Precordial bipolar leads: A new method to study anterior acute myocardial infarction

Introduction: A new ECG method produces Precordial Bipolar Leads (PBL) generated by subtraction of measurements of Standard Precordial Unipolar Leads (SPUL). This procedure brings new information about time/amplitude mismatch among SPUL, presenting it as tracings and local VCG loops exploring the precordial left-to-right axis on the horizontal plane. In this study, results of V2-V1 bipolar precordial derivation V2-V1 (right to left) and its relationship with the anteroposterior axis are presented.

Material and methods: Records of 37 patients and 15 controls from Physionet database were used to create new PBL and compare between V1 and V2 SPUL. So, bipolar V2-V1 was obtained by subtracting V1 measurements from V2, always having as positive the V2 SPUL and as negative V1. The algorithm used was subtracting, in every millisecond, the voltage recorded by the right electrode from the simultaneously recorded left electrode. Combination of SPUL and PBL can be presented as tracings or local loops, showing detailed information of the electric horizontal plane of the heart at retrosternal location. PBL V2-V1 reflects right ventricle and septal electric activity.

Results: The new method is able to detect changes in vectors and differences of milliseconds between SPUL and presents new and important information about the right-to-left electric axis. Right ventricle and interventricular septum electric activity can be differentiate in anterior AMI and LBBB.

Conclusion: Time/amplitude mismatch between SPUL could be the source of abundant and new information about cardiac depolarization and repolarization. As data to obtain PBL and new loops are already obtained in any ECG device that records simultaneously 12 leads, the system can be added to ECG software algorithms without any additional cable or recording work.