Cardioprotection stimulated by resveratrol and grape products prevents lethal cardiac arrhythmias in an animal model of ischemia and reperfusion

ABSTRACT Purpose To evaluate the preventive cardioprotective effects of resveratrol and grape products, such as grape juice and red wine, in animal model of cardiac ischemia and reperfusion. Methods Male Wistar rats orally pretreated for 21-days with resveratrol and grape products were anesthetized and placed on mechanical ventilation to surgically induce cardiac ischemia and reperfusion by obstruction (ischemia) followed by liberation (reperfusion) of blood circulation in left descending coronary artery. These rats were submitted to the electrocardiogram (ECG) analysis to evaluate the effects of pretreatment with resveratrol and grape products on the incidence of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) resulting from cardiac ischemia and reperfusion. Results It was observed that the incidence of AVB was significantly lower in rats pretreated with resveratrol (25%), grape juice (37.5%) or red wine (12.5%) than in rats treated with saline solution (80%) or ethanol (80%). Similarly, incidence of LET was also significantly lower in rats pretreated with resveratrol (25%), grape juice (25%) or red wine (0%) than in rats treated with saline solution (62.5%) or ethanol (75%). Conclusions These results indicate that the cardioprotective response stimulated by resveratrol and grape products prevents the lethal cardiac arrhythmias in animal model of ischemia and reperfusion, supporting the idea that this treatment can be beneficial for prevention of severe cardiac arrhythmias in patients with ischemic heart disease.

The effect of high-dose vitamin c on biochemical markers of myocardial injury in coronary artery bypass surgery

Abstract Objective: To evaluate the effect of high-dose vitamin C on cardiac reperfusion injury and plasma levels of creatine kinase-muscle/brain (CK-MB), troponin I, and lactate dehydrogenase (LDH) in patients undergoing coronary artery bypass grafting (CABG). Methods: This is a double-blind randomized clinical trial study. Fifty patients (50-80 years old) who had CABG surgery were selected. The intervention group received 5 g of intravenous vitamin C before anesthesia induction and 5 g of vitamin C in cardioplegic solution. The control group received the same amount of placebo (normal saline). Arterial blood samples were taken to determine the serum levels of CK-MB, troponin I, and LDH enzymes. Left ventricular ejection fraction was measured and hemodynamic parameters were recorded at intervals. Results: High doses of vitamin C in the treatment group led to improvement of ventricular function (ejection fraction [EF]) and low Intensive Care Unit (ICU) stay. The cardiac enzymes level in the vitamin C group was lower than in the control group. These changes were not significant between the groups in different time intervals (anesthesia induction, end of bypass, 6 h after surgery, and 24 h after surgery) for CK-MB, LDH, and troponin I. Hemodynamic parameters, hematocrit, potassium, urinary output, blood transfusion, arrhythmia, and inotropic support showed no significant difference between the groups. Conclusion: Vitamin C has significantly improved the patients' ventricular function (EF) 72 h after surgery and reduced the length of ICU stay. No significant changes in cardiac biomarkers, including CK-MB, troponin I, and LDH, were seen over time in each group. IRCT code: IRCT2016053019470N33

Comparison of the efficacy of oral versus intravascular magnesium in the prevention of hypomagnesemia and arrhythmia after cabg

