Exercise-induced left ventricular dysfunction in coronary heart disease. A model for studying the stunned myocardium in man.

The concept of myocardial stunning encompasses a wide variety of settings with major pathophysiological differences. Stresses, such as exercise-provoked myocardial ischaemia and dysfunction, are accompanied in most patients by a flow-limiting coronary stenosis, while contractile dysfunction persists in some with cessation of exercise. Twenty-six patients with proven coronary artery disease were studied by exercise echocardiography. Left ventricular (LV) volumes, wall motion and myocardial thickening were detected in apical four- and two-chamber views at rest and during upright bicycle exercise. All patients had an increase in total asynergy score and a decrease in ejection fraction (EF) during exercise. Myocardial dysfunction persisted after exercise in 22 patients (84%) as shown by the persistence of low values of LVEF on recovery up to 30 min. When compared to control, nisoldipine reduces total asynergy score and prevents the decline in LVEF during exercise by reducing the extent of myocardial ischaemia. The value of LVEF on recovery is normal. Thus, this particular form of myocardial stunning after exercise-induced ischaemia offers an interesting model for studying (1) the susceptibility of an individual patient and (2) to test the capability of a drug to prevent and to reverse myocardial stunning.