Improving the diagnosis of bundle branch block by analysis of body surface potential maps

Bundle branch block (BBB) is a defect on the electrical conduction system of the heart diagnosed by analyzing electrocardiogram (ECG) morphology. Our study aims to determine whether mapping information, specifically QRS duration and observation data from maps obtained using body surface potential mapping (BSPM), can be helpful in BBB diagnosis. We studied 64-lead BSPM recordings of 18 BBB patients and 9 controls with normal ventricular conduction. QRS duration was measured from the BSPM information obtained. The BSPM maps were computed along the QRS complex for each individual and group, and maps for each group were compared with maps for each individual. QRS complexes of the 12 standard leads were computed for each individual and group, and complexes of each group were compared with the complexes of each individual. QRS duration measured for all available leads (64 unipolar leads and 12 standard leads) was 7.4 +/- 3.9 milliseconds longer than QRS duration measured only in the standard 12-lead ECG for left BBB patients (LBBB) and 15.3 +/- 10.8 milliseconds longer for right BBB with left anterior fascicular block patients (RBBB_LAFB). In case of comparisons based on the standard ECG, sensitivity was 76.9% for LBBB patients and 66.6% for control subjects. However, classification based on map comparisons showed a sensitivity of 93% for LBBB patients and 89% for controls. QRS duration measured from BSPM information does not differ significantly from 12-lead standard ECG measurement for LBBB. However, differences are higher for RBBB_LAFB patients. Representative BSPM maps permit an automatic classification of the subjects.