Abstract Objective: Cardiac arrhythmias are a common challenge following open-heart surgeries. Hypomagnesemia is believed to be correlated with this condition. Prophylactic intravenous magnesium supplementation has been practiced for a long time in patients undergoing CABG. This study was designed in an attempt to compare the efficacy of oral versus intravenous routes in the prevention of hypomagnesemia and arrhythmia. Methods: In this interventional clinical study, 82 patients were randomly assigned to 2 groups. All patients were evaluated for baseline serum magnesium level and arrhythmias. One group received 1,600 mg of oral magnesium hydroxide through nasogastric (NG) tube prior to surgery, while the other group received 2 g of magnesium sulfate during the induction of anesthesia. The serum magnesium level was monitored for 48 hours after the operation. The difference in preoperative hypomagnesemia was non-significant (Sig: 0.576). Results: During the operation, the serum magnesium level peaked around 4 mg/dL, and no hypomagnesemia was detected in any patient. Although the curve of oral group declined parallel and below that of intravenous (IV) group, no significant differences were detected during postoperative monitoring. In addition, a prevalence of arrhythmia of 13.9% and 6.5% was noticed in IV and oral groups, respectively (OR: 0.428). Conclusion: Providing 1,600 mg of oral magnesium supplement to patients is as effective as 2,000 mg of magnesium sulfate IV in preventing hypomagnesemia and arrhythmia after CABG. Thus, the authors introduce this treatment regimen as a promising and cost-effective method.

Cardioprotective effect of preconditioning is more efficient than postconditioning in rats submitted to cardiac ischemia and reperfusion

Abstract Purpose: To investigate the cardioprotective effects of ischemic preconditioning (preIC) and postconditioning (postIC) in animal model of cardiac ischemia/reperfusion. Methods: Adult rats were submitted to protocol of cardiac ischemia/reperfusion (I/R) and randomized into three experimental groups: cardiac I/R (n=33), preCI + cardiac I/R (n=7) and postCI + cardiac I/R (n=8). After this I/R protocol, the incidence of ventricular arrhythmia (VA), atrioventricular block (AVB) and lethality (LET) was evaluated using the electrocardiogram (ECG) analysis. Results: After reestablishment of coronary blood flow, we observed variations of the ECG trace with increased incidence of ventricular arrhythmia (VA) (85%), atrioventricular block (AVB) (79%), and increase of lethality (70%) in cardiac I/R group. The comparison between I/R + preIC group with I/R group demonstrated significant reduction in VA incidence to 28%, AVB to 0% and lethality to 14%. The comparison of I/R + postIC group with I/R group was observed significance reduction in AVB incidence to 25% and lethality to 25%. Conclusion: The preconditioning strategies produce cardioprotection more efficient that postconditioning against myocardial dysfunctions and lethality by cardiac ischemia and reperfusion.

Cardioprotective effect of lipstatin derivative orlistat on normotensive rats submitted to cardiac ischemia and reperfusion

Abstract Purpose: To evaluate in vivo animal model of cardiac ischemia/reperfusion the cardioprotective activity of pancreatic lipase inhibitor of the orlistat. Methods: Adult male Wistar rats were anesthetized, placed on mechanical ventilation and underwent surgery to induce cardiac I/R by obstructing left descending coronary artery followed by reperfusion to evaluation of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) with pancreatic lipase inhibitor orlistat (ORL). At the end of reperfusion, blood samples were collected for determination of triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), lactate dehydrogenase (LDH), creatine kinase (CK), and creatine kinase-MB (CK-MB). Results: Treatment with ORL has been able to decrease the incidence of VA, AVB and LET. Besides that, treatment with ORL reduced serum concentrations of CK and LDL, but did not alter the levels of serum concentration of TG, VLDL and HDL. Conclusion: The reduction of ventricular arrhythmias, atrioventricular block, and lethality and serum levels of creatine kinase produced by treatment with orlistat in animal model of cardiac isquemia/reperfusion injury suggest that ORL could be used as an efficient cardioprotective therapeutic strategy to attenuate myocardial damage related to acute myocardial infarction.

