ABSTRACT
OBJECTIVES Our objective in this study was to evaluate Tpeak-Tend interval (Tp-e) and other electrocardiographic parameters as risk factors for recurrence of life-threatening cardiac events in patients with the Brugada syndrome (BS). BACKGROUND The Tp-e interval in the electrocardiogram (ECG) has been reported to predict life-threatening arrhythmias in the long QT syndrome. METHODS: Twenty-nine patients with the ECG pattern of BS and 29 healthy age- and gender-matched controls were studied. The follow-up period was 42.65 ± 24.42 months (range 11 to 108 months). RESULTS Upon presentation, five patients had suffered aborted sudden death, five syncope, and two presyncope. Eleven patients with the ECG pattern of BS had a prolonged (>460 ms) QTc in V2 but usually not in inferior or left leads. No patient had abnormally prolonged QT dispersion. Programmed electrical stimulation induced ventricular tachycardia/fibrillation in 5 out of 26 patients. Inducibility did not predict recurrence of events. Cardioverter-defibrillators were implanted in 14 patients (all symptomatic and two asymptomatic). During follow-up, nine symptomatic patients experienced recurrences. Previous cardiac events and a QTc >460 ms in V2 were significant risk factors (p = 0.00002 and p = 0.03, respectively). Tp-e and Tp-e dispersion were significantly prolonged in patients with recurrences versus patients without events (104.4 and 35.6 ms vs. 87.4 and 23.2 ms; p = 0.006 and p = 0.03, respectively) or controls (90.7 and 17.9 ms; p = 0.02 and p = 0.001, respectively).CONCLUSIONS Our study demonstrates significant correlation between previous events, QTc >460 ms in V2, Tp-e, and Tp-e dispersion and occurrence of life-threatening arrhythmic events, suggesting that these parameters may be useful in risk stratification of patients with the Brugada syndrome(AU)
OBJETIVOS Nuestro objetivo en este estudio fue evaluar Tpeak-Tienden intervalo (Tp-e) y otros parámetros electrocardiográficos como factores de riesgo para la recurrencia en peligro la vida de eventos cardíacos en pacientes con el síndrome de Brugada (BS). ANTECEDENTES El Tp-e intervalo en el electrocardiograma (ECG) se ha informado a predecir las arritmias que amenazan la vida en el síndrome del QT largo. MÉTODOS: Veintinueve pacientes con el patrón de ECG de BS y 29 sanos de edad y el sexo-los controles se estudiaron. El período de seguimiento fue de 42,65 ± 24,42 meses (rango 11 a 108 meses). RESULTADOS: Tras la presentación, cinco pacientes habían sufrido una muerte súbita abortada, cinco síncope, y dos presincope. Once pacientes con el patrón de ECG BS había un prolongado (> 460 ms) QTc en V2 pero generalmente no en la izquierda inferior o conduce. Ningún paciente había anormalmente dispersión QT prolongado. Inducida por la estimulación eléctrica programada taquicardia ventricular / fibrilación en 5 de 26 pacientes. Inducibility no predecir la recurrencia de eventos. Cardioverter-desfibriladores se implantaron en 14 pacientes (todos los sintomáticos y dos asintomáticos). Durante el seguimiento, nueve pacientes presentaron recidivas sintomáticas. Anteriores eventos cardíacos y un QTc> 460 ms en V2 fueron importantes factores de riesgo (p = 0,00002 yp = 0,03, respectivamente). Tp y Tp-e-e dispersión se prolongó significativamente en los pacientes con recidivas frente a los pacientes sin eventos (104,4 y 35,6 ms frente a 87,4 y el 23,2 ms, p = 0,006 y p = 0,03, respectivamente) o los controles (90,7 y 17,9 m, p = 0,02 yp = 0,001, respectivamente)..........
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Bundle-Branch Block/physiopathology , Electrocardiography/methods , Tachycardia, Ventricular/diagnosis , Ventricular Fibrillation/diagnosisABSTRACT
We present a Brugada syndrome patient who suffered an aborted sudden death. The ajmaline test (1 mg/kg body weight) induced accentuated alternans ST-segment elevation in V1-V2 without ventricular arrhythmias. It could represent silent ischaemia not detected before, failure of myocardial regions to repolarize in alternate beats due to transmural dispersion of conduction and refractoriness in the right ventricular outflow tract or a rate dependent sodium channel block by ajmaline. We need more studies to know whether this electrocardiographic sign is a risk factor for life-threatening ventricular arrhythmias in Brugada syndrome patients.
