Early prognostic value of an Algorithm based on spectral Variables of Ventricular fibrillAtion from the EKG of patients with suddEn cardiac death: A multicentre observational study (AWAKE) / Valor pronóstico precoz de un algoritmo basado en variables espectrales de la fibrilación ventricular del ECG de pacientes con muerte súbita cardiaca: estudio observacional multicéntrico (AWAKE)

Abstract Objective: Ventricular fibrillation (VF)-related sudden cardiac death (SCD) is a leading cause of mortality and morbidity. Current biological and imaging parameters show significant limitations on predicting cerebral performance at hospital admission. The AWAKE study (NCT03248557) is a multicentre observational study to validate a model based on spectral ECG analysis to early predict cerebral performance and survival in resuscitated comatose survivors. Methods: Data from VF ECG tracings of patients resuscitated from SCD will be collected using an electronic Case Report Form. Patients can be either comatose (Glasgow Coma Scale GCS --- ≤8) survivors undergoing temperature control after return of spontaneous circulation (RoSC), or those who regain consciousness (GCS = 15) after RoSC; all admitted to Intensive Cardiac Care Units in 4 major university hospitals. VF tracings prior to the first direct current shock will be digitized and analyzed to derive spectral data and feed a predictive model to estimate favorable neurological performance (FNP). The results of the model will be compared to the actual prognosis. Results: The primary clinical outcome is FNP during hospitalization. Patients will be categorized into 4 subsets of neurological prognosis according to the risk score obtained from the predictive model. The secondary clinical outcomes are survival to hospital discharge, and FNP and survival after 6 months of follow-up. The model-derived categorisation will be also compared with clinical variables to assess model sensitivity, specificity, and accuracy. Conclusions: A model based on spectral analysis of VF tracings is a promising tool to obtain early prognostic data after SCD.

Resumen Objetivo: La muerte súbita (MS) por fibrilación ventricular (FV) es una importante causa de morbilidad y mortalidad. Los métodos biológicos y de imagen actuales muestran limitaciones para predecir el pronóstico cerebral al ingreso hospitalario. AWAKE es un estudio observacional, multicéntrico, con el objetivo de validar un modelo basado en el análisis espectral del elec- trocardiograma (ECG), que predice precozmente el pronóstico cerebral y la supervivencia en pacientes resucitados y en estado de coma. Métodos: Se recogerán datos de los ECG con FV de pacientes reanimados de MS. Los pacientes pueden ser tanto supervivientes en estado de coma (Glasgow Coma Scale GCS ≤ 8) sometidos a control de temperatura tras la recuperación de circulación espontánea (RCE), como aquellos que recuperan la consciencia (GCS = 15) tras RCE; todos ellos ingresados en unidades de terapia intensiva cardiológica de 4 hospitales de referencia. Los registros de FV previos al primer choque se digitalizarán y analizarán para obtener datos espectrales que se incluirán en un modelo predictivo que estime el pronóstico neurológico favorable (PNF). El resultado del modelo se comparará con el pronóstico real. Resultados: El objetivo principal es el PNF durante la hospitalización. Los pacientes se categorizarán en 4 subgrupos de pronóstico neurológico según la estimación de riesgo obtenida en el modelo predictivo. Los objetivos secundarios son supervivencia al alta hospitalaria, y PNF y supervivencia a los 6 meses. El resultado de este modelo también se comparará con el pronóstico según variables clínicas. Conclusiones: Un modelo basado en el análisis espectral de registros de FV es una herramienta prometedora para obtener datos pronósticos precoces tras MS por FV.

Como identificar e enfrentar a tempestade elétrica na prática clínica? / How to identify and manage electrical storm in clinical practice

O uso na prática clínica de novas formas de terapia dos portadores de cardiopatia vem aumentando a sobrevida e melhorando sua qualidade de vida ao longo dos anos. O advento dos cardioversores-defibriladores implantáveis foi um marco no tratamento dos pacientes com cardiopatias graves e mais propensos a morte súbita, com redução da taxa de mortalidade nesses pacientes. Porém, surgiram novas questões no manejo desses pacientes, especialmente no que concerne o seguimento dos portadores desses dispositivos em relação à sua otimização para redução de terapias inapropriadas, melhora de qualidade psicossocial e a conduta frente a situações emergenciais representadas por arritmias frequentes, repetitivas erefratárias, como no caso da Tempestade Elétrica. O objetivo do presente trabalho é revisar as definições, epidemiologia e especialmente a conduta frente a esse grupo de pacientes, que deve aumentar nos próximos anos, com a maior prevalência das cardiopatias, especialmente a isquêmica, e o maior número de implantes de dispositivos cardíacos eletrônicos...