Effect of Lactation on myocardial vulnerability to ischemic insult in rats / Efeito da Lactação sobre a Vulnerabilidade do Miocárdio ao Insulto Isquêmico em Ratas

Abstract Background: Cardiovascular diseases are the leading cause of mortality and long-term disability worldwide. Various studies have suggested a protective effect of lactation in reducing the risk of cardiovascular diseases. Objective: This study was designed to assess the effects of pregnancy and lactation on the vulnerability of the myocardium to an ischemic insult. Methods: Eighteen female rats were randomly divided into three groups: ischemia-reperfusion (IR), in which the hearts of virgin rats underwent IR (n = 6); lactating, in which the rats nursed their pups for 3 weeks and the maternal hearts were then submitted to IR (n = 6); and non-lactating, in which the pups were separated after birth and the maternal hearts were submitted to IR (n = 6). Outcome measures included heart rate (HR), left ventricular developed pressure (LVDP), rate pressure product (RPP), ratio of the infarct size to the area at risk (IS/AAR %), and ventricular arrhythmias - premature ventricular contraction (PVC) and ventricular tachycardia (VT). Results: The IS/AAR was markedly decreased in the lactating group when compared with the non-lactating group (13.2 ± 2.5 versus 39.7 ± 3.5, p < 0.001) and the IR group (13.2 ± 2.5 versus 34.0 ± 4.7, p < 0.05). The evaluation of IR-induced ventricular arrhythmias indicated that the number of compound PVCs during ischemia, and the number and duration of VTs during ischemia and in the first 5 minutes of reperfusion in the non-lactating group were significantly (p < 0.05) higher than those in the lactating and IR groups. Conclusion: Lactation induced early-onset cardioprotective effects, while rats that were not allowed to nurse their pups were more susceptible to myocardial IR injury.

Resumo Fundamento: As doenças cardiovasculares são a principal causa de mortalidade e invalidez a longo prazo a nível mundial. Diversos estudos têm sugerido um efeito protetor da lactação na redução do risco para doenças cardiovasculares. Objetivo: Este estudo foi desenvolvido para avaliar os efeitos da gestação e da lactação sobre a vulnerabilidade do miocárdio ao insulto isquêmico. Métodos: Dezoito ratas foram divididas aleatoriamente em três grupos: isquemia-reperfusão (IR), no qual os corações de ratas virgens foram submetidos à IR (n = 6); lactantes, no qual as ratas amamentaram seus filhotes por 3 semanas e os corações maternos foram, em seguida, submetidos à IR (n = 6); e não lactantes, no qual os filhotes foram separados após o nascimento e os corações maternos foram submetidos à IR (n = 6). As medidas de desfecho incluíram frequência cardíaca (FC), pressão desenvolvida no ventrículo esquerdo (PDVE), duplo produto (DP), razão do tamanho do infarto sobre a área sob risco (TI/ASR %) e arritmias ventriculares - contração ventricular prematura (CVP) e taquicardia ventricular (TV). Resultados: O TI/ASR foi substancialmente menor no grupo de lactantes quando comparado ao grupo de não lactantes (13,2 ± 2,5 versus 39,7 ± 3,5, p < 0,001) e ao grupo IR (13,2 ± 2,5 versus 34,0 ± 4,7, p < 0,05). A avaliação das arritmias ventriculares induzidas pela IR indicou que o número de CVPs compostas na isquemia, e o número e a duração das TVs na isquemia e nos primeiros 5 minutos de reperfusão no grupo de não lactantes foram significativamente (p < 0,05) mais elevados do que os encontrados nos grupos IR e de lactantes. Conclusão: A lactação induziu o aparecimento precoce de efeitos cardioprotetores, enquanto ratas que não foram permitidas a amamentar seus filhotes se mostraram mais suscetíveis à lesão miocárdica por IR.

La repolarización precoz en el electrocardiograma del futbolista: Prevalencia, características y evolución

