[Effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/ß-catenin/PPARγ pathway in arrhythmic rats].

This paper aimed to investigate the effect of total flavonoids of buckwheat flower and leaf on myocardial cell apoptosis and Wnt/ß-catenin/peroxisome proliferator-activated receptor γ(PPARγ) pathway in arrhythmic rats. SD rats were randomly divided into a control group, a model group, a low-dose(20 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a medium-dose(40 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a high-dose(80 mg·kg~(-1)) group of total flavonoids of buckwheat flower and leaf, a propranolol hydrochloride(2 mg·kg~(-1)) group, with 12 rats in each group. Except the control group, rats in other groups were prepared as models of arrhythmia by sublingual injection of 1 mL·kg~(-1) of 0.002% aconitine. After grouping and intervention with drugs, the arrhythmia, myocardial cells apoptosis, myocardial tissue glutathione peroxidase(GSH-Px), catalase(CAT), malondialdehyde(MDA), serum interleukin-6(IL-6), prostaglandin E2(PGE2) levels, myocardial tissue apoptosis, and Wnt/ß-catenin/PPARγ pathway-related protein expression of rats in each group were measured. As compared with the control group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA levels in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and ß-catenin protein expression levels increased significantly in the model group, whereas the GSH-Px and CAT levels, and Bcl-2 and PPARγ protein expression levels in myocardial tissues reduced significantly. As compared with the model group, the arrhythmia score, the number of ventricular premature beats, ventricular fibrillation duration, myocardial cell apoptosis rate, MDA leve in myocardial tissues, serum IL-6 and PGE2 levels, Bax in myocardial tissues, and Wnt1 and ß-catenin protein expression levels reduced in the drug intervention groups, whereas the GSH-Px and CAT levels and Bcl-2 and PPARγ protein expression levels in myocardial tissues increased. The groups of total flavonoids of buckwheat flower and leaf were in a dose-dependent manner. There was no significant difference in the levels of each index in rats between the propranolol hydrochloride group and the high-dose group of total flavonoids of buckwheat flower and leaf. The total flavonoids of buckwheat flower and leaf inhibit the activation of Wnt/ß-catenin pathway, up-regulate the expression of PPARγ, reduce oxidative stress and inflammatory damage in myocardial tissues of arrhythmic rats, reduce myocardial cell apoptosis, and improve the symptoms of arrhythmia in rats.

The incidence of cardiac arrhythmias during exercise stress testing: a focus on patients with severe obesity undergoing sleeve gastrectomy.

INTRODUCTION: Obesity is associated with a higher risk of cardiac arrhythmias. Sleeve gastrectomy (SG) is a common bariatric surgery with beneficial effects on weight loss and comorbidities. The study aimed to investigate the prevalence of arrhythmias during maximal exercise testing in patients with moderate-severe obesity and to evaluate the impact of SG on these arrhythmic events. METHODS: All patients with moderate or severe obesity who were considered suitable candidates for SG between June 2015 and September 2020 were recruited. Each patient underwent three incremental, maximal, ECG-monitored cardiopulmonary exercise test 1 month before and 6 and 12 months after SG; the frequency and complexity of ventricular premature beats (VPBs) and atrial premature beats (APBs) have been evaluated during rest, exercise and recovery phases. RESULTS: Fifty patients with severe obesity (BMI 46.39 ± 7.89 kg/m2) were included in the study. After SG, patients presented a decreased BMI (34.15 ± 6.25 kg/m2 at 6 months post-SG and 31.87 ± 5.99 kg/m2 at 12 months post-SG). At 6 months post-SG, an increase in VPBs, mainly during the recovery phase, was observed. At 12 months post-SG, a reduction in VPBs compared with the 6 months evaluation was showed. CONCLUSION: Although in the early post-surgical phase the risk of exercise-induced arrhythmias may be higher, SG does not seem to increase the occurrence of arrhythmias in the long-term. No life-threating arrhythmias were found during post-SG evaluations.

