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Background: Some therapies used for COVID-19 can prolong the QT interval and produce severe arrhythmias. QT interval measuredfrom a standard electrocardiogram (ECG) requires additional personnel and risk of infection. Novel technologies to obtain anECG connected to smartphones provide an alternative for the evaluation of corrected QT interval (QTc).Objective: The aim of this study was to evaluate the feasibility of using a single-lead ECG device to measure the QT interval in patientswith suspected or confirmed COVID-19 before receiving treatment with drugs that can prolong the QT interval.Methods: The ECG was obtained with a KardiaMobile (KM) device and transmitted to a smartphone. The ECG recordings weresaved as pdf files and electronically submitted to the electrophysiology section which centralized the reception and assessed themeasured QT and QTc intervals.Results: A total of 31 patients (mean age 61 years, range 20-95 years) with suspected COVID-19 enrolled for treatment with hydroxychloroquine,azithromycin, ritonavir or lopinavir were analyzed. The recordings could be read in all the cases and had to be repeatedin two cases. The mean value of the QTc interval was 423 ms (range 380-457 ms) in men and 439 ms (range 391-540 ms) in women.The response time since the ECG recording was submitted for analysis was 11 min (range 1-155).Conclusions: The QTc interval could be measured from ECG recordings obtained with KM devices connected to a smartphone andtransmitted to a centralized reading center in all patients., Introducción: Se ha comunicado que algunos tratamientos utilizados para la infección por COVID-19 pueden ocasionar alteracionesdel intervalo QT y arritmias graves. La medición por electrocardiograma (ECG) convencional requiere personaladicional y riesgo de contagio. Nuevas tecnologías para obtención de un ECG conectados a teléfonos inteligentes (smartphones)proporcionan una alternativa para evaluación del QTc.Objetivo: El objetivo fue evaluar la factibilidad de un dispositivo para registro electrocardiográfico de un canal, para la medicióndel intervalo QT en pacientes con sospecha o confirmación de infección por COVID-19, antes de recibir drogas queprolongan el intervalo QT.Material y métodos: Se obtuvieron registros de ECG con un dispositivo Kardia Mobile (KM) con trasmisión a un smarthphone.La sección de electrofisiología cardíaca centralizó la recepción por medio electrónico de los ECG en formato de archivo pdf yrealizó las mediciones de los intervalos QTm y QTc.Resultados: Se estudiaron 31 pacientes, edad promedio 61 años (rango 20-95 años), sospechosos de presentar infección porCOVID-19 enrolados para tratamiento con hidroxicloroquina, azitromicina, ritonavir y lopinavir. Los registros pudieron serleídos en todos los casos, y debieron repetirse en dos casos. Los valores del intervalo QTc promedio en varones y mujeres fue423 mseg (rango 380-457 mseg) y 439 mseg (rango 391-540 mseg), respectivamente. El tiempo de respuesta desde el envíodel ECG al grupo de análisis fue 11 min (rango 1-155).Conclusiones: Los registros ECG obtenidos con dispositivos KM, para trasmisión a un smartphone a un grupo central delectura, permitieron la medición del intervalo QTc en todos los pacientes.

Background: Ventricular fibrillation is routinely induced during implantable cardioverter- -defibrillator insertion to assess defibrillator performance, but this strategy is experiencing a progressive decline. We aimed to assess the efficacy of defibrillator therapies and long-term outcome in a cohort of patients that underwent defibrillator implantation with and without defibrillation testing. Methods: Retrospective observational series of consecutive patients undergoing initial defibrillator insertion or generator replacement. We registered spontaneous ventricular arrhythmias incidence and therapy efficacy, and mortality. Results: A total of 545 patients underwent defibrillator implantation (111 with and 434 without defibrillation testing). After 19 (range 9–31) months of follow-up, the death rate per observation year (4% vs. 4%; p = 0.91) and the rate of patients with defibrillator-treated ventricular arrhythmic events per observation year (with test: 10% vs. without test: 12%; p = 0.46) were similar. The generalized estimating equations-adjusted first shock probability of success in patients with test (95%; CI 88–100%) vs. without test (98%; CI 96–100%; p = 0.42) and the proportion of successful antitachycardia therapies (with test: 87% vs. without test: 80%; p = 0.35) were similar between groups. There was no difference in the annualized rate of failed first shock per patient and per shocked patient between groups (5% vs. 4%; p = 0.94). Conclusions: In this observational study, that included an unselected population of patients with a defibrillator, no difference was found in overall mortality, first shock efficacy and rate of failed shocks regardless of whether defibrillation testing was performed or not.

