Rosenbaum Syndrome Successfully Treated With Left Bundle Branch Area Pacing

Trifascicular block can progress to complete atrioventricular (AV) block and sudden cardiac death. Its clinical and electrocardiographic presentation is usually dramatic but may occasionally be subtle and intermittent, making recognition difficult.

A 45-year-old man presented with exertional dyspnea and no structural heart disease. Surface electrocardiography revealed right bundle branch block with alternating left anterior and left posterior fascicular block and intermittent AV conduction delay, consistent with Rosenbaum syndrome and advanced His-Purkinje disease at high risk of progression to complete AV block. Anticipating this risk, a dual-chamber pacemaker was implanted using left bundle branch area pacing. At follow-up, symptoms resolved and ventricular activation normalized.

Rosenbaum syndrome is a rare, potentially life-threatening conduction disorder that may present insidiously. To our knowledge, this is the first report of left bundle branch area pacing used to treat it, illustrating the potential of physiological pacing to restore conduction and prevent adverse outcomes.

Trifascicular blocks carry a high risk of adverse outcomes. In rare cases, they present insidiously and intermittently. Physiological pacing via the left bundle branch area appears to be an appropriate therapeutic strategy in Rosenbaum syndrome.