Arrhythmic Risk During Acute Infusion of Infliximab : A Prospective, Single-blind, Placebo-controlled, Crossover Study in Patients with Chronic Arthritis

### Objective Reports suggest that infliximab (IFX) may be associated with life-threatening tachyarrhythmias and bradyarrhythmias. We evaluated the prevalence of cardiac rhythm disorders during acute infusion of IFX in a prospective, single-blind, placebo-controlled crossover study of patients with chronic arthritis. Effects of the drug on measures of arrhythmia risk such as QT interval and heart rate variability (HRV) were evaluated. ### Methods Seventy-five patients with spondyloarthritis (SpA; n = 55) or rheumatoid arthritis (RA) underwent an ambulatory 12-channel electrocardiogram (ECG) recording to monitor cardiac arrhythmias, QT interval, and HRV during the infusion of IFX and saline (placebo). ### Results The occurrence of both tachyarrhythmias and bradyarrhythmias was not statistically different during IFX or placebo infusion. During IFX infusion, new-onset ventricular tachyarrhythmias had an 8% incidence (2.7% with placebo; OR 3.17, 95% CI 0.61–16.26) and were more severe. In these patients, mainly with RA, baseline-corrected QT interval and HRV values were significantly prolonged and depressed, respectively, in comparison with subjects without such arrhythmias. IFX acutely produced a significant shift toward a relative vagal prevalence without affecting QT interval measurements. ### Conclusion New-onset cardiac arrhythmias, particularly ventricular tachyarrhythmias, developed during IFX infusion, but their incidence did not achieve statistical significance. We identified some specific risk factors possibly characteristic of the small subset of patients with a higher risk for ventricular arrhythmias. The acute effects of IFX on autonomic balance may substantiate the role of the complex interaction between autonomic nervous system and inflammation during chronic arthritis.