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.