Abstract
Automatic made switching (AMS) is absolutely dependent on atrial tachyarrhythmia detection. The effects of programming several features that could influence tachyarrhythmia detection were assessed in 18 patients (six women; mean age 64 years) with pacemakers having AMs capability. The atrial electrogram amplitude in sinus rhythm at implant (SR-EGM), last measured atrial sensing threshold prior to tachycardia (A-SENS), and atrial sensing threshold for effective AMS during atrial tachyarrhythmia (AMS-SENS) were obtained. Additionally, ten patients had A V intervals increased from 60 to 200 ms, while seven patients had detection algorithms made more stringent from 5 beats at 150 beats/min to 11 beats at 200 beats/min to assess their effects on AMS efficacy. Results: Sensitivities: Mean SR-EGM = 3.55 mV; mean A-SENS = 2.06 mV; and mean AMS-SENS = 1.46 mV. Fourteen patients developed a trial fibrillation and four atrial flutter. Thirteen of 14 patients who developed a trial fibrillation sensed adequately at ≤ 1.0 mV in normal sinus rhythm (NSR), but only six patients had effective AMS at these settings in atrial fibrillation. Three of four patients who developed atrial flutter had effective AMS at ≤ 2.0 mV. AV Interval: AMS was effective in eight often patients at A V intervals up to 200 ms. One patient lost AMS at an AV interval of 120 ms. Algorithm: In two of seven patients, AMS was not effective if the detection algorithm was more stringent than five beats at 150 beats/min. Conclusions: (1) In atrial fibrillation, effective AMS requires more sensitive atrial settings than in NSR; (2) AV intervals as short as 120 ms can interfere with AMS function; and (3) More stringent detection algorithms may be inappropriate for effective AMS function.
Original language | English (US) |
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Pages (from-to) | 1734-1739 |
Number of pages | 6 |
Journal | PACE - Pacing and Clinical Electrophysiology |
Volume | 19 |
Issue number | 11 II |
DOIs | |
State | Published - 1996 |
Keywords
- atrial tachyarrhythmias
- automatic mode switch
- sensors
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine