolol. The finding that ( ±)-propranolol reduces spontaneous atrial rate only in concentrations that affect 6-ND-induced positive chronotropism confirms the role of this catecholamine as an endogenous modulator of heart chronotropism. ( ±)-4-NO2-Propranolol behaves as a selective antagonist of 6-ND in the rat isolated atrium.

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Breast cancer (BCa) is related to chronic stress and can reduce the bone mineral density (BMD) through neurochemicals related to beta-adrenergic receptor (ADRB) 1 and 2. Selective beta blockers (sBBs) and nonselective beta blockers (nsBBs) are used to treat systemic arterial hypertension (SAH) and may have osteoprotective effects, as they inhibit ADRBs. To evaluate the effects of sBBs and nsBBs on the BMD of Mexican patients with BCa. A retrospective study was conducted. We included 191 Mexican women with BCa without SAH and with SAH treated with nsBBs, sBBs, and diuretics. BMD was evaluated using a bone density scan (DEX scan). A greater average BMD (p < 0.05) was observed in patients with prior treatment with both nsBBs and sBBs (0.54 ± 0.94 and -0.44 ± 1.22, respectively) compared to patients treated with diuretics or without SAH (-1.73 ± 0.83 and -1.22 ± 0.98, respectively). Regarding the diagnosis of osteoporosis/osteopenia, no cases were observed in patients treated with nsBBs, whereas 5.6% of the patients treated with sBBs presented osteopenia. A total of 23.1% and 10.6% patients managed with diuretics or without treatment presented with osteoporosis and 61.5% and 48% patients managed with loop diuretics and without treatment presented with osteopenia, respectively (p < 0.05). Treatment with nsBBs is a promising option for the prevention and management of osteoporosis/osteopenia in Mexican patients with BCa; however, further prospective studies are needed.

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INTRODUCTION: Ivabradine reduces heart rate (HR), episodes of angina, and nitrate consumption, and increases exercise capacity in patients with chronic angina (CA). In this exploratory study, myocardial perfusion scintigraphy (MPS) was used to evaluate changes in the percentage of myocardial ischemia after ivabradine therapy in patients with CA. METHODS: This prospective, open-label, single-arm study included patients with CA receiving maximum tolerated doses of beta blockers, who had a resting HR ≥ 70 bpm and had experienced ischemia according to MPS during an exercise test at baseline. Participants received ivabradine 5 mg twice daily (titrated according to HR) concomitant with beta blockers. A second MPS was performed after 3 months, without interruption of treatment with beta blockers or ivabradine. The primary outcome was change in the percentage of myocardial ischemia from baseline to 3 months. Time to ischemia during the exercise test, the proportion of patients presenting angina during the exercise test, and health status, assessed using the seven-item Seattle Angina Questionnaire-7 (SAQ-7), were also evaluated. RESULTS: Twenty patients (3 females) with a mean (± standard deviation [SD]) age of 62.2 ± 6.5 years were included in the study, of whom 55% had diabetes, 70% had previous myocardial revascularization, and 45% had previous myocardial infarction. The percentage of patients with myocardial ischemia significantly decreased from baseline to 3 months after initiation of treatment with ivabradine (- 2.9%; 95% confidence interval [CI] - 0.3 to - 5.5; p = 0.031). Mean time to appearance of ischemia increased from 403 ± 176 s at baseline to 466 ± 136 s at 3 months after initiation of ivabradine (Δ62 s; 95% CI 18-106 s; p = 0.008), and the proportion of patients experiencing angina during the exercise test decreased from 40% at baseline to 5% also at 3 months (p = 0.016). Mean resting HR decreased from 76 ± 7 bpm at baseline to 55 ± 8 bpm at 3 months (p < 0.001). The mean SAQ-7 summary score improved from 69 ± 21 at baseline to 83 ± 12 at 3 months (p = 0.001). No serious adverse effects were reported. CONCLUSION: Ivabradine added to beta blockers was associated with a reduction in detectable myocardial ischemia by MPS in patients with CA. Infographic available for this article. TRIAL REGISTRATION: The trial has been retrospectively registered with the Brazilian Registry of Clinical Trials (REBEC) under the following number RBR-5fysqrh (date of registration: 30 November 2023).