La repolarización precoz (RP) en el electrocardiograma (ECG) del deportista ha sido considerada un hallazgo benigno. Algunas publicaciones la han asociado a incremento de riesgo de muerte súbita. Los objetivos del presente trabajo fueron evaluar la prevalencia de RP inferolateral en una población de futbolistas entrenados, describir variables asociadas a esta patente e investigar la aparición de eventos en el seguimiento. Se analizaron ECG de futbolistas sin antecedentes personales y familiares de cardiopatía, con examen físico cardiovascular normal. Se consideró RP a la elevación del punto J ≥ 0.1 mV sobre la línea de base en, al menos, 2 derivaciones inferiores y/o precordiales laterales, asociada o no a deflexión positiva o muesca en la parte final del QRS. Se relacionaron con RP el voltaje de R en V5 o V6, el intervalo PR, la frecuencia cardíaca (FC) y la edad. Fueron contactados a los 60±5 meses de la evaluación inicial con ECG. Estadística: chi cuadrado y test t para datos no apareados. Fueron evaluados 210 ECG de futbolistas hombres, de origen europeo-sudamericano, con entrenamiento de alta intensidad. Edad: 18 ±4.6 años. La RP se encontró en 86 ECG (40.9%), incluida el subtipo inferior en 17 (8.1%). Un ECG mostró RP en cara inferior en forma aislada. Los futbolistas con RP tuvieron mayor edad, menor FC, PR más prolongado y menor voltaje de R. Ninguno de los futbolistas presentó eventos cardiovasculares a los 5 años de la evaluación.

Early repolarization (RP) on the electrocardiogram (ECG) of the athlete has been considered a benign finding. In some publications it has been associated with increased risk of sudden death. The objectives of this study were to evaluate the prevalence of infero-lateral RP in a population of trained players, to describe variables associated with this pattern and investigate the occurrence of events in the follow up. ECG of players with a normal cardiovascular physical examination and without family and personal history of heart disease, were analyzed. RP was considered the J-point elevation ≥ 0.1 mV over baseline in at least 2 inferior and / or lateral precordial leads, associated or not with positive deflection or notch in the end of the QRS. RP is related to the voltage of R in V5 or V6, the PR interval, heart rate (HR) and age. They were contacted at 60 ± 5 months after the initial assessment ECG. Statistics: chi square and t test for unpaired data. We evaluated ECG of 210 soccer players, of European-South American origin, with high intensity training. Age: 18 ± 4.6 years. The RP ECG was present in 86 (40.9%), including the lower subtype in 17 (8.1%). One ECG showed PR in lower face in isolation. RP footballers were older, with less FC, prolonged PR and lower voltage of R. None of the players presented cardiovascular events in a 5 years follow up after this evaluation.

Avaliação dos efeitos da cafeína sobre a modulação autonômica e o ritmo cardíaco em pacientes com queixa de palpitações / Evaluation of the caffeine effects about the cardiac autonomic modulation and rhythm in patients with palpitations

A cafeína pertence ao grupo das metilxantinas e apresenta efeitos farmacológicos que podem contribuirpara o desencadeamento de arritmias cardíacas, com o aumento da estimulação simpática. Objetivo: Avaliara associação entre o consumo de cafeína e o desencadeamento ou o agravamento de arritmias cardíacas e suainfluência sobre o tônus autonômico. Método: Foram avaliados 51 pacientes submetidos ao Holter de 24 horasdevido a queixa de palpitação. O Holter avaliou a presença de diferentes arritmias e tônus autonômico por meiode índices de variabilidade da frequência cardíaca, principalmente do SDNN. Todos os pacientes preencheramum diário alimentar durante o período do registro. Estes foram avaliados por uma nutricionista por meio dosoftware NutWin 1.5 para quantificar a ingestão de cafeína e outros nutrientes. Os indivíduos foram divididos emdois grupos de acordo com a mediana do consumo de cafeína (35 mg). Resultados: O consumo médio diário decafeína foi de 14 ± 15 mg no grupo de menor consumo (n=27) vs. 100 ± 61 mg no grupo de maior consumo (n=24)(p<0,0001). Não foi observada associação entre o maior consumo de cafeína e qualquer extrassístole ventricular ousupraventricular isolada, pareada, > 10 ectopias/hora ou taquicardia ventricular ou supraventricular (p>0,05). Nogrupo de maior consumo, observou-se tendência de maior estimulação simpática, predominantemente durante operíodo do sono. Contudo, a análise restrita a esse período também não mostrou associação com o desencadeamentode qualquer arritmia. Conclusão: O consumo leve a moderado de cafeína (aproximadamente 100 mg/dia) não seassociou com o desencadeamento de qualquer arritmia, apesar de acarretar um discreto aumento da estimulaçãosimpática, principalmente durante o período do sono.

