Clinical assessment of adrenergic tone and responsiveness to β-blocker therapy in patients with symptomatic ventricular tachycardia and no apparent structural heart disease

To further define the relation between changing adrenergic tone, β-blocker therapy, and clinical ventricular tachycardia (VT), we evaluated these factors in 35 patients with VT unrelated to coronary artery disease or ventricular dysfunction. Testing included Holter monitoring (91% had VT), exercise test (69% had VT), and programmed electrical stimulation (49% had VT). Adrenergic responsiveness of VT was graded according to diurnal variation, response to exercise, isoproterenol infusion, and response to β-blockers. β-Blockers were effective and well tolerated in this population. There was also a predictable relation between changing adrenergic tone and the arrhythmia response to β-blocker therapy.