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RESUMEN Introducción y objetivos : La insuficiencia cardíaca (IC) es una preocupación creciente de salud pública. Si bien los betabloqueantes (BB) son la base del tratamiento, lograr reducciones objetivo de frecuencia cardíaca puede ser difícil debido a los efectos secundarios y la tolerancia limitada. La ivabradina, un inhibidor único de la corriente If, ofrece un enfoque complementario para controlar la frecuencia cardíaca sin afectar la contractilidad. El objetivo de este estudio fue evaluar la eficacia de agregar ivabradina a la terapia BB en pacientes con IC. Métodos: Se realizó un estudio observacional retrospectivo en un hospital privado en San José, Costa Rica se analizaron 7 casos de pacientes tratados con BB a los cuales posteriormente se les adicionó ivabradina. Se recopilaron datos demo- gráficos, las características clínicas, la frecuencia cardíaca previa y posterior a la ivabradina, la clase funcional NYHA y los valores de laboratorio seleccionados. Resultados: La ivabradina redujo significativamente la frecuencia cardíaca en reposo en un promedio de 26,87 latidos por minuto. El 42,86% alcanzó la dosis meta de su BB inicial después de agregar ivabradina. La clase funcional NYHA se mantuvo estable o mejoró en todos los casos. Conclusiones: Estos resultados sugieren que agregar ivabradina a la terapia BB puede ser una estrategia eficaz para optimizar el control de la frecuencia cardíaca en pacientes con IC. Este enfoque puede mejorar la tolerabilidad de BB, lo que lleva a un mayor manejo de la dosis meta y posiblemente mejores resultados clínicos.

ABSTRACT Introduction and objectives: Heart failure (HF) is a growing public health concern. While beta-blockers (BBs) are the cornerstone of treatment, achieving target heart rate reductions can be difficult due to side effects and limited tolerance. Ivabradine, a unique inhibitor of the If current, offers a complementary approach to controlling heart rate without affecting contractility. This study aimed to evaluate the effectiveness of adding ivabradine to BB therapy in patients with HF. Methods : A retrospective observational study was conducted at a private hospital in San José, Costa Rica. Seven cases of patients treated with BBs who were subsequently added to ivabradine were analyzed. Demographic data, clinical characteristics, heart rate before and after ivabradine, NYHA functional class, and selected laboratory values were collected. Results : Ivabradine significantly reduced resting heart rate by an average of 26.87 beats per minute. Forty-two-point eight-six percent (42.86%) achieved the target dose of their initial BB after adding ivabradine. NYHA functional class remained stable or improved in all cases. Conclusions: These results suggest that adding ivabradine to BB therapy may be an effective strategy to optimize heart rate control in patients with HF. This approach may improve BB tolerability, leading to greater target dose management and possibly better clinical outcomes.

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Inflammatory pathways of Toll-like receptor 4 (TLR4) and NLRP3 inflammasome contribute to acute myocardial infarction (AMI) pathophysiology. The hypoxia-inducible factor 1α (HIF-1α), however, is a key transcription factor related to cardioprotection. This study aimed to compare the influence of carvedilol and thyroid hormones (TH) on inflammatory and HIF-1α proteins and on cardiac haemodynamics in the infarcted heart. Male Wistar rats were allocated into five groups: sham-operated group (SHAM), infarcted group (MI), infarcted treated with the carvedilol group (MI + C), infarcted treated with the TH group (MI + TH), and infarcted co-treated with the carvedilol and TH group (MI + C + TH). Haemodynamic analysis was assessed 15 days post-AMI. The left ventricle (LV) was collected for morphometric and Western blot analysis. The MI group presented LV systolic pressure reduction, LV end-diastolic pressure elevation, and contractility index decrease compared to the SHAM group. The MI + C, MI + TH, and MI + C + TH groups did not reveal such alterations compared to the SHAM group. The MI + TH and MI + C + TH groups presented reduced MyD88 and NLRP3 and increased HIF-1α levels. In conclusion, all treatments preserve the cardiac haemodynamic, and only TH, as isolated treatment or in co-treatment with carvedilol, was able to reduce MyD88 and NLRP3 and increase HIF-1α in the infarcted heart.

