Transesophageal atrial pacing in anesthetized patients with coronary artery disease: Hemodynamic benefits versus risk of myocardial ischemia

Background: Transesophageal atrial pacing (TEAP) provides prompt and precise control of heart rate and improves hemodynamics in anesthetized patients with bradycardia and hypotension. The authors' purpose in this study was to examine the hemodynamic benefits of TEAP versus the risk of myocardial ischemia in patients about to undergo coronary artery bypass surgery. Methods: Hemodynamics, ventricular filling pressures, mixed venous oxygen saturation, and end-diastolic, end-systolic, and fractional area change of the left ventricle, determined by transesophageal echocardiography (TEE), were measured after anesthesia induction with 30 μg/kg fentanyl and at incremental TEAP rates of 65, 70, 80, and 90 heats/min (bpm) in 40 adult patients. Monitoring for myocardial ischemia was accomplished with 12-lead electrocardiograms and biplane TEE assessment of left ventricular regional wall motion. Hemodynamics, electrocardiograms, and TEE measurements at each TEAP rate were compared with baseline awake measurements (except TEE) and with measurements obtained after anesthesia induction before TEAP. Results: Sinus bradycardia occurred in 15 patients after anesthesia induction and was associated with a hypotensive response and a decrease in cardiac output in 10 patients. In these patients, TEAP restored diastolic blood pressure and cardiac output to baseline values at TEAP rates of 65 and 80 bpm, respectively. Stroke volume was similar to baseline measurements after anesthesia induction and at TEAP rates of 65, 70, and 80 bpm, but was significantly reduced from baseline at TEAP 90 bpm. Myocardial ischemia was detected in 7 and 5 patients at a TEAP rate of 80 and 90 bpm, respectively. Conclusions: Control of heart rate with TEAP restores intraoperative hemodynamics to baseline in patients in whom bradycardia and a hypotensive response develop before coronary artery bypass surgery. When using TEAP for patients with severe coronary artery disease, these results support using the lowest TEAP rate titrated to achieve optimal hemodynamics, while closely monitoring for myocardial ischemia, especially at TEAP rates > 80 bpm.