Changes in arterial blood pressure characteristics following an extrasystolic beat or a fast 50 ml fluid challenge do not predict fluid responsiveness during cardiac surgery.

Prediction of fluid responsiveness is essential in perioperative goal directed therapy, but dynamic tests of fluid responsiveness are not applicable during open-chest surgery. We hypothesised that two methods could predict fluid responsiveness during cardiac surgery based on their ability to alter preload and thereby induce changes in arterial blood pressure characteristics: (1) the change caused by extrasystolic beats and (2) the change caused by a fast infusion of 50 ml crystalloid (micro-fluid challenge). Arterial blood pressure and electrocardiogram waveforms were collected during surgical preparation of the left internal mammary artery in patients undergoing coronary artery bypass surgery. Patients received a fluid challenge (5 ml/kg ideal body weight). The first 50 ml were infused in 10 s and comprised the micro-fluid challenge. Predictor variables were defined as post-ectopic beat changes (compared with sinus beats preceding ectopy) in arterial blood pressure characteristics, such as pulse pressure and systolic pressure, or micro-fluid challenge induced changes in the same blood pressure characteristics. Patients were considered fluid responsive if stroke volume index increased by 15% or more after the full fluid challenge. Diagnostic accuracy was calculated by the area under the receiver operating characteristics curve (AUC). Fifty-six patients were included for statistical analysis. Thirty-one had extrasystoles. The maximal AUC was found for the extrasystolic change in pulse pressure and was 0.70 (CI [0.35 to 1.00]). The micro-fluid challenge method generally produced lower AUC point estimates. Extrasystoles did not predict fluid responsiveness with convincing accuracy in patients undergoing cardiac surgery and changes in arterial waveform indices following a micro-fluid challenge could not predict fluid responsiveness. Given a low number of fluid responders and inherently reduced statistical power, our data does not support firm conclusions about the utility of the extrasystolic method. CLINICAL TRIAL REGISTRATION: Unique identifier: NCT02903316. https://clinicaltrials.gov/ct2/show/NCT02903316?cond=NCT02903316&rank=1 .

Intoxicación por adelfa, un caso poco frecuente / Oleander poisoning, a rare case

Introducción: Las intoxicaciones por plantas son infrecuentes, de complicada orientación diagnóstica, que en general, se dificulta la identificación de la planta, su potencial tóxico y el tratamiento específico. Entre ellas la adelfa, capaz de producir cuadros de intoxicación grave, como un caso consultado a la guardia del Centro Nacional de Toxicología. Objetivos: Presentar un caso clínico de intoxicación grave por adelfa. Caso clínico: Paciente adulto, con intranquilidad, vómitos, dolores abdominales, tensión arterial 150/90 mmHg, frecuencia cardiaca y respiratoria normales, refirió que había consumido vía oral y rectal una poción elaborada con una planta, como tratamiento antiparasitario. El médico de guardia decidió comunicarse con el Centro Nacional de Toxicología. Se identificó la planta como adelfa. A pesar de la aplicación de reposición de volumen, lavado gástrico y la administración de carbón activado; presentó bloqueo auriculoventricular, extrasístoles aisladas y bradicardia. Se suministró atropina endovenosa, luego se trasladó hacia la unidad de cuidados intensivos y posteriormente egresó. Conclusiones: El caso presentó una intoxicación aguda grave por adelfa, con un correcto diagnóstico y tratamiento, que requirió de la labor conjunta de los médicos del cuerpo de guardia del hospital, la terapia intensiva y del Centro Nacional de Toxicología(AU)

