Beneficial effects of the Ca2+ sensitizer EMD 57033 in exercising pigs with infarction-induced chronic left ventricular dysfunction.

1. It is unknown how cardiac stimulation by Ca(2+) sensitization modulates the cardiovascular response to exercise when left ventricular (LV) function is chronically depressed following a myocardial infarction. We therefore investigated the effects of EMD 57033 at rest and during exercise and compared these to those of the mixed Ca(2+)-sensitizer/phosphodiesterase-III inhibitor pimobendan.

Cardiac remodeling and contractile function in acid alpha-glucosidase knockout mice.

Pompe's disease is an autosomal recessive and often fatal condition, caused by mutations in the acid alpha-glucosidase gene, leading to lysosomal glycogen storage in heart and skeletal muscle. We investigated the cardiac phenotype of an acid alpha-glucosidase knockout (KO) mouse model. Left ventricular weight-to-body weight ratios were increased 6.

Role of K(ATP)(+) channels in regulation of systemic, pulmonary, and coronary vasomotor tone in exercising swine.

The role of ATP-sensitive K(+) (K(ATP)(+)) channels in vasomotor tone regulation during metabolic stimulation is incompletely understood. Consequently, we studied the contribution of K(ATP)(+) channels to vasomotor tone regulation in the systemic, pulmonary, and coronary vascular bed in nine treadmill-exercising swine. Exercise up to 85% of maximum heart rate increased body O(2) consumption fourfold, accommodated by a doubling of both cardiac output and body O(2) extraction.

Angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade prevent cardiac remodeling in pigs after myocardial infarction: role of tissue angiotensin II.

Background: The mechanisms behind the beneficial effects of renin-angiotensin system blockade after myocardial infarction (MI) are not fully elucidated but may include interference with tissue angiotensin II (Ang II).

Methods And Results: Forty-nine pigs underwent coronary artery ligation or sham operation and were studied up to 6 weeks. To determine coronary angiotensin I (Ang I) to Ang II conversion and to distinguish plasma-derived Ang II from locally synthesized Ang II, (125)I-labeled and endogenous Ang I and II were measured in plasma and in infarcted and noninfarcted left ventricle (LV) during (125)I-Ang I infusion.

Nitric oxide contributes to the regulation of vasomotor tone but does not modulate O(2)-consumption in exercising swine.

Objective: The role of nitric oxide (NO) in the regulation of vasomotor tone and tissue O(2)-consumption is incompletely understood. We therefore determined the contribution of endogenous NO to regulation of systemic, pulmonary and coronary vasomotor tone and myocardial (MV(O(2))) and whole body (BV(O(2))) O(2)-consumption in exercising swine.

Methods And Results: Exercise (1-5 km/h) up to 85% of maximum heart rate in 11 swine produced a 4-fold increase in BV(O(2)), which was accommodated for by 2-fold increases in both cardiac output (CO) and body O(2)-extraction.