RESUMO
Although diagnosis of acute myocardial infarction is usually based on the patient history and electrocardiographic findings, nuclear myocardial perfusion imaging has an important role in assessing myocardial damage and predicting patient prognosis. In this article, Dr Umfrid discusses the unique characteristics of technetium Tc 99m sestamibi that make it especially useful in managing acute myocardial infarction.
Assuntos
Infarto do Miocárdio/diagnóstico por imagem , Tecnécio Tc 99m Sestamibi , Radioisótopos de Tálio , Angioplastia Coronária com Balão , Eletrocardiografia/normas , Humanos , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/terapia , Prognóstico , Terapia de Salvação , Sensibilidade e Especificidade , Terapia Trombolítica , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia Computadorizada de Emissão de Fóton Único/normasRESUMO
A patient who developed 2:1 AV block ten weeks after the initiation of therapy for Graves' disease demonstrated a presystolic murmur related to atrial systole of the conducted beat. The murmur mimicked a pericardial friction rub. With the return of normal conduction as the thyrotoxicosis was finally controlled, the murmur disappeared. We postulate that the murmur resulted frm atrial contraction with rapid late-diastolic inflow into an increased right ventricular volume, causing premature opening of the pulmonic valve. This phenomenon was attainable only during 2:1 AV block with long diastolic filling periods and a hyperkinetic circulatory system. The murmur may be indicative of severe hyperthyroidism. Murmurs found in other disease entities may share similar physiologic principles.