Abstract: Objective: Caffeine belongs to the methylxanthine group and has pharmacological effects that maycontribute to the onset of cardiac arrhythmias such as sympathetic overstimulation. The objectives were to evaluatethe association between caffeine intake and the onset or worsening of cardiac arrhythmias and their influenceon the cardiac autonomic tonus. Methods: Fifty-one patients underwent a 24-hour Holter due to complaintsof palpitations. The Holter evaluated the presence of different arrhythmias and autonomic tonus according toheart rate variability rates, mainly the SDNN. A food diary was filled out by all patients throughout their Holterrecording and were evaluated by a dietician using the NutWin 1.5 software to quantify the intake of caffeine andother nutrients. Subjects were divided into two groups according to the median caffeine intake (35 mg). Results:The mean daily consumption of caffeine was 14 ± 15 mg in the lowest consumption group (n=27) vs. 100 ± 61 mgin the highest consumption group (n=24) (p<0.0001). No association was observed between higher caffeine intakeand supraventricular or ventricular isolated premature beats, paired premature beats, > 10 premature beats perhour or ventricular or supraventricular tachycardia (p>0.05). A trend of sympathetic overstimulation was observed.

Manuseio de portadores de dispositivos cardíacos implantáveis com arritmias atriais: uma revisão / Management of patients with implantable cardiac devices and atrial arrhythmias: a review

O manuseio do portador de dispositivos cardíacos implantáveis com arritmias atriais envolve profilaxia de eventos tromboembólicos, controle do ritmo ou da frequência cardíaca, cuidados com a anticoagulação e programação adequada. Esta revisão tem como objetivo avaliar o uso desses dispositivos na detecção de arritmias atriais, bem como a anticoagulação oral em seus portadores e o manuseio perioperatório de tais fármacos em implantes, revisões ou trocas de geradores de pulsos. Cuidados com a programação dos dispositivos, bem como a utilidade dos algoritmos de estimulação atrial rápida na interrupção de arritmias atriais também são destacados.

The management of patients with implantable cardiac devices and atrial arrhythmias involves the prophylaxis of thromboembolic events, heart rate or rhythm control, anticoagulation care and appropriate programming. This review aims to evaluate the use of these devices to detect atrial arrhythmias as well as oral anticoagulation in the patients and the peri-operative management of these drugs in the implants, reviews or exchange of pulse generators. Appropriate programming of the devices and the use of atrial overdrive pacing to prevent atrial tachycardia are also highlighted.

Estudo da sístole elétrica ventricular nos insuficientes renais crônicos hemodialisados / Study of ventricular electrical systole in patients with end-stage kidney disease on hemodialysis

FUNDAMENTO: Os indivíduos com insuficiência renal crônica terminal estão sujeitos a um elevado estresse cardíaco pelo carácter repetitivo e intermitente da terapia dialítica. As alterações na sístole elétrica ventricular induzidas pela necessária terapia dialítica são um contributo importante na predição da ocorrência de morte súbita arrítmica na insuficiência renal crônica terminal. OBJETIVO: O objetivo principal desta investigação é avaliar o comportamento da repolarização ventricular em face da terapia dialítica, mediante o estudo do intervalo QTc e dispersão do QTc. MÉTODOS: A amostra em estudo inclui 47 indivíduos sujeitos a hemodiálise (61,7% do sexo masculino e 38,3% do sexo feminino) com idade média de 66,79 ± 13,16 anos. Todos os indivíduos foram sujeitos a três eletrocardiogramas realizados em três momentos durante a terapia dialítica (pré, durante e após a sessão), sendo posteriormente analisada a sístole elétrica ventricular. RESULTADOS: Ocorreu um aumento do intervalo QTc máximo e da dispersão do QTc associado à terapia dialítica. Aliado ao aumento desses intervalos ocorreu um aumento do número de indivíduos com critérios eletrocardiográficos para hipertrofia ventricular esquerda, registando-se no período pós-diálise uma média superior do intervalo QTc máximo (473 ± 27,63 mseg) e da dispersão do QTc (58,95 ± 18,87 mseg) desses indivíduos, comparativamente aos indivíduos sem HVE, 455,21 ± 26,85 mseg e 44 ± 16,41 mseg, respectivamente. CONCLUSÃO: O presente estudo confirmou um aumento do intervalo QTc e da dispersão do QTc associado à terapia dialítica. Esse aspecto reforça a dependência da repolarização ventricular em relação ao equilíbrio hídrico e eletrolítico e sugere um perfil de maior vulnerabilidade arrítmica associada à terapia dialítica.

