Reproducibility of response to programmed atrial stimulation

The induction of atrial tachyarrhythmias (ATAs) is used to guide the medica l or ablative treatment of these tachycardias. To date no information is av ailable regarding the reproducibility of programmed atrial stimulation (PAS ) induced ATA. The purpose of the study was to look for the reproducibility of PAS. Two baseline electrophysiological tests ir ere performed in the dr ug-free state and within 6 months to 3 years of one another (mean 18 months ) in 62 patients. Twenty-six patients had spontaneous documented ATAs (grou p I); 36 patients did not have spontaneous ATAs (group II). PAS used one an d two extrastimuli delivered during three cycle lengths (sinus rhythm, 600 ms, 400 ms). The results were as follows. In group I, sustained (> 1 minute ) ATA was induced in 23 patients on the first PAS and remained inducible in 22 patients in the second study In three patients with noninducible ATA, P AS remained negative in only one; the reproducibility of PAS was 88%. In 17 (47%) group II patients, a sustained ATA was induced in the first study an d the ATA remained inducible in 10 patients in the second study. Nineteen o ther patients did not have inducible ATA on the first study: but 10 of them had an inducible ATA on the second PAS; the reproducibility of PAS was 53% . In conclusion, long-term reproducibility of PAS induced ATA in patients w ith spontaneous and documented ATA was good. In patients without spontaneou s ATA, the reproducibility of PAS induced ATA was low and the induction of ATA in these patients should be interpreted cautiously in light of this obs erved variability in induced atrial arrhythmias.