The use of new forms of therapy in patients with heart disease has increased the survival and quality of life of these patients in recent years. The advent of implantable cardioverter- defibrillators was a landmark in the treatment of patients with severe heart disease, who were more prone to sudden death, and led to a reduction in mortality rates among these patients. However, new issues emerged in the management of these patients, especially concerning the follow-up of cardioverter-defibrillator patients in terms of reducing inappropriate therapies, improving their quality of life, and managing emergency situations represented by frequent, repetitive and refractory arrhythmias, such as Electrical Storm. The purpose of this paper is to revise the definitions, epidemiology, and above all, the management of this group of patients, which is expected to grow in the coming years, with the greater prevalence of heart disease, especially ischemic heart disease, and thein creased use of electronic heart implants...

Right Ventricular Cardiomyopathy Meeting the Arrhythmogenic Right Ventricular Dysplasia Revised Criteria? Don't Forget Sarcoidosis!

A 53-year-old woman was referred for ventricular fibrillation with resuscitation. A CT-angiography showed signs of a right ventricular enlargement without obvious cause. A cardiac MRI demonstrated a dilated and hypokinetic right ventricle with extensive late gadolinium enhancement. Arrhythmogenic right ventricular dysplasia (ARVD) was suspected according to the "revised ARVD task force criteria". An endomyocardial biopsy was inconclusive. The patient developed purulent pericarditis after epicardial ablation therapy and died of toxic shock syndrome. The post-mortem pathologic examination demonstrated sarcoidosis involving the heart, lungs, and thyroid gland.

The Relationship Between J Wave on the Surface Electrocardiography and Ventricular Fibrillation during Acute Myocardial Infarction

We investigated whether the presence of J wave on the surface electrocardiography (sECG) could be a potential risk factor for ventricular fibrillation (VF) during acute myocardial infarction (AMI). We performed a retrospective study of 317 patients diagnosed with AMI in a single center from 2009 to 2012. Among the enrolled 296 patients, 22 (13.5%) patients were selected as a VF group. The J wave on the sECG was defined as a J point elevation manifested through QRS notching or slurring at least 1 mm above the baseline in at least two leads. We found that the incidence of J wave on the sECG was significantly higher in the VF group. We also confirmed that several conventional risk factors of VF were significantly related to VF during AMI; time delays from the onset of chest pain, blood concentrations of creatine phosphokinase and incidence of ST-segment elevation. Multiple logistic regression analysis demonstrated that the presence of J wave and the presence of a ST-segment elevation were independent predictors of VF during AMI. This study demonstrated that the presence of J wave on the sECG is significantly related to VF during AMI.

Síndromes de la onda J / J wave syndromes

Se realizó una revisión sobre los aspectos más novedosos y polémicos de los síndromes de la onda J, que incluyó el síndrome de repolarización precoz, la fibrilación ventricular idiopática y la muerte súbita nocturna inexplicable. Se enfatiza en las características electrocardiográficas de estos síndromes donde se destaca la presencia de un supradesnivel del ST tipo cóncavo con melladuras o empastamiento del mismo. Se profundiza en las bases genéticas, a veces común a todos ellos, en particular la mutación SCN5A asociada con el supradesnivel del ST y más recientemente la mutación S422L-KCNJ8 como causa de alteración de los canales I K-ATP, lo cual se asocia con mortalidad arrítmica cardíaca. Se concluye que aunque no todos los pacientes con este síndrome estén en riesgo de eventos arrítmicos o de muerte súbita cardíaca, existe un grupo de ellos no despreciable que sí lo están, por lo que el gran desafío de la comunidad médica es desarrollar mejores estrategias de estratificación de riesgo y desarrollar tratamientos más seguros y eficaces para estos

A review was conducted of the newest and most controversial aspects of J wave syndromes, including early repolarization syndrome, idiopathic ventricular fibrillation and sudden unexplained nocturnal death. Emphasis is made on the ECG features of these syndromes, among them the presence of an upwardly concave ST irregularity with notching or slurring. A detailed analysis is made of genetic bases, which are sometimes common to all syndromes, particularly the SCN5A mutation, associated with the ST upwardly irregularity, and more recently the S422L-KCNJ8 mutation causing the alteration in the lK-ATP channels, associated with arrhythmic cardiac mortality. It is concluded that not all patients with this syndrome are at risk of arrhythmic events or sudden cardiac death, but a significant number of them are. Therefore, a great challenge for the medical community is to develop better risk stratification strategies as well as safer and more effective treatments

Fever-Induced QTc Prolongation and Ventricular Fibrillation in a Healthy Young Man

Long QT syndrome is associated with lethal tachyarrhythmia that can lead to syncope, seizure, and sudden death. Congenital long QT syndrome is a genetic disorder, characterized by delayed cardiac repolarization and prolongation of the QT interval on the electrocardiogram (ECG). Type 2 congenital long QT is linked to mutations in the human ether a go-go-related gene (HERG). There are environmental triggers of adverse cardiac events such as emotional and acoustic stimuli, but fever can also be a potential trigger of life-threatening arrhythmias in long QT syndrome type 2 patients. Herein, we report a healthy young man who experienced fever-induced polymorphic ventricular tachycardia and QT interval prolongation.

