Navegando por Palavras-chave "Freqüência cardíaca"

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    Avaliação do sensor de contratilidade cardíaca em sistema DDDR: estudo multicêntrico
    (Sociedade Brasileira de Cirurgia Cardiovascular, 1998-10-01) Andrade, José Carlos S. [UNIFESP]; Andrade, Veridiana S. [UNIFESP]; Buffolo, Enio [UNIFESP]; Greco, Oswaldo Tadeu; Lopes, Marly Gerola; Macedo Júnior, Antônio; Menezes Júnior, Antônio da Silva; Moraes, Antônio Vitor; Mota, Newton José Martins; Pachón, José Carlos; Schaldach, Marc; Tebexreni, Antonio Sergio [UNIFESP]; Tomas, Aldo Auler; Universidade Federal de São Paulo (UNIFESP); Instituto de Moléstias Cardiovasculares de São José do Rio Preto; Hospital Osvaldo Cruz; Hospital Santa Helena; Santa Casa de Misericórdia de Ribeirão Preto; Hospital Santa Isabel; Instituto Dante Pazzanese de Cardiologia; Alexander Universitat; Hospital São Marcos
    Introduction: The treatment of AV conduction disorders associated with sinus node illness employing DDDR pacemakers, has motivated the surch for an ideal sensor.Objective: Evaluate the heart rate response of the contractility sensor pacemaker both during the physical effort and mental stress of daily life in out patient tests for patients with bradycardia and chronotropic incompetence.Material and Methods: We use the brazilian Multicentric Study Inos DR Project _ Brazil working with a DDDR stimulation system which uses the myocardial contractility state chronotropic 38 patients presenting; incompetence were selected, 21 men and 17 women, with age ranging from 13 to 83 years (mean 57 years). The pacemaker utilizes intrinsic cardiovascular information (cardiac contractility from the measure of the unipolar cardiac impedance) for heart rate adaptation, in a closed loop system that theoretically adjusts to all physiologic needs. The system calibration and programation were performed 30 days after implantation (stabilization of heart-lead interface), based on the tests of mental stress (mathematical) and treadmill test, monitoring heart rate histogram of frequency and oxygen consumption.Results: The acute stimulation threshold mean is 0.82 volts and 0.55 volts, and the mean sensibility is 2.37 mV and 10.61 mV, to atrium and ventricle respectively. The mean chronic stimulation threshold is 1.44 V and 1.18, and the mean sensibility threshold mean is 2.81 mV and 6 mV, to atrium and ventricle respectively. The heart rate varied from 5% to 128% on physical activity and from 5% to 80% on mental activity, with elevation right at the beginning of activity, permitting a normal oxygen consumption curve similar to that of normal person of the same age, sex and weight. The average data were compared using T Student test and the variables using variance analysis.Conclusion: The cardiac contractility sensor has an excelent performance on heart rate adaptation, with similar values produced by the autonomous nervous system of normal subjects.
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    Comparação da freqüência cardíaca máxima medida com as fórmulas de predição propostas por Karvonen e Tanaka
    (Sociedade Brasileira de Cardiologia - SBC, 2008-11-01) Camarda, Sergio Ricardo de Abreu [UNIFESP]; Tebexreni, Antonio Sergio [UNIFESP]; Páfaro, Cristmi Niero; Sasai, Fábio Bueno; Tambeiro, Vera Lúcia [UNIFESP]; Juliano, Yara; Barros Neto, Turibio Leite de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Metodista de Piracicaba; Universidade Santo Amaro
    BACKGROUND: Equations for predicting maximal heart rate (HRmax) are widely used in exercise testing and for training prescription, but their efficacy remains controversial in the literature. OBJECTIVE: To compare maximal heart rate during cardiopulmonary exercise testing (CPET) using the prediction equations developed by Karvonen and Tanaka. METHODS: Of the 24,120 maximal treadmill graded exercise tests stored in the CEMAFE database from 1994 to 2006, 2047 HRmax values were analyzed, 1091 of which were from male and 956 from female sedentary subjects. These data were used as a gold standard to compare Karvonen's and Tanaka's prediction formulas. RESULTS: Mean measured maximal heart rates were 181.0 ± 14.0; 180.6 ± 13.0, and 180.8 ± 13.8 for men, women, and both genders combined, respectively. Likewise, mean values from Karvonen's equation were 182.0 ± 11.4; 183.7 ± 11.5, and 183.9 ± 11.7; and from Tanaka's, 182.0 ± 8.0; 182.6 ± 8.0, and 182.7 ± 8.2. Karvonen's and Tanaka's equations yielded the same correlation coefficients, as compared with measured maximal heart rate (r = 0.72). CONCLUSION: Karvonen's and Tanaka's equations are similar in predicting maximal heart rate and show good correlation with measured maximal heart rate.
