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Myocardial dysfunction during percutaneous transluminal coronary angioplasty.

Balloon inflation during percutaneous transluminal coronary angioplasty (PTCA) transiently occludes the coronary artery, causing temporary ischemia. In patients without collaterals, regional hypokinesis of the ventricular myocardium at risk occurs within the first 20 seconds and persists throughout balloon inflation. Early PTCA procedures were performed with brief balloon inflations, but the desire to improve procedural results has led many operators to extend balloon inflation times to 45 seconds or longer. Although the ischemic indicators of pain and electrocardiographic changes are commonly noted with these longer inflations, actual hemodynamic consequences are often obscured by physiological compensation. The PTCA-induced ischemic period is often too short to measure changes in cardiac output by conventional methods, but it is increasingly evident that profound regional myocardial dysfunction, in fact, occurs. Continuous two-dimensional echocardiography with quantitative assessment of regional wall motion and ejection fraction is particularly effective in detecting the location, extent, and temporal change of ischemic regional contractile dysfunction. Echocardiographic recordings during baseline, ischemia, and post-balloon-deflation periods permit examination of PTCA-caused alterations in ejection fraction and ventricular volumes and allow the use of testing techniques aimed at mitigation of ischemia.