RESUMEN
Maximal treadmill testing was carried out in 50 patients with angiographically documented coronary artery disease (CAD) in the presence and absence of beta-adrenoceptor blockade. The results were related to the extent of CAD and interpreted relative to the clinical value of exercise testing. Maximal heart rate and systolic blood pressure were significantly lower during treatment with beta-blocking drugs. The average exercise duration was 1.3 +/- 1.9 minutes greater (+/- standard deviation), regardless of coronary anatomy. Of the 20 subjects with 3-vessel or left main CAD (severe CAD), 8 patients completed 3 stages (9 minutes) of exercise during treatment; only 4 did so without treatment. Angina was significantly more often the limiting symptom with severe CAD, and this association was abolished by beta blockade; 1 of 20 with severe CAD completed 3 stages of exercise and was not limited by angina without beta-blocking treatment, whereas 7 had these features during beta-blockade therapy. Maximal ST-segment depression was not related to the extent of CAD with or without therapy. Beta blockade suppressed the occurrence of ST depression, or delayed its appearance by an average of 2.0 +/- 2.3 minutes and reduced its severity by 0.5 +/- 0.9 mm. All tests in which ST depression was completely suppressed were associated with inadequate heart rate response, regarded as diagnostically inconclusive rather than negative. However, during beta-blocking treatment, 14 tests (28%) were inconclusive, which, in routine practice, would have necessitated repeat testing.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Antagonistas Adrenérgicos beta/farmacología , Enfermedad Coronaria/fisiopatología , Prueba de Esfuerzo , Adulto , Anciano , Angina de Pecho/etiología , Presión Sanguínea/efectos de los fármacos , Enfermedad Coronaria/complicaciones , Enfermedad Coronaria/tratamiento farmacológico , Electrocardiografía , Prueba de Esfuerzo/efectos adversos , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
Measures to control rodents have resulted in a decreased incidence of murine typhus, but it is also likely that it is being underdiagnosed because many medical practitioners do not include it in their differential diagnosis of pyrexia of unknown origin. Four recent cases are described, and historical aspects of this disease in Australia are presented.