Papel del sistema Purkinje y del tracto de salida del ventrículo derecho en las arritmias ventriculares malignas y la muerte súbita / Role of the Purkinje system and right ventricular outflow tract in malignant ventricular arrhythmias and sudden death

RESUMEN El sistema Purkinje y el tracto de salida del ventrículo derecho tienen un papel trascendente en relación con las arritmias ventriculares malignas (taquicardia y fibrilación ventriculares, torsión de puntas) y con la muerte súbita cardíaca. Se discuten su fisiopatología, participación en el origen (extrasístoles desencadenantes) y mantenimiento de estas arritmias, y las posibilidades ablativas para disminuir las recurrencias y los episodios de tormenta eléctrica. Se expone el diagnóstico diferencial entre variantes benignas y malignas de la taquicardia ventricular relacionada con el tracto de salida del ventrículo derecho y la relación entre factores genéticos, estructurales, electroanatómicos y funcionales (inflamación, fibrosis), con los eventos clínicos y la vulnerabilidad a las arritmias. Se necesita reclasificar algunas de estas enfermedades, vistas ahora en su carácter orgánico-funcional (síndrome de Brugada, por ejemplo), lo cual implica cambios revolucionarios en algunos conceptos clásicos y una nueva visión en cuanto a la estratificación de riesgo y la conducta terapéutica.

ABSTRACT The Purkinje system and the right ventricular outflow tract play a pivotal role in relation to malignant ventricular arrhythmias (ventricular tachycardia and fibrillation, torsades de pointes) and sudden cardiac death. Details such as their pathophysiology, origin involvement (triggering extrasystoles) maintenance of such arrhythmias, and ablative possibilities to reduce recurrences and electrical storm events are discussed herein. The differential diagnosis between benign and malignant ventricular tachycardia related to the right ventricular outflow tract, and the relationship between genetic, structural, electroanatomical and functional factors (inflammation, fibrosis) with clinical events and vulnerability to arrhythmias are presented. Some of these diseases need to be reclassified as they are now seen in their organic-functional character (Brugada syndrome, for example), and this implies radical changes in some classical concepts as well as a new perspective on risk stratification and therapeutic management.

Mapeo y ablación exitosa, desde el interior de la vena cardíaca magna, de extrasístoles ventriculares originados en el techo (summit) del ventrículo izquierdo / Mapping and successful ablation, from within the great cardiac vein, of premature ventricular contractions originating from the summit of the left ventricle

RESUMEN Se presenta el caso de una paciente de 43 años, con antecedentes de salud aparente, hasta varias semanas previas a su ingreso, cuando comenzó a presentar síncopes precedidos de palpitaciones. Se realizó estudio electrofisiológico y se demostró precocidad en la porción distal del electrodo de registro de seno coronario, que corresponde a la vena cardíaca magna (interventricular anterior) y techo (summit) del ventrículo izquierdo. A pesar del excelente registro precoz se estudiaron estructuras vecinas como el tracto de salida del ventrículo izquierdo en la cúspide coronaria izquierda, aquí el mapeo eléctrico (pace mapping) no fue concordante total. En el sitio de la precocidad obtenida dentro del sistema venoso cardíaco se realizó mapeo concordante 100%, con una precocidad del catéter de ablación de -30 milisegundos. Se decidió ablación con incrementos progresivos de temperatura y potencia con corte de impedancia (termomapping) y se logró el éxito de la ablación sin reproducibilidad de la arritmia y excelente evolución posterior.

