Congenial short QT syndrome: A review focused on electrocardiographic features.

Congenital short QT syndrome is a very low prevalence inherited primary arrhythmia syndrome first reported in 2000 by Gussak et al., who described two families with a short QT interval, syncope, and sudden cardiac death. In 2004, Ramon Brugada et al. identified the first genetic type of this entity. To date, a total of nine genotypes have been described. The diagnosis is easy from the electrocardiogram (ECG), not only due to the short QT duration, but also based on other aspects covered in this review. During 24-h Holter monitoring, paroxysmal atrial fibrillation spontaneously converting to sinus rhythm may be found. Even though the T wave may appear symmetric on the ECG, the T loop of the vectorcardiogram confirms that the T wave is constantly asymmetric due to the presence of dashes closer to each other in the efferent branch. In this review, we also describe the minus-plus T wave sign that we have described in a previously published article. In addition to congenital causes, we briefly highlight the existence of numerous acquired causes of short QT interval.

ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Temporal Analysis of COVID-19 Epidemiological Indicators in a Low-Income Brazilian Context: A Retrospective Analysis in Paraiba State.

Northeast Brazil is a region with great international tourist potential. Among the states that make up this region, Paraíba stands out due to the presence of vulnerable groups and factors that contribute to adverse outcomes of COVID-19. Therefore, the aim of this study was to analyze the epidemiological data on the incidence, mortality, and case fatality of COVID-19 in Paraíba. An ecological, population-based study was performed, with data extracted from the Brazilian Ministry of Health database. All cases and deaths from COVID-19 from March 2020 to December 2022 were included. The time series was built by applying the Prais-Winsten regression model, and the daily percent change was calculated to analyze the trends. The highest case fatality of the entire period was in April 2020 (7.8%), but in March 2021, the state broke the dismal record of 1248 deaths and the highest mortality rate (30.5 deaths per 100,000 inhabitants). Stationary mortality and case fatality were better in 2022; however, in February 2022, the mortality rate was at levels similar to the same month of the previous year. These results illustrate that COVID-19 is evolving and needs to be constantly monitored.

Effect of clonidine on heart rate variability during spinal anaesthesia: randomized clinical trial.

INTRODUCTION: Spinal anaesthesia consists of administering a local anaesthetic in the subarachnoid space, thus causing sensory, motor, and autonomic nerve conduction block. Currently, recovery from spinal anaesthesia is evaluated by the return of motor function, without considering the autonomic blockade, which is responsible for most complications of the technique. Heart rate variability (HRV) is an indirect method to measure the autonomic nervous system and may be useful in assessing autonomic recovery after spinal anaesthesia. The study objective was to evaluate the autonomic function, through HRV, at the moment of return of motor function in patients who received spinal anaesthesia when clonidine is used as an adjuvant. MATERIAL AND METHODS: This was a randomised, double-blind clinical trial. The sample consisted of 64 ASA I-II patients who underwent spinal anaesthesia and were divided into 2 groups. Group C received 20 mg of bupivacaine with 75 mcg of clonidine, and group B received 20 mg of bupivacaine. HRV was evaluated at rest (T1) and at the time of motor function recovery (T2). Data were collected using a Polar V800® heart rate monitor and then analysed and filtered using Kubios 3.0® software. RESULTS: There was no difference in the values of the low-frequency/high-frequency (LF/HF) ratio, Poincaré plot standard deviation (SD2/SD1), detrended fluctuation analysis (DFAα1, DFAα2), or correlation dimension (D2) indices in any of the groups between the 2 moments. In the clonidine group, there was a difference only in approximate entropy (ApEn), where a P of 0.0124 was obtained considering a 95% confidence interval ranging from 17.83 to 141.47. CONCLUSIONS: There was no significant difference between the duration of sympathetic blockade and motor blockade in spinal anaesthesia.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Left septal fascicular block: Evidence, causes, and diagnostic criteria.

The existence of a tetrafascicular intraventricular conduction system is widely accepted by researchers. In this review, we have updated the criteria for left septal fascicular block (LSFB) and the differential diagnosis of prominent anterior QRS forces. More and more evidence points to the fact that the main cause of LSFB is critical proximal stenosis of the left anterior descending coronary artery before its first septal perforator branch. The most important characteristic of LSFB that has been incorporated in the corresponding diagnostic electrocardiographic criteria is its transient/intermittent nature mostly observed in clinical scenarios of acute (ie, acute coronary syndrome including vasospastic angina) or chronic (ie, exercise-induced ischemia) ischemic coronary artery disease. In addition, the phenomenon proved to be phase 4 bradycardia rate dependent and induced by early atrial extrastimulus. Finally, we believe that intermittent LSFB has the same clinical significance as "Wellens syndrome" and the "de Winter pattern" in the acute coronary syndrome scenario.

