Right ventricular parameters
Right ventricular s’ and e’ waves were decreased and a’ wave tended to
increase with advancing age (13.1±2.3, 12.7±2.3, 12.4±2.5, 12±2.4 cm/s
for average s’ waves, 14.5±3.4, 13.9±3.2, 13.2±3.1, 11.7±3.2 cm/s for
average e’ waves, 11.6±3, 12.6±3.2, 13.7±3.5, 14.9±3.5 cm/s for average
a’ waves with advancing ages). Besides, a’ and e’ waves were higher in
women than in men. Table-4 shows data about right ventricular TDI.
Discussion
This study provides normal reference ranges for cardiac Doppler
parameters of healthy Turkish population according to age and gender
using conventional recommended echocardiographic approaches including PW
Doppler and TDI.
E wave and also E/A ratio were slightly higher in women than in men, and
tended to decrease with advancing ages, which were statistically
significant. On the other hand A wave and E wave deceleration time (Edt)
were increased with advancing decades. These results were similar to
data reported in European and American echocardiographic studies
(2,3,6,7).
Most diastolic parameters varied and changed according to age similarly
for both genders. Lateral and septal e’ were lower in men and in older
population, whereas lateral a’ and septal a’ had a positive correlation
with age and were slightly higher in men. These parameters were found to
be prominently higher in a study authored by Nagueh et al. (8) when
compared with our study . For example, the septal e’ wave velocities
they obtained were 14.9±2.4 cm/s (16-20 years), 15.5±2.7 cm/s (21-40
years), 12.2±2.3 cm/s (41-60 years) and 10.4±2.1 cm/s (≥61 years)
according to ages. On the other hand, Chahal et al. (9) obtained similar
results when compared with our study and, reported the septal e’wave
8.6±1.9 cm/s as an average value.
For evaluation of the left ventricular diastolic function, e’, E/A and
E/e’ values are highly important and are known to have a positive
correlation with left ventricular filling pressures. In our study we did
not observe any value of septal (and also lateral) e’ lower than 8 cm/s
whereas in the study authored by Cabellero et al. (10) 2 out of 170
(1.2%) in 20-40 years, 38 out of 193 (19.7%) in 40-60 years, 46 out of
83 (55.4%) in ≥60 years had values lower than 8 cm/s. Indeed, LAVI of
participants were lower than 34 mL/m² in all age groups. E/A ratio was
decreased with increasing age, as shown in several previous studies
(10-13). E/e’ tended to increase in older ages but none of the
participants had a value higher than 15, although it has been reported
in some European studies (11). In the present study, E/e’ was found to
be slightly higher in women compared to men, although it was not
statistically significant. Several studies have previously showed that
there is relatively a higher incidence of deteriorated diastolic
functions in elderly female patients and higher cardiovascular mortality
in female gender when compared to men (14-16).
s’ wave velocity measures longitudinal LV contraction and is a surrogate
of LV systolic function and it is also well-known that it has a good
correlation with left ventricular ejection fraction (LVEF). s’ wave
velocity ≥7.5 cm/s has a sensitivity of 79% and a specificity of 88%
in predicting LVEF ≥50% (2, 17). As summarized in Table-3, lateral s’
was higher than septal s’ in our study and also higher in younger
volunteers. Lateral s’ was higher in men whereas septal s’ was higher in
women, concordant with previous data (12,13).
Meluzin and co-workers (17), reported good correlation between right
ventricular (RV) s’ wave velocity and right ventricular ejection
fraction (RVEF); RV s’ wave velocity <11.5 cm/s predicted RV
dysfunction (EF < 45%) with a sensitivity of 90% and
specificity of 85%. In our study, none of the participants had a lower
RVs wave than these established data. Ischemic heart diseases, chronic
pulmonary hypertension and chronic lung diseases can cause a decrease in
RV s’ wave velocity which should be evaluated during echocardiographical
examinations.
In the present study, right ventricular parameters also exhibited
gender-related differences, e’ and a’ were higher in women whereas s’
wave was higher in men. s’ and e’ wave velocities were decreased with
advancing ages as demonstrated in previous studies (10,11, 13).
Systolic pulmonary artery pressure (sPAP), an important predictor of
several cardiac abnormalities, was also evaluated in the current study.
We did not obtain any sPAP above 36 mmHg in healthy volunteers, whereas,
higher levels have been rarely detected in past studies (11). However,
it should be kept in mind that echocardiography is a observer-dependent
modality, and the patients with slightly elevated pulmonary artery
pressure should be evaluated with further imaging modality to avoid
under-diagnosis of any organic heart disease.
In conclusion, the current data obtained from healthy Turkish volunteers
are comparable with most previous studies in this era
(2,3,5,6,10,11,13,18). E and A waves of mitral annulus and also E/A
ratios were greater compared to European registries, but these
differences were not statisitically significant. Data regarding E/e’
ratio especially seems interesting, as in a European study (6) that it
has been found to be significantly increased in advancing ages whereas
no remarkable difference has been detected in our study. But we have to
emphasize that E/e’ higher than 15 is correlated with diastolic
dysfunction and the study above-mentioned had several participants with
these values (0.05% of the population) (11).
As being the first large-scaled healthy population based Doppler study
in Turkey, ECHO-DOP-TR provides essential data regarding left and right
ventricular PW Doppler and TDI studies, and helps us to evaluate the
systolic and diastolic functions of the heart.
Limitations
The results mainly pertain to Turkish population who live in Turkey, a
bridge country between Europe and Asia. Despite the fact that all
patients were considered healthy normal subjects, the possibility of
subclinical coronary artery disease particularly in older subjects
cannot be excluded. The study groups were not equally distributed
according to age as it was not easy to find healthy patient without any
chronic disease in advancing ages. The data regarding e’ and a’ waves in
inferior, anterior, posterior segments are unavailable in most of the
patients and therefore were not included in the Results section.