Faster lower pacing rate immediately after atrioventricular node ablation with a gradual decrease helps to improve clinical outcome and may reduce the risk of sudden death in patients with atrial fibrillation. Ru-Xing Wang, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi, China, first author of the paper and his collaborators from the Mayo Clinic, Rochester, Minnesota, USA, reported the findings in a study ahead of print in Heart Rhythm.
According to Wang et al, previous studies have demonstrated that “radiofrequency catheter ablation of the atrioventricular node and implantation of a permanent pacemaker is an effective therapeutic strategy, especially for elderly patients with permanent atrial fibrillation and for highly symptomatic patients with atrial fibrillation refractory to pharmacologic therapy.”
Although atrial fibrillation cannot be eliminated with this so-called “ablate and pace” therapy, Want et al wrote, it helps to relieve patients’ symptoms. However, “some serious complications, such as ventricular arrhythmias and sudden death, have occurred post-operatively.” The authors highlighted that previous studies have shown that the incidence of these complications was 3.1% to 6.7%.
“It has been suggested that a higher pacing rate may decrease the occurrence of sudden death,” the authors wrote. Therefore, Wang et al set out to evaluate the effects of initial pacing at a faster rate after atrioventricular node ablation, with a gradual rate decrease over three months, on the rate of sudden death in atrial fibrillation patients.
Wang et al compared, in this retrospective, observational study-from a large database from the Mayo Clinic Pacemaker Database-the rate of likely or possible procedure-related sudden death in two groups of patients who had atrioventricular ablation and who were implanted with a pacemaker. The study cohort included 520 patients (mean age 73.6) who were treated between January 2005 and December 2009. In this group, pacemakers were programmed to a lower rate of 90bpm after ablation and had monthly decrements of 10bmp until 60bpm was achieved. The control group, treated between July 1990 and December 1998, included 334 patients (mean age 68.1 years) whose pacemakers were programmed to a lower rate of 60bpm immediately after ablation.
The authors defined the cause as “likely” related to the procedure if sudden death occurred within 48 hours postprocedure or anytime postprocedure in the absence of cardiovascular disease. If sudden death occurred between two days and three months postprocedure it was defined as “possibly” related to the procedure.
Seven patients (2.7%, mean age 68 years) from the control group had sudden death, likely or possibly related to the procedure of ablation and pacing. Sudden death occurred at a mean of 10 days after the procedure (range 1–35 days).
In the cohort group there were no cases of sudden death that were likely related to the procedure. Just one patient (0.2%) had sudden death categorised as possibly related to the procedure because the timing of the event was 34 days after the procedure.
In conclusion, the authors found that the rate of sudden death likely or possibly related to ablation in the study cohort was significantly lower than the rate of sudden death in the control group. “The decrease in sudden death compared with the control group is likely related to the faster lower pacing rate immediately after atrioventricular ablation,” Wang et al wrote. “These results affirmed that the contemporary protocol of programming the pacemakers to a faster lower rate of 90bpm immediately after the atrioventricular ablation, with a 10bpm monthly decrement until de desirable lower rate of 60bpm is reached, should be continued.”
This study was reviewed and approved by the Mayo Clinic Institutional Review Board.