Paradoxical behavior of the QT interval during exercise and recovery and its relationship with cardiac memory

Background: Few studies have dealt with the behavior of the corrected (QTc) and uncorrected QT intervals during exercise and recovery. Hypothesis: Based on previously published dynamics of the QT interval during treadmill testing, this study attempted to reevaluate the computer‐proposed underlying mechanisms of these dynamics and to determine whether the so‐called memory phenomenon could be operative in some subjects without evidence of structural heart disease. Methods: This study included 42 unmedicated healthcare volunteers, 23 men and 19 women aged between 20 and 42 (mean 31.7) years. All had normal physical examinations, x‐rays, and transthoracic echocardiograms. The electrocardiograms were also normal with 12‐lead QT interval dispersions of