RESUMEN
The changes in QRS complex morphology associated with acute myocardial infarction (AMI) can resolve spontaneously over time. Whether complete revascularization of the infarct-related myocardial territory after AMI affects this QRS resolution has not been studied adequately. The present study compares the evolution of the changes in the QRS complex associated with AMI during 1-year follow-up in patients treated with or without revascularization after their first thrombolyzed AMI. The study is a substudy of the DANish Trial in Acute Myocardial Infarction (DANAMI) (n = 1,008) that randomized patients with inducible ischemia after their first AMI, treated with intravenous thrombolytic therapy, to conservative treatment or coronary angiography followed by the appropriate revascularization strategy. A total of 817 patients had complete sets of evaluable electrocardiograms. Electrocardiograms were obtained at randomization, and at 3, 6, and 12 months of follow-up and subjected to blinded core-laboratory evaluation according to the Selvester QRS scoring method. This score considers Q-, R-, and S-wave duration and ratios to provide a semiquantitative estimate of AMI size. The median electrocardiographic estimated infarct size in the entire population was 15% of the left ventricle at randomization. At the end of the follow-up period this estimate had decreased to 12% (p < 0.00001). There was no difference in the rate of QRS resolution whether the patients were subgrouped according to randomization or subgrouped according to actual treatment with or without revascularization. The present study confirms the findings from previous studies conducted in the prethrombolytic era, that considerable normalization of the QRS complex also occurs after AMI treated with thrombolytic therapy. This QRS normalization seems unaffected by an aggressive treatment strategy with revascularization via balloon angioplasty or bypass surgery.
Asunto(s)
Sistema de Conducción Cardíaco , Infarto del Miocardio/fisiopatología , Adulto , Anciano , Angiografía Coronaria , Electrocardiografía , Humanos , Persona de Mediana Edad , Contracción Miocárdica , Infarto del Miocardio/terapia , Revascularización Miocárdica , Ensayos Clínicos Controlados Aleatorios como Asunto , Terapia TrombolíticaRESUMEN
The present study was performed to test the hypothesis that patients with a large amount of ischemic (hibernating) myocardium are most likely to develop a perioperative myocardial infarction undergoing coronary artery bypass grafting (CABG). Furthermore, we evaluated the Selvester QRS scoring system as a postoperative prognostic tool. A relationship between a high amount of hibernating myocardium determined by ventriculographic and electrocardiographic investigations and an increased risk of perioperative myocardial infarction was found. The Selvester QRS scoring system used in diagnosing and prognosing after acute myocardial infarction was proven valid in predicting prognosis after CABG as well.
Asunto(s)
Puente de Arteria Coronaria/efectos adversos , Electrocardiografía , Infarto del Miocardio/fisiopatología , Aturdimiento Miocárdico/fisiopatología , Adulto , Anciano , Cineangiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/etiología , Aturdimiento Miocárdico/diagnóstico por imagen , Aturdimiento Miocárdico/cirugía , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Volumen Sistólico , Factores de TiempoRESUMEN
Near-infrared spectrophotometry-determined cerebral (ScO2) and muscle oxygen saturations (SmO2) were followed in 15 volunteers during passive 50 degrees head-up-tilt-induced central hypovolaemia, and in nine volunteers during ventilatory manoeuvres affecting arterial carbon dioxide tension. During head-up tilt, mean arterial pressure [MAP, 88 (77-118) to 97 (80-136) mmHg, median and range] and heart rate [HR; 66 (49-77) to 87 (42-132) beats min-1 P < 0.01] increased, but after 22 (1-45) min they declined [to 61 (40-91) mmHg and 69 (38-109) beats min-1, respectively, P = 0.001] and pre-syncopal symptoms developed. Central hypovolaemia was indicated by an increased thoracic electrical impedance, and a decreased cardiac output and central venous oxygen saturation. The arterial oxygen saturation, pulmonal oxygen uptake and skin temperatures remained constant. The ScO2 remained stable at 72 (62-77)% until the pre-syncopal incidence, when it decreased to 62 (31-73)% (P = 0.001), and tilt down made it increase to 75 (36-87)% (P < 0.05) before the recovery value was established. In contrast, SmO2 decreased during tilting [75(70-87) to 65 (53-70)%], and recovered to 70 (53-83)%, P < 0.01) during the hypotensive episode. The end-tidal CO2 tension decreased only during tilt-up. The ScO2 decreased, and SmO2 increased during hyperventilation, and ScO2 increased during breathing of 5% carbon dioxide. Rebreathing from a bag made SmO2 decrease and resulted in a biphasic ScO2 response: it first increased and subsequently decreased. Cardiovascular changes during tilt were not reflected in skin temperature. The ScO2 reflected the maintained autoregulation of cerebral blood flow until the perfusion pressure decreased markedly. In contrast, SmO2 mirrored muscle vasoconstriction early during tilt, and vasodilatation when pre-syncopal symptoms appeared.
Asunto(s)
Presión Sanguínea , Encéfalo/metabolismo , Músculos/metabolismo , Oxígeno/metabolismo , Postura/fisiología , Adulto , Análisis de los Gases de la Sangre , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Factores de TiempoRESUMEN
Patients with unstable angina pectoris have increased thrombocyte aggregation and disturbances in serum prostaglandin balance. As a pilot project, we conducted a single-blind investigation of 24 patients with unstable angina pectoris treated with dilthiazem (n = 12, 240-360 mg) or verapamil (n = 12, 240-360 mg) for ten days. At the commencement of the investigation, both patient groups had hyperaggregating thrombocytes and increased serum-thromboxan-B2 (TXB2) as compared to healthy individuals (p < 0.01). In the patient group treated with dilthiazem, the aggregation threshold rose (p < 0.01), and the serum TXB2 values fell to approximately normal (p < 0.05). In the patient group treated with verapamil, no significant changes were observed in the measurements registered. The difference between the two groups remained significant during the entire therapeutic period (p < 0.01). Thus, dilthiazem appears to counteract thrombocyte aggregation in patients with unstable angina pectoris.