Echocardiographic methods for assessment of coronary artery disease

Detta är en avhandling från Linköping : Linköpings universitet

Sammanfattning: Upright bicycle exercise echocardiography with digital image acquisition in seated position during exercise and in recumbent position before and immediately after exercise was performed in 66 men, one month after an episode of unstable coronary arte1y disease. It was difficult to obtain images of adequate quality during exercise but new or worsening of wall motion abnormalities not seen in recumbent position after exercise were detected at peak-exercise in patients with good image quality. Therefore, image acquisition seated at peak bicycle exercise and in the recumbent position immediately after exercise are of complementary value.Bicycle exercise echocardiography and 201-Tl myocardial perfusion scintigraphy SPECT were compared in 65 men after an episode of unstable coronary artery disease. Reversible abnormalities were seen in 55 patients with cchocardiography and in 43 patients with 201-Tl scintigraphy {p<O.OS). The segmental agreement between the methods was 58%. The additional value of exercise echocardiography and 201-Tl SPECT to exercise test was greatest in patients with one-vessel disease as detected by coronary angiography.The hemodynamic alterations induced by dobutamine stress testing were investigated using Doppler-echocardiography and venous occlusion plethysmography in 11 healthy women and 18 female patients. The healthy subjects received a lower peak-dose of dobutamine, 22±7.5 j.lg kg-I miu-1 compared with 33±9.7 j.lg kg- I min-I administered to the patients (p<O.Ol). The increase in hemt rate during dobutamine infusion was significantly greater in the subjects, +68%, compared with the patients, +49%, {p<O.OS). Corresponding figures for changes in systolic blood flow velocity in the left ventricular outflow tracts were +82% versus +50% (p<0.01), cardiac output +93% versus +60% (p<0.05), total peripheral vascular resistance -49% versus -44% and leg peripheral vascular resistance -32% versus -26% (not significant) in subjects and patients respectively. The hemodynamic alterations were age and dose dependant in the subjects. Mean systolic blood pressure for the two groups was unchanged but one subject and four patients developed hypotension (decrease in systolic blood pressure >10 mm Hg). One patient in the hypotension group developed a paradoxical vagal reaction with bradycardia at peak-dose and two patients had a very low increase in cardiac output (12%). The fomth patient with hypotension did not differ in change in cardiac output compared to the other patients. Despite a more pronounced decrease in total peripheral vascular resistance in these four patients compared with other patients, there was no difference in leg peripheral vascular resistance between the groups. The disparity between the pattern of total to legperipheral vascular resistance in patients with hypotension might reflect a baroreceptor mediated compensatmy increase in vasoconstrictor tone of muscle vessels not matched in other vascular territories.Echocardiographic M-mode recordings of mitral annulus motion were compared with Doppler registrations of mitral and pulmonary venous flow velocities in 38 patients with heart failure (NYHA ll-IU) after myocm·dial infarction. Patients with an increased atlial component of annulus motion in absolute (a :::::5.1 mm, n::::l9) or relative terms (a/T >57%, n::::l2) had a higher miti·allate to early flow velocity ratio and pulmonmy venoussystolic to diastolic filling ratio (p<O.OS), which is associated with prolonged left ventricular relaxation. Patients with an increased afT ratio also had a more pronounced left ventricular systolic dysfunction compared with others {p<0.01). There was a significant con-dation between afT ratio and AlE ratio (r=0.61, p<0.001) but the information contained in the two indices was not identical.

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