Figure 4.

Apoptosis, troponin I release and stretch-induced stunning. A: measurements of serum TnI (aorta-blue; coronary sinus red) at baseline and selected time points following a transient 1-h elevation in left ventricular (LV) end-diastolic pressure to 35 mmHg in response to an increase in afterload with phenylephrine (PE). Troponin rose above the 99th URL within 30 min and reached ∼1,400 ng/L after 24 h. Western blot analysis of tissue at 3 h showed TnI proteolysis, light microscopy showed no evidence of necrosis or infarction, and microsphere flow measurements showed no evidence of ischemia (data not shown). B: myocyte apoptosis was increased sixfold in tissue harvested at 3 h and returned to normal levels 24 h after transient preload elevation. Values are means ± SD. *P < 0.05 vs. normal control; †P < 0.05 vs. 24-h post-PE. Adapted from Weil et al. (54) and published with permission of the American College of Cardiology.