Prevention of creatine kinase-MB release in coronary artery disease and pacing-induced myocardial ischemia by isosorbide dinitrate spray

The effect of isosorbide dinitrate (ISDN) spray on release of the isoenzyme creatine kinase-MB (CK-MB) after myocardial ischemia induced by atrial pacing was evaluated in 8 patients with coronary artery disease. Atrial pacing to ischemia (ST-segment depression of greater than or equal to 1.5 mm for greater than or equal to 80 ms) resulted in elevation of CK-MB levels in plasma drawn from the coronary sinus, from 1.8 +/- 1.5 to 6.8 +/- 7.0 ng/ml (p less than 0.001) at 30 minutes after onset of ischemia. When atrial pacing was repeated at the same rate after 1 squirt of ISDN spray, 1.25 mg, the CK-MB levels were not altered despite significant ischemic ST-segment depression. It is concluded that ISDN prevents the process responsible for myocardial release of CK-MB, being either micronecroses or a reversible consequence of ischemia.