Search

Objectives: Physical training in cardiac patients can increase exercise capacity and reduce plasma brain natriuretic peptide(BNP) concentration, but these effects may depend on the etiology of cardiac disease. The change in exercise capacity and BNP during the training period were investigated in patients with different cardiac diseases., Methods: Ninety-one patients after coronary artery bypass grafting(CABG) and 78 patients after valve replacement (VR) underwent a symptom-limited incremental cardiopulmonary exercise test before (1 month) and 6 months after physical training. Anaerobic threshold and peak oxygen uptake(peak-Vo2) were measured during the cardiopulmonary exercise test. Before each cardiopulmonary exercise test, a blood sample was obtained in the resting condition for measuring BNP., Results: Anaerobic threshold and peak-Vo2 were increased significantly from 1 month to 6 months in both groups. BNP in the CABG group indicated a tendency to decrease (194.6 +/- 155.3-->144.2 +/- 232.2 pg/ml, p < 0.1) from 1 month to 6 months. BNP in VR group was significantly decreased (159. 9 +/- 115.5-->112.8 +/- 131.7 pg/ml, p < 0.05) during the training period. The CABG group showed a significant negative correlation between peak-Vo2 and BNP at 1 month(r = -0.28, p < 0.01) and at 6 months(r = -0.39, p = 0.001). The VR group showed a significant negative correlation between peak-Vo2 and BNP at 6 months(r = -0.32, p < 0.01), but not at 1 month., Conclusions: Six months of physical training in patients after cardiac surgery may improve exercise capacity and reduce BNP. BNP concentration in the VR group before physical training did not reflect functional capacity.

Objectives: Power spectral analysis was used to analyze fluctuations of systolic blood pressure and heart rate., Methods: Non-invasive finger plethysmography and electrocardiography were performed in 20 patients with chronic atrial fibrillation and in 10 age-matched healthy subjects with normal sinus rhythm. The impulse train was stored on a personal computer and the power spectrum of R-R interval and systolic blood pressure were obtained by Fourier analysis (0.01-0.03 Hz). The power spectrum (log power vs log frequency) characteristically revealed a linear regression as 1/f beta., Results: The R-R interval spectrum during atrial fibrillation showed a white noise-like flat spectrum when plotted as log power against log frequency, whereas the systolic blood pressure spectrum during atrial fibrillation showed a 1/f noise-like negative slope linear pattern. The spectrum exponent of systolic blood pressure in patients with atrial fibrillation was significantly lower than that in subjects with normal sinus rhythm (2.3 +/- 0.1 vs 1.3 +/- 0.1, p < 0.0001)., Conclusions: Systolic blood pressure fluctuation in patients with atrial fibrillation has a fractal component and is more complex than that of healthy subjects with normal sinus rhythm.

Objectives: This study assessed the prevalence and clinical background of exercise-induced ventricular tachycardia during exercise testing., Methods: Complications during exercise testing were reviewed in 25,075 consecutive patients, 14,037 men and 11,038 women, who underwent a total of 47,656 maximal treadmill or bicycle exercise tests between April 1985 and March 1999. The mean age of the patients was 53.3 +/- 8.8 (mean +/- SD) years. Non-sustained ventricular tachycardia was defined as 8 or more consecutive ventricular ectopic beats at > 100 beats/min. A total of 126 patients undergoing exercise testing to evaluate the efficacy of pharmacotherapy for ventricular tachycardia were excluded., Results: The major reasons for the exercise test were chest pain (27.0%) and screening (20.3%). Twenty patients (0.08%) had exercise-induced ventricular tachycardia. Six patients had ischemic heart disease, two had cardiomyopathy, five had other cardiac diseases, and seven patients showed no clinical evidence of heart disease. The incidence of ventricular tachycardia in patients with cardiomyopathy (2/109) was higher than in other patients, but the number of patients with ventricular tachycardia was small. Ventricular tachycardia was documented at heart rates of more than 80% of predicted maximal heart rate in 12 of the 20 patients., Conclusions: These results suggest that the exercise testing can be done safely when the end-point criteria are properly applied.