ABSTRACT The case of a 43-year-old female patient is presented, with an apparent history of good health, up to several weeks prior to admission, when she began to present syncopes preceded by palpitations. An electrophysiological study was performed and prematurity in the distal portion of the coronary sinus recording electrode was demonstrated, which corresponds to the great cardiac vein (anterior interventricular vein) and summit of the left ventricle. Despite the excellent early registration, neighboring structures were studied, such as the left ventricular outflow tract in the left coronary cusp, here the pace mapping was not totally concordant. At the site of the precocity obtained within the cardiac venous system, a 100% concordant mapping was achieved, with an ablation catheter's precocity of -30 milliseconds. The ablation was decided with progressive increases in temperature and power with thermomapping and the success of the ablation was achieved without reproducibility of the arrhythmia and excellent subsequent evolution.

Ectopias atriais e associação com fibrilação atrial / Atrial ectopes and atrial fibrillation association

Instabilidade elétrica atrial é um termo recentemente incorporado na prática médica para descrever o amplo espectro de arritmias atriais que se sobrepõem. Essa relação já era intuitiva entre flutter atrial e fibrilação atrial (que deu berço ao anteriormente chamado "fibrilo-flutter"), e, mais recentemente, associou taquicardias atriais e fibrilação atrial. Essa relação é de suma importância, posto que o diagnóstico de fibrilação atrial implica estratégias para prevenção de eventos embólicos. Com novos métodos de rastreio, o diagnóstico de fibrilação atrial se mostrou mais frequente (monitorização prolongada, monitores implantáveis, telemetria de marcapassos). A presença de extrassistolia atrial e taquicardia atrial se torna um desafio: apesar da relação intuitiva de maior risco para fibrilação atrial e eventos cerebrovasculares, a evidência científica para tal se tornou mais robusta recentemente. Este artigo tem a intenção de agregar a evidência de melhor qualidade disponível para facilitar a seleção da estratégia adequada ante um paciente portador de taquicardia e extrassistolia atrial e avaliar adequadamente seu risco

Atrial electrical instability is a recently incorporated term in medical practice to describe the broad spectrum of overlapping atrial arrhythmias. This relationship was already intuitive between atrial flutter and atrial fibrillation (which gave birth to the so-called "fibril-flutter"), and has more recently been related to atrial tachycardias and atrial fibrillation. This relationship is extremely important, since the diagnosis of atrial fibrillation implies in strategies to prevent embolic events. With new screening methods, the diagnosis of atrial fibrillation has become more frequent (prolonged monitoring, implantable monitors, pacemaker telemetry). The presence of atrial extrasystoles and atrial tachycardia is a challenge: despite the intuitive relationship of higher risk for atrial fibrillation and cerebrovascular events, the scientific evidence became more robust recently. This article intends to aggregate the best quality evidence available to facilitate the choice of an appropriate strategy for a patient with tachycardia and atrial extrasystoles and to adequately assess their risk

Efecto agudo del consumo de yerba mate (Ilex paraguariensis) sobre el ritmo cardíaco en pacientes derivados para estudio Holter / Acute effect of yerba mate (Ilex paraguariensis) consumption on heart rhythm in patients referred for Holter study

Resumen Introducción: El consumo de yerba mate (YM) (Ilex paraguariensis) es común en Sudamérica y se extiende a todo el mundo. Contiene muchas sustancias bioactivas que pueden ser beneficiosas. También existe la opinión de que puede tener efectos nocivos sobre el ritmo cardíaco, pero no encontramos investigaciones al respecto. Objetivo: Nuestro objetivo fue evaluar el efecto agudo de YM sobre el ritmo, en pacientes enviados para realizar un Holter. Método: Realizamos un estudio clínico seudoexperimental, de tipo antes y después. Tomamos 50 pacientes consumidores habituales de YM y se les realizó un Holter tomando YM y otro luego de 24 sin consumir. También se controló el uso de otros productos que pudieran interferir. Resultados: El 52% fueron mujeres y la edad, de 55 ± 15 años. El 78% tenía al menos un factor de riesgo vascular, el 44% cardiopatía estructural y el 90% tomaba medicación cardiovascular. La frecuencia cardíaca (FC) con y sin YM fue similar. Solo la FC mínima horaria fue menor tomando YM (61 ± 10 vs. 63 ± 9, p = 0.021). No hubo diferencia significativa en la incidencia de arritmias sostenidas, no sostenidas ni en la extrasistolia ventricular. El total de extrasístoles supraventriculares fue mayor sin YM (952 ± 3,538 vs. 1,294 ± 5,201, p = 0.014) y la cantidad máxima horaria también (86 ± 302 vs. 107 ± 360, p = 0.032). No hubo diferencia en la variabilidad de la FC. Conclusiones: En pacientes cardiológicos tomadores de YM, su consumo de la forma habitual no se asoció con cambios importantes de la FC ni con un aumento en la incidencia de arritmias. Hubo menos actividad ectópica supraventricular.

