Compared with older series, we observed more prosthetic valve IE, nosocomial IE, and surgery. Staphylococcus aureus and Enterococcus faecalis were predominant microorganisms. Age, staphylococci, and a contraindication to surgery predicted 6-month mortality. Nearly half of deaths had a contraindication to surgery. Six-month mortality did not differ significantly between patients who received surgical treatment as against those who received medical treatment without a contraindication to surgery.

Background-Alterations in the balance of matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) are involved in left ventricular (LV) remodeling. Whether their expression is related to interstitial fibrosis or LV dysfunction in patients with chronic pressure overload-induced LV hypertrophy, however, is unknown. Methods and Results-Therefore, cardiac biopsies were taken in 36 patients with isolated aortic stenosis (AS) and in 29 control patients without LV hypertrophy. Microarray analysis revealed significantly increased mRNA expression of collagen types I, III, and IV and transcripts involved in collagen synthesis, including procollagen endopeptidase and lysine and proline hydroxylases, in AS compared with control patients. Collagen deposition was greater in AS than in control patients and was most pronounced in AS patients with severe diastolic dysfunction. Cardiac mRNA expression of TIMP-1 and TIMP-2 was significantly increased in AS compared with control patients (mRNA transcript levels normalized to GAPDH: TIMP-1, 0.67Ϯ0.1 in AS versus 0.37Ϯ0.08 in control patients; TIMP-2, 9.5Ϯ2.6 in AS versus 1.6Ϯ0.4 in control patients; PϽ0.05 for both) but did not differ significantly for MMP-1, -2, or -9. Cardiac TIMP-1 and -2 transcripts were significantly related to the degree of interstitial fibrosis and proportional to diastolic dysfunction in AS patients. Conclusions-Cardiac expression of TIMP-1 and TIMP-2 is significantly increased in chronic pressure-overloaded human hearts compared with controls and is related to the degree of interstitial fibrosis.

Background Ventricular expression of phosphodiesterase-5 (PDE5), an enzyme responsible for cGMP catabolism, is increased in human right ventricular hypertrophy, but its role in left ventricular (LV) failure remains incompletely understood. We therefore measured LV PDE5 expression in patients with advanced systolic heart failure and characterized LV remodeling after myocardial infarction (MI) in transgenic mice with cardiomyocyte-specific over-expression of PDE5 (PDE5-TG). Methods and Results Immunoblot and immunohistochemistry techniques revealed that PDE5 expression was greater in explanted LVs from patients with dilated and ischemic cardiomyopathy than in control hearts. To evaluate the impact of increased ventricular PDE5 levels on cardiac function, PDE5-TG mice were generated. Confocal and immunoelectron microscopy revealed increased PDE5 expression in cardiomyocytes predominantly localized to Z-bands. At baseline, myocardial cGMP levels, cell shortening and calcium handling in isolated cardiomyocytes, and LV hemodynamic measurements were similar in PDE5-TG and wild-type littermates (WT). Ten days after MI, LV cGMP levels increased to a greater extent in WT than PDE5-TG (P<0.05). Ten weeks after MI, LV end-systolic and -diastolic volumes were larger in PDE5-TG than in WT (57±5 vs 39±4 and 65±6 vs 48±4 µL, respectively, P<0.01 for both). LV systolic and diastolic dysfunction was more marked in PDE5-TG than WT associated with enhanced hypertrophy and reduced contractile function in isolated cardiomyocytes from remote myocardium. Conclusions Increased PDE5 expression predisposes mice to adverse LV remodeling after MI. Increased myocardial PDE5 expression in patients with advanced cardiomyopathy may contribute to the development of heart failure and represents an important therapeutic target.

451H emodynamic overload and ischemic or oxidative stress promote adverse cardiac remodeling, a leading cause of worsening heart failure.1,2 Most of these pathophysiologic conditions are associated with (and to a certain extent, mediated by) adrenergic stimulation and catecholamines release, resulting in adrenoceptor (AR) activation on different cell types within the myocardium. Among these, cardiac myocyte β1-ARs are classically considered to mediate short-term positive effects on all aspects of myocardial contractility; however, long-term stimulation produces adverse effects on myocardial remodeling, in part through activation of calciumdependent prohypertrophic effects, ultimately associated with cardiomyocyte loss. 3,4 Such maladaptive remodeling is usually accompanied by left ventricle (LV) geometry disruption Background-β1-2-adrenergic receptors (AR) are key regulators of cardiac contractility and remodeling in response to catecholamines. β3-AR expression is enhanced in diseased human myocardium, but its impact on remodeling is unknown. Methods and Results-Mice with cardiac myocyte-specific expression of human β3-AR (β3-TG) and wild-type (WT) littermates were used to compare myocardial remodeling in response to isoproterenol (Iso) or Angiotensin II (Ang II). β3-TG and WT had similar morphometric and hemodynamic parameters at baseline. β3-AR colocalized with caveolin-3, endothelial nitric oxide synthase (NOS) and neuronal NOS in adult transgenic myocytes, which constitutively produced more cyclic GMP, detected with a new transgenic FRET sensor. Iso and Ang II produced hypertrophy and fibrosis in WT mice, but not in β3-TG mice, which also had less re-expression of fetal genes and transforming growth factor β1.Protection from Iso-induced hypertrophy was reversed by nonspecific NOS inhibition at low dose Iso, and by preferential neuronal NOS inhibition at high-dose Iso. Adenoviral overexpression of β3-AR in isolated cardiac myocytes also increased NO production and attenuated hypertrophy to Iso and phenylephrine. Hypertrophy was restored on NOS or protein kinase G inhibition. Mechanistically, β3-AR overexpression inhibited phenylephrine-induced nuclear factor of activated T-cell activation. Conclusions-Cardiac-specific overexpression of β3-AR does not affect cardiac morphology at baseline but inhibits the hypertrophic response to neurohormonal stimulation in vivo and in vitro, through a NOS-mediated mechanism. Activation of the cardiac β3-AR pathway may provide future therapeutic avenues for the modulation of hypertrophic remodeling. and interstitial and replacement fibrosis leading to progressive diastolic and systolic heart failure. Deciphering the underlying signaling pathways may lead to new therapeutic strategies that favorably modulate remodeling. The use of β1-AR blockers provided a major advance in this direction, albeit far from totally efficient. 5 The third isotype of β-AR (β3-AR) has classically been considered as a metabolic regulator (eg, by mediating lipolysis in the adipose tissue).6 β3-ARs ...