Pitfalls of the AdaptivCRT algorithm for effective pacing: Optimization using the EffectivCRT algorithm data

Key Teaching Points•The adaptivCRT (aCRT) algorithm is effective for patients undergoing cardiac resynchronization therapy with normal atrioventricular (AV) conduction, and a higher percentage of synchronized left ventricular (LV) pacing is associated with favorable outcomes.•Even though LV pacing was delivered earlier than the intrinsic rhythm with aCRT, pacing could be ineffective owing to paced conduction delay at the pacing site.•Manual AV optimization, instead of aCRT based on data from the effectivCRT algorithm, could be an alternative method for effective pacing. •The adaptivCRT (aCRT) algorithm is effective for patients undergoing cardiac resynchronization therapy with normal atrioventricular (AV) conduction, and a higher percentage of synchronized left ventricular (LV) pacing is associated with favorable outcomes.•Even though LV pacing was delivered earlier than the intrinsic rhythm with aCRT, pacing could be ineffective owing to paced conduction delay at the pacing site.•Manual AV optimization, instead of aCRT based on data from the effectivCRT algorithm, could be an alternative method for effective pacing.