BACKGROUND Regional function in stunned myocardium is usually thought to be more depressed in the endocardium than the epicardium. This has been attributed to the greater loss of blood flow at the endocardium during ischemia. METHODS AND RESULTS We measured transmural distributions of 3D systolic strains relative to local myofiber axes in open-chest anesthetized dogs before 15 minutes of left...

Using microelectrode techniques we compared the effects of tetrodotoxin (TTX, 2-3 microM), DL-propranolol (1-3 micrograms/ml), and flecainide acetate (10-15 microM) on isolated canine ventricular epicardial (epicardium) and endocardial (endocardium) tissues. Propranolol, TTX, and flecainide decreased Vmax and phase 0 amplitude in a use-dependent manner in both tissues. The effects of propranolo...

Using microelectrode techniques we compared the effects of tetrodotoxin (TTX, 2-3 ,M), DL-propranolol (1-3 p,g/ml), and flecainide acetate (10-15 ,uM) on isolated canine ventricular epicardial (epicardium) and endocardial (endocardium) tissues. Propranolol, TTX, and flecainide decreased Vm.. and phase 0 amplitude in a use-dependent manner in both tissues. The effects of propranolol were slow to...

In response to cardiac damage, a mesothelial tissue layer enveloping the heart called the epicardium is activated to proliferate and accumulate at the injury site. Recent studies have implicated the epicardium in multiple aspects of cardiac repair: a source of paracrine signals for cardiomyocyte survival or proliferation; a supply of perivascular cells and possibly other cell types like cardiom...