Results suggest tilt and ATP tests individually and jointly determine the mechanism of vasovagal symptoms in most patients and that vagal cardiac inhibition increases with age.

In this rat HI model, arginine appears to be safe, contributes to a large extent to the immunomodulatory effects of the IED, and seems to limit enterobacterial translocation and dissemination more efficiently alone than in an IED.

This limited trial (1) supports the conclusion that patients with an abnormal ATP test who receive a dual-chamber pacemaker suffer fewer recurrences than those who are monitored only; and (2) consequently further supports the hypothesis that, among vasovagal patients, a cardiac pause of longer than 10 s in patients administered ATP identifies those at high risk of symptomatic vagal cardiac inhibition.

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The negative chronotropic and dromotropic vagal effect of ATP can be reproduced short term and long term in 84% and 78% of patients, respectively. Associated symptoms were related to the severity of the electrocardiographic outcome.

These results confirm that rapid atrial pacing is 1) significantly effective for preventing AF recurrence in symptomatic BTS patients, and 2) haemodynamically well tolerated.

Background: Previous studies have compared various atrial pacing rates and pacing sites for preventing atrial fibrillation (AF) recurrences, defined by symptoms or by channels markers and/or by mode switching counters. Counters and markers reliability has never been proven especially in case of muscular noise. New pacemakers provide EGMs storage allowing to optimize the detection of arrhythmia recurrences. Study design: The PREFIB study was designed to assess the time recurrence of AF on two different DDD pacing rates. Thirty patients (pts) with symptomatic recurrent AF or brady‐tachycardia syndromes have been implanted with a Guidant Pulsar 1280 pacemaker. In all pts, the atrial lead was positioned in the right atrial appendage. After a 5‐days observation period, the DDD pacing rate was randomly programmed at 60 (+ a 15 bpm hysteresis) or at 80 bpm for 12 weeks. Both programmings were crossed over at the end of this fixed period or when symptomatic AF recurred. Antiarrhythmic drug therapy was continued after implantation. AF recurrence was diagnosed by stored EGMs and confirmed by an external loop recorder. Results: Twenty two pts (12 males, 78 ± 7.1 years old) have already completed the study protocol. One pt withdrew for severe heart failure when paced at 80 bpm. For the 21 pts, AF recurred in 12 pts paced at 60 (−15) bpm, after a mean time of 28 days (range 1–64), and in 7 pts paced at 80 bpm, after a mean time of 47 days (range 4–79). Even if this difference is not statistically significant, these results indicate a beneficial trend for faster pacing rates. AF recurrence was asymptomatic in 43% of pts. Conclusion: These preliminary results confirm 1) the beneficial trend of rapid atrial pacing for preventing AF recurrence; 2) the utility of reliable stored EGMs for AF therapeutic management; 3) the need for increasing the EGMs memory size embodied in pacemakers.

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