Evaluation of autonomic cardiac modulation and body composition in elderly submitted to the protocol of exercise and the gametherapy: A clinical trial protocol (SPIRIT compliant).

INTRODUCTION: Aging affects the cardiovascular system by impairing the amount and strength of cardiac pumping. Heart rate variability (HRV) is a safe parameter to assess variations in the cardiovascular system, providing data on sympathetic and parasympathetic activations. OBJECTIVES: Our primary aim is to investigate the cardiac autonomic modulation and body composition of active older adults participating in a physical exercise protocol and gametherapy. Our secondary aim is to assess their functional capacity, cognitive function, balance, respiratory pressures, and functional autonomy. METHOD: This randomized clinical trial will include 100 active older adults aged 60 to 80 years. The exercise group (EG) will perform 24 supervised training sessions (strength and aerobic) for 12 weeks (2 60-minutes sessions per week). The gametherapy group (GG) will exercise using gametherapy. Assessments will occur on the first week, after the 12th week, after wash out and in the end of cross over. The primary outcome will be HRV and body composition (bioimpedance). Secondary outcomes will be functional capacity (6-minute walk test), cognitive function (mini-mental state examination), risk of falls and balance (berg balance scale and timed up and go test), inspiratory and expiratory pressures (manovacuometry) and functional autonomy (functional reach test and group of Latin American development to maturity [GDLAM] protocol). DISCUSSION: This study will provide relevant information about the effects of physical training (physical exercises and gametherapy) on HRV and other variables in active older adults.

Non-specific intraventricular conduction delay or atypical LBBB - How to predict acute coronary occlusion?

We describe two patient cases with acute coronary syndrome (ACS) and broad QRS in the acute phase electrocardiogram (ECG). The patients' ECG findings resembled left bundle branch block (LBBB), but with atypical features. Broad QRS not fulfilling the criteria for LBBB or right bundle branch block (RBBB) is diagnosed as non-specific intraventricular conduction delay (NSIVCD). The case report deals with the challenges of predicting acute coronary occlusion in patients with NSIVCD in their acute phase ECG. In one of the cases, the ECG changed from typical LBBB to NSIVCD or atypical LBBB with the development of systolic dysfunction and clinical heart failure.

Northwest axis in the electrocardiogram - A sign of right ventricular remodeling in tetralogy of Fallot. A case report.

The typical ECG changes in tetralogy of Fallot are right axis deviation, large R waves in the anterior precordial leads and large S waves in the lateral precordial leads. We present a patient with extreme deviation of the frontal QRS axis between -90° and ± 180°. The child underwent open heart surgery twice before one year of age and a third time at nine years of age. The axis change persisted into adulthood.

The S1S2S3 electrocardiographic pattern - Prevalence and relation to cardiovascular and pulmonary diseases in the general population.

BACKGROUND: There is lack of studies exploring the incidence and association with diseases of the S1S2S3 electrocardiogram (ECG) pattern in the general population. SUBJECTS AND METHODS: This population study included 6299 individuals aged 30+, and explored the prevalence and association between S1S2S3 and cardiovascular and pulmonary diseases. Criteria for the S1S2S3-I and S1S2S3-II ECG pattern were fulfilled when there was an S wave in the leads I, II and III, and the S-wave amplitude was greater than the R-wave amplitude in one or two of the leads, respectively. RESULTS: The S1S2S3-I ECG pattern was found in 2332 subjects (36.9%). After age adjustment, hypertension was associated with S1S2S3-I (Odds ratio [OR] 1.25, 95% CI 1.12-1.41, p < 0.001). This age-adjusted association was statistically significant among men but not among women (OR 1.37, 1.16-1.62, p < 0.001 and OR 1.13, 0.97-1.33, p = 0.126, respectively). The S1S2S3-II ECG pattern was present in 193 subjects (3.1%). After age adjustment, heart failure proved to be associated with S1S2S3-II (OR 1.85, 1.18-2.90, p = 0.007). Dividing the population by sex, resulted in a statistically significant age-adjusted association for men but not for women (OR 2.30, 1.22-4.33, p = 0.010 and OR 1.59, 0.83-3.03, p = 0.159, respectively). Interactions with sex were statistically non-significant. CONCLUSION: In the general adult population, the prevalence of the S1S2S3 ECG pattern is markedly affected by the diagnostic ECG criteria. The S1S2S3-I pattern was associated with hypertension, while S1S2S3-II was associated with heart failure, and both associations were enhanced in men. The associations with other studied cardiovascular and pulmonary diseases were minor and not clinically useful for risk stratification.

