Impact of echocardiographic left ventricular mass on mechanistic implications of exercise testing parameters
Electrocardiographic left ventricular (LV) hypertrophy has long been known to be associated with an abnormal ST-segment response to exercise; this association has been considered to represent a false-positive finding. There is a paucity of data relating echocardiographic LV mass to exercise ST-segment responses and other exercise parameters. As part of a routine evaluation, 1,408 men and 1,618 women from the Framingham Heart Study who were free of clinical cardiac disease underwent echocardiography and exercise treadmill testing according to the Bruce protocol at the same clinic visit. Abnormal ST-segment responses were defined both by standard criteria and the delta ST/heart rate index. LV mass was calculated from M-mode echocardiography. Echocardiographic LV hypertrophy was associated with an abnormal delta ST/heart rate index (in men, odds ratio [OR] 1.78, 95% confidence interval [CI] 1.05 to 3.01, p = 0.03; in women, OR 2.13, 95% CI 1.31 to 3.44, p = 0.002) but not with an abnormal response according to standard criteria. Echocardiographic LV hypertrophy was also associated with a lower likelihood of achieving an age-predicted target heart rate (in men, OR 0.45, 95% CI 0.31 to 0.65, p < 0.001; in women, OR 0.53, 95% CI 0.37 to 0.76, p < 0.001) and with a lower exercise capacity. Despite these associations, echocardiographic LV hypertrophy was associated with a higher peak heart rate-systolic blood pressure double product. In conclusion, echocardiographic LV hypertrophy is associated with an abnormal ST-segment response, a lower likelihood of achieving target heart rate, decreased exercise capacity, and an increased double product, which is a reflection of myocardial oxygen demand.