Normative values of cardiac chamber dimensions and global longitudinal strain in Indians: the Indian Normative Data of Echocardiography Analyzed (INDEA) study.

Ethnic-specific normal reference ranges for various echocardiographic measurements are essential for accurate diagnostic interpretation and clinical decision-making. Unfortunately, such normative data for Indians is lacking. A total of 880 healthy volunteers (mean age 39.7 ± 12.3 years, 63.8% men) from six centers across different regions of India were enrolled in this study. Comprehensive transthoracic echocardiographic study was performed in all subjects, in accordance with the existing guideline recommendations. Cardiac chamber dimensions [Left ventricular (LV) end-diastolic diameter and volume; right ventricular (RV) basal diameter, left atrial volume] were obtained and indexed to body surface area. LV ejection fraction, LV global longitudinal strain (LVGLS) and measures of RV systolic function were also obtained. The subjects were divided into 3 age groups (35 years or less, 36-55 years and 56 years or above) for analysis. Age- and gender-specific reference values for various clinically relevant echocardiographic parameters were derived. Compared with women, men had larger cardiac chamber dimensions and volumes, but not when indexed. In contrast, the women had higher LV systolic function, but right ventricular systolic function was not different. The indexed LV volumes in our study were much smaller than those recommended in the American Society of Echocardiography (ASE)/European Association of Cardiovascular Imaging (EACVI) 2015 chamber quantification guidelines but were similar to those reported in the Indian patients included in the recent World Alliance Societies of Echocardiography (WASE) Normal Values Study. LVGLS was also comparable with the WASE data. INDEA study is the first, multi-centric study to provide normal echocardiographic references values for Indian adults. Our findings underscore the need to follow India-specific reference values, instead of those recommended by the ASE/EACVI, which are largely applicable to the western populations.