Prediction of Depressed Left Ventricular Ejection Fraction Using Electrocardiogram

Cardiac Failure is an organ system failure with a time sensitive treatment and is usually due to the failure of the left ventricle. Left ventricular function is most easily calculated by a 2D echocardiogram (ECHO). The 2D echo estimates accurately the ejection fraction(EF) of the heart thus, indicating the functioning of the left ventricle. But because of the restrains in availability of the 2D echo in rural set ups of India, it is essential to develop another method to calculate left ventricular function, which is cheap, rapid and accessible in peripheral settings. The objective of this study to calculate the sensitivity and specificity to predict low ejection fraction by Electrocardiogram (ECG).

This cross-sectional study was conducted in medicine department of B R Ambedkar medical college and hospital in Bangalore, from 1st November, 2019 to 31st August, 2021. The consenting participants underwent ECG and 2D ECHO. The ejection fraction values were obtained from the ECG using the formula (2.808 x QRS complex of aVR + 27.198) and by 2D Echo using the Simpson's method. Comparison of ECG and 2D ECHO derived ejection fraction was done, and the sensitivity and specificity was calculated for prediction of low ejection fraction by ECG, followed by stratification for age.

A total of 340 subjects were included in this study. it was found that the EF value calculated using the ECG showed a sensitivity of 87.28% and a specificity of 40.12% to predict EF< 50%, with an accuracy of 64.12%. While the sensitivity and specificity to predict very low EF< 35% was 6.06% and 98.91% respectively, with an accuracy of 80.88%. The sensitivity and specificity of ECG to predict low EF was more for ages above 40 years.

The ECG is found to be a good bedside screening tool of the left ventricle ejection fraction in age groups above 40 years of age. In primary care set ups in developing countries like India, the ECG can be used for decisions regarding emergency management and for referral to a cardiac centre/cardiologist, though it is always suggested to be followed up by a 2D- Echocardiogram whenever indicated. It can also be used to avoid unnecessary expensive testing like 2D ECHO, for patients belonging to poorer socio-economic status.