Sinus Bradycardia Limiting Beta-Blockade in Catecholaminergic Polymorphic Ventricular Tachycardia

Beta-blockade is the cornerstone of therapy in catecholaminergic polymorphic ventricular tachycardia (CPVT), but coexisting sinus node dysfunction can prevent adequate dosing. A woman aged in her late 20s presented with exertional syncope. She had profound sinus bradycardia and reproducible exercise-induced multiform ventricular ectopy in a structurally normal heart, supporting a diagnosis of CPVT, later confirmed with genetic testing (pathogenic RYR2 variant). Resting heart rates in the low 30s precluded beta-blocker initiation. After shared decision-making in which she declined transvenous leads, an atrial leadless pacemaker was implanted, permitting up-titration of nadolol with flecainide and deferral of an implantable cardioverter-defibrillator. Sinus node dysfunction is recognized in CPVT but is seldom framed as a modifiable obstacle to guideline-directed therapy. Treating the bradycardia allowed medical therapy to be maximized before device therapy, consistent with consensus recommendations. Bradycardia that limits beta-blockade in CPVT is a pacing problem rather than drug intolerance.