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Introduction: Propranolol was the first non-selective beta-adrenergic blocker to be developed. Initially it was used in the treatment of cardiovascular diseases, but since the 60's it has been used in the prevention of migraine. Objective: The objective of this study was to know the history of propranolol and its use as a migraine prophylactic. Methods: This study was an integrative literature review using articles with historical data on propranolol, from its origin in cardiology to its indication in the preventive treatment of migraine. Results: Propranolol was described in 1962 for the treatment of cardiovascular diseases. In the same decade, it was prescribed for the preventive treatment of migraine and, recently, included in the consensus of the Brazilian Headache Society. Conclusion: Although propranolol was initially synthesized for the treatment of heart disease, it has proved to be an effective drug in preventing migraine attacks

Introdução: O propranolol foi o primeiro bloqueador beta-adrenérgico não seletivo a ser desenvolvido. Inicialmente era utilizado no tratamento de doenças cardiovasculares, mas desde a década de 60 tem sido utilizado na prevenção de enxaquecas. Objetivo: O objetivo deste estudo foi conhecer a história do propranolol e seu uso como profilático para enxaqueca. Métodos: Este estudo foi uma revisão integrativa da literatura utilizando artigos com dados históricos sobre o propranolol, desde sua origem na cardiologia até sua indicação no tratamento preventivo da enxaqueca. Resultados: O propranolol foi descrito em 1962 para o tratamento de doenças cardiovasculares. Na mesma década, foi prescrito para o tratamento preventivo da enxaqueca e, recentemente, incluído no consenso da Sociedade Brasileira de Cefaleia. Conclusão: Embora o propranolol tenha sido inicialmente sintetizado para o tratamento de doenças cardíacas, provou ser um medicamento eficaz na prevenção de crises de enxaqueca

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Objectives: The objective of this study was to explore a possible association between ED and the severity of airflow obstruction in patients with COPD. Materials and methods: A cross-sectional study was conducted using the International Index Erectile Function (IIEF), a scale validated and translated to Spanish. Bivariate analyses between subgroups were made for quantitative variables using a t-test for means and Mann­Whitney U for medians; qualitative variables were compared using the χ2 test or Fisher's test, depending on distribution. Confusion bias in the association between ED and airflow obstruction was controlled using a logistic regression model. Results: The Spanish version of the IIEF-15 scale was valid and applicable to the Colombian population. The prevalence of ED in COPD patients living at high altitudes was similar to that found at sea level. Such prevalence is higher than in general population. Beta-blockers increased 7 times the risk of ED, but we found no association between the degree of airflow obstruction and ED. Conclusion: Although the severity of COPD is not associated with ED, the prevalence of ED in COPD is higher than in general population. Therefore, ED screening in COPD patients using the IIEF could be justified. The strong association between beta-blockers and ED had not been previously described in patients with COPD but must be considered in their clinical management.

Objetivos: Explorar una posible asociación entre DE y severidad de la obstrucción al flujo aéreo en pacientes con EPOC. Materiales y métodos: Estudio de corte transversal aplicando el Índice Internacional de Función Eréctil (IIFE), validado y traducido al español. Se realizó análisis bivariado para variables cuantitativas usando prueba-t para medias y U de Mann Whitney para medianas; las variables cualitativas fueron comparadas usando prueba de Chi2 o test de Fisher, según distribución. Los sesgos de confusión en la asociación entre DE y obstrucción al flujo aéreo fueron controlados usando un modelo de regresión logística. Resultados: La versión en español de la escala IIFE-15 fue aplicable en población colombiana. La prevalencia de DE en pacientes con EPOC viviendo a gran altura fue similar a lo encontrado a nivel del mar. Esta prevalencia es mayor que en población general. El uso de beta-bloqueadores aumentó hasta siete veces el riesgo de DE, pero no se encontró asociación entre el grado de obstrucción y la DE. Conclusiones: Aunque la severidad de la EPOC no está asociada con DE, la prevalencia de DE en EPOC es mayor que en población general. Está justificada la realización de tamizaje usando el IIFE. La asociación fuerte entre beta-bloqueadores y DE no se ha descrito previamente en pacientes con EPOC, pero debe considerarse en su manejo.

