Atrial dimensions in health and left ventricular disease using cardiovascular magnetic resonance

Background. Cardiovascular magnetic resonance (CMR) has superior spatial resolution compared with echocardiography, but assessment of normal measurements has lagged behind its increasing clinical application. We assessed atrial size by CMR in healthy and diseased subjects to determine normal adult ranges. Methods. Twenty normal adults and 20 cardiac patients with hypertrophic or dilated cardiomyopathy were studied. Four and two chamber left and four chamber right atrial areas and left and right atrial depths were measured and compared, and a normal range for these measures was proposed. Results. Normal four-chamber left and right atrial systolic areas each averaged 21 cm(2). Average depths were 53 and 52 cm, respectively. For both the left and right atrium, a systolic area of < 24 cm(2) included the upper 95th percentile of the normal range and ( especially for the left atrium) best separated normal from abnormal hearts. For atrial depth, a systolic value of < 58 cm best distinguished normal from abnormal and also included the upper 95th percentile of the normal range. Conclusions. Normal ranges for 1- and 2-dimensional left and right atrial size by CMR are proposed. These values are in general greater than those reported for echocardiography.