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    Influência da freqüência cardíaca na qualidade de vida e capacidade física em pacientes com fibrilação atrial crônica
    (Universidade Federal de São Paulo (UNIFESP), 2008-09-24) Jaber, Jefferson [UNIFESP]; De Paola, Angelo Amato Vincenzo de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Background: Rate control is an acceptable alternative to rhythm control in patients with chronic atrial fibrillation. However, current criteria for rate control are empirical and based on a small amount of scientific data. Objective: This study was designed to analyse the influence of heart rate measured by the 6-minute walk test, 24-hour Holter monitoring and cardiopulmonary exercise test on quality of life and exercise capacity in patients with atrial fibrillation. Methods: Eighty-nine males patients with chronic atrial fibrillation and resting heart rate < 90 bpm were included. These patients underwent a quality of life questionnaire (assessed by Medical Outcomes Study Short Form Health Survey SF-36), 6-minute walk test, cardiopulmonary exercise test and 24-hour Holter monitoring. Results: There was a significant difference on quality of life in physical and mental summary scores in patients with maximal heart rate . 110 bpm on 6-minute walk test in comparison with heart rate > 110 bpm (284.10 } 81.37 vs 247.45 } 85.03, p = 0.04 and 316.59 } 75.91 vs 266.84 } 93.75, p = 0.01, respectively) and in physical summary score in patients with average heart rate . 80 bpm on Holter monitor in comparison with heart rate > 80 bpm (284.25 } 70.91 vs 240.81 } 93.55, p = 0.02). There was no significant difference on quality of life in patients with maximal heart rate between 85 and 115% of the maximum age-predicted heart rate at peak exercise in comparison with peak heart rate > 115% of the maximum age-predicted heart rate. Quality of life was also compared among 3 groups of patients classified by heart rate testing results (Group 1 had heart rate . 110 bpm on 6-minute walk test and . 80 bpm on Holter monitor; Group 2 had heart rate in the target area by one but no both tests; and Group 3 had heart rate > 110 bpm on 6-minute walk test and > 80 bpm on Holter monitor), demonstrating significant difference among 3 groups in physical and mental component summary scores (p = 0.035 e p = 0.026, respectively). Exercise capacity assessment demonstrated that patients with heart rate variation index not over 10 bpm/min showed higher maximal oxygen uptake compared to patients with heart rate variation index > 10 bpm/min (26.76 } 6.17 vs 22.83 } 4.84 ml O2/Kg/min, p = 0.002). Conclusions: Patients with both heart rate . 110 bpm on 6-minute walk test and heart rate . 80 bpm on Holter monitor had better quality of life than patients with higher average heart rates. Holter monitoring and 6-minute walk test shoud be performed as complementary methods to better predict quality of life. The simple heart rate control at rest was not sufficient when we desire to obtain better qualty of life. Better heart rate variation control on cardiopulmonary exercise test was correlated with better exercise capacity in patients with chronic atrial fibrillation.