Introduction: Poisoning by plants is infrequent, with a complicated diagnostic orientation, which in general makes it difficult to identify the plant, its toxic potential and specific treatment. Among them the oleander, capable of producing serious intoxication, as a case consulted to the National Toxicology Center. Objectives: To present a clinical case of severe oleander poisoning. Clinical case: Adult patient with restlessness, vomiting, abdominal pain, blood pressure 150/90 mmHg, normal heart and respiratory rates, and reported that he had consumed orally and rectally a potion made with a plant, as an antiparasitic treatment. The doctor who assisted him decided to communicate with the National Toxicology Center. The plant was identified as oleander. Despite the application of volume replacement, gastric lavage and the administration of activated charcoal; the patient presented atrioventricular block, isolated extrasystoles and bradycardia, intravenous atropine was administered, and subsequent transfer to the intensive care unit, and later he was discharged. Conclusions: The case presented a severe acute oleander poisoning, there was correct diagnosis and treatment, which required the joint work of the doctors from hospital emergency, the intensive care unit and the National Toxicology Center(AU)

Electrocardiographic markers of myocardial conduction and repolarization in Boxer dogs / Marcadores eletrocardiográficos de condução e repolarização miocárdica em cães da raça Boxer

ABSTRACT: Electrocardiographic markers have been used in people to classify arrhythmogenic risk. The aims of this study were to investigate electrocardiographic markers of conduction and repolarization in Boxers and non-Boxer dogs, and compare such findings between groups. Ten-lead standard electrocardiograms of Boxer dogs and non-Boxers recorded from 2015 to 2018 were retrospectively reviewed. Dogs >/ 4 years of age and weighing > 20kg were included. Animals with valvular insufficiencies, congenital cardiopathies, cardiac dilation, suspected systolic dysfunction, biphasic T-wave, bundle branch blocks, and those receiving antiarrhythmics were excluded. Electrocardiographic markers of conduction, QRS duration (QRSd) and dispersion (QRSD), and repolarization (corrected QT interval, Tpeak-Tend, JT and JTpeak), as well as derived indices, were measured. Two hundred dogs met the inclusion/exclusion requirements, including 97 Boxers (8.1±2.5 years old; 30±7kg) and 103 non-Boxer (8.8±2.5 years old, 30±8kg). QRSd and QRSD, and repolarization markers in lead II and left precordial lead V4 were considered similar between groups. Dispersion of late repolarization on lead rV2, Tpeak-Tend interval, was considered longer in Boxers (45±8ms vs 38±10ms, P=0.01). The Tpeak-Tend/JTpeak and the JTpeak/JT also differed between groups. Our results indicate that the dispersion of myocardial late repolarization in lead rV2 is slower in Boxers than other dog breeds.(AU)

Marcadores eletrocardiográficos têm sido estudados em seres humanos para estratificação do risco arritmogênico. Os objetivos deste estudo foram investigar os marcadores eletrocardiográficos de condução e repolarização miocárdica em Boxers e em cães de outras raças, e comparar tais resultados entre os grupos. Para tal, a eletrocardiografia convencional de 10 derivações registradas de 2015 a 2018 foram avaliadas de maneira retrospectiva. Cães com idade igual ou superior a 4 anos e pesando > 20kg foram incluídos. Animais com insuficiência valvar, cardiopatias congênitas, dilatação cardíaca, suspeita de disfunção sistólica, onda T bifásica, bloqueio(s) de ramo(s), ou aqueles que recebiam antiarrítmicos foram excluídos. Variáveis eletrocardiográficas de condução, como a duração e dispersão do complexo QRS (QRSd e QRSD, respectivamente), e repolarização (intervalo QT corrigido, Tpico-Tfinal, JT e JTpico), bem como índices derivados, foram mensurados. Duzentos cães que se adequaram aos critérios de inclusão/exclusão foram incluídos, 97 Boxers (8,1±2,5 anos; 30±7kg) e 103 não Boxers (8,8±2,5 anos; 30±8kg). O QRSd e o QRSD, e os marcadores de repolarização nas derivações II e V4 foram similares entre os grupos. O marcador de dispersão da repolarização tardia na derivação rV2, Tpico-Tfinal, foi considerado mais longo no Boxers (45±8ms vs 38±10ms, P=0.01). O Tpico-Tfinal/JTpico e o JTpico/JT também diferiram entre os grupos. Nossos resultados indicam que a dispersão da repolarização miocárdica tardia na derivação precordial direita, rV2, é mais lenta no Boxer do que nas outras raças.(AU)

Isolated Non-Compacted Myocardium: Should We Consider the Presence of Extrasystoles as the Initial Manifestation?

