Usefulness of accelerated exercise following mild hyperventilation for theinduction of coronary artery spasm - Comparison with an acetylcholine test

Study objectives: This study was performed to compare the results of accele rated exercise following mild hyperventilation and a standard acetylcholine (ACh) test for the induction of coronary artery spasm in patients with dru g-induced coronary artery spasm. Methods and results: The subjects were 74 patients with angiographically co nfirmed coronary artery spasm who were examined using accelerated exercise tie, exercise that was accelerated every minute according to the protocol o f Bruce and Horsten) following mild hyperventilation and who were not recei ving any medication. ACh was injected in incremental doses of 20 mug and 50 mug into the right coronary artery and incremental doses of 20 mug, 50 mug , and 100 mug into the left coronary artery. Positive coronary spasm was de fined as greater than or equal to 99% luminal narrowing. Accelerated exerci se following a mild hyperventilation test was as useful for detecting evide nce of ischemia as was an ACh test (48 patients [64.9%] vs 49 patients [66. 2%], respectively; not significant). No difference was observed between isc hemic changes on ECG as a result of the newly combined method and the occur rence of ACh-induced spasm. ACh-induced coronary vasospasm occurred in gl p atients (82.4%). In the remaining 13 patients, intracoronary administration of ergonovine provoked coronary spasms. No serious irreversible complicati ons were detected as a result of this newly combined method. Conclusions: The effectiveness of our newly combined procedure is equivalen t to that of an ACh test to diagnose patients with coronary artery spasm.