Introducción: La ablación por catéter (AC) es beneficiosa en pacientes con taquicardia ventricular (TV) recurrente. Nuestro objetivo es revisar los casos de tormenta eléctrica (TE) tratados con AC. Métodos: Análisis retrospectivo de pacientes con TE debida a TV monomorfa sostenida (TVMS) tratados mediante AC. Se definió éxito del procedimiento: ausencia de TV inducible al final del mismo; éxito parcial: inducción de TV no clínica; no éxito: inducibilidad de la TV clínica. Resultados: Se realizaron 16 procedimientos en 14 pacientes: 10 exitosos, 3 éxito parcial y 3 no exitosos. Todos los pacientes evolucionaron sin arritmia ventricular inmediatamente post-ablación. Diez pacientes (71,4%) evolucionaron sin TV y 86,7% sin TE (seguimiento 8 [3-30] meses). Cinco pacientes (35,7%) murieron de causa no arrítmica. Conclusiones: La AC se asocia a una supresión aguda de TV en todos los pacientes con TE debida a TVMS y a una evolución sin recurrencia en la mayoría de ellos.

Introduction: Radiofrequency catheter ablation of atrial fibrillation is more effective than antiarrhythmic drugs for symptoms control, particularly in paroxysmal atrial fibrillation. The procedure is laborious and complex and not exempt from complications.Objective: The aim of this study was to evaluate the outcomes of radiofrequency catheter ablation in a consecutive and selectedpopulation with recurrent atrial fibrillation refractory to antiarrhythmic drugs.Methods: One-hundred and eleven patients (90 men) with paroxysmal (n = 75) or persistent (n = 36) atrial fibrillation,refractory to 2 (1.5-3) antiarrhythmic drugs were selected for radiofrequency catheter ablation. All the procedures wereperformed following a uniform methodology.Mean age was 56 ± 11 years, left atrial diameter was 41.5 (39-45) mm and left ventricular ejection fraction was 60% (56.5-66.5%).A total of 126 radiofrequency catheter ablation procedures were performed, including 15 second procedures, and 476/489(97.3%) pulmonary veins were isolated. Twenty-five patients (22.5%) presented spontaneous ectopic activity in the pulmonaryveins. Nonfatal complications occurred in 7/126 procedures (5.5%) and were satisfactorily resolved. Three patients presentedvascular complications; other complications included one related to anesthesia, one subacute cardiac tamponade, one pericarditiswithout effusion and one pulmonary vein stenosis.After 22-month follow-up (13-35 months), 83 patients (74.8%) remained in sinus rhythm without antiarrhythmic drugs. Theremaining 28 patients (25.2%) presented recurrences. Four of these patients had a favorable response to these previouslyinefficient drugs, 8 had atrial fibrillation in spite of receiving antiarrhythmic drugs and 1 patient will undergo a new ablation.The remaining 15 patients underwent a second ablation procedure; 10 of them are free of recurrences after 12 (9-31) months.Conclusion: In this consecutive series of patients with atrial fibrillation refractory to dr, La ablación de la fibrilación auricular (ARF-FA) es más eficaz que las drogas antiarrítmicas (DAA) en el control de síntomas, particularmente cuando la arritmia es paroxística. Consiste en un procedimiento laborioso y complejo no exento de complicaciones. Objetivos: Evaluar los resultados de la ablación en una población seleccionada consecutiva con fibrilación auricular recurrente y refractaria a DAA. Metodología y resultados: Se evaluaron 111 pacientes (p), 90 hombres, con FA paroxística (75p) o persistente (36p), refractaria a 2 (1,5-3) DAA que fueron seleccionados para la ARF-FA. Todos los procedimientos fueron realizados siguiendo una metodología uniforme. La edad fue 56±11 años, el diámetro de AI 41,5 (39-45) mm y la fracción de eyección ventricular izquierda 60% (56,5%-66,5%). Se realizaron 126 procedimientos de ARF-FA, incluyendo 15 segundos procedimientos. Se aislaron 476/489 (97,3%) venas pulmonares (VP). Veinticinco pacientes (22,5%) presentaron actividad ectópica espontánea de VP. Se presentaron complicaciones no fatales en 7/126 procedimientos (5,5%) que se resolvieron satisfactoriamente. Tres pacientes presentaron complicaciones vasculares y se observó una complicación anestésica, un taponamiento cardiaco subagudo, una pericarditis sin derrame y una estenosis de VP. Luego de un seguimiento de 22 (13-35) meses, 83p (74,8%) se mantuvieron en ritmo sinusal sin DAA. Los 28p restantes (25,2%) presentaron recurrencias. Cuatro de ellos respondieron satisfactoriamente a DAA (previamente ineficaces), ocho tuvieron FA a pesar de recibir DAA y 1p se encuentra en plan de reablación. A los 15p restantes se les realizó un segundo procedimiento de ablación. Diez de ellos se mantienen sin recurrencias luego de 12 (9-31) meses. Conclusión: En esta serie consecutiva de pacientes con FA refractaria a DAA, la ARF-FA mostró una adecuada tasa de éxito y bajo nivel de complicaciones.

