Echocardiographic data acquisition
We performed a conventional transthoracic echocardiogram with subjects
in lateral decubitus using a Siemens Acuson 2000 (Germany) with a phased
array transducer that provided M-mode, color and tissue Doppler, with
two and three-dimensional capabilities and software for atrial and
ventricular mechanics following current guide-lines (11). Briefly,
two-dimensional data were acquired from the parasternal long-axis and
short axis views and three standard apical views. We recorded three
consecutive cardiac cycles during expiration and obtained in a frame
sequence of 50 to 80 frames per second. Left ventricular end-diastolic
and end-systolic diameters (LVEDd; LVESd), interventricular septal
thickness (IVST) and posterior wall thickness (PWT) were measured in the
parasternal long axis view. Left ventricular ejection fraction (LVEF)
was calculated based on the apical 4- and 2-chamber views, using the
modified Simpson‘s biplane method or by 3D. LVEF was considered normal
when it was ≥52% for men and ≥54% for women. Pulsed-wave Doppler of
mitral valve inflow was used to measure the mitral peak early (E) and
late (A) velocities and the ratio of early-to-late (E/A) diastolic flow
velocities in the apical four chamber view, with the sample volume
between mitral leaflet tips. Diastolic dysfunction was classified as:
Grade I diastolic dysfunction (E/A<0.8, deceleration time
>200 ms), impaired relaxation, Grade II (E/A
>0.8 -1.5, deceleration time: 160-200 ms),
pseudonormalization, Grade III, restrictive filling (E/A
>2.0, deceleration time <160 ms). The septal
early diastolic myocardial velocity e´ and the ratio between early
transmitral flow velocity E and e´ (E/e´ ratio) was measured in the four
chamber view by pulsed Doppler and tissue Doppler, and the normal value
was <14. (Figure 1) . Left atrial (LA) volume was
assessed in the apical four chamber view at end-systole and was indexed
to the BSA. The upper normal limit for LA volume index was 34
mL/m2 for both genders.
Left ventricular mass was calculated from the formula:
0.80*(1.04*[LVEDd + PWd + IVSd)3 − (
LVEDd)3] + 0.6 gr (11). Left ventricular mass (LVM)
was indexed to BSA in gr/m2. LV hypertrophy was
identified when the derived LVMI was ≥115 g/m2 for men
and ≥95 g/m2 for women (11). The relative wall
thickness (RWT) was calculated as (2 x PW thickness)/LV internal
diameter at end-diastole. The RWT permits categorization of an increase
in LV mass as either concentric (RWT > 0.42) or eccentric
(RWT < 0.42) hypertrophy and makes it possible to identify
concentric remodeling (normal LV mass with increased RWT
>0.42) (11). The subjects were divided into four
ventricular geometric groups: normal geometry (normal LVMI and normal
RWT), concentric remodeling (normal LVMI and increased RWT), concentric
hypertrophy (increased LVMI and increased RWT), eccentric hypertrophy
(increased LVMI and normal RWT) (11).
Left ventricular wall motion was assessed with the 16-segment model.
Each segment was evaluated in four, three and two-chamber views, and a
four-grade score was applied: (1) normal or hyperkinetic, (2)
hypokinetic (reduced thickening), (3) akinetic (absent or negligible
thickening), and (4) dyskinetic (systolic thinning or stretching)