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ABSTRACT Introduction: Classic coronary artery bypass grafting (CABG) surgery involves diastolic cardiac arrest under cardiopulmonary bypass, while off-pump CABG (OPCABG) has become widespread in recent years. Methods: 174 patients who underwent OPCABG were included in the study. Patients were divided into two groups. Group I (n=90) received ivabradine and Group M (n=84) received metoprolol before surgery until postoperative day 10. Intraoperative arrhythmias and hypotension were recorded. Postoperative atrial fibrillation (AF) and arrhythmia, mortality and morbidity rates were assessed based on the 30-day postoperative follow-up. Results: There were no significant differences in the intraoperative amount of inotropic support and red blood cell transfusion between groups (P=0.87 and P=0.31). However, the rates of intraoperative arrhythmias and hypotension were not significantly higher in Group M (P=0.317 and P=0.47). Ventricular tachycardia/ventricular fibrillation (VT/VF) was observed in 2 patients in both groups. Postoperative AF occurred in 7 patients (7.7%) in Group I and in 10 patients (11.9%) in Group M. Although there was a trend towards a higher prevalence of AF in Group M patients, this did not reach statistical significance. In addition, mortality and morbidity rates were comparable between groups.

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OBJECTIVES: The aim of this study was to ascertain the effect of a drop of timolol 0.5% ophthalmic solution on the systolic function of the left ventricle (LV) and left atrium (LA), and to confirm if timolol helped appraisal of diastolic function by reducing heart rate (HR) and separating the transmitral outflow waves from tissue Doppler imaging (TDI). METHODS: A total of 41 client-owned healthy cats underwent two echocardiograms 20 mins apart. The timolol group (33 cats) received a drop of timolol solution after the first examination. Standard and speckle-tracking echocardiography evaluated the LV and LA function of both groups at the two time points evaluated. RESULTS: Timolol reduced HR (19%), and fractional shortening from LV (20.3%) and LA (16.6%). Septal S' decreased by 51% (from 7.7 to 5.2 cm/s) and lateral S' dropped by 43.1% (7.3 to 5.1 cm/s). Most longitudinal techniques did not change after timolol, including the mitral annular plane systolic excursion from the interventricular annulus, tricuspid annular plane systolic excursion, LV longitudinal strain and LV tissue motion annular displacement. The isovolumic relaxation time increased by 15.2% (from 54 to 64.6 ms), with most cats presenting this variable above the reference (>60 ms). Timolol did not support diastolic assessment, enabling evaluation in only 2/11 cats when using lateral TDI and 1/9 cats using septal TDI. Regarding side effects, miosis occurred in 18 cats (54.5%). CONCLUSIONS AND RELEVANCE: Timolol reduced systolic function, decreasing standard echocardiographic variables. Regarding diastolic evaluation, although timolol decreased HR, it did not separate the mitral diastolic waves, as expected.

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INTRODUCTION: Classic coronary artery bypass grafting (CABG) surgery involves diastolic cardiac arrest under cardiopulmonary bypass, while off-pump CABG (OPCABG) has become widespread in recent years. METHODS: 174 patients who underwent OPCABG were included in the study. Patients were divided into two groups. Group I (n=90) received ivabradine and Group M (n=84) received metoprolol before surgery until postoperative day 10. Intraoperative arrhythmias and hypotension were recorded. Postoperative atrial fibrillation (AF) and arrhythmia, mortality and morbidity rates were assessed based on the 30-day postoperative follow-up. RESULTS: There were no significant differences in the intraoperative amount of inotropic support and red blood cell transfusion between groups (P=0.87 and P=0.31). However, the rates of intraoperative arrhythmias and hypotension were not significantly higher in Group M (P=0.317 and P=0.47). Ventricular tachycardia/ventricular fibrillation (VT/VF) was observed in 2 patients in both groups. Postoperative AF occurred in 7 patients (7.7%) in Group I and in 10 patients (11.9%) in Group M. Although there was a trend towards a higher prevalence of AF in Group M patients, this did not reach statistical significance. In addition, mortality and morbidity rates were comparable between groups.

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BRASH (Bradycardia, Renal failure, Atrioventricular [AV]-node blocker medications, Shock, and Hyperkalemia), a novel syndrome, is a synergistic interaction between AV node blockers and hyperkalemia, resulting in bradycardia. We report a case of BRASH syndrome with marked bradycardia in a patient with End-Stage Renal Disease (ESRD) associated with synergistic interaction between mild hyperkalemia and AV node blockers. Anesthesiologists should be aware of these clinical features, in which ESRD patients with baseline mild hyperkalemia are particularly susceptible to bradycardia. This report will help in its early recognition as well as enable comprehensive and appropriate treatment strategies without further invasive therapy.