Early ischemic ST-segment and T-wave changes during balloon angioplasty.

BACKGROUND: Acute coronary occlusion results in increased T-wave amplitude and ST-segment elevation in the ECG leads facing the ischemic region. MATERIAL AND METHODS: We performed continuous ECG recording in 34 patients during balloon occlusion of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA). Delta (Δ) ST and ΔT amplitudes were calculated by subtracting the preinflation values from the values measured during balloon inflation. RESULTS: Occlusion of the LAD resulted in greater increase in the amplitude of the T wave than of the ST segment in lead V2 (ΔT +3.4 mm, inter-quartile range [IQR] 1-6 mm; ΔST +1.4 mm, 0.5-3 mm). During RCA occlusion, ΔST and ΔT didn't differ significantly. LCx occlusion resulted in significant differences between ΔST and ΔT in all leads, except aVF and V3-V4. In two patients (LCx), we observed a biphasic ST-T response: an initial negative change of the T-wave amplitude was followed by a positive change in leads V1-V2. In leads II, III, aVF and V4-V6, there was an initial positive change, followed by a final negative change towards the end of the occlusion. CONCLUSION: Continuous 12­lead ECG recording during balloon occlusion of the LCx resulted in significant differences between the ΔST and ΔT values in all leads except aVF and V3-V4. LAD and RCA occlusion resulted in less evident differences between the ST-segment and T-wave changes. A change in polarity of T-wave changes during balloon occlusion (initial negative and final positive change, or vice versa) proved to be a rare finding.

The prognostic significance of the electrical QRS axis on long-term mortality in acute coronary syndrome patients - The TACOS study.

INTRODUCTION: There are several potential causes of QRS-axis deviation in the ECG, but there is limited data on the prognostic significance of QRS-axis deviation in ACS patients. SUBJECTS AND METHODS: We evaluated the long-term prognostic significance of acute phase frontal plane QRS-axis deviation and its shift during hospital stay in ACS patients. A total of 1026 patients who met the inclusion criteria were divided into three categories: normal (n = 823), left (n = 166) and right/extreme axis (n = 37). RESULTS: The median survival time was 9.0 years (95% CI 7.9-10.0) in the normal, 3.6 years (95% CI 2.4-4.7) in the left and 1.3 years (95% CI 0.2-2.4) in the right/extreme axis category. Both short and long-term all-cause mortality was lowest in the normal axis category and highest in the right/extreme axis category. Compared to normal axis, both admission phase QRS-axis deviation groups were independently associated with a higher risk of all-cause mortality. When including left ventricular hypertrophy in the ECG, only the right/extreme axis retained its statistical significance (aHR 1.76; 95% CI 1.16-2.66, p = 0.007). Axis shift to another axis category had no effect on mortality. CONCLUSION: In ACS patients, acute phase QRS-axis deviation was associated with higher risk of all-cause mortality. Among the axis deviation groups, right/extreme QRS-axis deviation was the strongest predictor of mortality in the multivariable analysis. Further studies are required to investigate to what extent this association is caused by pre-existing or by ACS-induced axis deviations. QRS-axis shift during hospital stay had no effect on all-cause mortality.

Prevalence and long-term prognostic implications of prolonged QRS duration in left ventricular hypertrophy: a population-based observational cohort study.

