Impact of pharmacological spasm provocation test in patients with a history of syncope

Coronary artery spasm is involved in the pathogenesis of various cardiac disorders. We investigated patients with a history of syncope who underwent elective coronary angiography. We retrospectively analyzed 5781 consecutive patients who had diagnostic or follow-up angiography during a 26-year period. During this period, we found 95 patients with a history of syncope before elective coronary angiography. Pharmacological spasm provocation testing was performed in 64 patients with a history of syncope (<1 year). Positive pharmacological response was observed in 48 patients, while the remaining 16 patients had negative tests. Positive spasm was defined as a transient ≥90% narrowing with ischemic electrocardiographic changes. Among the 64 patients, definite coronary spastic angina (CSA) was found in 35 patients (54.7%) and suspected CSA was found in 13 patients (20.3%). Among the 35 patients with definite CSA, 22 patients (62.9%) had chest symptoms before syncope, but 13 (37.1%) had no chest symptom before syncope. No difference in clinical characteristics was observed between the two groups. Focal spasm during pharmacological spasm provocation tests was significantly higher in patients with chest symptoms than in those without chest symptoms before syncope (54.3 vs. 12.0%, p < 0.002). CSA was observed in 75.0% of patients with a history of syncope (<1 year). Thirteen patients with definite CSA had neither chest pain nor chest pressure before syncope. We should therefore investigate coronary artery spasm as a potential etiology in patients with a history of syncope.