Ventricular non-compaction occurs due to failure in myocardial morphogenesis during the fetal period. Patients can have heart failure, as well as systemic complications due to thromboembolism and cardiac arrhythmias. Early diagnosis is essential. We present the case of an asymptomatic 49-year-old woman who initially manifested ventricular extrasystoles and heart failure with reduced ejection fraction and a myocardial noncompaction diagnosis

Compression of a giant pseudomeningocele causing transient anoxic seizures-a case report.

Transient anoxic seizure upon application of pressure on a giant pseudomeningocele has never been reported in the literature; such abrupt changes in intracranial pressure due to large volume of cerebrospinal fluid (CSF) translocation, if left untreated may lead to permanent cerebral hypoxic injury and death. Here we describe a case of a 26-year-old woman who had undergone lumbar disc surgery in another unit few months ago and developed a large lump around her back. Any pressure on the lump resulted in headaches and at times episodes of seizures. Clinical examination revealed a very large fluid-filled lump consistent with a giant pseudomeningocele, confirmed by an MRI. A video EEG while applying pressure on the lump was recorded. The patient developed a typical seizure attack with a characteristic pattern of cerebral anoxia, and a paired ECG showed irregular rhythm with junctional and ventricular ectopic beats during the latter part of the attack, raising a suspicion of asystole. Upon relieving the pressure off the lump, the patient gradually regained consciousness with no permanent neurological deficit. We then discuss the pathophysiology of anoxic seizures and highlight the need to be vigilant in managing patients with such lesions in order to prevent permanent cerebral hypoxic injury and death.

Influence of irregular heart rhythm on radiation exposure, image quality and diagnostic impact of cardiac computed tomography angiography in 4,339 patients. Data from the German Cardiac Computed Tomography Registry.

BACKGROUND: Coronary computed tomography angiography (coronary CTA) provides non-invasive evaluation of the coronary arteries with high precision for the detection of significant coronary artery disease (CAD). AIM: To investigate whether irregular heart rhythm including atrial fibrillation and premature beats during data acquisition influences (i) radiation and contrast media exposure, (ii) number of non-evaluable coronary segments and (iii) diagnostic impact of coronary CTA. METHODS: Twelve tertiary care centers with ≥64 slice CT scanners and ≥5 years of experience with cardiovascular imaging participated in this registry. Between 2009 and 2014, 4339 examinations were analysed in patients who underwent clinically indicated coronary CTA for suspected CAD. Clinical and epidemiologic data were gathered from all patients. In addition, clinical presentation, heart rate and rhythm during the scan, Agatston score, radiation and contrast media exposure and the diagnostic impact of coronary CTA were systematically analysed. RESULTS: Of 4339 patients in total, 260 (6.0%) had irregular heart rhythm, whereas the remaining 4079 (94.0%) had stable sinus rhythm. Patients with irregular heart rhythm were older (63.2 ± 12.5yrs versus 58.6 ± 11.4yrs. p < 0.001), exhibited a higher rate of pathologic stress tests before CTA (37.1% versus 26.1%, p < 0.01) and higher heart rates during CTA compared to those with sinus rhythm (62.5 ± 11.6bpm versus 58.9 ± 8.5bpm, p < 0.001). Both contrast media exposure and radiation exposure were significantly higher in patients with irregular heart rhythm (90 mL (95%CI = 80-110 mL) versus 80 mL (95%CI = 70-90 mL) and 6.2 mSv (95%CI = 2.5-11.7) versus 3.3 mSv (95%CI = 1.7-6.9), p < 0.001 for both). Coronary CTA excluded significant CAD less frequently in patients with irregular heart rhythm (32.9% versus 44.8%, p < 0.001). This was attributed to the higher rate of examinations with at least one non-diagnostic coronary segment in patients with irregular heart rhythm (10.8% versus 4.6%, p < 0.001). Subsequent invasive angiography could be avoided in 47.2% of patients with irregular heart rhythm compared to 52.9% of patients with sinus rhythm (p = NS), whereas downstream stress testing was recommended in 3.2% of patients with irregular heart rhythm versus 4.0% of patients with sinus rhythm (p = NS). CONCLUSION: A significant number of patients scheduled for coronary CTA have irregular heart rhythm in a real-world clinical setting. In such patients, heart rate during coronary CTA is higher, possibly resulting in (i) higher radiation and contrast agent exposure and (ii) more frequent coronary CTA examinations with at least one non-diagnostic coronary artery segment. However, this does not seem to lead to increased downstream stress testing or subsequent invasive procedures.

