Aims To risk stratify and shorten hospital stay in patients with spontaneous (resting) chest pain and a non-diagnostic electrocardiogram (ECG).
Methods and Results The study comprised 102 patients (mean age 58±12 years, 67 men) with spontaneous chest pain and a non-diagnostic ECG. Forty-three patients had suspected coronary artery disease and 59 had known (but of unknown actual significance) coronary artery disease. All patients underwent serial creatine kinase enzyme measurements, continuous ECG monitoring for at least 12h and early dobutamine–atropine stress echocardiography in patients with negative creatine kinase enzymes and normal findings at ECG monitoring. Dobutamine–atropine stress echocardiography was considered positive in patients with new or worsening wall thickening abnormalities. Patients with negative dobutamine–atropine stress echocardiography were discharged after the test. In-hospital and 6 month follow-up events noted were cardiac death, non-fatal myocardial infarction, unstable angina, and coronary artery bypass surgery or angioplasty. Thirteen patients had evidence of evolving myocardial infarction by elevated creatine kinase enzymes, or unstable angina by ECG monitoring. In the remaining 89 patients, dobutamine–atropine stress echocardiography was performed after a median observation period of 31h (range 12–68h). During dobutamine–atropine stress echocardiography no serious complications (death, non-fatal myocardial infarction, sustained ventricular tachycardia or ventricular fibrillation) occurred. Dobutamine–atropine stress echocardiography results were of poor quality in three, non-diagnostic in six, negative in 44 and positive in 36 patients. In the 80 patients with diagnostic dobutamine–atropine stress echocardiography, variables associated with in-hospital events (n=7) were history of exertional angina (P<0·005), chest pain score (P<0·005), stress-induced angina (P<0·001) and positive dobutamine–atropine stress echocardiography (P<0·005). Variables associated with follow-up events (n=11) were history of exertional angina (P<0·05), chest pain score (P<0·001), stress-induced angina (P<0·01) and positive dobutamine–atropine stress echocardiography (P<0·01). At multivariate analysis the only significant predictor of events was positive dobutamine–atropine stress echocardiography (P<0·01).
Conclusion Early dobutamine–atropine stress echocardiography may safely distinguish between low- and high-risk subsets for subsequent cardiac events in patients with spontaneous chest pain and a non-diagnostic ECG.