RESUMO
With the frequent use and excellent longevity of the internal mammary artery graft, knowledge about the behaviour of this graft under different conditions is becoming relevant. We studied 20 patients with combined two-dimensional and pulsed Doppler sonography before and after exercise testing and established values for peak velocities and flow duration. During exercise flow duration shortened in systole and diastole by the same order of magnitude, while peak diastolic velocity especially increased during exercise.
Assuntos
Doença das Coronárias/cirurgia , Ecocardiografia Doppler , Teste de Esforço , Hemodinâmica/fisiologia , Revascularização Miocárdica , Complicações Pós-Operatórias/diagnóstico por imagem , Adulto , Idoso , Angina Pectoris/diagnóstico por imagem , Angina Pectoris/tratamento farmacológico , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Velocidade do Fluxo Sanguíneo/fisiologia , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/tratamento farmacológico , Teste de Esforço/efeitos dos fármacos , Feminino , Oclusão de Enxerto Vascular/diagnóstico por imagem , Oclusão de Enxerto Vascular/tratamento farmacológico , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Metoprolol/administração & dosagem , Pessoa de Meia-Idade , Complicações Pós-Operatórias/tratamento farmacológicoRESUMO
The noninvasive examination of internal mammary artery grafts is gaining importance with the increasing use of this vessel in the surgical treatment of coronary atherosclerosis of the left anterior descending artery. We studied 36 patients (37 internal mammary artery grafts) with combined two-dimensional and pulsed Doppler echography from the supraclavicular fossa. Adequate visualization and Doppler signals were obtained in 95% of arterial grafts. Twenty-four grafts leading to an area without evidence of old myocardial infarction or ischemia and 10 grafts leading to an area of old myocardial infarction but without evidence of ischemia on exercise showed a significant decrease of the peak systolic velocity and of the peak systolic velocity/peak diastolic velocity ratio as compared to the controls, which consisted of the contralateral internal mammary arteries in situ. One patient with a distally subtotally occluded mammary artery graft had a flow pattern different from the other bypassed mammary arteries. It seems that combined two-dimensional and pulsed Doppler echography is a useful method to evaluate the functional status of internal mammary artery grafts.
Assuntos
Doença das Coronárias/cirurgia , Ecocardiografia Doppler , Ecocardiografia , Oclusão de Enxerto Vascular/diagnóstico por imagem , Revascularização Miocárdica , Complicações Pós-Operatórias/diagnóstico por imagem , Adulto , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Doença das Coronárias/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/cirurgiaRESUMO
The practising physician's knowledge of paroxysmal attacks of tachycardia is frequently disappointing. In this article a description is given of mechanisms and possible sites of origin of tachycardia. This is followed by a discussion on the typical history and the findings in these patients. Lastly, therapeutic guidelines are given. A discussion of the electrocardiographic features of the different types of paroxysmal tachycardias falls outside the scope of this article.
Assuntos
Taquicardia/diagnóstico , Eletrocardiografia , Sistema de Condução Cardíaco/fisiopatologia , Hemodinâmica/fisiologia , Humanos , Nó Sinoatrial/fisiopatologia , Taquicardia/fisiopatologia , Taquicardia/terapiaRESUMO
In a group of 22 patients, Doppler signals from the proximal part of the internal mammary artery graft were studied from the supraclavicular fossa as well as from the high intercostal spaces. An adequate signal was found more often from the supraclavicular position. Both positions showed higher peak systolic than peak diastolic velocities. Transition of the flow to the typical coronary flow pattern with higher peak diastolic velocity seems to occur in lower parts of the graft.