Atrial Dynamic Overdrive Pacing Trial - ADOPT (Atrial Dynamic Overdrive Pacing)


The Atrial Dynamic Overdrive Pacing Trial (ADOPT) was designed to test the efficacy of a new feature in a low-voltage bradycardia pacemaker, Dynamic Atrial Overdrive (DAO), in treating atrial fibrillation (AF).


AF burden can be reduced by an implanted pacemaker with atrial overdrive pacing features.

Study Design

Patients Enrolled: 288
Mean Follow Up: 6 months
Mean Patient Age: mean age 71.3 years
Female: 49

Patient Populations:

1) Symptomatic paroxysmal or persistent AF with ≥2 symptomatic episodes in the month preceding implant on a stable antiarrhythmic drug and/or atrioventricular nodal blocking agent (or no drugs) and ≥1 episode in the 12 weeks preceding implant documented by electrocardiogram or rhythm strip; 2) sinus node dysfunction with class I bradycardia indication for a dual-chamber pacemaker; and 3) written informed consent for participation, and willingness and ability to comply with follow-up testing and evaluation procedures


Presence of another arrhythmia control device, cardiac surgery in the last six months, or expected cardiac surgery during the six-month study period

Primary Endpoints:

Symptomatic AF burden (percentage of days during which symptomatic AF occurred)

Secondary Endpoints:

Number of symptomatic AF episodes, hospitalizations, cardioversions, and quality of life

Drug/Procedures Used:

Patients enrolled in the study received the St. Jude Medical Trilogy DR or Integrity Afx Autocapture Pacing System and were randomized into two groups: one with the DAO algorithm ON and DDDR pacing set at 60 ppm; the other with the DAO algorithm OFF and DDDR pacing at 60 ppm.

Principal Findings:

Over 90% of the atrial arrhythmias observed during the six-month follow-up period were AF (vs. other organized atrial arrhythmias). The percentage of beats that were atrial paced was significantly greater in the DAO ON group (92.9%) than in the DAO OFF group (67.9%; p<0.0001), demonstrating="" that="" the="" algorithm="" performed="" as="" specified="" in="" stimulating="" the="" patients’="" atrium="" a="" very="" high="" percentage="" of="" the="">

Overall AF burden was reduced in the DAO ON group compared with the DAO OFF group (2.50% for DAO OFF vs. 1.87% for DAO ON), and there was a consistent and decreasing AF burden observed over time (p

Patients in the DAO ON group showed a 60% reduction in symptomatic AF episodes from baseline levels (from 8.0 to 4.3 episodes), while patients in the DAO OFF group showed a 45% reduction in symptomatic AF episodes from baseline levels (from 8.3 to 3.2 episodes, both p<0.001), but="" there="" was="" no="" difference="" between="" treatment="" groups="" in="" the="" number="" of="" episodes="" at="" six="" months="" (p="">

Quality of life scores improved during follow-up in both patient groups. Scores in the DAO OFF group improved significantly during follow-up in five of eight subscales and in the standardized mental component scales, and improved in the DAO ON in four of eight subscales and both the standardized physical and mental component scales. The only significant difference between the DAO OFF and DAO ON groups was a higher social function score in the treatment group at six months.

No DAO-related complications and no unanticipated adverse events were recorded. Total hospitalizations were similar in both arms (17 DAO OFF vs. 15 DAO ON).


Among patients with AF, dynamic atrial overdrive pacing with the AF suppression algorithm demonstrated overall reductions in atrial arrhythmia burden compared with conventional DDDR pacing alone. Despite the large relative decrease in AF burden (25%), the absolute difference was small (2.50% DAO OFF vs. 1.87% for DAO ON).


Carlson MD, Ip J, Messenger J, et al., for the Atrial Dynamic Overdrive Pacing Trial Investigators. A new pacemaker algorithm for the treatment of atrial fibrillation. Results of the Atrial Dynamic Overdrive Pacing Trial (ADOPT). J Am Coll Cardiol 2003;42:627–33.

Presented at AHA 2001

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, EP Basic Science

Keywords: Heart Atria, Quality of Life, Heart Conduction System, Sick Sinus Syndrome, Pacemaker, Artificial, Bradycardia, Informed Consent, Cost of Illness, Hospitalization

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