Trigeminia de la bigeminia ventricular por mecanismo reentrante: reentrada de la reentrada / Trigeminy of ventricular bigeminy caused by reentrant mechanism: reentry of reentry

El proceso post-infarto agudo de miocardio genera el sustrato apropiado para la formación de circuitos de reentrada, los cuales son considerados como el mecanismo más frecuente de las extrasístoles y taquiarritmias ventriculares. Presentamos el trazado electrocardiográfico de un paciente con infarto agudo de miocardio en quien se observó la inusual concurrencia de una trigeminia ventricular acoplada a extrasístoles ventriculares bigeminadas, que originó una secuencia de trigeminia sobre la bigeminia, evidenciando la existencia de dos circuitos reentrantes (reentrada de la reentrada); después de una dupla de la extrasístole bigeminada se genera un aleteo ventricular.

The process that follows an acute myocardial infarction generates an appropriate substrate for the formation of reentry circuits, considered to be the most frequent mechanism of ventricular extrasystoles and tachyarrhythmias. We present the case of a patient with an acute myocardial infarction unusually concurring with ventricular trigeminy coupled to ventricular bigeminated extrasystoles giving rise to a trigeminy sequence over the bigeminy, which indicates the existence of two reentry circuits (reentry of reentry) that trigger ventricular flutter.

[Malignant bileaflet mitral valve prolapse syndrome in otherwise idiopathic ventricular fibrillation]. / Malignes Mitralklappenprolapssyndrom bei "idiopathischem" Kammerflimmern.

A 32-year-old, otherwise healthy woman was admitted after successful out-of-hospital resuscitation due to ventricular fibrillation. Established cardiac, pulmonary, metabolic, and toxicological causes were excluded. However, persisting (biphasic) negative T waves in the inferior ECG leads and premature ventricular contractions (PVC) were noted. PVC morphology indicated a focus alternating between the posterior papillary muscle/the left posterior fascicle and the left ventricular outflow tract region/anterior papillary muscle. Echocardiography revealed a bileaflet mitral prolapse with mild mitral valve regurgitation. This case is a typical presentation of the recently described malignant bileaflet mitral valve prolapse syndrome. The patient was discharged without overt neurological deficit after implantation of a cardioverter-defibrillator.

[Effect of bronchoalveolar lavage on the heart rhythm and conduction of the children with severe pneumonia].

