A prospective evaluation of the effect of atazanavir on the QTc interval and QTc dispersion in HIV-positive patients

Background: Atazanavir (ATV), an HIV protease inhibitor (PI) that may be preferred for the treatment of HIV-infected patients with cardiovascular comorbidities because of its favourable effects on plasma lipids, has been associated with cardiac rhythm disturbances. Objective: To quantify the effect of ATV on corrected QT (QTc) and QTc dispersion (QTd), markers of the potential for cardiac dysrhythmia, in patients switching from other PIs to ATV. Methods: In this prospective, single-centre, open-label study, 12-lead electrocardiograms were performed for subjects at baseline, 2 h after the first dose of ATV, and 1 month after initiation of ATV. Results: Twenty-one patients (19 received ritonavir-boosted ATV) completed the study. There was a trend towards an increase in the QTc at 2 h after the first dose [mean ± standard deviation 3.19 ± 8.0 ms; 95% confidence interval (CI) - 0.47 to 6.85 ms; P = 0.084]. There was no difference between QTc values at baseline and at 1 month (-1.5 ± 8.75 ms; 95% CI - 5.50 to 2.46; P = 0.43). There was a nonsignificant decrease in the QTd between baseline and 2 h (- 5.1 ± 15.19 ms; 95% CI - 13.22 to 2.96; P = 0.197) and between baseline and 1 month (-0.61 ± 15.04 ms; 95% CI - 8.1 to 6.87; P = 0.865). A significant increase in the PR interval (7.4 ± 10.7 ms; 95% CI 2.5 to 12.25 ms; P = 0.005) was observed at 1 month. Conclusions: The use of ATV did not result in increases in the QTc interval or QTd. However, PR interval monitoring may be warranted in patients with underlying heart block or those treated with atrioventricular nodal blocking agents.