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Background: Vasovagal syncope (VVS) is a common clinical condition involving genetic background. The role of beta-blockers in the treatment is controversial. Objective: The aim of this study was to investigate the effect of beta-1 gene polymorphism on beta-blocker therapy in patients with VVS. Methods: We included 123 patients who were diagnosed with VVS after the tilt-table test. We searched for the polymorphism Arg389Gly (rs1801253) in the beta-1 adrenoceptor gene. Results: Overall, 64 patients (52%) had Arg389Arg genotype and 59 patients (48%) had Arg389Gly genotype. The syncopal episodes of patients with Arg389Arg genotype were more frequent compared with patients having Arg389Gly genotype (total syncopal episodes [TSE], 7.9 ± 3.7 vs. 6.4 ± 3.0; p = 0.012). TSE in patients with Arg389Arg genotype decreased significantly after 18 months of beta-blocker treatment (7.9 ± 3.7 vs. 3.0 ± 1.4, p < 0.001). After 18 months of beta-blocker treatment, patients with Arg389Arg genotype had significantly fewer syncopal episodes than patients with Arg389Gly genotype (3.0 ± 1.4 vs. 6.8 ± 3.2, p < 0.001). Conclusions: Results of beta-blocker therapy in patients with Arg389Arg genotype suggest that VVS pathophysiology is a multifactorial condition, with genetic, psychological, and environmental components, and therefore, treatment selection can be based on gene polymorphism. (REV INVEST CLIN. 2020;72(5):300-7)

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BACKGROUND: In recent years, there have been reports of contact dermatitis due to the beta-blockers that are used in the treatment of glaucoma, such as timolol, levubonolol, carteolol, or betaxolol. CASE REPORT: A 37-year-old male patient, who was diagnosed with bilateral primary open-angle glaucoma two years ago, was in therapy with dorzolamide and a topical ß-adrenergic blocker (timolol) in drops twice a day. Months later, he reported conjunctival hyperemia, stinging, and inflammation of both eyelids, followed by erythematous dermatitis, which improved upon treatment discontinuation. The patch test came back negative, but the conjunctival provocation test came back positive 48 hours later. CONCLUSION: Sensitization to the ophthalmic drops that are used to control glaucoma proved to be the mechanism that was causing the clinical picture of the patient. Performing a tolerance test for active anti-glaucoma agents may be helpful in improving tolerance to the medical treatment of some patients, thus, avoiding laser procedures and/or precipitated antiglaucomatous surgeries.

Antecedentes: En los últimos años se han comunicado casos de dermatitis de contacto debido a betabloqueadores utilizados en el tratamiento del glaucoma como el timolol, levubonol, carteolol o betaxolol. Caso clínico: Hombre de 37 años de edad con diagnóstico dos años atrás de glaucoma primario de ángulo abierto bilateral, en terapia con dorzolamida y un agente betabloqueador adrenérgico tópico (timolol) en gotas, dos veces al día. Meses después consultó por hiperemia conjuntival, escozor e inflamación de párpados de ambos ojos seguida de dermatitis eritematosa, que mejoraban al suspender el tratamiento. La prueba del parche resultó negativa, pero la prueba de provocación conjuntival resultó positiva a las 48 horas. Conclusión: La sensibilización a las gotas oftálmicas que se emplean para controlar el glaucoma resultó ser el mecanismo responsable del cuadro clínico de la paciente. La prueba de tolerancia a los principios activos antiglaucomatosos puede resultar de ayuda para mejorar la tolerancia al tratamiento médico de algunos pacientes, con lo que podría evitarse procedimientos con láser o cirugías antiglaucomatosas precipitadas.