BACKGROUND: Patients with end-stage kidney disease (ESKD) experience elevated cardiac stress because of the repetitive and intermittent character of dialysis. Changes in ventricular electrical systole induced by necessary dialysis significantly contribute to predict sudden death due to arrhythmia in ESKD. OBJECTIVE: The major objective of this study was to assess the behavior of ventricular repolarization in dialysis by analyzing QTc interval and QTc dispersion. METHODS: This study sample consisted of 47 patients undergoing hemodialysis (61.7% males and 38.3% females), whose mean age was 66.79±13.16 years. All of them underwent three electrocardiograms performed before, during and after one dialysis session. Ventricular electrical systole was analyzed later. RESULTS: An increase in maximum QTc interval and QTc dispersion associated with dialysis was observed. In addition, an increase in the number of individuals meeting the electrocardiographic criteria for left ventricular hypertrophy (LVH) was observed. After dialysis, higher means of the maximum QTc interval (473 ± 27.63 mseg) and of the QTc dispersion (58.95 ± 18.87 mseg) were observed in individuals with LVH as compared with those in individuals without LVH (455.21 ± 26.85 mseg and 44 ± 16.41 mseg, respectively). CONCLUSION: This study confirmed an increase in the QTc interval and QTc dispersion associated with dialysis. That emphasizes the dependence of ventricular repolarization on fluid and electrolyte balance, and suggests a profile of higher vulnerability to arrhythmia associated with dialysis .

Variabilidade da frequência cardíaca em pacientes pré-diabéticose portadores de diabetes mellitus tipo 2 / Heart rate variability in pre-diabetic and type 2 diabetes mellitus patients

O diabetes mellitus é um dos principais problemas de saúde pública, responsável por cerca de 5% de todasas mortes a cada ano e com prevalência e morbimortalidade em ascensão no Brasil e no mundo. Níveis glicêmicosacima do normal, mas sem preencher os critérios para diabetes mellitus, constituem o pré-diabetes. Estudosdemonstram que o diabetes mellitus está associado a alterações do sistema nervoso autônomo, constituindo fatorfisiopatológico importante no desenvolvimento de comorbidades, como a neuropatia autonômica cardiovascular.Porém, poucos estudos correlacionaram essas alterações com o período pré-diabetes, embora haja indícios de quepossam estar presentes já nessa fase. Objetivos: Demonstrar, por meio da variabilidade da frequência cardíaca, aexistência de correlação entre alterações do sistema nervoso autônomo, em pacientes pré-diabéticos e diabéticos.Métodos: Foram estudados 40 pacientes, divididos em quatro grupos: (A) controle; (B) pré-diabéticos; (C)portadores de diabetes mellitus tipo 2 controlados; e (D) portadores de diabetes mellitus tipo 2 não controlados. Osdados obtidos no Holter 24h foram correlacionados com os níveis glicêmicos de jejum e a hemoglobina glicada,além de dados clínicos, como pressão arterial, índice de massa corporal e circunferência abdominal. Resultados:Foi encontrada associação significativa ao se comparar o SDNN do grupo controle com pacientes diabéticoscontrolados (p=0,026) e não controlados (p=0,022). Conclusões: Os resultados encontrados sugerem que ospacientes diabéticos apresentam distúrbios na modulação autonômica cardíaca, conforme descrito na literatura,não sendo encontrada disautonomia cardíaca significativa em pré-diabéticos.

