Introduction: High-dose isoproterenol (IPN) is commonly used to elicit triggers during AF ablation. However, it is not available worldwide and, in the US, its cost per dose has significantly increased due to a change in its ownership rights. Dobutamine (DBT), a similarly non-selective β-agonist, is a potential alternative.
Hypothesis: The effect of high-dose DBT IPN is comparable to that of IPN during AF ablation.
Methods: This is a prospective, single-arm, before-after study. Patients undergoing AF ablation and without significant CAD, VHD, obstructive HCM, ventricular arrhythmias, and uncontrolled HTN were enrolled. After conventional ablation and in SR, patients were assigned to receive IPN (20-30 μg/min) followed by DBT (40-50 μg/kg/min) or vice versa in a 1:1 fashion. Both drugs were administered for 10’ separated by an adequate wash-out. Atrial arrhythmias were classified as PAC, sustained PAC (>50 over 10’), AT and AFL/AF. The type, number and location of triggers, as assessed by multicatheter mapping and surface P-wave morphology, as well as side effects were noted.
Results: As of March 2017, 39 patients were enrolled (PAF 56%, persistent AF 38%, LSPAF 5%; redo 49%). Both drugs caused a significant increase in heart rate, with a lower peak for DBT (-10 bpm). BP was significantly increased with DBT (systolic and mean BP, +20 and +8 mmHg), while there was a significant reduction with IPN (mean and diastolic, -8/-7 mmHg), despite phenylephrine support. When considering triggers in patients during DBT and IPN, there was no significant difference in the number of PACs (median of differences 1, 95% CI 0-5) and type of induced arrhythmias (binomial test P=NS). PAC triggered AF in 2 vs 4 patients; of note, in the 2 patients with PACs triggering AF during IPN but not DBT, PACs from the same location were present during DBT challenge. When sustained arrhythmias were present during both drugs’ challenge (N=7), their location was comparable.
Conclusions: Our data suggest that high-dose DBT can be used as an alternative to high-dose IPN to elicit triggers during AF ablation, with less side effects (namely, hypotension). Of note, while AF appears to be triggered less frequently with DBT, the number and location of triggers is comparable.