Correlation of Heart Rate and Geographical Environmental Factors with Reference Values of Left Ventricular Ejection Fraction in Healthy Adult Males

Abstract

Objective To establish a model for obtaining the reference values of left ventricular ejection fraction(LVEF) in Chinese healthy adult males by exploring the relationships of these reference values with heart rate and geographical environment factors. Methods LVEF and heart rate reference values (X1) were collected from 3502 healthy adult males from 2006 to 2016. Correlation analysis and ridge regression were employed to extract dependent geographical environment factors and predict the LVEF reference values. The Kriging interpolation was applied to reveal the spatial distribution of the LVEF reference values. Results LVEF and heart rate (X1) were significantly correlated with five geographical environment factors. LVEF was negatively correlated with heart rate (X1),latitude (X3),and annual range of temperature (X9) and positively correlated with annual mean air temperature (X6),annual mean relative humidity (X7),and annual precipitation amount (X8). The reference values of LVEF had a negative correlation with heart rate. The ridge regression equation of LVEF reference values and geographical environment factors was as follows:Y=68.464-0.0949X3-0.0619X6-0.00128X7+0.00069X8-0.0199X9±3.329. The equation of LVEF reference values with heart rate and geographical environment factors was Y=75.923-0.1035X1-0.0958X3-0.0741X6+0.00094X7+0.00081X8-0.0211X9±3.288. Conclusion The LVEF reference values among Chinese healthy adult males decreased from south to north. They can be determined based on the regression models after the geographical factors of a certain region are obtained. The new model offers a geographic basis for the establishment of LVEF reference values.