OBJECTIVES: ECG left ventricular hypertrophy (ECG-LVH) has been associated with left ventricular dysfunction and adverse prognosis, but little is known about the prevalence and prognostic significance of different levels of QRS duration in the presence of ECG-LVH in a general population. DESIGN: Population-based observational prospective cohort study. PARTICIPANTS: Nationally representative random cluster of Finnish adult population. METHODS: We assessed the prevalence and long-term (median 15.9 years) prognostic significance of QRS duration in ECG-LVH, and compared the risk to individuals without ECG-LVH in a predominantly middle-aged random sample of 6033 Finnish subjects aged over 30 years (mean age 52.2, SD 14.6 years), who participated in a health examination including a 12-lead ECG. MAIN OUTCOME MEASURES: Cardiovascular and all-cause mortality, incidence of heart failure (HF). RESULTS: ECG-LVH was present in 1337 (22.2%) subjects; 403 of these (30.1%) had QRS duration ≥100 ms and 100 (7.5%) had ≥110 ms. The increased risk of mortality in ECG-LVH became evident after a QRS threshold of ≥100 ms. After controlling for known clinical risk factors, QRS 100-109 ms was associated with increased cardiovascular (HR 1.38, 95% CI 1.01 to 1.88, p=0.045) and QRS≥110 ms with cardiovascular (1.74, 95% CI 1.07 to 2.82, p=0.025) and all-cause mortality (1.52, 95% CI 1.02 to 2.25, p=0.039) in ECG-LVH. The risk of new-onset HF was two-fold in subjects with QRS 100-109 ms and threefold in subjects with QRS ≥110 ms, even after adjustment for incident myocardial infarction within the follow-up. When the prognosis was compared with subjects without ECG-LVH, subjects with ECG-LVH but QRS duration <100 ms displayed similar mortality rates with or without ECG-LVH but higher rates of incident HF. CONCLUSIONS: In ECG-LVH, the risk of excess mortality and new-onset HF markedly increases with longer QRS duration, but even QRS duration within normal limits in ECG-LVH carried a risk of HF compared with the risk in individuals without ECG-LVH.

Transient ascending ST-segment depression and widening of the S wave in 3-channel Holter monitoring-A sign of dromotropic disturbance in the right ventricular outflow tract in the Brugada syndrome: A report of five cases.

BACKGROUND: Brugada syndrome (BrS) is somewhat a challenging diagnosis, due to its dynamic pattern. One of the aspects of this disease is a significant conduction disorder located in the right ventricular outflow tract (RVOT), which can be explained as a consequence of low expression of Connexin-43. This decreased conduction speed is responsible for the typical electrocardiographic pattern. Opposite leads located preferably in inferior leads of the electrocardiogram may show a deep and widened S wave associated with ascending ST segment depression. Holter monitoring electrocardiographic (ECG) aspects is still a new frontier of knowledge in BrS, especially in intermittent clinical presentations. METHODS: We describe, as an exploratory analysis, five case series of intermittent type 1 BrS to demonstrate the appearance of ascending ST segment depression and widening of the S wave, during 3-channel 24h-Holter monitoring (C1, C2 and C3) with bipolar leads. RESULTS: In the five cases described, the ST segment depression was observed mainly in C2, but in some cases also in C1 and C3. Only case 1 presented concomitant intermittent elevation of the ST segment in C1. All cases were intermittent. CONCLUSION: The recognition of an ECG pattern with ascending ST-segment depression and widening of the S wave in 3-channel Holter described in this case series should raise a suspicion of the BrS and suggests the counterpart of a dromotropic disturbance registered in the RVOT and/or reciprocal changes.

Three urgent needs in the battle against COVID-19: specific medications, information and acceptance of Pandemic / Três necessidades urgentes na batalha contra covid-19: medicamentos específicos, informações e aceitação da pandemia

The first confirmed case of COVID-19 was notified to the Brazilian Ministry of Health on February 26, 2020. On November 20, 2021, by the end of Epidemiological Week-46 (EW-46) 257,168,692 confirmed cases of COVID-19 reported worldwide. Among the countries with the highest number of accumulated cases the United States of America ranks number one (47,701,872), followed by India (34,510,413), Brazil (22,012,150), the United Kingdom (9,857,658), and Russia (9,135,149). Concerning deaths, 5,146,467 were confirmed worldwide until November 20, 2021. The United States was the country with the highest accumulated number of deaths (771,013), followed by Brazil (612,587), India (465,662), Mexico (292,145), and Russia (257,891).

O primeiro caso confirmado de COVID-19 foi notificado ao Ministério da Saúde (MS) do Brasil em 26 de fevereiro de 2020. Até o final da Semana Epidemiológica (SE) 46 de 2021, no dia 20 de novembro de 2021, foram confirmados 257.168.692 casos de covid-19 no mundo. Os Estados Unidos foram o país com o maior número de casos acumulados (47.701.872), seguido pela Índia (34.510.413), Brasil (22.012.150), Reino Unido (9.857.658) e Rússia (9.135.149). Em relação aos óbitos, foram confirmados 5.146.467 no mundo até o dia 20 de novembro de 2021. Os Estados Unidos foram o país com maior número acumulado de óbitos (771.013), seguido do Brasil (612.587), Índia (465.662), México (292.145) e Rússia (257.891)

Relevance of the vectorcardiogram in the Brugada syndrome with "northwest QRS axis".

