ObjectivesTo assess the impact of (1)-adrenoceptor blockers ((1)-blocker) and isoprenaline on the incidence of idiopathic repetitive ventricular arrhythmia that apparently decreases with preprocedural anxiety. MethodsFrom January 2010 to July 2012, six patients were identified who had idiopathic ventricular arrhythmias that apparently decreased (by greater than 90%) with preprocedural anxiety. The number of ectopic ventricular beats per hour (VPH) was calculated from Holter or telemetry monitoring to assess the ectopic burden. The mean VPH of 24 hours from Holter before admission (VPH-m) was used as baseline (100%) for normalization. (1)-Blockers, isoprenaline, and/or aminophylline were administrated successively on the ward and catheter lab to evaluate their effects on the ventricular arrhythmias. ResultsAmong 97 consecutive patients with idiopathic ventricular arrhythmias, six had reduction in normalized VPHs in the hour before the scheduled procedure time from (104.6 4.6%) to (2.8 +/- 1.6%) possibly due to preprocedural anxiety (P < 0.05), then increased to (97.9 +/- 9.7%) during (1)-blocker administration (P < 0.05), then quickly reduced to (1.6 +/- 1.0%) during subsequent isoprenaline infusion. Repeated (1)-blocker quickly counteracted the inhibitory effect of isoprenaline, and VPHs increased to (120.9 +/- 2.4%) from (1.6 +/- 1.0%; P < 0.05). Isoprenaline and (1)-blocker showed similar effects on the arrhythmias in catheter lab. ConclusionsIn some patients with structurally normal heart and ventricular arrhythmias there is a marked reduction of arrhythmias associated with preprocedural anxiety. These patients exhibit a reproducible sequence of (1)-blocker aggravation and catecholamine inhibition of ventricular arrhythmias, including both repetitive ventricular premature beats and monomorphic ventricular tachycardia.