Biomedical subjects

Neil Smart

Publications and source records attributed to Neil Smart.

5 recordsLinked to original sources

PubMed2006

Cardiac contributions to exercise training responses in patients with chronic heart failure: a strain imaging study.

The improvement of exercise capacity due to exercise training in heart failure has been associated with peripheral adaptation, but the contribution of cardiac responses is less clear. We sought the extent to which the improvement of functional capacity in patients undergoing exercise training for heart failure was related to myocardial performance. Thirty-seven patients (35 men, age 64 +/- 11) with symptomatic heart failure and left ventricular ejection fraction < or = 35% (29 +/- 9%) were studied during a 16-week exercise training program. LV function was assessed by resting and exercise 2D-echocardiography, tissue Doppler derived myocardial strain, and strain rate. Peak oxygen consumption (VO2) and LV function were measured at baseline and follow-up, and the contribution of LV function at baseline and its response to training to the change of each parameter was sought. Baseline peak VO2 (12.4 +/- 4.6) increased by 9% at 8 weeks (13.5 +/- 4.2, P = 0.26), and by 21% at 16 weeks (15.0 +/- 4.9, P < 0.001). Although there were no overall changes in myocardial parameters in this study, change in peak VO2 at 16 weeks was significantly correlated with baseline strain (r = 0.51, P = 0.003) and the improvement of strain at 8 weeks (r = 0.44, P = 0.01), independent of baseline functional capacity and clinical variables. Thus, change in peak VO2 following 16 weeks exercise training is related to myocardial function at baseline.

Aged↗

PubMed2005

Determinants of functional capacity in patients with chronic heart failure: role of filling pressure and systolic and diastolic function.

BACKGROUND: Previous work suggesting a better correlation of diastolic than systolic function with exercise capacity in heart failure may reflect the relative insensitivity and load-dependence of ejection fraction (EF). We sought the correlation of new and more sensitive methods of quantifying systolic and diastolic function and filling pressure with functional capacity. METHODS: We studied 155 consecutive exercise tests on 95 patients with congestive heart failure (81 male, aged 62 +/- 10 years), who underwent resting 2-dimensional echocardiography and tissue Doppler imaging before and after measurement of maximum oxygen uptake (peak VO2). RESULTS: The resting EF was 31% +/- 10% and a peak VO2 was 13 +/- 5 mL/kg.min; the majority of these patients (80%) had an ischemic cardiomyopathy. Resting EF (r = 0.14, P = .09) correlated poorly with peak VO2 and mean systolic (r = 0.23, P = .004) and diastolic tissue velocities (r = 0.18, P = .02). Peak EF was weakly correlated with the mean systolic (r = 0.18, P = .02) and diastolic velocities (r = 0.16, P < .04). The mean sum of systolic and diastolic velocities in both annuli (r = 0.30, P < .001) and E/Ea ratio (r = -0.31, P < .001) were better correlated with peak VO2 . Prediction of peak VO2 was similar with models based on models of filling pressure (R = 0.61), systolic factors (R = 0.63), and diastolic factors (R = 0.59), although a composite model of filling pressure, systolic and diastolic function was a superior predictor of peak VO2 (R = 0.69; all P < .001). CONCLUSIONS: The reported association of diastolic rather than systolic function with functional capacity may have reflected the limitations of EF. Functional capacity appears related not only to diastolic function, but also to systolic function and filling pressure, and is most closely associated with a combination of these factors.

Aged↗

PubMed2005

Predictors of a sustained response to exercise training in patients with chronic heart failure: a telemonitoring study.