Background: Diabetes mellitus (DM) is a major public health problem, accounting for about 5% ofall deaths each year and rising prevalence and morbidity and mortality in Brazil and worldwide. Pre-diabetes isconstituted by blood glucose levels over the normal range which do not meet DM criteria. Studies have shown thatDM is associated with changes in the autonomic nervous system and is an important pathophysiological factorin the development of comorbidities such as cardiovascular autonomic neuropathy. However, few studies havecorrelated these changes with pre-diabetes although there are indications that they may be present at this stage.Objectives: Demonstrate a correlation between the autonomic nervous system, pre-diabetes and diabetes changesusing heart rate variability. Methods: We studied 40 patients, divided into four groups: (A) control; (B) prediabetics;(C) patients with controlled type 2 diabetes mellitus, (D) patients with uncontrolled type 2 diabetes.Data obtained by the 24-hour Holter were correlated with fasting glucose levels and glycated hemoglobin, inaddition to clinical data such as blood pressure, BMI and waist circumference. Results: A significant associationwas observed when the control group SDNN was compared to that of controlled (p=0.026) and uncontrolled (p=0.022) diabetic patients. Conclusions: Based on the results we can suggest that diabetic patients have cardiacautonomic modulation disturbances, as described in the literature and significant cardiac dysautonomia was notobserved in pre-diabetics.

Fundamento: La diabetes mellitus (DM) es uno de los principales problemas de salud pública,responsable de un 5% de la totalidad de las muertes todos los años y con prevalencia y morbimortalidad enascensión en Brasil y en el mundo. La pre diabetes comprende niveles glucémicos arriba de lo considerado normal,pero no rellena los criterios para DM. Estudios demuestran que la DM está asociada con alteraciones del sistemanervioso autónomo, constituyéndose en importante factor fisiopatológico para el desarrollo de comorbilidades,como la neuropatía autonómica cardiovascular. Sin embargo, pocos estudios han correlacionado dichas alteracionescon el período pre diabetes, aunque existan indicios de que puedan estar presentes ya en esa fase. Objetivos:Demostrar una correlación, por medio de la variabilidad de la frecuencia cardiaca, entre las alteraciones del sistemanervioso autónomo, la pre diabetes y la DM. Métodos: Se estudiaron 40 pacientes, divididos en cuatro grupos:(A) control; (B) pre diabéticos; (C) portadores de diabetes mellitus tipo 2 controlados; y (D) portadores de DMtipo 2 no controlados. Los datos obtenidos en el Holter 24h fueron correlacionados con los niveles glucémicosde ayuno y hemoglobina glicada, además de datos clínicos, tales como: presión arterial, IMC y circunferenciaabdominal. Resultados: Se encontró asociación significativa al compararse el SDNN del grupo control conpacientes diabéticos controlados (p=0,026) y no controlados (p=0,022). Conclusiones: A partir de los resultadosencontrados, se puede sugerir, mediante los resultados hasta entonces obtenidos, que los pacientes diabéticospresentan disturbios en la modulación autonómica cardiaca, conforme descrito en la literatura, no encontrándosedisautonomía cardiaca significativa en pre diabéticos.

