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M D Cheitlin

Publications and source records attributed to M D Cheitlin.

At least 145 records · Page 8Linked to original sources
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Echocardiography in serial evaluation of left ventricular systolic and diastolic function: importance of image acquisition, quantitation, and physiologic variability in clinical and investigational applications.

Quantitative echocardiography is frequently used for serial evaluation of left ventricular performance. This prospective study was designed to determine the extent to which the acts of image acquisition and quantitation, and the subjects themselves, affect total variability in two-dimensional and Doppler echocardiographic indexes of left ventricular morphology and performance. Therefore, two technicians and two readers acquired and analyzed 60 echocardiograms from 15 normal subjects, each of whom was studied four times (twice on each of two visits). Analysis of variance based on generalizability theory was used to estimate the magnitude of these variability sources by calculating standard deviations (SD) and used to estimate their contribution to total variability. Of the two-dimensional echocardiographic indexes tested, ejection fraction varied least (SD, 6.6%) and left ventricular mass varied most (SD, 35.3 gm). Of the Doppler indexes, normalized early diastolic filling velocity integral varied least (SD, 8.4%) and deceleration time varied most (SD, 48.6 msec). Technical (image acquisition and quantitation) variability contributed most (and subject variability least) to total variability of stroke volume (68%) and deceleration time (67%). Technical variability contributed least (and subject variability most) to variability of ejection fraction (43%) and diastolic filling time (25%). The acts of image acquisition and quantitation varied more between than within technicians and readers. Peak atrial filling velocity and the ratio of peak early to atrial filling velocity significantly differed between technicians. Left ventricular ejection fraction, left ventricular mass, peak atrial filling velocity, early filling integral, and deceleration of early filling differed significantly between readers. Therefore the acts of image acquisition and quantitation, and subject variability itself, all contribute to total variability in echocardiographic indexes. Changes seen on clinical studies should be interpreted as abnormal only when exceeding the total variability originating from these sources. Generalizability theory allows one to tailor strategies to reduce variability. These strategies include increasing the number of observations, readers, and technicians for any given "baseline" study and using the same readers and technicians for sequential follow-up studies.

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PubMedDate not supplied

Database Conference January 27-30, 2000, Washington D.C.--Do existing databases answer clinical questions about geriatric cardiovascular disease and stroke?

EXECUTIVE SUMMARY: Most randomized, controlled trials evaluating the effectiveness of pharmaceutical, surgical, and device interventions for the prevention and treatment of cardiovascular disease have excluded patients over 75 years of age. Consequently, the use of these therapies in the older population is based on extrapolation of safety and effectiveness data obtained from younger patients. However, there are many registries and observational databases that contain large amounts of data on patients 75 years of age and older, as well as on younger patients. Although conclusions from such data are limited, it is possible to define the characteristics of patients who did well and those who did poorly. The goal of this conference was to convene the principal investigators of these databases, and others in the field of geriatric cardiology, to address questions relating to the safety and effectiveness of treatment interventions for several cardiovascular conditions in the elderly. Seven committees discussed the following topics: (I) Risk Factor Modification in the Elderly; (II) Chronic Heart Failure; (III) Chronic Coronary Artery Disease: Role of Revascularization; (IV) Acute Myocardial Infarction; (V) Valve Surgery in the Elderly; (VI) Electrophysiology, Pacemaker, and Automatic Internal Cardioverter Defibrillators Databases; (VII) Carotid Endarterectomy in the Elderly. The chairs of these committees were asked to invite principal investigators of key databases in each of these areas to discuss and prepare a written statement concerning the available safety and efficacy data regarding interventions for these conditions and to identify and prioritize areas for future study. The ultimate goal is to stimulate further collaborative outcomes research in the elderly so as to place the treatment of cardiovascular disease on a more scientific basis.

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