Effect of beta-adrenergic blockade on dynamic electrical restitution in vivo.

The slope of the action potential duration (APD) restitution curve may be a significant determinant of the propensity to develop ventricular fibrillation, with steeper slopes associated with a more arrhythmogenic substrate. We hypothesized that one mechanism by which beta-blockers reduce sudden cardiac death is by flattening the APD restitution curve. Therefore, we investigated whether infusion of esmolol modulates the APD restitution curve in vivo.

In-vivo biocompatibility evaluation of stents coated with a new biodegradable elastomeric and functional polymer.

Background: In-stent restenosis may be prevented by impregnating an antiproliferative agent in a polymer from a stent platform. This approach requires both an antiproliferative agent effective in small doses and a biocompatible polymer.

Methods: A series of new biodegradable elastomeric poly(ester-amide)(co-PEA) polymers having functional carboxyl groups for drug conjugation were synthesized from non-toxic building blocks.

Platelet-derived growth factor-AB limits the extent of myocardial infarction in a rat model: feasibility of restoring impaired angiogenic capacity in the aging heart.

Background: Compared with younger patients, myocardial infarction in the elderly has been associated with less favorable clinical outcomes, which may be attributable to a decline in angiogenic capacity in the aging heart.

Methods And Results: To test the hypothesis that the functional phenotype of cardiac microvascular endothelial cells is maintained partly by a cardiac myocyte platelet-derived growth factor (PDGF)-B-induced paracrine pathway, we conducted in vitro studies with murine cardiac cells. These studies demonstrated that unlike young endothelial cells, endothelial cells of the aging heart do not express PDGF-B when cultured in the presence of cardiac myocytes.