DETERMINANTS OF EXERCISE CAPACITY IN THE HYPERTENSIVE ELDERLY - A STUDY BASED ON THE ASSESSMENT OF CARDIAC RESERVE BY DIPYRIDAMOLE RADIONUCLIDE ANGIOGRAPHY

To evaluate the determinants of exercise capacity in the hypertensive elderly with an assessment of cardiac reserve by dipyridamole radionuc lide angiography, 31 elderly subjects (aged 62 to 78 years, 15 hyperte nsive and 16 normotensive) underwent symptom-limited maximum treadmill exercise with measurement of maximal oxygen consumption along with ra dionuclide angiography in list mode at rest and after dipyridamole inf usion. In the normotensive elderly, maximal oxygen consumption correla ted with relative filling volume during the rapid filling period at re st (r=0.58; p<0.05), and correlated inversely with the percent change in the peak ejection rate with dipyridamole (r= -0.63; p< 0.01). In co ntrast, maximal oxygen consumption correlated with atrial contribution at rest (r=0.69; p<0.005), and correlated inversely with the percent change in atrial contribution with dipyridamole (r= -0.87; p<0.0001) i n the hypertensive elderly. These results indicate that the mechanisms for maintaining exercise capacity are different in elderly subjects w ith or without hypertension.