Left bundle branch area pacing too far away from the tricuspid annulus may cause pacing induced cardiomyopathy.

Background: Physiologic pacing through left bundle branch area pacing (LBBAP) has recently been shown to be a very promising alternative for cardiac resynchronization therapy (CRT) and to avoid pacing induced cardiomyopathy. However, it is not clear whether the position of LABBP lead may affect the clinical outcomes.

Case Report: We here report a case of likely LBBAP induced worsening heart failure and cardiomyopathy reversed by re-positioning of the pacing lead towards a more annular position. A 70-year-old male with a previous history of non-ischemic dilated cardiomyopathy (ejection fraction 40%) who developed intermittent complete heart block and required permanent ventricular pacing. LBBAP was performed with the lead positioned to a position relatively far away from the tricuspid annulus (3.7 cm), due to difficulty in fixating the lead deep into the septum at a more annular position. One month post procedure, the patient's heart failure symptoms worsened, and his EF decreased to 31% despite good heart failure management. He underwent CRT upgrade with successful revision of the originally implanted LBBAP lead to a more annular position, using a deflectable delivery sheath. This resulted in further narrowing of the paced QRS duration from 135 to 106 ms. Two months post procedure, his heart failure symptoms improved by one functional class, and EF improved to 41% by echocardiogram.

Conclusions: LBBAP may be harmful when the lead is placed too far away from the annulus and may cause paced induced cardiomyopathy.