Electrical Storms in Patients with an Implantable Cardioverter Defibrillator

PURPOSE: In some patients with an implantable cardioverter defibrillator (ICD), multiple episodes of electrical storm (ES) can occur. We assessed the prevalence, features, and predictors of ES in patients with ICD. MATERIALS AND METHODS: Eighty-five patients with an ICD were analyzed. ES was defined as the occurrence of two or more ventricular tachyarrhythmias within 24 hours. RESULTS: Twenty-six patients experienced at least one ES episode, and 16 patients experienced two or more ES episodes. The first ES occurred 209 +/- 277 days after ICD implantation. In most ES cases, the index arrhythmia was ventricular tachycardia (65%). There were no obvious etiologic factors at the onset of most ES episodes (57%). More patients with a structurally normal heart (p = 0.043) or ventricular fibrillation (VF) as the index arrhythmia (p = 0.017) were in the ES-free group. Kaplan-Meier estimates and a log-rank test showed that patients with nonischemic dilated cardiomyopathy (DCMP) (log-rank test, p = 0.016) or with left ventricular ejection fraction < 35% (p = 0.032) were more likely to experience ES, and that patients with VF (p = 0.047) were less affected by ES. Cox proportional hazard regression analysis showed that nonischemic DCMP correlated with a greater probability of ES (hazard ratio, 3.71; 95% confidence interval, 1.16-11.85; p = 0.027). CONCLUSION: ES is a common and recurrent event in patients with an ICD. Nonischemic DCMP is an independent predictor of ES. Patients with VF or with a structurally normal heart are less likely to experience ES.

Implantable Cardioverter-Defibrillator Implantation in a Patient with Atrial Standstill

We report a 55-year-old female patient who presented with no P waves but with a wide QRS complex escape rhythm at 44 beats/min and prolonged QTc of 0.55 seconds on ECG. The patient had recurrence of ventricular fibrillations and loss of consciousness, and underwent defibrillation and cardiopulmonary resuscitation (CPR) several times because of cardiac arrest. The transthoracic echocardiography showed dilated cardiomyopathy and enlargement of both atria. The Doppler echocardiography documented the absence of A wave in the tricuspid and mitral valve flow. An electrophysiologic study demonstrated electrical inactivity in the right and left atria. Atrial pacing with maximum output did not capture the atria. These findings together with her electrocardiographic finding indicated atrial standstill. Sudden cardiac death was her first clinical manifestation of ventricular arrhythmia. The patient remained asymptomatic after receiving a single chamber implantable cardioverter-defibrillator (ICD) with VVI pacemaker function.

Implante de desfibrilador: a propósito de um limiar de desfibrilação elevado / Defibrillator implant: aiming at a high defibrillator threshold

Este artigo tem por finalidade orientar a conduta nos casos de pacientes com taquicardia ventricular sustentada e disfunção grave, encaminhados para implante de desfibrilador, situação cada vez mais frequente. Discute-se a possibilidade de utilizar alternativas cirúrgicas para solucionar situações em que os limiares de desfibrilação permanecem altos durante os testes realizados no momento do implante

Algoritmos de detecção de taquicardias incorporado e desfibriladores automáticos implantáveis 1)Desfibriladores monocamerais / tachycardias algorithms detectors incorporated to automatic implantable defibrillators 1)Monocameral defibrillators

Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDis) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que não necessitam terapia. Esses benefícios também são encontrados nos CDis bicamerias que têm como benefício a detecção atrial acoplada à detecção do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100 por cento), para que sejam tratadas corretamente. Devem ainda evitar erros de identificação de arritmias supraventriculares (especificidade máxima). Infelizmente, não é possível alcançar 100 por cento de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuição da sensibilidade. Essa diminuição de especificidade pode conduzir a falha na detecção dos distúrbios do ritmo ventricular, e como consequência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular

Effect of smoking on QT interval, QT dispersion and rate pressure product.

