Author/Authors :
Dominique Johnson، نويسنده , , Helène Perrault، نويسنده , , Anne Fournier، نويسنده , , Jean-Marie Leclerc، نويسنده , , Jean-Luc Bigras، نويسنده , , André Davignon and From the Cardiology Unit Ste-Justine Hospital; the Physical Education Department، نويسنده , , McGill University; and the Hematology Unit، نويسنده , , Ste-Justine Hospital.، نويسنده ,
Abstract :
This study assessed the long-term (5-year) outcomeof pediatric low-dose anthracycline therapy on the circulatory response to moderate exercise. Thirteen patients(13 ± 4 years old) and 15 age-matched control subjectscompleted a maximal cycle ergometer protocol as wellas two 5-minute cycling tests at 33% and 66% maximaloxygen uptake (v̇ o2 max) for determination of cardiac index (carbon dioxide rebreathing). v̇ o2 max was lower in patients than in control subjects (1.3 ± 0.5 L/min vs 2.3 ± 0.6 L/min) (p < 0.05). Smaller relative increases in cardiac index for similar increases in relative exercise intensities were found in patients (33% v̇ o2 max, 73% vs 116%; 66% v̇ o2 max, 115% vs 192%), as a result of smaller increases in stroke index from rest (33% v̇ o2 max, 33% vs 54%; 66% v̇ o2 max, 33% vs 69%; p < 0.05). Similarly, despite normal resting systolic function, patients exhibited a lower stroke index and higher heart rate for any given value of oxygen uptake (milliliters per minute per square meter). Children who had survived cancer exhibited stroke index impairment during exercise similar in intensity to that of recreational activities or play, attesting to a limited inotropic reserve. (Am Heart J 1997; 133:169-73.)