Abstract Introduction: The consumption of yerba mate (YM) (Ilex paraguariensis) is common in South America and is now used all over the world. It contains many bioactive substances that can be beneficial. There is also the opinion that it may have harmful effects on heart rhythm, but no studies have been found on this. Objective: The aim of this study was to evaluate the acute effect of YM on heart rhythm in patients referred for a Holter study. Method: A before and after pseudo-experimental clinical study was conducted by performing a Holter on 50 habitual users of YM, and another one after 24 without YM consumption. The use of other products that could interfere was also controlled. Results: The mean age of the subjects was 55 ± 15 years, and 52% were women. At least one vascular risk factor was found in 78%, with 44% structural heart disease, and 90% taking cardio- vascular medication. The heart rate (HR) with and without YM was similar. Only the minimum hourly HR was lower when taking YM (61 ± 10 vs. 63 ± 9, P = .021). There was no significant diffe- rence in the incidence of sustained or non-sustained arrhythmias, or in ventricular extrasystoles. The total number of supra-ventricular premature beats was higher without YM (952 ± 3,538 vs. 1,294 ± 5,201, P = .014) and also the maximum hourly (86 ± 302 vs. 107 ± 360, P = .032). There was no difference in HR variability. Conclusions: In cardiology patients, usual users of YM, habitual consumption was not associated with significant changes in HR or an increase in the incidence of arrhythmias. There was less ectopic supraventricular activity.

Management of Common Arrhythmia in the Neurological Intensive Care Unit

Cardiac arrhythmias are a common problem in the neurological intensive care unit and represent a major cause of ischemic stroke. Significant arrhythmias are most likely to occur in elderly patients. In this review, we focus on three arrhythmias: premature beats, atrial fibrillation, and QT prolongation. The goal of this review is to provide a current concept of diagnosis and acute management of arrhythmias in the neurological intensive care unit.

The change of QRS duration after pulmonary valve replacement in patients with repaired tetralogy of Fallot and pulmonary regurgitation / 소아과

PURPOSE: This study aimed to analyze changes in QRS duration and cardiothoracic ratio (CTR) following pulmonary valve replacement (PVR) in patients with tetralogy of Fallot (TOF). METHODS: Children and adolescents who had previously undergone total repair for TOF (n=67; median age, 16 years) who required elective PVR for pulmonary regurgitation and/or right ventricular out tract obstruction were included in this study. The QRS duration and CTR were measured pre- and postoperatively and postoperative changes were evaluated. RESULTS: Following PVR, the CTR significantly decreased (pre-PVR 57.2%±6.2%, post-PVR 53.8%±5.5%, P=0.002). The postoperative QRS duration showed a tendency to decrease (pre-PVR 162.7±26.4 msec, post-PVR 156.4±24.4 msec, P=0.124). QRS duration was greater than 180 msec in 6 patients prior to PVR. Of these, 5 patients showed a decrease in QRS duration following PVR; QRS duration was less than 180 msec in 2 patients, and QRS duration remained greater than 180 msec in 3 patients, including 2 patients with diffuse postoperative right ventricular outflow tract hypokinesis. Six patients had coexisting arrhythmias before PVR; 2 patients, atrial tachycardia; 3 patients, premature ventricular contraction; and 1 patient, premature atrial contraction. None of the patients presented with arrhythmia following PVR. CONCLUSION: The CTR and QRS duration reduced following PVR. However, QRS duration may not decrease below 180 msec after PVR, particularly in patients with right ventricular outflow tract hypokinesis. The CTR and ECG may provide additional clinical information on changes in right ventricular volume and/or pressure in these patients.

