INTEROBSERVER VARIABILITY OF LEFT-VENTRICULAR MEASUREMENTS IN A POPULATION OF PREDOMINANTLY OBESE HYPERTENSIVES USING SIMULTANEOUSLY ACQUIRED AND DISPLAYED M-MODE AND 2-D CINE ECHOCARDIOGRAPHY

Achieving low interobserver variability is a goal of echocardiographic determined left ventricular (LV) mass measurements. In a group of hyp ertensives, we evaluated interobserver variation using a method of sim ultaneously acquired two-dimensional (2-D) cine and M-mode images disp layed in a split screen format. Sixty echocardiographic images from on going hypertension trials, including serial studies of the same patien ts, were obtained with an UltraMark(TM) 6 Ultrasound System (Advanced Technology Laboratories, Inc., Bothell, WA, USA). Images were digitize d online, coded with a random number, and pooled prior to the analysis to minimize observer bias. Studies were read by two independent obser vers in a blinded fashion and in a random order using a Color Vue II N ova MicroSonics(TM) analyzer (Nova Microsonics, Mahwah, NJ, USA). The M-mode tracing and cine of three consecutive frames of 2-D parasternal short-axis views of the LV were simultaneously displayed in a split s creen. format. The 2-D cine was used as a reference image during M-mod e measurements of LV dimensions. Measurements were obtained and the LV mass estimated according to the Penn convention. Interobserver variab ility for Left ventricular internal dimension (LVID), interventricular septal thickness (NS), posterior wall thickness (PWT), and left ventr icular mass (LV mass) is low when either correlated (Pearson correlati on coefficients of 0.94, 0.82, 0.75, and 0.93, respectively) or expres sed as a percent of the mean (3.0%, 10.0%, 10.2%, and 8.9%, respective ly). When read in a blinded fashion, interobserver variability (especi ally for LV mass) is small using digitized, simultaneously acquired an d displayed cines of 2-D and M-mode echocardiograms. This is likely du e to the ability to discriminate myocardial wall edges (endocardium) f rom other associated structures such as tricuspid and mitral apparatus . This method may prove useful in studies of LV mass.