The 43rd International Society for Computerized Electrocardiology ECG initiative for the automated detection of strict left bundle branch block.

The presence of left bundle branch block (LBBB) is an important predictor of benefit from cardiac resynchronization therapy (CRT). New "strict" electrocardiographic (ECG) criteria for LBBB have been shown to better predict benefit from CRT. The "strict" LBBB criteria include: QRS duration ≥140 ms (men) or ≥130 ms (women), QS- or rS-configurations of the QRS complex in leads V1 and V2, and mid-QRS notching or slurring in ≥2 of leads V1, V2, V5, V6, I and aVL. The "strict" LBBB criteria are not regularly used and most hospital automated ECG systems and physicians still use more conventional LBBB criteria. As part of the 43rd International Society for Computerized Electrocardiology (ISCE) meeting, we conducted an initiative on the automated detection of "strict" LBBB where industry and academic investigators could present their algorithm results on digital 12-lead ECGs with varying QRS morphologies from the MADIT-CRT trial (300 training and 302 test set ECGs that were manually adjudicated for "strict" LBBB presence). The results revealed a 64-82% accuracy, 48-76% sensitivity and 46-87% specificity for automated "strict" LBBB detection from 7 participants. Most mismatches were likely attributed to differences in detection and absence of specific definitions for notches and slurs while differences in QRS duration and S-waves in leads V1 and V2 were less problematic. The full unblinded training and test datasets including all ECG signals are being made available through the Telemetric and Holter ECG Warehouse (THEW) for further exploration.