REGIONAL WALL MOTION ABNORMALITIES AFTER PROLONGED EXERCISE IN THE NORMAL LEFT-VENTRICLE

To determine whether regional wall motion abnormalities exist or contribute to left ventricular dysfunction, we obtained two-dimensional echocardiograms in 12 athletes before (baseline), immediately after (race finish), and 1 day after (recovery) the Hawaii Ironman Triathlon (a 3.9-km swimming, 180.2-km bicycling, and 42.2-km running event). Left ventricular short-axis and apical four-chamber views were computer digitized and divided into six segments, and radial chord shortening and area ejection fraction were calculated. Global ejection fraction fell at race finish (51% versus 46%, p<0.05) but recovered by 1 day (54%, p<0.01 by repeated-measures analysis of variance). With the apical four-chamber view, midseptal and apical-septal motion were reduced at race finish but returned to baseline during recovery (midseptal radial chord shortening: 21%, 8%, 22%; apical-septal radial chord shortening: 27%, 12%, 25%; midseptal area ejection fraction: 39%, 30%, 40%; apical-septal area ejection fraction: 44% baseline, 33% race finish, 43% recovery; all p<0.01). In contrast, with the parasternal short-axis view, wall motion did not change at race finish but tended to be elevated during recovery and became significant for anteroseptal motion (radial chord shortening: 29%, 30%, 36%; area ejection fraction: 49% baseline, 51% race finish, 58% recovery; both p<0.05). Lateral wall motion was unchanged. In addition, an index of septal curvature was calculated using the ratio of the septal-lateral wall minor axis to the perpendicular anteroposterior minor axis. At all three data collections, this ratio remained close to 1.0 at end systole and end diastole. Thus, the normal left ventricle may demonstrate heterogeneity of regional wall motion after prolonged exercise. Given the lack of change in septal position, substantial ventricular interactions are unlikely.