The American journal of cardiology
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Multicenter Study Comparative Study
Trends in hospitalization for the implantation of cardioverter-defibrillators in the United States, 1990-2005.
Implantable cardioverter-defibrillators were first approved for use in the United States in 1985. Their efficacy in improving the survival of patients at risk for sudden cardiac death has been shown, and the number of patients eligible for ICDs has increased. ⋯ The rate of ICD procedures was substantially greater in men than women, and the rate increased significantly with age, although there was no increase in ICD use in patients aged >or=75 years. In conclusion, as the list of clinical indications and insurance coverage for ICD use expand, continued surveillance to monitor trends in the use of ICDs is warranted.
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Multicenter Study Comparative Study
Usefulness of cardiac magnetic resonance imaging combined with low-dose dobutamine stress to detect an abnormal ventricular stress response in children and young adults after fontan operation at young age.
After Fontan operation, patients are limited in increasing cardiac output and in exercise capacity. This has been related to impaired preload or other factors leading to decreased global ventricular performance with stress. To study these factors, the stress responses of functionally univentricular hearts were assessed at rest and during low-dose dobutamine stress using cardiovascular magnetic resonance imaging. ⋯ At rest, dominant left ventricles had higher ejection fractions than dominant right ventricles (p = 0.01), but this difference disappeared with stress testing. In conclusion, a functionally univentricular heart after Fontan completion at young age has an adequate increase in ejection fraction with beta-adrenergic stimulation. However, as a result of impaired preload with stress, cardiac output can be increased only by increasing heart rate.