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Papers by John Paras
Echocardiography, 2004
ABSTRACT Introduction: The ejection fraction (EF) is an ecocardiographic parameter of left ventri... more ABSTRACT Introduction: The ejection fraction (EF) is an ecocardiographic parameter of left ventricle (LV) systolic function usually used in the cardiovascular evaluation. However, instead only contractility, EF is a measure that analyzes changes of LV dimensions, which are preload and afterload dependent, and evaluates mainly the contraction of the circumferentially orientated myocardic fibers. The longitudinal fibers of the LV are probably more important in the contractile function and the inotropic stimulation would affect its function in a different way to the EF. Objectives: To evaluate the proportional increase of EF and S peak induced by stress with dobutamine in healthy subjects, and the relationship between both parameters of LV systolic function. Methods: 80 patients were prospectively included. The clinical examination, the electrocardiogram, and the ecocardiographic evaluation of them all were normal. No one was on any medication. An echocardiogram with EF calculated by Simpson's method was made. To obtain the systolic peak (S) PTD was performed from an apical four-chamber view to obtain long axis velocities, with a 5-mm. sample size on the middle of basal septum, at the union with the mitral annulus. Both parameters were recorded at rest and after the intravenous infusion of increasing doses of 10 mg/min every 3 minutes of dobutamine until reaching 40 mg/min or an appropriate heart rate if necessary; atropine in a dose of up to 1 mg was added. The parameters obtained of S peak and EF were expressed as proportional increase from baseline in percentage. Both parameters were correlated by means of linear regression and differences were considered significant at p Results: The mean age was 63 ± 9 years, 22 were male (27.5%), the mean heart rate achieved with stress was 125 ± 18, systolic blood pressure was 125 ± 28 mmHg, and double product of 15,822 ± 3,495. The data of EF and S peak are shown in the following table. The correlation between proportional increase of EF and S peak was r = 0.13 (p = 0.22). Conclusions: In healthy subjects the proportional increase of S peak was significantly higher than EF with inotropic stimulation. These data suggest that the longitudinal myocardial oriented fibers are more sensitive to dobutamine stimulation.
Echocardiography, 2004
ABSTRACT Introduction: The ejection fraction (EF) is an ecocardiographic parameter of left ventri... more ABSTRACT Introduction: The ejection fraction (EF) is an ecocardiographic parameter of left ventricle (LV) systolic function usually used in the cardiovascular evaluation. However, instead only contractility, EF is a measure that analyzes changes of LV dimensions, which are preload and afterload dependent, and evaluates mainly the contraction of the circumferentially orientated myocardic fibers. The longitudinal fibers of the LV are probably more important in the contractile function and the inotropic stimulation would affect its function in a different way to the EF. Objectives: To evaluate the proportional increase of EF and S peak induced by stress with dobutamine in healthy subjects, and the relationship between both parameters of LV systolic function. Methods: 80 patients were prospectively included. The clinical examination, the electrocardiogram, and the ecocardiographic evaluation of them all were normal. No one was on any medication. An echocardiogram with EF calculated by Simpson's method was made. To obtain the systolic peak (S) PTD was performed from an apical four-chamber view to obtain long axis velocities, with a 5-mm. sample size on the middle of basal septum, at the union with the mitral annulus. Both parameters were recorded at rest and after the intravenous infusion of increasing doses of 10 mg/min every 3 minutes of dobutamine until reaching 40 mg/min or an appropriate heart rate if necessary; atropine in a dose of up to 1 mg was added. The parameters obtained of S peak and EF were expressed as proportional increase from baseline in percentage. Both parameters were correlated by means of linear regression and differences were considered significant at p Results: The mean age was 63 ± 9 years, 22 were male (27.5%), the mean heart rate achieved with stress was 125 ± 18, systolic blood pressure was 125 ± 28 mmHg, and double product of 15,822 ± 3,495. The data of EF and S peak are shown in the following table. The correlation between proportional increase of EF and S peak was r = 0.13 (p = 0.22). Conclusions: In healthy subjects the proportional increase of S peak was significantly higher than EF with inotropic stimulation. These data suggest that the longitudinal myocardial oriented fibers are more sensitive to dobutamine stimulation.