Cardiorespiratory responses of cardiac transplant patients to graded, symptom-limited exercise.

Savin, William M.; Haskell, William L.; Schroeder, John S.; Stinson, Edward B.

doi:10.1161/01.cir.62.1.55

Cited by 183 publications

(61 citation statements)

References 13 publications

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“…HR decayed more slowly after treadmill exercise in cardiac transplant recipients than normal subjects (35), suggesting that the cardiac autonomic nerves control the recovery process of HR. In this study, CSNA returned promptly to the resting level within 1 s after the end of exercise, whereas HR decreased slowly for Ͼ30 s (Figs.…”

Section: Discussionmentioning

confidence: 95%

Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Tsuchimochi

Matsukawa

Komine

et al. 2002

American Journal of Physiology-Heart and Circulatory Physiology

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The assumption that tachycardia during light to moderate exercise was predominantly controlled by withdrawal of cardiac parasympathetic nerve activity but not by augmentation of cardiac sympathetic nerve activity (CSNA) was challenged by measuring CSNA during treadmill exercise (speed, 10–60 m/min) for 1 min in five conscious cats. As soon as exercise started, CSNA and heart rate (HR) increased and mean arterial pressure (MAP) decreased; their time courses at the initial 12-s period of exercise were irrespective of the running speed. CSNA increased 168–297% at 7.1 ± 0.4 s from the exercise onset, and MAP decreased 8–13 mmHg at 6.0 ± 0.3 s, preceding the increase of 40–53 beats/min in HR at 10.5 ± 0.4 s. CSNA remained elevated during the later period of exercise, whereas HR and MAP gradually increased until the end of exercise. After the cessation of exercise, CSNA returned quickly to the control, whereas HR was slowly restored. In conclusion, cardiac sympathetic outflow augments at the onset of and during dynamic exercise even though the exercise intensity is low to moderate, which may contribute to acceleration of cardiac pacemaker rhythm.

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Section: Discussionmentioning

confidence: 95%

Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Tsuchimochi

Matsukawa

Komine

et al. 2002

American Journal of Physiology-Heart and Circulatory Physiology

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“…The absence of a relationship between the hemodynamic effects and exercise capacity has been also described for other forms of heart failure therapies, including the use of vasodilators 23 , inotropic agents 24 , and heart transplantation 25 . It is believed that measurements such as functional class, 6-minute walk test, or quality of life scores may reflect physical capacity during daily activities better than ergospirometry 7 .…”

Section: Discussionmentioning

confidence: 92%

Efeito do bisoprolol sobre a função cardíaca e o exercício em pacientes com insuficiência cardíaca

Issa¹,

Guimarães²,

Rezende³

et al. 2007

Arq. Bras. Cardiol.

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SummaryObjectives: To assess the effects of bisoprolol on exercise capacity and ventricular function in patients with heart failure.Methods: Clinical and hemodynamic variables, ventricular function and remodeling, and ergospirometry of patients with heart failure of different etiologies were evaluated before and after the administration of bisoprolol.Results: Twenty-two patients were analyzed; one patient did not tolerate medication and 14 patients reached the study goal. The group consisted of 9 men and 5 women, the mean age was 52 (36-64) years, and patients were followed during 551 days (238-1109). We observed an improvement in NYHA functional class, reduction in resting heart rate (78.8±8.7 vs 63±6.4 bpm, p <0.001), increase in left ventricular ejection fraction (31.3±8.5% vs 39±14.7%. p=0.043), and a tendency towards improved quality of life scores (31±20.6 vs 17.8±14.8. p=0.058). The maximum heart rate dropped during exercise (138.1±20.2 vs 116.7±27.1. p=0.01), as did peak oxygen consumption (20.9±6.8 vs 15.1±3.5. p<0.001); no change was observed on the EV/VCO2 slope. The effects were observed for all etiologies, including Chagas' disease.Conclusion: Bisoprolol was safe and well tolerated in patients with heart failure. Bisoprolol therapy improved the symptoms, hemodynamic variables, as well as the cardiac function for all etiologies; however, it did not result in improved exercise capacity.

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“…It has been reported that this pattern persists for 10 years following transplantation 38 . Due to posttransplantation denervation, heart rate is controlled by the humoral route dependent of the levels of catecholamines released from the suprarenal gland 9,10 . Nevertheless, submaximal heart rate remains significantly higher in transplanted patients relative to controls up to levels of 50% of maximal exercise ( fig.1) 39 .…”

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confidence: 99%

Adaptation to exercise following cardiac transplantation

Af¹,

Ja²

2000

Arq. Bras. Cardiol.

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Cardiac transplantation has been the treatment of choice for patients with terminal cardiac insufficiency, increasing survival time by more than 80% in the first year 1 and by more than 50% over ten years 2 . Following cardiac transplantation, the quality of life improves considerably, and many transplanted patients return to work becoming reintegrated into the community 3 . During regular activity, transplanted subjects have shown physical conditioning similar to that of healthy individuals 4-7 . Starling's axiom, "today's physiology will be tomorrow's medicine" 8 , emphasizes the need for knowledge about post-transplantation cardiovascular adaptations, to serve as the basis for clinical treatment and rehabilitation. The present article has the aim of discussing the state-of -the-art of this subject.Aerobic capacity -Aerobic capacity is the total amount of O 2 capable of being metabolized by an organism. Aerobic potency is the amount of 0 2 consumed per unit of time (VO 2 ). Maximal O 2 consumption (VO 2 max.) or maximal aerobic potency is the maximum VO 2 obtained in an endurance (of progressive loads) test, in which VO 2 reaches a maximal value without additional increase due to an additional work load. In tests in which the patient does not reach maximum oxygen consumption, as frequently occurs in cardiopathy patients and transplanted subjects, peak VO 2 is defined as the highest value of VO 2 obtained. Following cardiac transplantation, patients progress with a reduction of peak VO 2 9-15 of 30-50% [16][17][18][19][20][21][22] . In our study 6,7 , deficits were 32.4% and 25.7% at peak exercise and at the anaerobic threshold, respectively. Marzo et al 18 found a 35% reduction in the absolute values of the anaerobic threshold. Degré et al 23 reported an early and intense accumulation of lactate during exercise, attributed to increased production in active tissues and reduced clearance secondary to decreased blood flow in the liver and other inactive tissues. In our study 7 , VO 2 in light to moderate submaximal exercise (40 watt load) below the anaerobic threshold was 12.34 and 12.38ml/kg/ min, in transplanted and healthy subjects, respectively, without significant differences between these groups. Meyer et al 24 , working with a load of 50 watts, reported a VO 2 of 0.96 ±0.1 and 0.95±0.08 L/min -1 in transplanted and control subjects, respectively.The reduction of peak VO 2 is due to multiple factors, both central and peripheral. Chronotropic incompetence and alteration in diastolic function are central factors 21,22,25,26 . At the peripheral level, reduction of peripheral oxygen extraction occurs 17,21,22,[27][28][29] . An exaggerated neuroendocrine response 19 and reduced capacity of pulmonary diffusion 20,30 also seem to be involved in decreased tolerance to exercise.Heart Rate -Heart rate values at rest have been observed to be higher in transplanted compared with healthy individuals due to the absence of parasympathetic innervation and corresponding to the intrinsic frequency of the sinus node 17,23,[31...

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Cardiorespiratory responses of cardiac transplant patients to graded, symptom-limited exercise.

Cited by 183 publications

References 13 publications

Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Efeito do bisoprolol sobre a função cardíaca e o exercício em pacientes com insuficiência cardíaca

Adaptation to exercise following cardiac transplantation

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