Neonatal arrhythmias: diagnosis, treatment, and clinical outcome / 소아과

Arrhythmias in the neonatal period are not uncommon, and may occur in neonates with a normal heart or in those with structural heart disease. Neonatal arrhythmias are classified as either benign or nonbenign. Benign arrhythmias include sinus arrhythmia, premature atrial contraction, premature ventricular contraction, and junctional rhythm; these arrhythmias have no clinical significance and do not need therapy. Supraventricular tachycardia, ventricular tachycardia, atrioventricular conduction abnormalities, and genetic arrhythmia such as congenital long-QT syndrome are classified as nonbenign arrhythmias. Although most neonatal arrhythmias are asymptomatic and rarely life-threatening, the prognosis depends on the early recognition and proper management of the condition in some serious cases. Precise diagnosis with risk stratification of patients with nonbenign neonatal arrhythmia is needed to reduce morbidity and mortality. In this article, I review the current understanding of the common clinical presentation, etiology, natural history, and management of neonatal arrhythmias in the absence of an underlying congenital heart disease.

Electrocardiogram PR Interval Is a Surrogate Marker to Predict New Occurrence of Atrial Fibrillation in Patients with Frequent Premature Atrial Contractions

The clinical significance of prolonged PR interval has not been evaluated in patients with frequent premature atrial contractions (PACs). We investigated whether prolonged PR interval could predict new occurrence of atrial fibrillation (AF) in patients with frequent PACs. We retrospectively analyzed 684 patients with frequent PACs (> 100 PACs/day) who performed repeated 24-hour Holter monitoring. Prolonged PR interval was defined as longer than 200 msec. Among 684 patients, 626 patients had normal PR intervals (group A) and 58 patients had prolonged PR intervals (group B). After a mean follow-up of 59.3 months, 14 patients (24.1%) in group B developed AF compared to 50 patients (8.0%) in group A (P < 0.001). Cox regression analysis showed that prolonged PR interval (hazard ratio [HR], 1.950; 95% CI, 1.029-3.698; P = 0.041), age (HR, 1.033; 95% CI, 1.006-1.060; P = 0.015), and left atrial (LA) dimension (HR, 1.061; 95% CI, 1.012-1.112; P = 0.015) were associated with AF occurrence. Prolonged PR interval, advanced age, and enlarged LA dimension are independent risk factors of AF occurrence in patients with frequent PACs.

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

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

Long-term Prognosis of Paroxysmal Atrial Fibrillation and Predictors for Progression to Persistnt or Chronic Atrial Fibrillation in the Korean Population

Little is known about the long-term prognosis of or predictors for the different clinical types of atrial fibrillation (AF) in Korean populations. The aim of this study was to validate a risk stratification to assess the probability of AF progression from paroxysmal AF (PAF) to persistent AF (PeAF) or permanent AF. A total of 434 patients with PAF were consecutively enrolled (mean age; 71.7 +/- 10.7 yr, 60.6% male). PeAF was defined as episodes that are sustained > 7 days and not self-terminating, while permanent AF was defined as an ongoing long-term episode. Atrial arrhythmia during follow-up was defined as atrial premature complex, atrial tachycardia, and atrial flutter. During a mean follow-up of 72.7 +/- 58.3 months, 168 patients (38.7%) with PAF progressed to PeAF or permanent AF. The mean annual AF progression was 10.7% per year. In univariate analysis, age at diagnosis, body mass index, atrial arrhythmia during follow-up, left ventricular ejection fraction, concentric left ventricular hypertrophy, left atrial diameter (LAD), and severe mitral regurgitation (MR) were significantly associated with AF progression. In multivariate analysis, age at diagnosis (P = 0.009), atrial arrhythmia during follow-up (P = 0.015), LAD (P = 0.002) and MR grade (P = 0.026) were independent risk factors for AF progression. Patients with younger age at diagnosis, atrial arrhythmia during follow-up, larger left atrial chamber size, and severe MR grade are more likely to progress to PeAF or permanent AF, suggesting more intensive medical therapy with close clinical follow-up would be required in those patients.

