EchocardiographyM-mode and two-dime

Echocardiography
M-mode and two-dimensional echocardiograms were recorded
with patients in the left lateral decubitus position, by a technician unaware
of the study assignments. M-mode tracings that were guided
two-dimensionally were recorded on light-sensitive paper at 50 mm
per second (Hewlett–Packard Sonos 1000, with a 2.5-MHz transducer),
from the short parasternal axis at the chordal level between the
free edges of the mitral leaflets at the tips of the papillary muscles. To
decrease variability, five cardiac cycles were read and the values averaged.25
Only tracings with optimal visualization of left ventricular
interfaces were used. In our echocardiographic laboratory, the range
of variability of observations by a single reader is 0 mm to 1.5 mm for
the dimensions of the left ventricular cavity, and 0 mm to 0.5 mm for
wall thickness. Tracings were read at the end of the study independently
by two cardiologists, who were unaware of the study groups and
the date of echocardiographic assessment. When there was a disagreement
between the two readers, the final value was settled by
consensus.
Left ventricular diastolic dimensions (LVDD), systolic dimensions
(LVSD), interventricular septal thickness (IVS), and posterior-wall
thickness (PW) were measured in all patients according to the guidelines
of the American Society of Echocardiography.26 Left ventricular
mass was calculated with the use of the anatomically validated formula
left ventricular mass 1.04 [(IVSLVDDPW)3(LVDD)3
]13.6 g.
Left ventricular mass was divided by body-surface area to obtain
the left-ventricular-mass index. Left ventricular fractional shortening
was calculated with the use of the standard formula
fractional shortening (%) [(LVDDLVSD)/LVDD]100.