The outcome in the Brugada syndrome (BrS) is more benign in female than in male individuals. However, outcome could be adversely affected by sinus node dysfunction (SND). Long sinus pauses indicate an overlap between the phenotypes of BrS and SND. We present a 29-year-old woman with syncopal episodes at rest since adolescence.

Brugada syndrome: current concepts and genetic background / Síndrome de Brugada: conceitos atuais e antecedentes genéticos

BACKGROUNG: Brugada syndrome (BrS) is a hereditary clinical-electrocardiographic arrhythmic entity with low worldwide prevalence. The syndrome is caused by changes in the structure and function of certain cardiac ion channels and reduced expression of Connexin 43 (Cx43) in the Right Ventricle (RV), predominantly in the Right Ventricular Outflow Tract (VSVD), causing electromechanical abnormalities. The diagnosis is based on the presence of spontaneous or medicated ST elevation, characterized by boost of the J point and the ST segment ≥2 mm, of superior convexity "hollow type" (subtype 1A) or descending rectilinear model (subtype 1B). BrS is associated with an increased risk of syncope, palpitations, chest pain, convulsions, difficulty in breathing (nocturnal agonal breathing) and/or Sudden Cardiac Death (SCD) secondary to PVT/VF, unexplained cardiac arrest or documented PVT/VF or Paroxysmal atrial fibrillation (AF) in the absence of apparent macroscopic or structural heart disease, electrolyte disturbance, use of certain medications or coronary heart disease and fever. In less than three decades since the discovery of Brugada syndrome, the concept of Mendelian heredity has come undone. The enormous variants and mutations found mean that we are still far from being able to concretely clarify a genotype-phenotype relationship. There is no doubt that the entity is oligogenetic, associated with environmental factors, and that there are variants of uncertain significance, especially the rare variants of the SCN5A mutation, with European or Japanese ancestors, as well as a spontaneous type 1 or induced pattern, thanks to gnomAD (coalition) researchers who seek to aggregate and harmonize exome and genome sequencing data from a variety of large-scale sequencing projects and make summary data available to the scientific community at large). Thus, we believe that this in-depth analytical study of the countless mutations attributed to BrS may constitute a real cornerstone that will help to better understand this intriguing syndrome.

INTRODUÇÃO: A Síndrome de Brugada (SBr) é uma entidade arrítmica clínico-eletrocardiográfica hereditária com baixa prevalência mundial. A síndrome é causada por alterações na estrutura e função de certos canais iônicos cardíacos e redução da expressão da Connexina 43 (Cx43) no Ventrículo Direito (VD), predominantemente no Trato de Saída do Ventricular Direito (VSVD), causando anormalidades eletromecânicas. O diagnóstico é baseado na presença de supradesnivelamento de ST espontâneo ou medicamentoso caracterizado por supradesnivelamento do ponto J e do segmento ST ≥2 mm, de convexidade superior "tipo covado" (subtipo 1A) ou modelo retilíneo descendente (subtipo 1B). A SBr está associado a um risco aumentado de síncope, palpitações, dor precordial, convulsões, dificuldade em respirar (respiração agonal noturna) e/ou Morte Cardíaca Súbita (MSC) secundária a PVT/VF, parada cardíaca inexplicada ou PVT/VF documentado ou Fibrilação atrial paroxística (FA) na ausência de doença cardíaca macroscópica ou estrutural aparente, distúrbio eletrolítico, uso de certos medicamentos ou coração coronário e febre. Em menos de três décadas desde a descoberta da síndrome de Brugada, o conceito de hereditariedade mendeliana se desfez. As enormes variantes e mutações encontradas significam que ainda estamos longe de sermos capazes de esclarecer concretamente uma relação genótipo-fenótipo. Não há dúvida de que a entidade é oligogenética associada a fatores ambientais, e que há variantes de significado incerto, principalmente as raras variantes da mutação SCN5A, com ancestrais europeus ou japoneses, bem como padrão espontâneo tipo 1 ou induzido, graças ao gnomAD (coalizão de pesquisadores que buscam agregar e harmonizar dados de sequenciamento de exoma e genoma de uma variedade de projetos de sequenciamento em grande escala e disponibilizar dados resumidos para a comunidade científica em geral). As enormes variantes e mutações encontradas significam que ainda estamos longe de sermos capazes de esclarecer concretamente uma relação genótipo-fenótipo. Assim, acreditamos que este estudo analítico em profundidade das inúmeras mutações atribuídas à BrS pode constituir uma verdadeira pedra angular que ajudará a compreender melhor esta síndrome intrigante.