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OBJECTIVE: To describe the successful management of 2 dogs with septic shock and persistent tachycardia using norepinephrine and esmolol, a short-acting beta receptor antagonist. SERIES SUMMARY: Two cases are reviewed. In the first case, septic shock with ventricular tachycardia was diagnosed in a 4-year-old neutered female Great Dane that underwent jejunoileal resection and anastomosis for a partial mesenteric torsion. The patient's tachyarrhythmias failed to respond to lidocaine, and an esmolol infusion was used for heart rate control. The condition of the dog improved and she was discharged after 4 days of hospitalization. The second case was a 7-year-old neutered female Cavalier King Charles Spaniel with septic peritonitis. Following surgery for intestinal resection and anastomosis, supraventricular tachycardia developed that was not responsive to volume resuscitation and was treated with an esmolol infusion. The condition of the dog improved and she was discharged after 6 days of hospitalization. Both patients were doing well at the time of long-term follow-up. NEW OR UNIQUE INFORMATION PROVIDED: This case series highlights a novel method of managing dogs in septic shock with persistent tachycardia based on recently published data in the human literature. The use of esmolol may be considered in certain veterinary patients with septic shock to improve persistent tachycardia not related to hypovolemia.

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Fibrodysplasia ossificans progressiva (FOP) is a rare, intractable and devastating genetic connective tissue disorder characterized by progressive ectopic ossification in the soft tissues and skeleton. Three patients, one teenage girl (P1), one male adult (P2) and one male child (P3), were studied and treated with FOPCON (combined formulation of 14 mg of propranolol and 250 mg of ascorbic acid), given three times per day. P1 started treatment in March 2012, P2 in October 2012 and P3 in July 2015. The clinical follow-up of these three patients, before initiating treatment with FOPCON, showed that FOP flare-ups used to occur frequently and that under FOPCON therapy, none of these patients had flare-ups. The striking feature of this treatment with FOPCON, is that, all three cases suffered accidental falls with documented injures until complete healing and that where major flare-ups should occur, injures or sequels, there was none. The present clinical observation shows that ascorbic acid plus the nonspecific beta blocker propranolol can be effectively useful, when administered previously and continually, in the prophylaxis of FOP flare-ups, especially for accidental falls. In this regard, FOPCON could be a prophylactic aid in cases of surgery of patients with FOP, hoping that it may benefit patients from having the severe sequels, characteristic of heterotopic bone formation. All three patients reported, to date, they no longer had flare-ups nor heterotopic ossification and showed normal scar healing.

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Considering the recognized role of thyroid hormones on the cardiovascular system during health and disease, we hypothesized that type 2 deiodinase (D2) activity, the main activation pathway of thyroxine (T4)-to-triiodothyronine (T3), could be an important site to modulate thyroid hormone status, which would then constitute a possible target for β-adrenergic blocking agents in a myocardial infarction (MI) model induced by left coronary occlusion in rats. Despite a sustained and dramatic fall in serum T4 concentrations (60-70%), the serum T3 concentration fell only transiently in the first week post-infarction (53%) and returned to control levels at 8 and 12 weeks after surgery compared to the Sham group (P<0.05). Brown adipose tissue (BAT) D2 activity (fmol T4·min-1·mg ptn-1) was significantly increased by approximately 77% in the 8th week and approximately 100% in the 12th week in the MI group compared to that of the Sham group (P<0.05). Beta-blocker treatment (0.5 g/L propranolol given in the drinking water) maintained a low T3 state in MI animals, dampening both BAT D2 activity (44% reduction) and serum T3 (66% reduction in serum T3) compared to that of the non-treated MI group 12 weeks after surgery (P<0.05). Propranolol improved cardiac function (assessed by echocardiogram) in the MI group compared to the non-treated MI group by 40 and 57%, 1 and 12 weeks after treatment, respectively (P<0.05). Our data suggested that the beta-adrenergic pathway may contribute to BAT D2 hyperactivity and T3 normalization after MI in rats. Propranolol treatment maintained low T3 state and improved cardiac function additionally.

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PURPOSE OF REVIEW: Resting heart rate is an independent risk factor for all-cause and cardiovascular mortality in patients with heart failure. The main objectives are to discuss the prognosis of heart rate, its association with coronary atherosclerosis, and the modalities of control of the heart rate in sinus rhythm and in the rhythm of atrial fibrillation in patients with chronic heart failure. RECENT FINDINGS: As a therapeutic option for control heart rate, medications such as beta-blockers, digoxin, and finally ivabradine have been studied. Non-dihydropyridine calcium channel blockers are contraindicated in patients with heart failure and reduced ejection fraction. The influence of the magnitude of heart rate reduction and beta-blocker dose on morbidity and mortality will be discussed. Regarding the patients with heart failure and atrial fibrillation, there are different findings in heart rate control with the use of a beta-blocker. Patients eligible for ivabradine have clinical benefits and increased ejection fraction. Vagal nerve stimulation has low efficacy for the control of heart rate. Complementary therapies such as tai chi and yoga showed no effect on heart rate. In this review, we discuss the main therapeutic options for the control of heart rate in patients with atherosclerosis and heart failure. More research is needed to examine the effects of therapeutic options for heart rate control in different population types, as well as their effects on clinical outcomes and impact on morbidity and mortality.

