Three-dimensional echocardiography in coronary artery disease

Two-dimensional echocardiography has proven to be a very useful tool in the evaluation of global and regional left ventricular function in patients with coronary artcry disease. It has also been used in recognizing viable versus non-viable myocardium, combined with exercise or pharmacological stress. Recent development in transpulmonary ultrasound contrast agents inspired new interest in the cardiologists in myocardial perfusion imaging. Though most agents have proven helpful in (a few agents, including Optison and Leovist , have been approved for clinical application in several continents) left ventricular border delineation, their roles in myocardial perfusion imaging has not been studied extensively. The ability of two-dimensional methods in accurate assessment of the site and extent of wall motion and perfusion abnormalities is limited to the use of a few selected cross-sectional views of the left ventricle and employment of geometric assumptions of the ventricular cavity and walls. This leads to source of errors in quantitative studies of non-symmetric ventricles such as those undergone myocardial infarction and geometric remodeling. Twodimensional echocardiography is also limited in the evaluation of the mechanism of and in quantifying the severity of mitral regurgitation in patients with ischemic heart diseasc. Other complications of ischemic heart disease such as intracardiac thrombus can be diagnosed by two-dimensional echocardiography, but a more reproducible technique, such as three-dimensional echocardiography, may provide more reliable data on the therapeutic results in serial follow-up studies. Imaging of the blood vessels inc1uding coronary and carotid arteries has been relied mainly on invasive techniques. Two-dimensional ultrasound has shown limited promises in vascular imaging. Both the heart and the blood vessels are three-dimensional structures. An ideal approach in accurate and comprehensive examination of the heart and blood vessels is one that can collect volumetric information of the heart or vessels and is able to display them in three dimensions. Threedimensional echocardiography has demonstrated its superiority over two-dimensional methods in quantification of chamber volumes and function and in display of congenital or valvular abnormalities. Its role in the evaluation of coronary artery disease has not been fully explored. The purpose of this thesis was to examine the potential of three-dimensional echocardiography in qualitative and quantitative evaluation of coronary artery disease and related abnormalities

Taxonomic studies of the hydras

9 p. : ill. ; 24 cm.Includes bibliographical references (p. 9).Description of Hydra cauliculata, new species -- Further notes on Hydra littoralis Hyman, 1931 -- Distributional notes on other species

Genetic Interactions with Age, Sex, Body Mass Index, and Hypertension in Relation to Atrial Fibrillation: The AFGen Consortium

It is unclear whether genetic markers interact with risk factors to influence atrial fibrillation (AF) risk. We performed genome-wide interaction analyses between genetic variants and age, sex, hypertension, and body mass index in the AFGen Consortium. Study-specific results were combined using meta-analysis (88,383 individuals of European descent, including 7,292 with AF). Variants with nominal interaction associations in the discovery analysis were tested for association in four independent studies (131,441 individuals, including 5,722 with AF). In the discovery analysis, the AF risk associated with the minor rs6817105 allele (at the PITX2 locus) was greater among subjects ≤ 65 years of age than among those > 65 years (interaction p-value = 4.0 × 10-5). The interaction p-value exceeded genome-wide significance in combined discovery and replication analyses (interaction p-value = 1.7 × 10-8). We observed one genome-wide significant interaction with body mass index and several suggestive interactions with age, sex, and body mass index in the discovery analysis. However, none was replicated in the independent sample. Our findings suggest that the pathogenesis of AF may differ according to age in individuals of European descent, but we did not observe evidence of statistically significant genetic interactions with sex, body mass index, or hypertension on AF risk