Validação de um Algoritmo Simples para Detecção de Taquicardia Ventricular no Eletrocardiograma / Validation of a Simple Electrocardiographic Algorithm for Detection of Ventricular Tachycardia

Resumo Fundamento O diagnóstico diferencial de taquicardia de QRS largo, entre taquicardia ventricular (TV) ou taquicardia supraventricular com condução aberrante (TSV-A) é algumas vezes difícil de ser feito na sala de emergência. Objetivo Avaliar a acurácia de um algoritmo novo e simples para a detecção de TV no eletrocardiograma (ECG) em pacientes com taquicardia de QRS largo. Métodos ECGs de 12 derivações para detecção de taquicardia de QRS largo foram obtidos prospectivamente de 120 pacientes durante estudo eletrofisiológico. Seis médicos com diferentes experiências analisaram os ECGs, e fizeram o diagnóstico com base no algoritmo D12V16, que envolve a análise da polaridade predominante do complexo QRS nas derivações I, II, V1 e V6. O diagnóstico foi comparado com os obtidos pelo algoritmo tradicional de Brugada e pelo estudo eletrofisiológico, o qual é considerado padrão ouro. Adotou-se um nível de significância de 5% (p<0,05) nas análises estatísticas. Resultados De acordo com o estudo eletrofisiológico, 82 ECGs eram de TV e 38 de TSV-A. Doenças cardíacas estruturais estavam presentes em 71 (86,6%) dos pacientes com TV e em oito (21,1%) com TSV-A. O algoritmo de Brugada teve uma maior sensibilidade global (87,2%), enquanto o algoritmo D12V16 apresentou maior especificidade global (85,1%) para TV. Tanto o algoritmo D12V16 como o de Brugada apresentou um alto valor preditivo positivo (90,9% vs. 85,8%, respectivamente) e acurácia similar (73,8% vs. 81,4%, respectivamente) para o diagnóstico de TV. Nos avaliadores experientes, a acurácia foi maior utilizando o algoritmo de Brugada que o algoritmo D12V16, mas a acurácia dos dois algoritmos foi similar segundo os avaliadores menos experientes. Conclusão O algoritmo simplificado pode ser um método útil para reconhecer TV no ECG, principalmente para médicos menos experientes. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0)

Abstract Background The differential diagnosis of wide QRS complex tachycardia (WCT) between ventricular tachycardia (VT) or supraventricular tachycardia with aberrant conduction (SVT-A) is sometimes difficult in the emergency room. Objective The aim of this study was to evaluate the accuracy of a new simple electrocardiographic algorithm to recognize VT in patients with wide complex tachycardia. Methods The 12-lead electrocardiograms (ECG) for WCT were prospectively obtained from 120 patients during electrophysiological study. Six physicians with different expertise analyzed the electrocardiographic recordings, and made the diagnosis based on the D12V16 algorithm, that involves the analysis of the predominant polarity of QRS in leads I, II, V1 and V6. The diagnosis was compared with that made using the traditional Brugada algorithm and the "gold-standard" electrophysiological study. Statistical analyses were performed with a significance level of 5% (p<0.05). Results According to the EPS study, 82 ECG recordings were VT and 38 SVT-A. Structural heart diseases were present in 71 (86.6%) patients with VT and in 8 (21.1%) with SVT-A. The Brugada algorithm had higher global sensitivity (87.2%), and the D12V16 algorithm had higher global specificity (85.1%) for VT. Both D12V16 and Brugada's algorithms presented a high positive predictive value (90.9% vs 85.8%, respectively) and similar accuracy (73.8% vs 81.4%, respectively) for the diagnosis of VT. Experienced evaluators were more accurate using Brugada algorithm than the D12V16 algorithm, but the accuracy of both algorithms was similar according to less experienced examiners. Conclusion The simplified algorithm may be a useful method to recognize VT in the ECG, especially for less experienced doctors. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0)