Syncope due to Pacing Inhibition During VT Detection in a Conduction System Pacing ICD Programmed in AAI(R) Mode.

The lack of dedicated generators for conduction system pacing can force the use of unconventional device configurations in selected patients. We report the case of a 74-year-old pacing-dependent man with non-ischemic cardiomyopathy who underwent an upgrade to LBBAP-ICD, programmed in AAI(R) mode. Syncope occurred after a nonsustained ventricular tachycardia episode due to activation of the Ventricular Tachycardia Response algorithm in a Boston Scientific ICD. This case highlights a potential interaction between device algorithms and pacing configuration that may result in clinically significant pauses in pacing-dependent patients.