Indexing cardiac parameters in echocardiographic practice : do estimates depend on how weight and height have been assessed? A study on left atrial dilatation

We examined the difference between self-reported and measured height and weight in detecting echocardiographic left atrial dilatation (LAD), as defined by LA diameter indexed to body size parameters in an outpatient population referred to echocardiographic laboratories for routine examination. LAD was defined by 2 criteria: (1) LA diameter indexed to height greater than 24 mm/m; (2) LA diameter indexed to body surface area greater than 23 mm/m(2). Prevalence of LAD was calculated by indexing LA diameter to both self-reported and measured anthropometric values. In the whole population, LAD tended to be underestimated when LA diameter was indexed to self-reported compared with measured values, by 3.6% according to criterion 1(26.4% versus 30.0%, P < .001) and by 0.6% according to criterion 2 (21.1% versus 21.6%, P = not significant). The difference between LAD estimates was more pronounced in older than in younger patients, either by criterion 1 (6.4% versus 1.6 %, P < .001) or by criterion 2 (2.1% versus 0.1%, P < .001). The error is related to demographic characteristics of patients and is more pronounced when LA diameter is normalized to height.