Swallowing-Induced Atrial Tachyarrhythmias Successfully Ablated at the Left Posterior Interatrial Septum in Patient with Wolff-Parkinson-White Syndrome

We reported a case of a 55-year-old patient who presented with palpitation after swallowing. Initial surface electrocardiogram revealed ventricular preexcitation utilizing a left lateral bypass tract. The orthodromic atrioventricular reentrant tachycardia (AVRT) was induced during electrophysiologic studies. After successful ablation of the AVRT utilizing a left lateral free wall bypass tract, 2 different atrial tachycardias (ATs) were induced under isoproterenol infusion. When the patient swallowed saliva or drank water, 2 consecutive beats of atrial premature complexes (APCs) preceded another non-sustained AT repeatedly, which was coincident with the patient's symptom. The preceding APC couplet had the same activation sequence with one induced AT, and the subsequent non-sustained AT had the same activation sequence with the other induced AT, respectively. We first targeted the preceding 2 consecutive APCs at the left posterior interatrial septum. The following non-sustained AT was also eliminated following ablation of the APCs. After ablation, the patient remained free from the swallowing-induced atrial tachyarrhythmias during the one year follow-up.

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...

QTc Prolongation after Ventricular Septal Defect Repair in Infants

BACKGROUND AND OBJECTIVES: Prolonging of the corrected QT interval (QTc) has been reported after cardiac surgery in some studies. However, there have not been many studies on infant open cardiac surgery for ventricular septal defect (VSD) repair. This study was performed to define the changes in QTc and to find related post-surgery factors in this patient group. SUBJECTS AND METHODS: From 2008 to 2012, 154 infants underwent VSD repair at the Severance Cardiovascular Hospital. This study includes 105 of these cases. QTc was measured in these patients retrospectively. Demographic data and peri-procedural data, such as Aristotle score, cross-clamp time and bypass time, were analyzed. The exclusion criteria included multiple and small VSDs that underwent direct closure. RESULTS: Mean post-operative QTc was increased compared to the pre-operative measurements (from 413.6+/-2.3 to 444.9+/-2.5, p<0.001). In multiple linear regression, the comprehensive Aristotle score was associated with increasing QTc (p=0.047). The incidence of transient arrhythmia, such as atrial tachycardia, junctional ectopic tachycardia, premature atrial contraction, or premature ventricular contraction, was associated with QTc prolongation (p=0.005). Prolonged QTc was also associated with cross-clamp time (p=0.008) and low weight (p=0.042). Total length of stay at the intensive care unit and intubation time after surgery were not associated with QTc prolongation. CONCLUSION: Prolonged QTc could be seen after VSD repair in infants. This phenomenon was associated with peri-procedural factors such as the Aristotle score and cross-clamp time. Patients with QTc prolongation after cardiac surgery had an increased tendency towards arrhythmogenicity in the post-operative period.

