QRS-T angle as a biomarker for LBBB strict diagnose

Abstract

Currently, the diagnosis of left bundle branch block (LBBB)is based on the duration of the QRS complexes. However, aberrant QRScomplexes, characteristic of LBBB, obscure the delineation process, andtherefore, unreliable QRS durations are produced, due to erratic fidutialpoints. To overcome this flaw, we propose the QRS-T angle as analternative LBBB biomarker, which is independent of QRS duration. Asubset of heart failure patients with and without LBBB was comparedto a set of healthy patients, all obtained from the Telemetric and ECGHolter Warehouse Project. The methodology included signal filtering,construction of QRS and T loops and obtention of depolarization andrepolarization dominant vectors. Finally, the QRS-T angle in the different2D and 3D spaces were calculated. Results show that patients withLBBB have much larger QRS-T angles compared to Controls. Moreover,QRS-T angles in the XY plane and the XY Z volume were the markersthat best separated LBBB from intact conduction patients, with accuraciesof 100% and 96.9%, respectively. These results set the foundationsto further investigate the QRS-T angle as a biomarker for the diagnosisof left bundle branch block.