Subject(s)
Ajmaline , Anti-Arrhythmia Agents , Bundle-Branch Block/physiopathology , Death, Sudden, Cardiac/etiology , Electrocardiography , Electrophysiologic Techniques, Cardiac , Humans , Syndrome , Ventricular Fibrillation/complicationsABSTRACT
Dynamic cardiomyoplasty was performed in twenty patients with dilated cardiomyopathy. The electrical stimulation was produced by a double chambered pacemaker. Patients were studied by nuclear ventriculography one week before surgery, in the immediate postoperative phase and 8 or 12 months later. Five patients died (four of them were operative deaths). In this group the left ventricular ejection fraction (LVEF) was lower than in survivors (22 +/- 8% vs 28 +/- 4%; p less than 0.001). The end-diastolic volume and the mitral regurgitation index were greater (200 +/- 76 ml/m2 vs 153 +/- 34 ml/m2; p less than 0.001 and 2.12 +/- 0.75 vs 1.68 +/- 0.54; p less than 0.001, respectively). The immediate effect of cardiomyoplasty was the significative reduction in the contractility. However, at 8 or 12 months of follow-up, the LVEF increased in the 72% of the survivors. The end-diastolic volume and the regurgitation index decreased significantly. The clinical status improved in the 81% of the survivors. The best results were obtained in those patients in which a pulse train stimulation was employed in the training phase. Nevertheless, the changes in LVEF are not consistent with the improvement in the clinical status. The improve in the cardiac performance should be also due to the reduction in the left ventricular diameters and in the mitral functional regurgitation.
Subject(s)
Cardiac Surgical Procedures/methods , Gated Blood-Pool Imaging , Muscles/transplantation , Adult , Cardiac Surgical Procedures/statistics & numerical data , Cardiomyopathy, Dilated/diagnostic imaging , Cardiomyopathy, Dilated/mortality , Cardiomyopathy, Dilated/surgery , Cuba , Female , Follow-Up Studies , Gated Blood-Pool Imaging/methods , Heart Ventricles/surgery , Humans , Male , Middle Aged , Postoperative Period , PrognosisABSTRACT
In order to evaluate the influence of the autonomic nervous system in the incidence and characteristics of the early arrhytmias that follows myocardial infarction, we have developed an experimental myocardial infarction in rabbits by acute occlusion of the left ventricular artery. The influence of adrenergic and cholinergic suppression over rhythm disorders and hemodynamics changes after experimental infarction in the rabbit was also studied. We found that after the acute experimental infarction in the rabbit heart, arose an early stage of rhythm disorders in 60% of the animals. In a group of animals that were injected with Practolol before coronary occlusion, the incidence of arrhythmias was 25% and in a group of animals with vagotomy prior to occlussion none of them developed rhythm disorders. It was concluded that the model is highly steemed for the study of early arrhytmias and that automatic nervous system has an important role in the incidence of such arrhythmias.
Subject(s)
Arrhythmias, Cardiac/physiopathology , Autonomic Nervous System/physiopathology , Heart Ventricles/physiopathology , Myocardial Infarction/physiopathology , Acute Disease , Animals , Electrocardiography , Heart Conduction System/innervation , Heart Conduction System/physiopathology , Heart Ventricles/innervation , RabbitsABSTRACT
The close relationship between disturbances of heart rhythm that follow acute myocardial infarction, and the autonomic nervous system is of particular interest. These disturbances have been attributed to the sympathetic and parasympathetic influences upon the heart. The present investigation was undertaken in order to study the influence of parasympathetic suppression on early arrhythmias following acute myocardial infarction in dogs with acute coronary occlusion. Two series were examined: control and vagotomized animals. In vagotomized dogs, the incidence of early post-infarction arrhythmias was 9 per cent against 66 per cent in the control series. The heart rate and blood pressure did not show significant changes in either series. The results emphasize the importance of the afferent and efferent vagal ways in the genesis of early arrhythmias.
