Journal of the American College of Cardiology
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J. Am. Coll. Cardiol. · Aug 1998
Comparative StudyChronic L-arginine treatment increases cardiac cyclic guanosine 5'-monophosphate in rats with aortic stenosis: effects on left ventricular mass and beta-adrenergic contractile reserve.
We tested the hypothesis that nitric oxide (NO) cyclic guanosine 5'-monophosphate (GMP) signaling is deficient in pressure overload hypertrophy due to ascending aortic stenosis, and that long-term L-arginine treatment will increase cardiac cyclic GMP production and modify left ventricular (LV) pressure overload hypertrophy and beta-adrenergic contractile response. ⋯ Left ventricular hypertrophy due to chronic mechanical systolic pressure overload is not characterized by a deficiency of LV cNOS and cyclic GMP levels. In rats with aortic stenosis, L-arginine treatment increased cardiac levels of cyclic GMP, but it did not modify cardiac mass in rats with aortic stenosis. However, long-term stimulation of NO-cyclic GMP signaling depressed in vivo LV systolic function in LVH rats and markedly blunted the contractile response to beta-adrenergic stimulation.
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J. Am. Coll. Cardiol. · Aug 1998
Gender differences in use of stress testing and coronary heart disease mortality: a population-based study in Olmsted County, Minnesota.
We sought to examine the utilization of exercise stress testing in relation to age and gender in a population-based setting. ⋯ These population-based data show that during the study period, the utilization of stress testing in Olmsted County was lower in women than in men. Women in the incidence cohort were older and more symptomatic and had poorer exercise performance than men. Such differences should be considered when examining the utilization of subsequent invasive procedures according to gender.
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J. Am. Coll. Cardiol. · Aug 1998
Comparative StudyThree-dimensional echocardiographic planimetry of maximal regurgitant orifice area in myxomatous mitral regurgitation: intraoperative comparison with proximal flow convergence.
We sought to validate direct planimetry of mitral regurgitant orifice area from three-dimensional echocardiographic reconstructions. ⋯ 3D echo imaging of the MV allows direct visualization and planimetry of the ROA in patients with severe MR with good agreement to flow-based proximal convergence measurements.
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J. Am. Coll. Cardiol. · Aug 1998
Comparative StudyFrequency of 22q11 deletions in patients with conotruncal defects.
This study was designed to determine the frequency of 22q11 deletions in a large, prospectively ascertained sample of patients with conotruncal defects and to evaluate the deletion frequency when additional cardiac findings are also considered. ⋯ A substantial proportion of patients with IAA, TA, TOF and PMVSD have a deletion of chromosome 22q11. Deletions are more common in patients with aortic arch or vessel anomalies. These results begin to define guidelines for deletion screening of patients with conotruncal defects.
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J. Am. Coll. Cardiol. · Aug 1998
The effects of ventricular fibrillation duration and site of initiation on the defibrillation threshold during early ventricular fibrillation.
The purpose of this study was to determine if the defibrillation threshold (DFT) is lower during the first few cycles of ventricular fibrillation (VF) than after 10 s of VF and, if so, if the effect is caused by local or global factors. ⋯ This study demonstrates that the DFT is significantly lower during the first few VF cycles of VF than after 10 s of VF and that this decrease may be caused by both local factors and global factors. These results provide an impetus for exploring earlier shock delivery in implantable devices.