The presence of resting sinus bradycardia (less than or equal to 45 bpm) with junctional escapes in an 8 year old child with catecholamine induced ventricular tachycardia, raised the problem of an underlying sinus node dysfunction. This was an important consideration bearing in mind the potential risk of the high dose betablocker therapy aggravating the sinus bradycardia. Electrophysiological studies showed pathological sinus node recovery times. Betablocker therapy did not aggravate the bradycardia, even after 6 months' treatment. A review of the literature showed the association of sinus bradycardia and catecholamine-induced ventricular tachycardia to be relatively common (39 p. 100). However, no mention was found of aggravation of this sinus bradycardia by betablocker therapy.