Is There any Relationship Between Myocardial Repolarization Parameters and the Frequency of Ventricular Premature Contractions? / Há Alguma Relação entre os Parâmetros de Repolarização do Miocárdio e a Frequência de Contrações Ventriculares Prematuras?

Abstract Background: Ventricular premature contractions (VPCs) may trigger lethal ventricular arrhythmias in patients with structural heart disease. However, this role of VPCs in healthy people remains controversial once that not enough clinical trials are available. Recently, some myocardial repolarization markers, such as Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios, have been reported to be useful for predicting lethal ventricular arrhythmias in various clinical disorders without structural heart disease. Objective: In this study, we aimed to investigate the relation between VPC frequent and myocardial repolarization markers in individuals without structural heart disease. Methods: This study included 100 patients who had complaints of dizziness and palpitations. Twelve-lead electrocardiography and 24-hour ambulatory Holter recordings were obtained from all patients. VPC burden was calculated as the total number of VPCs divided by the number of all QRS complexes in the total recording time. P-values < 0.05 were considered significant. Results: Tp-e interval and Tp-e/QTc ratio were significantly higher in patients with higher VPC burden than in patients with lower VPC burden, and a positive correlation was found between these markers and VPC burden. Tp-e (β = 1.318, p = 0.043) and Tp-e/QTc (β = -405.136, p = 0.024) in the lead V5 were identified as independent predictors of increased VPC burden. Conclusions: Tp-e interval and Tp-e/QTc ratio increased in patients with high VPC number. Our study showed that VPCs may have a negative effect on myocardial repolarization. This interaction may lead to an increased risk of malignant arrhythmias.

Resumo Fundamento: As contrações ventriculares prematuras (CVPs) podem provocar arritmias ventriculares letais em pacientes com doença cardíaca estrutural, no entanto o papel das CVPs em indivíduos saudáveis permanece controverso, já que não há muitos estudos clínicos disponíveis. Recentemente, alguns marcadores de repolarização do miocárdio, tais como o intervalo Tp-e e as relações Tp-e/QT e Tp-e/QTc, foram relatados como úteis para prognosticar arritmias ventriculares letais em diversos transtornos clínicos sem doença cardíaca estrutural. Objetivo: Neste estudo, o objetivo foi investigar a relação entre os marcadores de repolarização do miocárdio e as CVPs frequentes em indivíduos sem doença cardíaca estrutural. Métodos: Este estudo incluiu 100 pacientes com queixas de tonturas e palpitações. Eletrocardiografia de 12 derivações e registros de Holter ambulatorial de 24 horas foram obtidos de todos os pacientes. A carga de CVP foi calculada como o número total de CVPs dividido pelo número de todos os complexos de QRS no tempo de registro total. Foram considerados significativos valores p < 0,05. Resultados: O intervalo Tp-e e a relação Tp-e/QTc foram significativamente mais altos em pacientes com carga de CVP mais alta do que nos pacientes com carga de CVP inferior, e encontrou-se correlação positiva entre esses marcadores e a carga de CVP. Tp-e (β = 1,318, p = 0,043) e Tp-e/QTc (β = -405,136, p = 0,024) na derivação V5 foram identificados como preditores independentes da carga de CVP aumentada. Conclusões: O intervalo Tp-e e a razão Tp-e/QTc foram mais altos em pacientes com um valor mais alto de CVP. Nosso estudo mostrou que CVPs podem ter um efeito negativo na repolarização do miocárdio. Essa interação pode resultar em risco aumentado de arritmias malignas.

Association between premature ventricular complexes during exercise, long-term occurrence of life-threatening arrhythmia and mortality / Asociación entre ectopia ventricular en ejercicio, la ocurrencia de arritmias potencialmente mortales y mortalidad a largo plazo

Abstract Objective: Exercise-induced premature ventricular complexes (EiPVCs) are often considered as benign arrhythmias, although they are associated with a high risk of all-cause death in the general healthy population. However, an intermediate pathophysiological process remains unclear, particularly in patients with known cardiovascular disease. The aim of this study was to find an association between EiPVCs, the occurrence of life-threatening ventricular arrhythmias (LACO), and all-cause mortality in patients with cardiovascular disease. Methods: This was an observational study of a cohort of patients with coronary artery disease (CAD) or idiopathic cardiomyopathy (ICM). Stress testing was performed as a part of the routine cardiovascular evaluation. The occurrence of EiPVCs was evaluated during exercise testing (ET). At follow-up, long-term occurrence of LACO was evaluated. A bivariate and multivariate analysis was performed. Results: Out of the total of 1442 patients analysed, 700 (49%) had EiPVCs. During 14 years of following-up after ET, 106 LACO outcomes were observed. Long-term all-cause mortality was 4% (n = 61). A bivariate analysis showed that patients with EiPVCs had an increased risk for LACO (RR = 2.81, 95% CI; 1.9---4.3, P < .001), and for mortality (RR = 2.1, CI95% 1.2---3.4, P < .01). Occurrence of LACO was also associated with a higher mortality risk (RR = 5.7, 95% CI; 3.4---9.4, P < .001). After a post hoc analysis, LACO remained as a highly predictive variable for mortality. Conclusion: Patients with EiPVCs have a high risk of LACO and all-cause mortality. The presence of LACO could be an intermediate stage between EiPVCs and mortality in subjects with cardiovascular disease.

