B-PO03-159 INTERPRETATION OF PRONE-POSITION 12-LEAD SURFACE ELECTROCARDIOGRAM AND MAIN DIFFERENCES WHEN COMPARED TO SUPINE-POSITION ECGS: INSIGHTS FROM A CASE-CONTROL STUDY

Background: Prone position is a valuable treatment strategy in acute respiratory distress syndrome (ARDS) and is frequently used in surgical scenarios. Nonetheless, prone position may hinder proper acquisition and interpretation of the 12-lead electrocardiogram (ECG) as there is a sparsity of data regarding standardization of lead position and interpretation. Objective: We aimed to analyze and compare ECGs in the supine and prone positions to provide guidance for adequate interpretation and clinical utility of the ECG in prone position. Methods: This was a multicenter prospective cohort study in which ECGs in the prone and supine position were compared, including patients with COVID-19 infection and healthy controls. The precordial leads for the prone ECGs were placed in the following fashion: V1 in the right paraspinal region at the level of the T7 vertebra, V2 in the left paraspinal region at the level of the T7 vertebra, V4 in the mid-scapular region at the level of the T8 vertebra (approximately bellow the tip of the scapula), V3 halfway between V3 and V4, V5 at the posterior axillary line at the level of the T8 vertebra, and V6 at the mid-axillary line at the level of T8 vertebra - same position as the V6 in the supine position. Results: A total of 45 patients with COVID-19 infection were compared with 40 healthy volunteers (48% of the patients were female, the mean age in the entire cohort was 48.8 years, and the mean BMI was 27.9). The mean heart rate, PR interval, QRS duration, QT and QTc interval, and QRS axis in the frontal plane were found to positively correlate in supine and prone ECGs. The main difference found was no correlation of the QRS amplitude between supine and prone ECGs in leads V1, V2, V3, and V4;but there was positive correlation in leads V5 and V6. Prominent Q waves were present in the anteroseptal leads (V1-V3) in the prone posterior position. In addition, T-wave inversions or flattening were observed in leads V1 and V2 were present in a majority of patients in the prone posterior position. Conclusion: ECGs performed in the prone position are an acceptable alternative to supine ECGs. Special attention and review of prior supine ECGs may be necessary for precise interpretation of the anteroseptal precordial leads which may be misleading (i.e, septal infarct).