Left-bundle branch pacing as bail-out strategy after failed coronary sinus lead placement for cardiac resynchronization: a case report

BACKGROUND: Cardiac resynchronization therapy (CRT) by implantation of an endocardial coronary sinus (CS) pacing lead is an established heart failure therapy. The recent European Society of Cardiology (ESC) guidelines on cardiac pacing and CRT recommend conduction system pacing (CSP) as a potential bail-out therapy in patients with previously unsuccessful CS-lead implantation. We present a case in which unsuccessful implantation of a CS pacing and ineffective QRS correction by His-bundle pacing (HBP) was overcome by left-bundle branch pacing (LBBP) to achieve cardiac resynchronization. CASE SUMMARY: The patient had to undergo revision of a CS lead for CRT due to rising pacing thresholds and pacing impedance. CS-lead implantation was omitted by a stenotic posterolateral CS branch. HBP did not lead to adequate QRS correction. The patient underwent successful LBB lead implantation as bail-out therapy. After LBBP lead implantation electrocardiographic and echocardiographic parameters were evident of effective CRT. DISCUSSION: Conduction system pacing may be an alternative to CS pacing for CRT in heart failure patients, which is endorsed by the current European guidelines. LBBP may overcome limitations of HBP and provide an alternative to other strategies such as surgical implantation of epicardial left-ventricular pacing leads. Further studies are needed to fully clarify the role of LBBP for heart failure treatment.