RESUMEN
The aim of this study was to analyze the very early (first 24 hours) effect of successful or failed thrombolytic therapy on the autonomic nervous system. Thirty consecutive patients with a first acute myocardial infarction were enrolled in the study, and admitted to the Coronary Care Unit within 6 hours of the onset of symptoms and treated with systemic thrombolytic therapy. All patients underwent 24-hour Holter monitoring in order to analyze ST segment variation. The autonomic nervous system was evaluated by frequency-domain heart rate variability: low frequency/high frequency ratio (LF/HF) was measured at the beginning of Holter monitoring (T1), 15 min after reperfusion or 1 hour from the start of thrombolytic therapy (T2) and after 24 hours (T3). Reperfusion status was assessed by a > or = 50% reduction in ST segment elevation within 90 min of thrombolytic therapy, and early CK-MB peak. Early coronary reocclusion was detected by early reduction in ST segment elevation followed by stable ST segment re-elevation. Twenty patients (66%) showed successful thrombolytic therapy (Group 1), 5 patients (17%) had no evidence of successful thrombolytic therapy (Group 2) and 5 patients (17%) showed an early reocclusion (Group 3). LF/HF ratio values at T1 were similar in the three groups (5.66 +/- 1.7 vs 5.65 +/- 1.2 vs 5.51 +/- 0.9, NS). At T2, LF/HF ratio was significantly higher in Group 1 and 3 than Group 2 patients (9.21 +/- 1.7 and 11.1 +/- 1.2 vs 5.58 +/- 1.4, respectively, p < 0.001). In Group 1 LF/HF ratio was significantly lower at T3 when compared with T1 and T2 (1.9 +/- 1 vs 5.66 +/- 1.7 and 9.21 +/- 1.7, respectively, p < 0.001). Conversely, in Group 3 LF/HF ratio at T3 was similar to values measured at T1 (5.59 +/- 1.7 vs 5.51 +/- 0.9, respectively, NS) and significantly higher than those detected in Group 1. In Group 2, LF/HF ratio resulted substantially unchanged at T3 (5.49 +/- 1.7, NS). In conclusion, 1) successful thrombolytic therapy induces early beneficial effects on the autonomic nervous system function, as shown by increased heart rate variability values, when compared with failed thrombolytic therapy; 2) however, during the early period following coronary reperfusion, a transient but dramatic increase in sympathetic activity is observed. This could trigger coronary flow instability, thus facilitating reocclusion, by activating different pathogenetic mechanisms (increased vascular tone, platelet activation, thrombogenic factor prevalence); 3) early coronary vessel reocclusion precludes favorable effects of reperfusion on sympatho-vagal balance observed after the first 24 hours.
Asunto(s)
Frecuencia Cardíaca , Infarto del Miocardio/tratamiento farmacológico , Plasminógeno/uso terapéutico , Estreptoquinasa/uso terapéutico , Terapia Trombolítica , Anciano , Circulación Coronaria , Electrocardiografía , Electrocardiografía Ambulatoria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/fisiopatología , Factores de TiempoRESUMEN
Although the efficacy of intravenous thrombolysis in the treatment of acute myocardial infarction has been widely proved, some uncertainty concerning the "temporal window" of administration still persists. The aim of the present investigation was to study whether the late administration of a thrombolytic agent (6 or more hours after the onset of symptoms of acute myocardial infarction) offers any short or long-term advantages with regards to left ventricular function and clinical outcome. We studied 100 consecutive patients at their first episode of myocardial infarction, admitted to Coronary Unit within 24 hours of the onset of symptoms. Of these patients, 62 were administered rt-PA (44 patients within the 6th hour, and 18 between the 6th and 24th hour after the onset of symptoms) and the 38 remaining patients, who did not receive the thrombolytic agent (due to concerns with respect to possible complications), constituted the control group (18 admitted within 6 hours and 20 between 6 and 24 hours). All patients underwent serial electrocardiograms, and echocardiograms upon admission and at discharge to assess the ejection fraction, the asynergy score and the percentage of ischemic area. Furthermore, the survivors were invited for a follow-up examination one year after their acute initial episode. Seven cases of heart failure occurred, before discharge, among the control patients admitted 6 to 24 hours after onset of symptoms, compared with no cases in the subgroup of patients treated with rt-PA during the same time period (p = 0.0068).(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Infarto del Miocardio/tratamiento farmacológico , Terapia Trombolítica , Función Ventricular Izquierda , Adulto , Anciano , Ecocardiografía , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/fisiopatología , Activadores Plasminogénicos/administración & dosificación , Factores de Tiempo , Función Ventricular Izquierda/efectos de los fármacos , Función Ventricular Izquierda/fisiologíaRESUMEN
Three patients fulfilling criteria for Sudeck's atrophy (reflex sympathetic dystrophy syndrome--RSDS) are described and etiological, pathogenetic and clinical features of the disease are reviewed. RSDS is associated with a wide variety of precipitating factors, each of whom, often in concomitance with metabolic diseases and psychiatric disturbances, may cause the same clinical syndrome, which continues in a "vicious circle" of feed-back mechanisms, correlated with sympathetic hyperactivity. The symptoms may begin gradually and the disorder progresses in stages lasting from weeks to months. The management has not yet been established. Generally, the earlier the syndrome is recognized, the better the results of treatment will be. Analgesics, salmon calcitonin and physiokinesitherapy are recommended. Psychological support is advisable. In more severe patients sympathetic blockade and surgical sympathectomy may be necessary. The effects of hyperbaric oxygen treatment must still be assessed.