Potential pro-arrhythmic effect of cardiac resynchronization therapy

A decline in mortality due to pump failure has been clearly documented after cardiac resynchronization therapy [CRT], however the impact on sudden cardiac death and the development of malignant ventricular arrhythmias remains questionable. Our study aims to investigate this alleged pro-arrhythmic effect of CRT using surface electrocardiogram [ECG] markers of pro-arrhythmia. Seventy five patients, who received CRT were included in this study. Manual measurement of corrected QT interval [QTc], T[peak-end] T[p-e] interval, QT dispersion [QTd] and T[peak-end] dispersion during baseline 12 lead surface ECG and after applying atrial-biventricular pacing were done. Arrhythmias post CRT was recorded from ECG, 24 h holter monitoring or pacemaker programmer event recorder. QTc interval showed significant prolongation after CRT [498.9 +/- 50.8 vs. 476.2 +/- 41.6 msec, P = 0.0001]. Comparing patients with major arrhythmogenic events [MAE] and increased frequency of premature ventricular contractions [PVCs] post CRT pacing to those patients without arrhythmias, there was a significant prolongation of the QTc interval [527 +/- 63.29 vs. 496.95 +/- 45.2 msec, P = 0.043] and T p-e interval [94.16 +/- 9 vs. 87.41 +/- 16.37 msec, P = 0.049]. While in the arrhythmogenic group, there was an insignificant decrease in QTd and T[peak-end] dispersion. QTc and T[p-e] intervals are a potential predictor of occurrence of MAE and PVCs. On the other hand, T[p-e] dispersion and QTd did not show a predictive potential for arrhythmia

Efficacy of high dose of magnesium sulphate for cardiac arrhythmias in patients of wheat pill poisoning

To study the prophylactic effects of High Dose Magnesium Sulphate on Cardiac Arrhythmias, Cardiogenic shock and associated mortality in Cases of Aluminum Phosphide Poisoning. Seventy One patients of wheat pill poisoning were randomly selected. Thirty seven were given high dose of Magnesium Sulphate [study group] and 34 were given low dose of magnesium sulphate [control group] through intravenous route along with other supportive measures. Patients were observed for cardiac arrhythmias and mortality in both groups. Study end point was safe discharge from the hospital or death. The mean age of the sample was 25.27 +/- 7.48 years. Frequency of cardiac arrhythmias was 40.54%[n=15] in study group versus 55.88% [n=19] in the control group. Average length of stay and frequency of cardiogenic shock was slightly lower in the study group, i.e., 1.42 +/- 0.65 days while it was 1.78 +/- 1.38 days for the control group. Overall, mortality in both the groups was 66.20% [n=47], which remained almost equal in both groups or slightly favored study group with 64.86% [n=24] in the study and 67.65% [n=23] in the control group. High dose magnesium sulphate administration was found to be helpful for cardiac arrhythmia and shock but mortality remained unchanged

Effects of short-term administration of estradiol on reperfusion arrhythmias in rats of different ages

Little is known about age-related differences in short-term effects of estradiol on ischemia-reperfusion (I/R) insults. The present study was designed to evaluate the effects of short-term treatment with estradiol on reperfusion arrhythmias in isolated hearts of 6-7-week-old and 12-14-month-old female rats. Wistar rats were sham-operated, ovariectomized and treated with vehicle or ovariectomized and treated with 17β-estradiol (E2; 5 µg·100 g-1·day-1) for 4 days. Hearts were perfused by the Langendorff technique. Reperfusion arrhythmias, i.e., ventricular tachycardia and/or ventricular fibrillation, were induced by 15 min of left coronary artery ligation and 30 min of reperfusion. The duration and incidence of I/R arrhythmias were significantly higher in young rats compared to middle-aged rats (arrhythmia severity index: 9.4 ± 1.0 vs 3.0 ± 0.3 arbitrary units, respectively, P < 0.05). In addition, middle-aged rats showed lower heart rate, systolic tension and coronary flow. Four-day E2 treatment caused an increase in uterine weight. Although E2 administration had no significant effect on the duration of I/R arrhythmias in middle-aged rats, it induced a marked reduction in the rhythm disturbances of young rats accompanied by a decrease in heart rate of isolated hearts. Also, this reduction was associated with an increase in QT interval. No significant changes were observed in the QT interval of middle-aged E2-treated rats. These data demonstrate that short-term estradiol treatment protects against I/R arrhythmias in hearts of young female rats. The anti-arrhythmogenic effect of estradiol might be related to a lengthening of the QT interval.