BACKGROUND: Exercise training (ExT) improves exercise capacity in chronic heart failure, but the results of home-based training have been variable. We sought the predictors of favorable outcome using a telemonitoring approach. METHODS: Exercise capacity and quality of life (QOL) were assessed in 30 patients (28 men, age 64 +/- 8 years) with symptomatic chronic heart failure and left ventricular ejection fraction < or = 35% (28% +/- 9%) undergoing 8 months of home ExT. Patients were provided with heart rate monitors and exercise diaries after undergoing 4 months of hospital-based ExT. Weekly telephone contact was established and heart rate data were downloaded bimonthly. Changes in peak oxygen consumption per unit time (V*O2) and QOL were compared between the 15 most and 15 least adherent patients defined by the number of hours per week at > 60% maximum heart rate, observed during heart-rate monitoring. RESULTS: Peak V*O2 increased by 26% (P < .001) after 4 months of hospital ExT, but this increase had fallen to 8% (P = .07) at 12 months; only adherent patients (n = 15) showed persistent improvement of peak V*O2 at 12 months (P = .02). Improvement in peak V*O2 at 12 months was associated with baseline peak V*O2 (r = -0.61, P < .001) and hours logged on the heart rate monitor (r = 0.47, P = .01). Quality of life improvements were sustained at 12 months for the Minnesota Living with Heart Failure Questionnaire and Hare-Davis Depression Questionnaire. Nevertheless, QOL improvements achieved during the outpatient program were lost or attenuated at 12 months in nonadherent patients but were maintained in adherent patients. CONCLUSIONS: Telemonitoring is feasible for following adherence to home ExT. Ongoing adherence is critical in obtaining sustained benefit from ExT in heart failure.

Aged↗

PubMed2004

Exercise training for patients with heart failure: a systematic review of factors that improve mortality and morbidity.

PURPOSE: To determine the efficacy of exercise training and its effects on outcomes in patients with heart failure. METHODS: MEDLINE, Medscape, and the Cochrane Controlled Trials Registry were searched for trials of exercise training in heart failure patients. Data relating to training protocol, exercise capacity, and outcome measures were extracted and reviewed. RESULTS: A total of 81 studies were identified: 30 randomized controlled trials, five nonrandomized controlled trials, nine randomized crossover trials, and 37 longitudinal cohort studies. Exercise training was performed in 2387 patients. The average increment in peak oxygen consumption was 17% in 57 studies that measured oxygen consumption directly, 17% in 40 studies of aerobic training, 9% in three studies that only used strength training, 15% in 13 studies of combined aerobic and strength training, and 16% in the one study on inspiratory training. There were no reports of deaths that were directly related to exercise during more than 60,000 patient-hours of exercise training. During the training and follow-up periods of the randomized controlled trials, there were 56 combined (deaths or adverse events) events in the exercise groups and 75 combined events in the control groups (odds ratio [OR] = 0.98; 95% confidence interval [CI]: 0.61 to 1.32; P = 0.60). During this same period, 26 exercising and 41 nonexercising subjects died (OR = 0.71; 95% CI: 0.37 to 1.02; P = 0.06). CONCLUSION: Exercise training is safe and effective in patients with heart failure. The risk of adverse events may be reduced, but further studies are required to determine whether there is any mortality benefit.

Exercise↗

PubMed2003

A practical guide to exercise training for heart failure patients.

BACKGROUND: Exercise training has been shown to improve exercise capacity in patients with heart failure. We sought to examine the optimal strategy of exercise training for patients with heart failure. METHODS: Review of the published data on the characteristics of the training program, with comparison of physiologic markers of exercise capacity in heart failure patients and healthy individuals and comparison of the change in these characteristics after an exercise training program. RESULTS: Many factors, including the duration, supervision, and venue of exercise training; the volume of working muscle; the delivery mode (eg, continuous vs. intermittent exercise), training intensity; and the concurrent effects of medical treatments may influence the results of exercise training in heart failure. Starting in an individually prescribed and safely monitored hospital-based program, followed by progression to an ongoing and progressive home program of exercise appears to be the best solution to the barriers of anxiety, adherence, and "ease of access" encountered by the heart failure patient. CONCLUSIONS: Various exercise training programs have been shown to improve exercise capacity and symptom status in heart failure, but these improvements may only be preserved with an ongoing maintenance program.

Exercise Therapy↗