Resumen Objetivo: La extrasistolia ventricular inducida por ejercicio (EVIE) suele considerarse una arritmia benigna, sin embargo, ha sido asociada a mayor mortalidad en población general. Hasta hoy no se ha encontrado el proceso fisiopatológico involucrado, particularmente en pacientes con enfermedad cardiovascular. El objetivo del estudio fue establecer una asociación entre EVIE con la ocurrencia de arritmias ventriculares potencialmente malignas (APM) y letalidad a largo plazo, en sujetos con enfermedad cardiovascular. Método: Estudiamos una cohorte de pacientes con enfermedad coronaria o miocardiopatía dilatada, que realizaron una prueba de ejercicio al inicio del estudio. Inicialmente evaluamos la ocurrencia de EVIE, APM y letalidad a largo plazo y posteriormente se realizó un estudio bivariable y multivariable. Resultados: Se incluyeron 1,442 pacientes de los cuales 700 presentaron EVIE (49%). Durante 14 an˜os de seguimiento, 106 sujetos presentaron APM y la mortalidad total fue de 61 casos (4%). El estudio bivariable mostró que aquellos pacientes con EVIE tuvieron un riesgo de presentar APM de 2.81 (IC95% de 1.9 a 4.3, p < 0.001) y de mortalidad de 2.1 (IC95% de 1.2 a 3.4, p < 0.01). Los individuos con APM tuvieron mayor riesgo de mortalidad (RR= 5.7, IC95% de 3.4 a 9.4, p < 0.001). Después de un análisis multivariable, la APM continuó siendo una variable altamente predictiva de mortalidad. Conclusión: Los pacientes con EVIE tienen un riesgo elevado de presentar APM y de mortalidad a largo plazo. Los resultados sugieren que las APM podrían representar un estado intermedio entre la presencia de EVIE y la mortalidad en pacientes con enfermedad cardiovascular.

Premature ventricular contractions associated with isotretinoin use

Abstract Isotretinoin has been considered a unique drug for acne treatment. However, it is associated with numerous adverse effects. Isotretinoin can trigger premature ventricular contractions. This report describes a 33-year-old-woman who presented with palpitations for 1 week while undergoing 1-month isotretinoin treatment for mild-moderate facial acne. An electrocardiogram and Holter monitoring showed premature ventricular contractions during isotretinoin (Roaccutane, Roche) treatment. Isotretinoin-related premature ventricular contractions were strongly suggested in this case due to the existence of documented premature ventricular contractions on electrocardiograms and the disappearance of these premature ventricular contractions two weeks after termination of the treatment To the authors' knowledge, there has been 1 reported case of premature ventricular contractions linked to isotretinoin use; this report describes a second such case.

Radiofrequency ablation can reverse the structural remodeling caused by frequent premature ventricular contractions originating from the right ventricular outflow tract even in a normal heart

OBJECTIVE: The aim of this study was to evaluate whether frequent premature ventricular contractions originating from the right ventricular outflow tract remodel the cardiac structure and function in patients with a “seemingly normal heart” and whether radiofrequency ablation can reverse this remodeling. METHODS: Sixty-eight patients with idiopathic frequent premature ventricular contractions originating from the right ventricular outflow tract and normal heart structure and function were enrolled in this study. The patients were divided into three groups according to the therapeutic method: radiofrequency ablation group (24 cases), anti-arrhythmia drug group (26 cases), and control group (18 cases without any treatment). Clinical Registration number: ChiCTR-ONRC-12002834 RESULTS: The basic patient characteristics were comparable between the three groups, except for the premature ventricular contraction rate, which was significantly lower in the control group. After six months of follow up, the premature ventricular contraction rate was significantly reduced in the radiofrequency ablation group, which was accompanied by a significant decrease in the following cardiac cavity inner diameters, as determined by echocardiography: right atrium (33.33±3.78 vs. 30.05±2.60 mm, p = 0.001), right ventricle (23.24±2.40 vs. 21.05±2.16 mm, p = 0.020), and left ventricle (44.76±4.33 vs. 41.71±3.44 mm, p = 0.025). These results were similar in the anti-arrhythmia drug group, although this group exhibited a smaller extent of change (right atrium: 33.94±3.25 vs. 31.27±3.11 mm, p = 0.024; right ventricle: 22.97±3.09 vs. 21.64±2.33 mm, p = 0.049; left ventricle: 45.92±6.38 vs. 43.84±5.67 mm, p = 0.039), but not in the control group (p>0.05). There was a tendency toward improvement in the cardiac functions in both the radiofrequency ablation and anti-arrhythmia drug groups. However, ...

