Prevalence, Etiology and Outcome of Catheterization Laboratory False Alarms in Patients With Suspected ST-Elevation Myocardial Infarction

Introduction and objectives. To investigate the prevalence, causes and outcome of catheterization laboratory false alarms (CLFAs) in a regional primary angioplasty network. Methods. A prospective registry of 1,662 patients referred for primary angioplasty between January 2003 and August 2008 was reviewed to identify CLFAs (i.e. when no culprit coronary lesion could be found). Results. No culprit coronary lesion could be identified in 120 patients (7.2%; 95% confidence interval [CI], 5.9-8.5%). Of these, 104 (6.3%, 95% CI, 5.1-7.4%) had a discharge diagnosis other than ST-elevation myocardial infarction, 91(5.5%; 95% CI, 4.3-6.6%) had no significant coronary disease, and 64 (3.8%; 95% CI, 2.9-4.8%) tested negative for cardiac biomarkers. The most frequent alternative diagnoses were: previous Q-wave myocardial infarction (18 cases), nonspecific ST-segment abnormalities (11), pericarditis (10) and transient apical dyskinesia (10). The 30-day mortality rate was similar in patients with and without culprit lesions (5.8% vs. 5.8%; P=.99). The prevalence of CLFAs was slightly higher in patients not previously evaluated by a cardiologist and referred from emergency departments in hospitals without catheterization laboratories than in those referred by cardiologists from emergency departments at hospitals with such facilities (9.5% vs. 6.1%; P=.02; odds ratio=1.64; 95% CI, 1.08-2.5). The prevalence of CLFAs was not significantly higher in patients referred by physicians with out-of-hospital emergency medical services (7.2%; P=.51; odds ratio=1.37; 95% CI, 0.79-2.37). Conclusions. The prevalence of CLFAs was 7.2%, with the criterion of no culprit coronary lesion. Our findings suggest that different patterns of referral to catheterization laboratories could account for small variations in the prevalence of CLFAs.