BACKGROUND: Smoking may predispose to ventricular fibrillation and sudden cardiac death by altering ventricular recovery time dispersion indices. However, effect of acute smoking on QT interval and QT dispersion in chronic smokers has not been studied so far. METHODS AND RESULTS: Effect of cigarette smoking on ventricular recovery time dispersion indices and rate pressure product (product of heart rate and systolic blood pressure) was investigated in 25 chronic smokers and compared with 25 age- and sex-matched non-smoker controls. There was increase in R-R interval (p<0.05). corrected QT interval, QT dispersion (p<0.001) and rate pressure product (p<0.05) in chronic smokers at baseline (before smoking) compared to non-smoker controls. On cigarette smoking, there was further increase in heart rate, blood pressure, QT dispersion and rate pressure product (p<0.001) with reduction in R-R interval (p<0.05) in chronic smokers compared to non-smoker controls. CONCLUSIONS: Our observations indicate that there may be some relationship between prolonged ventricular recovery time dispersion indices and ventricular fibrillation and sudden cardiac death associated with smoking.

Dynamics of QT dispersion in acute myocardial infarction.

BACKGROUND: We studied the dynamics of QT dispersion in patients with acute myocardial infarction, and compared them with those in controls. METHODS AND RESULTS: Serial electrocardiograms of patients admitted to our institute with acute myocardial infarction were analyzed for QT dispersion, and compared with those of healthy age- and sex-matched controls. QT dispersion from 12 leads was measured as maximum QT minus minimum QT interval in ms. The mean QT dispersion of 114 +/- 29.6 ms was significantly higher in patients with acute myocardial infarction on admission as compared to 51.45 +/- 5.56 ms in controls (p < 0.001). QT dispersion showed a dynamic change in patients with acute myocardial infarction who were thrombolyzed, being 109.11 +/- 5.77 ms, 87.59 +/- 5.88 ms, 75.89 +/- 18.33 ms, and 68.20 +/- 12.66 ms on admission, post-thrombolysis, and on days 3 and 7, respectively. During a similar time period, nonthrombolyzed patients showed a QT dispersion of 132.38 +/- 36.04 ms, 130.47 +/- 34.42 ms, 111.11 +/- 24.94 ms, and 106.25 +/- 27.64 ms, respectively: the difference between the 2 groups at all periods was significant (p < 0.01). Mean QT dispersion values in patients who developed ventricular tachycardia or ventricular fibrillation were significantly higher than in patients who did not develop ventricular tachycardia or ventricular fibrillation (p < 0.01). CONCLUSIONS: Mean QT dispersion is significantly increased after acute myocardial infarction, and shows a dynamic decrease with time, the difference being more marked in thrombolyzed patients. Mean QT dispersion levels are higher in patients with ventricular tachycardia and ventricular fibrillation compared to patients with acute myocardial infarction without these arrhythmias. The changes in QT dispersion are dynamic, and it may serve as a non-invasive marker of susceptibility to malignant ventricular arrhythmias.

Síndrome de Brugada: observaçöes sobre a evoluçä de um caso / The Brugada syndrome: outcome of one case

The Brugada syndrome is a rare condition, and due to its mutating manner of presentation it may be difficult to diagnose. We report one case and discuss the diagnostic aspects and the clinical outcome of one patient with characteristic findings of this syndrome. These findings are especially defined by J-ST elevation in the right leads of serial electrocardiographic records, wide oscillations of J points and ST segments during 24-hour Holter monitoring, and nocturnal sudden death. We stress the importance of the Holter monitor findings for diagnostic complementation. Through this method it is possible to establish a correlation between vigil activities and sleep and the variability of the degree of impairment in ventricular repolarization.

Casi muerte súbita recuperada tras fibrilación ventricular / Near sudden death recovered to ventricular fibrillation

El síndrome de bloqueo de rama derecha, elevación del segmento ST en las derivaciones V1 a V3 y muerte súbita es una nueva entidad (distinta de otros síndromes, como el síndrome del QT largo o la displasia ventricular derecha), que está determinada por anomalías genéticas que afectan al canal de sodio y se denomina síndrome de Brugada. El único tratamiento que podemos ofrecer a estos pacientes actualmente es un desfibrilador implantable

Parada cardiorrespiratória / Cardiac arrest

Entende-se por socorro básico ou ressuscitaçäo cardiopulmonar básico o conjunto de procedimentos de emergência que podem ser executados por profissionais de saúde ou por leigos treinados. Consiste fundamentalmente no reconhecimento da obstruçäo das vias aéreas, das paradas respiratória e cardíaca e da aplicaçäo da ressucitaçäo cardiopulmonar por meio da sequência: abertura das vias aéreas, respiraçäo boca a boca e compressäo torácica externa. O suporte avançado de vida ou socorro especializado é o conjunto de medidas que deve ser istalado de forma imediata e realizado por profissionais de saúde. Consiste em desfibrilaçäo elétrica, intubaçäo endotraqueal e administraçäo de medicaçöes. Os autores comentam aspectos importantes desses procedimentos, para que o soccoro básico e o socorro especializado da vítima de parada cardiorrespiratória sejam eficientes.