Potenciação pós-extra-sistólica na cardiopatia chagásica crônica: estudo com ventriculografia de contraste radiológico / Post-extrasystolic potentiation in chronic Chagas' heart disease: a radiologic contrast ventriculography study

OBJETIVO: Determinar a existência e freqüência do fenômeno da potenciação pós-extra-sistólica em áreas miocárdicas discinérgicas de pacientes com cardiopatia chagásica crônica estudados por ventriculografia de contraste radiológico. MÉTODOS: Análise retrospectiva semiquantitativa da ventriculografia de contraste radiológico em pacientes com cardiopatia chagásica crônica, consecutivamente estudados para avaliação de mecanismos de taquicardia ventricular. RESULTADOS: De 72 pacientes inicialmente incluídos, apenas em 20 o ventriculograma foi analisável para os propósitos do estudo. O fenômeno da potenciação pós-extra-sistólica foi verificado em 11 (55 por cento) desses pacientes, obtendo-se melhora de 15,31 por cento no escore de contração, da situação basal para a de pós-extra-sístole (p= 0,0001). Sua ocorrência verificou-se mesmo em segmentos ventriculares com déficit intenso de contratilidade. CONCLUSAO: O fenômeno da potenciação pós-extra-sistólica é verificável em proporção significante de pacientes com cardiopatia chagásica crônica em que, angiograficamente, foi possível analisar o fenômeno, indicando a existência de reserva contrátil, potencialmente recrutável, em regiões ventriculares, exibindo discinergia acentuada. Estudos adicionais para se entender os mecanismos subjacentes são requeridos.

Avaliaçäo de potenciais fragmentados em presença de bloqueio de ramo direito sem alteraçöes estruturais miocárdicas ventriculares. Estudo pelo eletrocardiograma de alta resoluçäo no domínio da frequência / Evaluation of fragmented potentials in the presence of right bundle branch block without structural myocardium abnormalities. Study made by signal-averaged electrocardiogram on time and frequency domain

Objetivo - Em ausência de alterações estruturais miocárdicas (AEM), avaliar se o bloqueio de ramo direito (BRD) gera potenciais fragmentados (PF) e turbulência espectral (TE) no eletrocardiograma de alta resolução (ECGAR). Métodos - Doze crianças com comunicação interatrial (CIA) e bloqueio incompleto do ramo direito (BIRD) sem AEM (Grupo I), foram comparadas com 17 crianças com tetralogia de Fallot (TF) operada, BCRD e AEN, 5 com extra sistoles ventriculares e 2 com taquicardia ventricular sustentada (Grupo II). Todas fizeram ECGAR nos domínios do tempo (DT) e da freqüência (DF), com cinco variáveis analisadas. Resultados - Os pacientes do grupo I tiveram as variáveis normais apesar do BIRD. No grupo II, 4 das cinco variáveis foram anormais, sugerindo a presença de PF e TE atribuíveis a AEM inerentes à malformação e ao ato cirúrgico. Conclusão - Na CIA o BIRD não complicado de AEM não gera PF e TE, não constituindo fator de risco para taquicardia ventricular sustentada.

Radiofrequency catheter ablation for frequent premature ventricular contractions: a preliminary report of 15 cases.

Between February 1995 and March 1997, 15 patients, 13 women and 2 men, underwent radiofrequency catheter ablation (RFCA) for symptomatic frequent premature ventricular contractions (PVC's). The mean age was 43.3 +/- 11.9 years. Thirteen patients (86.7%) had right PVC's and the remainder had both right and left PVC's. RFCA were done under local anesthesia, using both earliest endocardial activation time and pace mapping in complement. The immediate success rate was 14/15 (93%) with only minor complications in 2 patients (13.3%). The fluoroscopic and procedure times were 40.6 +/- 24.0 and 170.7 +/- 81.2 minutes, respectively. From the Holter monitoring, total PVC count, per cent of PVC per total heart beat in 24 hours and couplets count were significantly reduced, (more than 90%, p < 0.05), by RFCA. Triplets and repetitive ventricular tachycardia were totally abolished. During the follow-up period of 10.1 +/- 7.5 months, 2 patients (14.3%) had recurrences of right PVC's within 2 weeks after ablation. Reablation was successfully done in both patients without recurrence, giving the final success rate of 93 per cent. In conclusion, RFCA could be safely performed with a high success rate in patients with symptomatic frequent PVC's. It can be considered an alternative treatment in patients resistant to medical therapy.