RESUMEN
Signal averaging has been performed to evaluate late potentials following infarction and the administration of thrombolytic therapy. Most studies have recorded signal-averaged electrocardiograms (SAECGs) at least 12 hours after the onset of the infarction. In this study, SAECGs were recorded before thrombolytic therapy and serially over 7-10 days following infarction in 21 patients. The high frequency QRS duration was significantly shortened at 1 and 24 hours compared to presentation (96.8 +/- 11.3 ms and 93.4 +/- 8.0 ms vs 103.3 +/- 14.3 ms, respectively, P < 0.05) and there was an increase in the terminal voltage over time, significant at 1 hour and 3 days (57.3 +/- 29.1 microV and 58.6 +/- 44.7 microV vs 44.4 +/- 35.5 microV, respectively, P < 0.01). Five patients met criteria for ventricular late potentials on at least one SAECG. The prevalence of late potentials was higher in patients with Q wave infarctions, or with occluded infarct related arteries. These changes in myocardial activation may be related to ischemia and reperfusion, and may not correlate with the development of a fixed substrate for reentry.
Asunto(s)
Electrocardiografía , Infarto del Miocardio/fisiopatología , Terapia Trombolítica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/tratamiento farmacológico , Activadores Plasminogénicos/uso terapéutico , Estudios Prospectivos , Procesamiento de Señales Asistido por Computador , Factores de Tiempo , Activador de Tejido Plasminógeno/uso terapéutico , Función VentricularRESUMEN
The implantable cardioverter-defibrillator (ICD) has been used in conjunction with surgical coronary revascularization for prevention of postoperative malignant arrhythmias. However, there is no consensus regarding which patient should receive concomitant insertion of the ICD system in a one stage (patches and generator) or two stage (patches, and subsequent implantation of the generator) procedure. To assess differences in hospital course and outcome, the authors studied 8 survivors of sudden death syndrome and 17 patients with preoperative ventricular tachycardia refractory to conventional antiarrhythmic therapy who underwent coronary revascularization and prophylactic implantation of an ICD system in either one or two stages. Patients with advanced coronary disease, poor ventricular function, and silent ischemia received the ICD system in one stage. Those with good ventricular function and well defined coronary pathology received only patches concomitant with myocardial revascularization. Seventy-nine percent of the patients with patches needed subsequent implantation of the ICD generator, as determined by postoperative electrophysiologic studies. There were three postoperative deaths unrelated to arrhythmias. There was no difference between the groups regarding the number of ICD discharges. It was concluded that the prophylactic use of the ICD system is an important adjuvant in the treatment of postoperative malignant arrhythmias for patients undergoing myocardial revascularization. The insertion of the ICD, however, should be based on pathophysiologic considerations and postoperative electrophysiologic findings. This may result in important savings in terms of unnecessary cost and operative procedures.