Noninvasive pacemaker stress echocardiography for diagnosis of coronary artery disease: A multicenter study

Objectives We evaluated the feasibility, safety, and diagnostic accuracy of noninvasive pacemaker stress echocardiography (PASE) test as a potential alternative to exercise or pharmacologic stress in patients with suspected or known coronary artery disease (CAD). Background Transesophageal atrial pacing echocardiography is an accurate test for detection of CAD, but its practical impact has been blunted by semi-invasiveness. In the expanding population of patients with permanent pacemakers (PMs), a pacing stress test can be administered noninvasively by external programming of the PM. Methods In a prospective, multicenter, international study design, transthoracic stress-pacing echocardiography was performed in 46 consecutive patients with a permanent PM (33 men, 13 women; age 66.6 ± 11.1 years) with suspected or known CAD. All patients underwent noninvasive PM-stress test by external programming (10 beats/min increments up to ischemia or target heart rate). Coronary angiography was performed in all patients independently of test results. Significant CAD was defined as ≥50% visually assessed diameter reduction in at least one major epicardial coronary artery. All coronary angiograms were scored by Duke prognostic weight values. Results Fifteen patients were stimulated in atrial, and the remaining 31 in ventricular mode during stress. No significant side effects were observed. Echocardiographic images were interpretable in all patients. The average duration of stress was 8.9 ± 3.5 min. Significant CAD was found in 27 patients. Sensitivity of PASE for identifying patients with significant CAD was 70%, specificity was 90%, and accuracy was 78%. When any abnormal wall motion at rest that remained unchanged at peak stress was regarded as a positive result of PASE, then the sensitivity, specificity, and accuracy levels for identifying patients with significant CAD were 85%, 84%, and 85%, respectively. Four of the eight patients with a false negative did not reach the target heart rate. The Duke values had significant correlation with values of wall motion score index at peak stress (r = 0.67) and with peak heart rate (r = −0.3). Conclusions Noninvasive PASE is a simple, rapid, safe, and diagnostically efficient option for patients with permanent PM and suspected or known CAD.