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Wall Segments (wall + segment)

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Medical Sciences	100%

Selected Abstracts

Risk Stratification and Prognosis in Octogenarians Undergoing Stress Echocardiographic Study

ECHOCARDIOGRAPHY, Issue 8 2007
F. A. C. C., Farooq A. Chaudhry M.D.
Background: The prognostic value of stress echocardiography (SE) for the diagnosis and risk stratification of coronary artery disease in octogenarians is not well defined. Methods: Follow-up of 5 years (mean 2.9 ± 1.0 years) for confirmed nonfatal myocardial infarction (n = 17) and cardiac death (n = 37) was obtained in 335 patients, age ,80 years (mean age 84 ± 3 years, 44% male), undergoing SE (33% treadmill, 67% dobutamine). Left ventricular (LV) regional wall motion was assessed by a consensus of two echocardiographers and scored as per standard five-point scale, 16-segment model of wall motion analysis. Ischemic LV wall segment was defined as deterioration in the thickening and excursion during stress (increase in wall-motion score index (WMSI) ,1). Results: By univariate analysis, inducible ischemia (chi-square = 38.4, P < 0.001), left ventricular ejection fraction (chi-square = 41.2, P < 0.001), a history of previous myocardial infarction (chi-square = 22.3, P < 0.01), hypertension (chi-square = 33, P < 0.01), and age (chi-square = 27.7, P < 0.01) were significant predictors of future cardiac events. WMSI, an index of inducible ischemia, provided incremental prognostic information when forced into a multivariable model where clinical and rest echocardiography variables were entered first. WMSI effectively stratified octogenarians into low- and high-risk groups (annualized event rates of 1.2 versus 5.8%/year, P < 0.001). Conclusions: Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data. [source]

Palpable Cardiac Impulse Predicts Adequate Acoustic Windows

ECHOCARDIOGRAPHY, Issue 1 2000
F.A.C.C., JAMES P. EICHELBERGER M.D.
In this study, we sought to determine the usefulness of palpating an apical cardiac impulse on physical examination in predicting adequate echocardiographic images for stress echocardiography. A variety of stress tests using either echocardiographic imaging or nuclear imaging are available to referring physicians. Deciding which test is best for a given patient is often dificult. In the case of stress echocardiography, the most significant limitation is poor image quality i n a small portion of patients. We enrolled 136 consecutive outpatients referred for echocardiography. The presence or absence of a palpable cardiac apex on physical examination was recorded by two independent and blinded examiners. Data, including age, sex, weight, prior chest surgery, and smoking, were also collected. Echocardiographic imaging of the left ventricle was scored according to the number of adequately visualized wall segments in a standard 16-segment model. One hundred eleven patients (82%) had adequate visualization of at least 14 of 16 wall segments. Ninety-eight patients (72%) had a palpable cardiac impulse, of whom 90 (92%) also had adequate acoustic image quality versus only 21 (55%) of the 38patients in whom an apex was not palpable (P < 0.0001). Other variables that were measured were not significantly related to image quality, with the exception of weight; patients with adequate images weighed a mean of 75 kg versus 91 kg i n those with inadequate images (P < 0.0006). However, multivariate analysis showed a palpable apex to be the only independent predictor after controlling for other variables. A physical examination assessment for a palpable apical impulse is useful to predict adequate echocardiographic image quality for stress echocardiography. When used in conjunction with other parameters, this may lead to more appropriate referral to augmented stress testing. (ECHOCARDIOGRAPm, Volume 17, January 2000) [source]

Anthelmintic paraherquamides are cholinergic antagonists in gastrointestinal nematodes and mammals

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2002
Erich W. Zinser
Oxindole alkaloids in the paraherquamide/marcfortine family exhibit broad-spectrum anthelmintic activity that includes drug-resistant strains of nematodes. Paraherquamide (PHQ), 2-deoxoparaherquamide (2DPHQ), and close structural analogs of these compounds rapidly induce flaccid paralysis in parasitic nematodes in vitro, without affecting adenosine triphosphate (ATP) levels. The mechanism of action of this anthelmintic class was investigated using muscle tension and microelectrode recording techniques in isolated body wall segments of Ascaris suum. None of the compounds altered A. suum muscle tension or membrane potential. However, PHQ blocked (when applied before) or reversed (when applied after) depolarizing contractions induced by acetylcholine (ACh) and the nicotinic agonists levamisole and morantel. These effects were mimicked by the nicotinic ganglionic blocker mecamylamine, suggesting that the anthelmintic activity of PHQ and marcfortines is due to blockade of cholinergic neuromuscular transmission. The effects of these compounds were also examined on subtypes of human nicotinic ACh receptors expressed in mammalian cells with a Ca2+ flux assay. 2DPHQ blocked nicotinic stimulation of cells expressing ,3 ganglionic (IC50 , 9 µm) and muscle-type (IC50 , 3 µm) nicotinic cholinergic receptors, but was inactive at 100 µm vs. the ,7 CNS subtype. PHQ anthelmintics are nicotinic cholinergic antagonists in both nematodes and mammals, and this mechanism appears to underlie both their efficacy and toxicity. [source]