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| Chacon-Mikahil,M.P.T.; Forti,V.A.M.; Catai,A.M.; Szrajer,J.S.; Golfetti,R.; Martins,L.E.B.; Lima-Filho,E.C.; Wanderley,J.S.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Jr.,L.. |
| We investigated the effects of aerobic training on the efferent autonomic control of heart rate (HR) during dynamic exercise in middle-aged men, eight of whom underwent exercise training (T) while the other seven continued their sedentary (S) life style. The training was conducted over 10 months (three 1-h sessions/week on a field track at 70-85% of the peak HR). The contribution of sympathetic and parasympathetic exercise tachycardia was determined in terms of differences in the time constant effects on the HR response obtained using a discontinuous protocol (4-min tests at 25, 50, 100 and 125 watts on a cycle ergometer), and a continuous protocol (25 watts/min until exhaustion) allowed the quantification of the parameters (anaerobic threshold, VO2 AT;... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sympathetic modulation of heart rate; Dynamic exercise; Aerobic training; Autonomic nervous system; Anaerobic threshold; Middle-aged men. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000500016 |
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| Tanaka,D.M.; Romano,M.M.D.; Carvalho,E.E.V.; Oliveira,L.F.L.; Souza,H.C.D.; Maciel,B.C.; Salgado,H.C.; Fazan-Júnior,R.; Simões,M.V.. |
| Determination of left ventricular ejection fraction (LVEF) using in vivo imaging is the cardiac functional parameter most frequently employed in preclinical research. However, there is considerable conflict regarding the effects of anesthetic agents on LVEF. This study aimed at assessing the effects of various anesthetic agents on LVEF in hamsters using transthoracic echocardiography. Twelve female hamsters were submitted to echocardiography imaging separated by 1-week intervals under the following conditions: 1) conscious animals, 2) animals anesthetized with isoflurane (inhaled ISO, 3 L/min), 3) animals anesthetized with thiopental (TP, 50 mg/kg, intraperitoneal), and 4) animals anesthetized with 100 mg/kg ketamine plus 10 mg/kg xylazine injected... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Echocardiography; Anesthetics; Systolic function; Hamsters. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2016001000602 |
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| Schmidt,A.; de Almeida-Filho,O.C.; Ayres-Neto,E.M.; Carneiro,J.J.; Marin-Neto,J.A.; Maciel,B.C.. |
| To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter). In each study, dobutamine (5 to 40 µg kg-1 min-1 in 3-min stages) and pacing (20 bpm increments, each 2 min, up to 260 bpm) were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min). The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05) reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stress echocardiography; Pacing; Dobutamine; Dipyridamole; Animal model. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000700010 |
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| Pazin-Filho,A.; de Jesus,A.M.X.; Magalhães,P.K.R.; Melato,L.H.; Campos,D.; Maciel,B.C.; Maciel,L.M.Z.. |
| Amiodarone-induced thyroid dysfunction (AITD) is a common complication of amiodarone therapy and its prevalence varies according to iodine intake, subclinical thyroid disorders and the definition of AITD. There is no consensus about the frequency of screening for this condition. We evaluated 121 patients on chronic regular intake of amiodarone (mean intake = 248.5 ± 89 mg; duration of treatment = 5.3 ± 3.9 years, range = 0.57-17 years) and with stable baseline cardiac condition. Those with no AITD were followed up for a median period of 3.2 years (range: 0.6-6.7) and the incidence rate of AITD, defined by clinical and laboratorial findings as proposed by international guidelines, was obtained (62.8 per 1000 patients/year). We applied the Cox proportional... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amiodarone; Chagas’ disease; Thyroid dysfunction; Antiarrhythmic drug. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000800009 |
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| Murta Jr.,L.O.; Ruiz,E.E.S.; Pazin-Filho,A.; Schmidt,A.; Almeida-Filho,O.C.; Simões,M.V.; Marin-Neto,J.A.; Maciel,B.C.. |
| The present study describes an auxiliary tool in the diagnosis of left ventricular (LV) segmental wall motion (WM) abnormalities based on color-coded echocardiographic WM images. An artificial neural network (ANN) was developed and validated for grading LV segmental WM using data from color kinesis (CK) images, a technique developed to display the timing and magnitude of global and regional WM in real time. We evaluated 21 normal subjects and 20 patients with LVWM abnormalities revealed by two-dimensional echocardiography. CK images were obtained in two sets of viewing planes. A method was developed to analyze CK images, providing quantitation of fractional area change in each of the 16 LV segments. Two experienced observers analyzed LVWM from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Artificial neural network; Color kinesis images; Left ventricular function. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000100001 |
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| Pazin-Filho,A.; Romano,M.M.D.; Almeida-Filho,O.C.; Furuta,M.S.; Viviani,L.F.; Schmidt,A.; Marin-Neto,J.A.; Maciel,B.C.. |
| Recent data from our laboratory have shown that patients with the indeterminate form of Chagas' disease can have impairment of left ventricular contractility, as evaluated by the slope of the left ventricle end-systolic pressure-dimension relationship. We also showed that Chagas' disease patients with minimal baseline wall motion abnormalities detected by two-dimensional echocardiography have more intense contractility impairment when compared to patients with the indeterminate form of the disease without this abnormality. The prognostic implications of these findings have not been established. We evaluated 59 patients (37-76 years, mean = 55 years) with different clinical forms of Chagas' disease, who had normal left ventricular global systolic function... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Echocardiography; Chagas' disease; Left ventricular function; Indeterminate form of Chagas' disease. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000400008 |
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| Catai,A.M.; Chacon-Mikahil,M.P.T.; Martinelli,F.S.; Forti,V.A.M.; Silva,E.; Golfetti,R.; Martins,L.E.B.; Szrajer,J.S.; Wanderley,J.S.; Lima-Filho,E.C.; Milan,L.A.; Marin-Neto,J.A.; Maciel,B.C.; Gallo-Junior,L.. |
| The purpose of the present study was to evaluate the effects of aerobic physical training (APT) on heart rate variability (HRV) and cardiorespiratory responses at peak condition and ventilatory anaerobic threshold. Ten young (Y: median = 21 years) and seven middle-aged (MA = 53 years) healthy sedentary men were studied. Dynamic exercise tests were performed on a cycloergometer using a continuous ramp protocol (12 to 20 W/min) until exhaustion. A dynamic 24-h electrocardiogram was analyzed by time (TD) (standard deviation of mean R-R intervals) and frequency domain (FD) methods. The power spectral components were expressed as absolute (a) and normalized units (nu) at low (LF) and high (HF) frequencies and as the LF/HF ratio. Control (C) condition: HRV in TD... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heart rate variability; Power spectral density analysis; Anaerobic threshold; Aerobic exercise training; Autonomic nervous system and aging processes in man. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002000600016 |
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