OBJECTIVE: To observe the effect of bronchoalveolar lavage on the heart rhythm and conduction of children with severe pneumonia through monitoring the electrocardiogram change of different step of the bronchoalveolar lavage, for proving the safety of the operation of bronchoalveolar lavage from the perspective of cardiac electrophysiology. METHOD: From July 2011 to March 2012, 30 patients who were hospitalized in pneumology department of Dalian Children's Hospital and met the inclusion criteria and therapeutic indications of bronchoalveolar lavage were chosen. They were 3 to 12 years old, the average age was 5.3 years, including 17 boys and 13 girls, the ratio of boys and girls is 1.3: 1. Continuous sampling the electrocardiogram before and during the process including anesthesia, entering into glottis, lavage, aspiration, and revive, and recording the heart rate, rhythm amplitude and width of P wave, the PR interval, the form and width of QRS complex were also measured. The recorded data were analyzed and statistical analysis to reflect the change of the cardiac electrophysiology. RESULT: The incidence of heart rate increase was 100.0%, 26 (86.7%) patients began to emerge after anesthesia, the rest of the patients also developed heart rate increase after the start of bronchoscopic operation. All patients had sinus tachycardia, and were most obvious in the progress of lavage and revive. In the process of entering into glottis, lavage, aspiration, 13 (43.3%) patients had arrhythmia episodes. Types of arrhythmia included sinus bradycardia, atrioventricular block and premature beat. Incidences of intraoperative arrhythmia compared with the pre- and post-operation were all statistically significantly different (P = 0.00). The most common arrhythmia were premature beat, in 17 of the 30 cases there were premature beat including 9 cases with atrial premature beats and 8 cases ventricular premature contraction. Two patients had III° atrioventricular block accompanied by serious sinus bradycardia. All kinds of arrhythmias except sinus tachycardia disappeared after the operation was ended. Five patients (16.7%) had PR interval prolongation. Five patients (16.7%) had incomplete right bundle branch block (IRBBB) . Incidences of IRBBB compared with the pre-operation and post-operation were all not significantly different [13.3% (n = 4) vs. 0(n = 0) and 3.3% (n = 1), all P > 0.05]. Different operating progress made no significant difference in the measurement value of electrocardiogram[13.3% (n = 4) vs. 0(n = 0) and 3.3% (n = 1), all P > 0.05], but showed the most notable effect on heart rate. CONCLUSION: Bronchoalveolar lavage can influence the heart rhythm and conduction, but most of the influence with pathological significance are transient. Cardiac electrophysiological changes were the most obvious in endotracheal operation with the risk of malignant arrhythmia but the risk is low, the bronchoalveolar lavage technique is safe. The contingency plans for dealing with all kinds of adverse reactions must be ready before the operations of bronchoalveolar lavage. During the procedure, the patient's ECG changes should be closely monitored to reduce the incidence of adverse reactions.

Heart rate variability and arrhythmias evaluated with Holter in dogs with degenerative mitral valve disease / Variabilidade da frequência cardíaca e arritmias detectadas pelo exame Holter em cães com degeneração valvar mitral

Cardiac diseases promote alterations in the autonomic control of the heart, leading to an increase in heart rate and, as a result, a decrease in heart rate variability (HRV).The aim of this study was to evaluate if the development of heart failure secondary to degenerative mitral valve disease (DMVD) concurs with changes in autonomic modulation of heart rhythm which are assessed by long electrocardiography examination (Holter). Dogs were evaluated by clinical examination and echocardiography in order to be categorized into the following groups: Control (healthy; n=6), DMVD (disease without heart failure; n=8), and DMVD heart failure (disease with heart failure; n=13). Arrhythmias and frequency domain HRV were determined by Holter. Diseased animals, when compared to healthy, had significantly lower total power, which indicates overall HRV. DMVD heart failure dogs also showed other disturbances such as high incidence of supraventricular arrhythmias, high heart rate, little amount of pauses (2.0s long between consecutive heartbeats), longer time in tachycardia, shorter time in bradycardia, low high frequency (parasympathetic control), and high low frequency (sympathetic and parasympathetic control) when compared to control (p<0.05). In DMVD dogs, Holter-derived variables changed with the development of heart failure...