Redução da densidade de extrassístoles e dos sintomas relacionados após administração de magnésio por via oral / Successful improvement of frequency and symptoms of premature complexes after oral magnesium administration

FUNDAMENTO: As extrassístoles ventriculares e supraventriculares (EV e ESSV) são frequentes e muitas vezes sintomáticas. O íon magnésio (Mg) desempenha um papel importante na fisiologia do potencial de ação transmembrana celular e do ritmo cardíaco. OBJETIVO: Avaliar se a administração do pidolato de magnésio (PMg) em pacientes com EV e ESSV tem desempenho superior ao uso do placebo (P) na melhora dos sintomas e densidade das extrassístoles (DES). MÉTODOS: Estudo duplo-cego, randomizado, com 60 pacientes sintomáticos consecutivos, com mais de 240/EV ou ESSV ao Holter de 24 horas e selecionados para receber P ou PMg. Para avaliar a melhora da sintomatologia, foi feito um questionário categórico e específico de sintomas relacionados às extrassístoles. Após o tratamento, foi considerada significante uma redução de mais de 70% na DES por hora. A dose do PMg foi de 3,0 g/dia por 30 dias, equivalente a 260 mg do elemento Mg. Nenhum paciente tinha cardiopatia estrutural ou insuficiência renal. RESULTADOS: Dos 60 pacientes estudados, 33 eram do sexo feminino (55%). A faixa etária variou de 16 a 70 anos. No grupo PMg, 76,6% dos pacientes tiveram redução maior que 70%, 10% deles maior que 50% e somente 13,4% tiveram redução menor que 50% na DES. No grupo P, 40% dos pacientes tiveram melhora de apenas 30% na frequência de extrassístoles (p < 0,001). A melhora dos sintomas foi alcançada em 93,3% dos pacientes do grupo PMg, comparada com somente 16,7% do grupo P (p < 0,001). CONCLUSÃO: A suplementação de Mg via oral reduziu a DES, resultando em melhora dos sintomas.

BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE:We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260mg of Mg element. None of the patients had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the premature complexes frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.

Caracterização do desconforto respiratório em recém-nascidos a termo e pré-termo em unidade de terapia intensiva neonatal / Characterization of respiratory distress in newborns at term and preterm infants in neonatal intensive care unit

A doença respiratória no período neonatal representa a principal causa de internação do recém nascido em unidade de terapia intensiva neonatal (UTIN). Está envolvida em diversos diagnósticos neste período independente da idade gestacional, acometendo tanto prematuros quanto recém-nascidos a termo. Representa importante questão de saúde pública, pois figura entre as causas de mortalidade infantil. Objetivo: Descrever o desconforto respiratório em recém-nascidos a termo e pré-termo, admitidos em UTIN, identificando fatores de risco materno e fetais para morbidade respiratória, bem como as afecções mais freqüentes em cada grupo. Metodologia: Foram coletados dados de prontuários de 585 recém-nascidos (RN) admitidos em UTIN no período de 2 anos, sendo que 557 RN preencheram os critérios de inclusão no estudo. As variáveis incluíram dados gestacionais, aspectos relacionados ao parto e evolução clínica. Foram utilizadas tabelas de freqüência para descrever a distribuição dos recém-nascidos a termo e pré-termo segundo variáveis independentes, com associação averiguada pelo teste do qui-quadrado. Para descrição das variáveis quantitativas, utilizaram-se valores de mediana e percentis 25 e 75. A digitação dos dados foi feita no programa Excel e a análise no Stata 11.0, estabelecendo como nível de significância 5 por cento. Resultados: 89,8 por cento dos nascimentos foram partos operatórios. Baseado em critérios do Ministério da Saúde as gestantes foram adequadamente assistidas no pré-natal e estavam em idade reprodutiva considerada de baixo risco. A afecção gestacional não infecciosa mais freqüente foi a doença hipertensiva específica da gestação (DHEG) e a infecciosa foi a infecção do trato urinário. Os recém-nascidos a termo representaram 38,2 por cento das admissões. As afecções mais freqüentes destes foram a taquipnéia transitória, seguida da pneumonia congênita e sepse clínica. Os prematuros representaram 61,8 por cento das admissões, o principal diagnóstico foi a síndrome do desconforto respiratório, seguida da sepse clínica e pneumonia. Conclusões: observaram-se altas taxas de cesarianas, concordantes com a tendência de aumento verificadas em muitos países, porém em proporções muito mais elevadas. Tais taxas associaram-se com a morbidade respiratória, especialmente nas cesarianas eletivas (sem indicação obstétrica) e nos recém-nascidos a termo. A maioria dos recém-nascidos submeteu-se a oxigenioterapia.

