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)

El electrocardiograma de 12 derivaciones asociado con las derivadas accesorias (precordiales derechas altas) es el método complementario con el cual se obtiene la mayor información diagnóstica y pronostica en pacientes portadores con síndrome de Brugada. Mediante este método sencillo, económico, reproducible y operador independiente, podemos estudiar las alteraciones tanto de la despolarización como de la repolarización ventricular. También permite el diagnóstico de las distintas arritmias supraventriculares que pueden acontecer así como caracterizar las diferentes taquicardias ventriculares. Por otro lado, el análisis vectocardiográfico con el método de Frank en pacientes con síndrome de Brugada, sugiere la dualidad de los mecanismos fisiopatológicos del patrón electrocardiográfico característico o tipo 1, demostrándose características distintivas y particulares, con respecto a individuos portadores de bloqueo de rama derecha. La compresión de todos estos mecanismos, pueden contribuir a orientar futuros esfuerzos terapéuticos que permitan controlar la disfunción de los canales asociados a esta rara y compleja canalopatía.

Twelve-lead ECG associated to high right parasternal accessory leads is the resource that yields a greatest number of diagnostic and prognostic information in patients carriers of BrS. By this simple, cheap, reproducible, and operator-independent method, depolarization alterations can be studied as well as ventricular repolarization aspects. The method allows diagnosing frequent episodes of atrial fibrillation and other supraventricular arrhythmias, as well as characterizing the different ventricular tachyarrhythmias. The analysis of the Frank VCG (F-VCG) of patients with BrS suggests the duality of the underlying physiopathological mechanisms of the Brugada Type-1 ECG pattern. F-VCG of patients with Brugada type-1 ECG pattern has distinctive characteristics from the F-VCG of individuals with RBBB pattern. The understanding of these mechanisms may help to guide future therapeutic efforts to control the channels dysfunction associated with this intriguing channelopaty.

OBJECTIVE: Analyze the dromotropic disturbances (vector-electrocardiographic), and the possible anatomic causes, provoked by selective alcohol injection in the septal branch, for percutaneous treatment, of obstructive hypertrophic cardiomyopathy. METHODS: Ten patients with a mean age of 52.7 years underwent percutaneous septal ablation (PTSA) from october 1998; all in functional class III/IV). Twelve-lead electrocardiogram was performed prior to and during PTSA, and later electrocardiogram and vectorcardiogram according to Frank's method. The patients were followed up for 32 months. RESULTS: On electrocardiogram (ECG) prior to PTSA all patients had sinus rhythm and left atrial enlargement, 8 left ventricular hypertrophy of systolic pattern. On ECG immediately after PTSA, 8 had complete right bundle-branch block; 1 transient total atrioventricular block; 1 alternating transient bundle-branch block either right or hemiblock. On late ECG 8 had complete right bundle-branch block confirmed by vectorcardiogram, type 1 or Grishman. CONCLUSION: Septal fibrosis following alcohol injection caused a predominance of complete right bundle-branch block, different from surgery of myotomy/myectomy.