RESUMO
The purpose of this study is to measure QRS duration changes in the human model of ischemia during percutaneous transluminal coronary angioplasty (PTCA) and compare these results to the commonly used ischemia markers, chest pain, and classical ST-T changes. Using a computerized method, QRS duration was measured in 51 patients undergoing elective PTCA. Three milliseconds (msec) or more prolongation of the QRS at peak inflation was considered to be an ischemic response. The results were compared to chest pain and ST-T changes and were analyzed for inflation site within individual coronary arteries. Forty-two patients had a pathological prolongation of the QRS during PTCA. Thirty-two patients developed chest pain, while 19 had ischemic ST-T changes. QRS duration was more prolonged in PTCA to proximal or middle segments of major arteries or their large branches, while it was less prolonged in distal segments or smaller branches. Using our method, QRS prolongation was an ischemia marker in most patients during PTCA and was more sensitive than chest pain or ST-T changes. QRS duration was more prolonged with occlusion of proximal and middle segments of major arteries. Cathet. Cardiovasc. Intervent. 50:177-183, 2000.
Assuntos
Angioplastia Coronária com Balão , Sistema de Condução Cardíaco/fisiopatologia , Isquemia Miocárdica/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Circulação Colateral , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/fisiopatologia , Valor Preditivo dos Testes , Estudos ProspectivosRESUMO
Cardiotoxicity is one of the major side effects of doxorubicin therapy. The side effect presents in an acute and chronic form. It has been observed mainly when the cumulative dosage exceeds 450 mg/m2 of body surface. The cardiotoxicity presents with a low left ventricular ejection fraction. We report three patients who developed selective right ventricular dysfunction, expressed by low right ventricular ejection fraction as measured by radionuclide angiography. This complication was observed with rather low cumulative dosages of the drug (105 to 318 mg/m2). Two of the patients received concurrent mitomycin-C chemotherapy and the third patient underwent prior mediastinal irradiation. The possible mechanism for this selective cardiotoxicity is discussed. Monitoring of right ventricular performance by radionuclide angiography during doxorubicin therapy is recommended so that therapy can be discontinued before the left ventricle is damaged.