Reproducibility of Occurrence of Paroxysmal Atrial Fibrillation in Patients Who Had Acetylcholine Testing

Objectives: Paroxysmal atrial fibrillation (PAF) is observed in some certain patients with acetylcholine (ACh) testing. However, it is uncertain for the reproducibility of ACh-induced PAF. We investigated the reproducibility of occurrence of ACh-induced PAF. Methods: We retrospectively investigated the reproducibility of occurrence of PAF in 70 patients who had ACh testing two times apart from at last one month. Incremental intracoronary injection of ACh into the right coronary artery was 20, 50, and 80 µg, while incremental dose of ACh into the left coronary artery was 20, 50, 100, and 200 µg. Positive provoked spasm was defined as > 90% transient narrowing with ischemic ECG changes or chest symptoms. Results: Among 70 patients, concordance was observed in 59 patients including 50 patients with both sinus rhythm and 9 patients with both positive PAF. The remaining 11 patients had discordance between the first and the second ACh tests. There were no clinical and angiographical differences except organic stenosis between the first and second ACh testing. All 70 patients had neither past PAF nor future PAF. The rate of coincidence was 84%, while discordance was 16%. ACh-inducible PAF was reproduced in 45% of patients who had two times of ACh testing, while the remaining 55% of patients revealed the discordance of ACh-inducible PAF. Conclusions: Less than half patients disclosed the reproducibility of ACh-inducible PAF.