Effect of obstructive sleep apnea syndrome on serum C-reactive protein level, left atrial size and premature atrial contraction / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the changes of serum C-reactive protein (CRP) level, left atrial size and atrial premature contraction (PAC) in patients with obstructive sleep apnea syndrome (OSAS).</p><p><b>METHODS</b>This study involved 277 patients with OSAS diagnosed after an overnight polysomnography, who underwent a 24-h Holter electrocardiography and ambulatory blood pressure monitoring for detection of PAC. According to the apnea-hypopnea index (AHI), 137 patients with PAC identified from these patients were classified into 3 groups, namely the mild (5≥AHI<15), moderate (15≥AHI<30) and severe (AHI≥30) groups. Serum CRP level was assessed by a high-sensitivity radio-immunoassay. The left atrial diameter and echocardiographic parameters were recorded by transthoracic Doppler echocardiography (TTE).</p><p><b>RESULTS</b>We found a high prevalence of PAC in these OSAS patients (137/277, 49.4%). Serum CRP was significantly higher in severe OSAS group (5.01∓4.68 mg/L) than in the moderate (3.03∓1.94 mg/L) and mild OSAS (2.98∓1.82 mg/L) groups (P=0.040 and 0.033, respectively). The left atrial diameter was significantly increased in severe OSAS group (40.1∓7.9 mm) as compared to that in moderate (37.9∓5.5 mm) and mild (33.7 ∓ 3.8 mm) groups (P=0.025 and 0.002, respectively). The severity of OSAS was positively correlated to both CRP (r=0.304, P=0.034) and left atrial diameter (r=0.411, P=0.003). After adjusting for gender, age and body mass index (BMI), a strong correlation was found between the left atrial diameter and CRP (r=0.594, P=0.0005).</p><p><b>CONCLUSION</b>There is a high prevalence of PAC in OSAS patients. The progression of OSAS is associated with increased serum CRP level and left atrial size in patients with premature atrial complexes. Our study suggests that inflammation associated with OSAS might contribute to atrial structural and electrical remodeling in OSAS patients with PAC.</p>

Detection of sinus arrhythmias and atrial arrhythmias based on multiscale time irreversibilty / 生物医学工程学杂志

Time irreversibility is a fundamental property of nonequilibrium systems. It is significant to measure the trend of change of time irreversible index under different physiological and pathological state of electrocardiosignal. We analyzed and tested the heart rate variability (HRV) signals of the normal sinus rhythm, atrial contraction, sinus bradycardia in the MIT-BIH standard database using the multiscale time irreversiblity method. It was shown that the time irreversiblity index of the normal heart rhythm, atrial premature beats and bradycardia were in the decreasing trend. The results would be helpful to clinical diagnosis as a secondary means.

Wavelet modulus maxima of multifractality based analysis of the pathological ECG signals / 生物医学工程学杂志

In this paper, wavelet moudulus maxima based multifractal analysis was used to study the multifractal characteristics of the atrial premature beat (APB) signal, the premature ventricular contraction (PVC) signal and normal ECG signal. By analyzing the multifractal spectrum, it was obtained that three kinds of signals had different multifractal strengths. Normal ECG signals had the strongest singularity strength. The PVC beats had the second stronger singularity strength. And the APB beats had the weakest singularity strength. The T test indicated that above-mentioned analysis could disclose significant differences among these three signals. It has meaningful reference for clinical diagnosing and distinguishing with PVC and APB signals.