As cardiopatias cursam com alterações do controle autonômico do coração, resultando em taquicardia e consequente diminuição na variabilidade da frequência cardíaca (VFC). O objetivo deste estudo foi avaliar se o desenvolvimento de insuficiência cardíaca secundária à degeneração valvar mitral (DVM) leva a alterações no controle autonômico do coração, as quais podem ser determinadas pela eletrocardiografia contínua (Holter). Cães foram distribuídos em grupos experimentais após avaliação clínica e ecocardiográfica da seguinte maneira: controle (saudáveis; n=6), DVM sem insuficiência cardíaca (n=8) e DVM com insuficiência cardíaca (n=13). Arritmias e VFC foram determinadas pelo Holter. Animais portadores de DVM, quando comparados ao controle, apresentaram diminuição significativa da potência total, a qual é representativa de toda a VFC. Somente cães doentes e com insuficiência cardíaca apresentaram incidência elevada de arritmias supraventriculares, frequência cardíaca aumentada, pequena quantidade de pausas superiores a 2,0s entre batimentos consecutivos, permanência por mais tempo em taquicardia do que em bradicardia, diminuído índice de alta frequência (indicativo de controle parassimpático) e elevado índice de baixa frequência (indicativo de controle simpático e parassimpático), quando comparados ao controle (p<0,05). Assim, conclui-se que, em cães portadores de DVM, as variáveis obtidas com o Holter apresentam-se alteradas devido ao desenvolvimento de insuficiência cardíaca...

Cardiologia intervencionista das arritmias ventriculares / Interventional Cardiology of ventricular arrhythmias

A ablação por radiofrequência (RF) das arritmias ventriculares visa, principalmente, melhorar a qualidade de vida dos pacientes. Tem recomendação precisa nos pacientes recebendo choques dos cardiodesfibriladores implantáveis (CDI) e, em particular, naqueles com taquicardias incessantes com função ventricular em franca deterioração. As técnicas de ablação atuais permitem que os procedimentos sejam bastante eficazes e realizados em ambiente de muita segurança. Os benefícios da sua realização dependem do tipo de arritmia e das características clínicas dos paciente.

The ablation of ventricular arrhythmias with RF aims chiefly to improve the quality of life of patients. It is recommended for patients receiving shocks of IDUs and in particular those with incessant tachycardia with ventricular function in full decay. Current ablation techniques allow procedures to be quite effective and carried out in a safe environment. The benefits of its implemention will depend on the type of arrhythmia and the clinical characteristics of the patients.

Successful catheter cryoablation of Hisian ectopy using 2 new diagnostic criteria based on unipolar and bipolar recordings of the His electrogram.

We describe the case of a 61-year-old woman who underwent successful catheter cryoablation of a symptomatic Hisian ectopy. Diagnosis was based on features of the HV interval assessed from a bipolar recording during mapping. The location of the arrhythmic focus was identified using simultaneous unipolar and bipolar recordings of the His electrogram. This case report highlights the use of 2 new criteria for the diagnosis and mapping of Hisian ectopy, and the successful use of cryothermia for the ablation of extrasystoles arising from the His bundle.

Role of sarcolemmal BK(Ca) channels in stretch-induced extrasystoles in isolated chick hearts.

BACKGROUND: It remains unclear whether sarcolemmal BK(Ca) channels in post-hatch chick ventricular myocytes contribute to stretch-induced extrasystoles (SIE), and whether they are stretch-activated BK(Ca) (SAK(Ca)) channels or a non-stretch-sensitive BK(Ca) variant. METHODS AND RESULTS: To determine the role of sarcolemmal BK(Ca) channels in SIE and their stretch sensitivity, an isolated 2-week-old Langendorff-perfused chick heart and mathematical simulation were used. The ventricular wall was rapidly stretched by application of a volume change pulse. As the speed of the stretch increased, the probability of SIE also significantly increased, significantly shortening the delay between SIE and the initiation of the stretch. Application of 100 nmol/L of Grammostola spatulata mechanotoxin 4, a cation-selective stretch-activated channel (SAC) blocker, significantly decreased the probability of SIE. The application of Iberiotoxin, however, a BK(Ca) channel blocker, significantly increased the probability of SIE, suggesting that a K(+) efflux via a sarcolemmal BK(Ca) channel reduces SIE by balancing out stretch-induced cation influx via SACs. The simulation using a cardiomyocyte model combined with a new stretch sensitivity model that considers viscoelastic intracellular force transmission showed that stretch sensitivity in BK(Ca) channels is required to reproduce the present wet experimental results. CONCLUSIONS: Sarcolemmal BK(Ca) channels in post-hatch chick ventricular myocytes are SAK(Ca) channels, and they have a suppressive effect on SIE.