Identifying Patients for Rate Responsive Atrial Pacing: A New Method for Patient Selection and Pacemaker Programming

In patients with sinus node disease (SND) and chronotropic incompetence, atrial rate adaptive stimulation (AAI,R pacing) is regarded as the most appropriate pacing mode. Since coronary artery disease is the most common etiology in these patients, we evaluated a new technique combining two-dimensional transesophageal echocardiography and atrial transesophageal pacing to detect pacing induced wall motion abnormalities and assess safe upper rate limits. Thirty-five patients were studied: 26 with and 9 without angiographic coronary artery disease. Stable atrial capture was achieved in all patients using 12 +/- 3 msec pulse width and 12 +/- 4 mA current strength. Sensitivity and specificity for the detection of coronary artery disease was highest for transesophageal echocardiography during pacing (sensitivity 81%, specificity 100%). Simultaneous 12-lead ECG during pacing had lower values (sensitivity 57%, specificity 75%). Pacing induced wall motion abnormalities preceded ST segment changes in all patients. Exercise stress testing showed similar values (sensitivity 62%, specificity 89%). It is concluded that simultaneous transesophageal echocardiography and transesophageal pacing is a safe and useful technique in selecting patients for AAI,R pacing and for the detection of safe upper rate limits, particularly when coronary artery disease is suspected.