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BACKGROUND: The role of beta-blockers in patients with acute coronary syndromes is mainly derived from studies including patients with ST-segment elevation myocardial infarction. Little is known about the use of beta-blockers and associated long-term clinical outcomes in patients with non-ST-elevation acute coronary syndromes (NSTEACS). METHODS: We analyzed short- and long-term clinical outcomes of 2921 patients with NSTEACS using or not oral beta-blockers in the first 24 h of the acute coronary syndromes (ACS) presentation. The association between beta-blocker use and mortality was assessed using a propensity score adjusted analysis (N = 1378). RESULTS: Patients starting oral beta-blockers in the first 24 h of hospitalization, compared with patients who did not, had lower rates of in-hospital mortality (OR = 0.52, 95% CI 0.33 to 0.74, P = 0.002) and higher mean survival times in the long-term follow-up (11.86±0.4 years vs. 9.92±0.39 years, P < 0.001). CONCLUSION: The use of beta-blockers in the first 24 h of patients presenting with NSTEACS was associated with better in-hospital and long-term mortality outcomes.

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Heart rate recovery (HRR) is a strong mortality predictor. Exercise training (ET) and ß-blocker therapy have significant impact on the HRR of patients following myocardial infarction (MI). However, the combination of ET and ß-blocker therapy, as well as its effectiveness in patients with a more compromised HRR (≤12 bpm), has been under-studied. Male patients (n = 64) post-MI were divided: Training + ß-blocker (n = 19), Training (n = 15), ß-blocker (n = 11) and Control (n = 19). Participants performed an ergometric test before and after 3 months of intervention. HRR was obtained during 5 min of recovery and corrected by the cardiac reserve (HRRcorrCR ). Compared to pre-intervention, HRRcorrCR was significantly increased during the 1st and 2nd minutes of recovery in the Training + ß-blocker group (70·5% and 37·5%, respectively; P<0·05). A significant improvement, lasting from the 1st to the 4th minute of recovery, was also observed in the Training group (47%, 50%, 25% and 8·7%, respectively; P<0·05). In contrast, the ß-blocker group showed a reduction in HRRcorrCR during the 2nd and 3rd minutes of recovery (-21·2% and -16·3%, respectively; P<0·05). In addition, interventions involving ET (Training + ßb, Training) were significantly more effective in patients with a pre-intervention HRR ≤ 12 bpm than for patients with HRR > 12 bpm. Combination of ß-blocker therapy with ET does not compromise the effect of training and instead promotes HRR and aerobic capacity improvement. In addition, this combination is particularly beneficial for individuals presenting with a more compromised HRR. However, chronic administration of ß-blocker therapy alone did not promote improvement in HRR or aerobic capacity.

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Heart rate recovery (HRR) is a strong mortality predictor. Exercise training (ET) and β-blocker therapy have significant impact on the HRR of patients following myocardial infarction (MI). However, the combination of ET and β-blocker therapy, as well as its effectiveness in patients with a more compromised HRR (≤12 bpm), has been under-studied. Male patients (n = 64) post-MI were divided: Training + β-blocker (n = 19), Training (n = 15), β-blocker (n = 11) and Control (n = 19). Participants performed an ergometric test before and after 3 months of intervention. HRR was obtained during 5 min of recovery and corrected by the cardiac reserve (HRRcorrCR ). Compared to pre-intervention, HRRcorrCR was significantly increased during the 1st and 2nd minutes of recovery in the Training + β-blocker group (70·5% and 37·5%, respectively; P 12 bpm. Combination of β-blocker therapy with ET does not compromise the effect of training and instead promotes HRR and aerobic capacity improvement. In addition, this combination is particularly beneficial for individuals presenting with a more compromised HRR. However, chronic administration of β-blocker therapy alone did not promote improvement in HRR or aerobic capacity.

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