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The aim of this study was to assess if right atrial overdrive pacing can suppress symptomatic episodes of paroxysmal atrial fibrillation (PAF) in patients without bradyarrhythmias. Forty-two patients with frequent and symptomatic PAF without other pacing indication had a pacemaker implanted after a 4-week run-in period, during which the frequency of symptomatic PAF episodes and the mean heart rate were objectively documented. Depending on the mean heart rate recorded during run-in, the pacemaker was programmed in random order to right atrial AAI pacing at 10–19 beats/min > mean heart rate (medium overdrive [MO]), at 20–29 beats/min > mean heart rate (high overdrive [HO]) and to no pacing (OAO mode) for 4–12 weeks each using a crossover design. In the 35 patients who completed the protocol, the number of symptomatic episodes of PAF (>30-second duration) per week was significantly lower during MO pacing (median 0.88, P = 0.001, n = 35) and during HO pacing (median 0.75, P = 0.002, n = 20) than during OAO (median 2.02 and 2.04, respectively). There was no difference between MO and HO pacing in the 20 patients paced at both rates (0.97 vs 0.75, P = 0.33). Seven patients did not complete the protocol due to persistent atrial fibrillation (n = 4), angina pectoris requiring surgery (n = 1), and unwillingness to continue the study due to improvement (n = 1) or worsening (n = 1) of symptoms during the study periods. Right atrial overdrive pacing can reduce the number of symptomatic PAF episodes in patients with frequent and drug refractory PAF but without bradyarrhythmias. (PACE 2003; 26:1841–1848) [ABSTRACT FROM AUTHOR]

LÖNNERHOLM, S., et al.: Autonomic Denervation After the Maze Procedure.The Maze III procedure is a surgical operation for curative treatment of AF. The procedure is extensive, however, with multiple incisions in both atria, and its effects on autonomic regulation of the heart rhythm are not known. This study comprises 17 patients, 10 with paroxysmal AF and 7 with chronic AF, who had no concurrent cardiac disease known to affect heart rate variability (HRV). A 24‐hour Holter recording was performed preoperatively and 2 months (early) and 7 months (late) after surgery, for analysis of HRV in the time and frequency domains. Early after the Maze procedure all HRV components were markedly reduced compared to baseline (mean ± 1 SD): SDNN 73 ± 13 versus 148 ± 50 (ms), total power 168 ± 126 versus 560 ± 1567 (ms2), low frequency (LF) power 47 ± 67 versus 826 ± 677 (ms2), high frequency (HF) power 47 ± 40 versus 678 ± 666 (ms2), and LF:HF 1.22 ± 0.9 versus 2.55 ± 1.4. Late after the Maze procedure all variables were still reduced. Only total power increased significantly between early and late follow‐up (168 ± 126 vs 496 ± 435 ms2). Late after Maze surgery, values of the different HRV components did not differ between the patients with paroxysmal AF and chronic AF. Early after the Maze procedure there is a marked decrease of all HRV components, which is maintained 7 months after surgery, a pattern consistent with denervation of the heart. (PACE 2003; 26[Pt. I]:587–592) [ABSTRACT FROM AUTHOR]