Thoracic Epidural Anesthesia Improves Global and Regional Left Ventricular Function During Stress-Induced Myocardial Ischemia in Patients With Coronary Artery Disease

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Abstract
The aim of the present investigation was to study the effects of high thoracic epidural anesthesia (TEA), including the cardiac sympathetic segments, on ischemic ST-segment changes and left ventricular global and regional wall motion abnormalities. Ten patients with a two- or three-vessel coronary artery disease, all treated with the β-adrenergic blocker metoprolol because of severe stable angina pectoris, performed two identical exercise stress tests, the first without TEA (control exercise) and the second with TEA (TEA exercise). Before each stress test, intravenous metoprolol was given to achieve maximal or near maximal β-adrenoceptor blockade. Systolic and diastolic arterial pressures (radial artery cannula), heart rate, and rate-pressure product, as well as global and regional ejection fractions, using equilibrium radionuclide angiography in the left anterior oblique projection, were measured at rest and during maximal exercise. ST-segment analysis (V3 or V5) was performed, and the regional wall motion score was calculated at control exercise and TEA exercise. Intravenous metoprolol or intravenous metoprolol plus TEA at rest did not cause any significant changes of any of the variables. During TEA exercise, systolic arterial pressure, diastolic arterial pressure, and rate-pressure product, but not heart rate, were significantly lower compared to control exercise. The global and anterolateral ejection fractions were significantly higher (52.8% versus 46.5% and 53.2% versus 46.0%, respectively, P < 0.05), and the regional wall motion score was significantly lower (8.8 versus 11.8, P < 0.01) during TEA exercise than during control exercise. ST-segment depression was significantly lower during TEA exercise (−1.03 versus −1.84 mV, P < 0.01). It is concluded that cardiac sympathetic blockade with TEA, in patients with coronary artery disease, improves ischemia-induced left ventricular global and regional wall motion abnormalities at a certain physical stress, associated with less pronounced ST-segment depression.

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