While verapamil has been proposed as a treatment for reducing electrophysiological remodeling due to atrial fibrillation and atrial tachyarrhythmias, no previous study has tested its effects in brady-tachy patients implanted with a dual-chamber pacemaker. Fourteen patients with frequent episodes of atrial fibrillation(≥ 2 episodes/month) in the setting of brady-tachy syndrome, implanted with a DDDR pacing system with extensive monitor function(Selection 900, Vitatron) were enrolled. Four months after implantation, they were randomly allocated to a 2-month period of treatment with verapamil(240 mg/day) or to no treatment, followed by a crossover. The burden of atrial tachyarrhythmias, the total number of hours spent in atrial tachyarrhythmia and the mean number of hours per day spent in atrial tachyarrhythmia were retrieved from diagnostic devices. The accuracy of atrial tachyarrhythmias detection was confirmed independently by two observers. The main results showed that treatment with verapamil was associated with a trend towards an higher percentage of atrial pacing in comparison with control(mean value± S.D.=63.2± 29.9% vs. 57.3± 30.6% ,median value 53% vs. 49% , P value at Wilcoxon signed rank test=0.069), but without any significant reduction in atrial tachyarrhythmia burden(4.5± 11.8 vs. 3.3± 9.1% )or total hours spent in atrial tachyarrhythmia(65± 161 vs. 48± 131 h). Palpitation episodes were not significantly reduced by verapamil treatment in comparison with control(10.3± 7.8 vs. 6.1± 6.5). In conclusion, verapamil does not exert any beneficial effect on documented episodes of atrial tachyarrhythmia in patients with brady-tachy syndrome implanted with a DDDR device. Moreover, this drug was ineffective in reducing the number of palpitation episodes reported by the patient. While verapamil has been proposed as a treatment for reducing electrophysiological remodeling due to atrial fibrillation and atrial tachyarrhythmias, no previous study has tested its effects in brady-tachy patients implanted with a dual-chamber pacemaker. Fourteen patients with frequent episodes of atrial fibrillation (≥ 2 episodes / month) in the setting of brady-tachy syndrome, implanted with a DDDR pacing system with extensive monitor function (Selection 900, Vitatron) were enrolled. Four months after implantation, they were randomly allocated to a 2-month period of treatment with burden of atrial tachyarrhythmias, the total number of hours spent in atrial tachyarrhythmia and the mean number of hours per day spent in atrial tachyarrhythmia were retrieved from diagnostic devices The accuracy of atrial tachyarrhythmias detection was confirmed independently by two observers. The main results showed that treatment wit h verapamil was associated with a trend towards an higher percentage of atrial pacing in comparison with control (mean value ± SD = 63.2 ± 29.9% vs. 57.3 ± 30.6%, median value 53% vs. 49%, P value at Wilcoxon signed rank test = 0.069), but without any significant reduction in atrial tachyarrhythmia burden (4.5 ± 11.8 vs. 3.3 ± 9.1%) or total hours spent in atrial tachyarrhythmia (65 ± 161 vs. 48 ± 131 h). by verapamil treatment in comparison with control (10.3 ± 7.8 vs. 6.1 ± 6.5). In conclusion, verapamil does not exert any beneficial effect on documented episodes of atrial tachyarrhythmia in patients with brady-tachy syndrome implanted with a DDDR device. Moreover, this drug was ineffective in reducing the number of palpitation episodes reported by the patient.