Respostas cardiorrespiratórias durante exercício em portadores de transplante cardíaco. Análise ergoespirométrica comparativa com indivíduos normais

Abstract

The cardiorespiratory performance in GI was significantly lower at peak exercise and similar to GII in the 40W load, showing the HT benefits cardiac patients during usual activities.

Adaptation to exercise following cardiac transplantation

“…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.…”

“…Pulmonary ventilation at peak exercise is significantly reduced in transplanted subjects relative to that in healthy controls 6,7,11,18,19,26 ( fig.3). However, when analyzing values of pulmonary ventilation, ventilatory equivalent for oxygen, ventilatory equivalent for carbon dioxide at the anaerobic threshold and at the 40W potency, no significant differences between healthy and transplanted patients are apparent 7 . The mechanism responsible for the excessive ventilation response in transplanted individuals has not been clarified.…”

“…The resting heart rate of transplanted subjects is 14 to 15 bpm above that of their controls paired by sex and age 36 , and 0 to 26 bpm above controls paired by sex, age, weight and height 6,7 . At the beginning of exercise, the heart rate rises slowly with a pattern of a depressed curve relative to that in healthy individuals; frequency acceleration is restricted to about one third of that of healthy individuals 37 .…”

“…In the cycloergometer, increments of 50 or 100 Kpm/min at each minute have been used 49 . We have used increasing load protocols with increments of 5 watts/minute after an initial stage of 3 min at 25 W, maintaining an average of 50 rotations per min 6,7 . The electrocardiogram is continuously monitored, and the arterial pressure is measured every two min, at the peak of the exercise and during recovery.…”