Fig. 7.

(A) The difference in peak circumferential stretch, ${\lambda }_c$, following myocardial infarction (MI). Increased peak ${\lambda }_c$ was associated with more ventricular enlargement in prior studies [21,25]. (B) The difference in postinfarction peak ${\lambda }_c$ with administration of a pharmacologic agent, either nitroglycerin (NG) or dobutamine (DB). (C) Difference in peak radial stretch, ${\lambda }_r$, following MI. Increased peak ${\lambda }_r$ was indicative of ventricular thickening and decreased peak ${\lambda }_r$ was indicative of ventricular thinning in prior studies. (D) The difference in postinfarction peak ${\lambda }_r$ with administration of NG or DB. In all plots no change is indicated by the gray dashed line and a significant average difference is indicated by a dark solid line (p < 0.05). Paired parametric t-tests were performed for all analyses since peak stretches were both normally distributed at all time points. Each rat’s response is shown in a different color.