IntroductionThe CHADS2 score and the CHA2DS2-VASc score recently adopted by the medicalcommunity have been developed with international registry data and are widely usedin clinical practice. However, they have not been evaluated in national registries.ObjectivesThe aims of this study were first to evaluate the predictive power of the CHADS2and CHA2DS2-VASc stroke risk scores in the Atrial Fibrillation Registry conductedby the Argentine Society of Cardiology Research Area and second to compare bothscoring systems.MethodsThe Atrial Fibrillation Registry of 2001 was a multicenter, prospective study of allconsecutive patients with chronic atrial fibrillation (permanent and persistent)treated in 70 medical centers in Argentina. Demographic data, socioeconomic characteristics,background and clinical features were obtained. A 2-year follow-up wasperformed to assess stroke rate. For the present analysis patients without anticoagulanttreatment were selected. In this population, the two risk score systems wereassessed; a ROC curve was built for each score (reported as C statistic) and bothscoring systems were compared.ResultsThe study population consisted of 303 patients (49.3 %) not receiving anticoagulanttherapy. The stroke rate in the selected population was 9.5%. Both scoring systemspredicted significant stroke risk.The stroke rate increased as the CHADS2 and the CHA2DS2-VASc scores were higher,and were similar in both risk scales.The CHADS2 and CHA2DS2-VASc scores had C statistic values of 0.67 (0.55-0.78)and 0.69 (0.59 to 0.78), respectively, without significant differences between them.The score analyses divided into three risk profiles -low, moderate and high- revealedthat the predictive power decreased markedly. The C statistic of the CHADS2 was0.63 (95% CI 0.57-0.68) and that of the CHA2DS2-VASc score was 0.57 (95% CI 0.51-0.62, with a slightly better predictive trend for the CHADS2 score but without statisticalsignificance.ConclusionsThe two scoring systems used to, Introducción:El puntaje CHADS2 y el recientemente adoptado por la comunidad médica CHA2DS2 VASc Han sido confeccionados con datos de registros internacionales y son ampliamente usados en la práctica clínica, sin embargo, no han sido testeados en registros nacionales.Objetivo:El objetivo del presente estudio es evaluar el poder de predicción de los puntajes de riesgo de ACV (CHADS2 y CHA2DS2 VASc ) en el registro de fibrilación auricular realizado por área de investigación de nuestra sociedad y comparar ambos sistemas de puntajes.Métodos:El registro de fibrilación auricular fue un estudio Multicéntrico y prospectivo de todos los pacientes consecutivos asistidos con Fibrilación Auricular Crónica (permanente y persistente) en 70 centros médicos de Argentina realizado en año 2001.Se obtuvieron los datos demográficos, las características socioeconómicas, los antecedentes y las características clínicas de la población con fibrilación auricular crónica (permanente y persistente).Se realizó un seguimiento a 2 años evaluando la tasa de ACV . Se seleccionaron los pacientes sin tratamiento anticoagulante para el análisis. Se Testeo en esta población los dos sistemas de puntajes de riesgo confeccionándose una curva de ROC para cada puntaje (informándose como C estadístico) y realizándose un comparación entre ambos sistemas de puntajes.Resultados:El 49, 3 % (303 pacientes) de los pacientes seguidos no recibían tratamiento anticoagulante y esta fue nuestra población en estudio. La tasa de ACV en la población seleccionada fue del 9,5 %.Los dos sistemas de puntajes de riesgo predijeron el ACV significativamente.En la tabla se ve la tasa de ACV por cada punto sumado. 012345678CHADS22,6%5.1%9,1%14,2%12,5%50%0% CHADVASC0%2,8%6.3%1,4%14,4%20%7,6%22,2% El C estadístico para ACV del CHADS2 fue de 0,67 (0,55-0,78) y C estadístico para ACV del CHA2DS2 VASc fue 0,69 (0,59-0,78) sin diferencias significativas entre ambos. Conclusiones En una población con fibrilación auricu

Background— The occurrence of monomorphic ventricular tachycardia (M-VT) with >1 QRS morphology during the same episode (pleomorphism [PL]) or in different episodes (multiple morphologies [MM]) has been described through ECG. Implantable cardioverter-defribillator (ICD) electrograms (EGs) provide the opportunity to analyze virtually all spontaneous M-VT episodes. We sought to study the incidence, determinants, and prognostic significance of PL and MM as assessed by ICD-EG in a prospective series of patients with ICDs. Methods and Results— Spontaneous episodes of M-VT were analyzed before ICD intervention. PL was defined as >1 ICD-EG morphology, each having ≥6 consecutive identical beats during the same VT episode, and MM as >1 ICD-EG morphology in different M-VT episodes in the same patient. We analyzed 1881 M-VT episodes from 315 patients followed for 17 months. PL and MM occurred in 6% and 19%, respectively, of the total population (16% and 62% of patients with M-VT). Recurrent M-VT as diagnosis for ICD indication predicted PL and MM. Patients with PL more frequently developed MM (85% versus 15%; P<0.001) compared to patients without PL. Total mortality (5%) was significantly higher in patients with PL (20%), in patients with MM (11.5%), and in women (12%). In multivariate analysis, only PL (odds ratio, 5.33; P=0.009) and female sex (odds ratio, 3.1; P=0.038) predicted mortality. Conclusions— In a prospective series of patients with ICDs, mostly indicated for secondary prevention, both PL and MM of VT, as judged by ICD-EG, were not uncommon and were strongly associated. Female sex and the development of PL VT were the only independent predictors of mortality., Postprint (published version)