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Biomedical subjects

C L Feldman

Publications and source records attributed to C L Feldman.

11 recordsLinked to original sources
PubMed1979

Approaches to determination of left ventricular volume and ejection fraction by real-time two-dimensional echocardiography.

Left ventricular volumes and ejection fraction were derived from real time two-dimensional echocardiographic images (2 DE) and single plane (RAO) left ventricular cineangiograms in a series of 50 patients. Prospective application of a series of 6 alternate algorithms showed that a modified Simpson's rule approach using mitral and papillary muscle cross sections and an apical four chamber view provided the best 2 DE - angiographic correlations: for end-diastolic volume r = 0.82, SEE = 39 ml; for end-systolic volume r = 0.90, SEE = 29 ml and for ejection fraction r = 0.80, SEE = 0.09. The large SEE for volume determination indicates that further refinements are necessary to predict left ventricular volumes adequately; however, ejection fraction can be derived with an accuracy which allows practical clinical decisions in patients with satisfactory 2 DE images.

Cardiac Output↗
PubMed1979

Assessment of left ventricular ejection fraction and volumes by real-time, two-dimensional echocardiography. A comparison of cineangiographic and radionuclide techniques.

Five different algorithms for determining left ventricular (LV) ejection fraction (EF) and volumes from two-dimensional echocardiographic examination (TDE) were compared with standard methods for obtaining EF and volume from x-ray cineangiography (cine) and EF from radionuclide ventriculography (RVG) in 35 patients. Although all methods correlated positively, the degree of correlation varied with the algorithm used. For EF determination, TDE algorithms (especially those using multiple planes of section) were superior to unidimensional algorithms commonly used with M-mode echocardiography. The best algorithm (modified Simpson's rule) correlated well enough with cine EF (r = 0.78; SEE 0.097) and RVG EF (r = 0.75; SEE 0.087) to make clinically useful estimates. TDE volumes also correlated meaningfully with cine end-diastolic and end-systole volumes (r = 084; n = 70) but were associated with a large standard error of the estimate (43 ml) and offered less advantage over unidimensional volume estimates. Quantitative application of TDE appears to be a useful noninvasive method of evaluating LVEF, but is not as useful for estimating LV volumes.

Cineangiography↗
PubMed1976

Vectorial characteristics of ventricular extrasystoles stimulated during cardiac catheterization.

Ventricular extrasystoles (VES) from different areas of the ventricular muscle mass were obtained by mechanical stimulation of inflow and outflow regions of the right ventricle (RV) and apical and basal portions of the left ventricle (LV) during cardiac catheterization. Cube system vectorcardiogram (VCG) patterns of VES from each location were analyzed to determine the specificity of vector orientation from each site. Transverse plane VCG distinguished between nonseptal LVES and RVES, while a combination of transverse and either sagittal or frontal planes permitted further localization of septal VES to inflow or outflow regions of the RV and apical and basal areas of the LV.

Adult↗
PubMed1975

Decreased premature ventricular contractions through use of the relaxation response in patients with stable ischaemic heart-disease.

To determine whether decreased sympathetic-nervous-system activity achieved by the relaxation response could decrease premature ventricular contractions (P.V.C.s), eleven ambulatory patients with proven, stable ischaemic heart-disease and P.V.C.s were investigated. The patients, who were taking no medication for the P.V.C.s, were trained to elicit regularly the relaxation response through a non-cultic psychological technique. The frequency of the P.V.C.s was measured by computer analysis of Holter monitor tapes for 2 complete days before learning the technique, which was learned in approximately 5 minutes after the second day. Patients were instructed to evoke the response for 20 minutes twice daily thereafter. After 4 weeks, a reduced frequency of P.V.C.s was documented in eight of the eleven patients. This effect was especially striking during the sleeping hours and less so during the entire monitoring session. The relaxation response is a simple, no cost, non-pharmacological mechanism without side-effects which seemed to decrease the frequency of P.C.V.s in most patients with ischaemic heart-disease.

Aged↗
PubMed1975

Ventricular premature beats and mortality of men with coronary heart disease.

Frequency and qualitative characteristics of ventricular premature beats (VPB) are determined from 1 hour of electrocardiogram (ECG) monitoring of men with coronary heart disease in a continuing study among members of the Health Insurance Plan of Greater New York. Mortality among 924 such men during an average observation period of 10 months was higher among men with VPB than among those free of VPB. In comparison with the routine 12-lead ECG, the hour of ECG monitoring increased the proportion of men identified as showing ectopic activity from 15% to 52%. Only half of men with 10 or more VPB in the hour of monitoring were noted as having VPB on the routine ECG; mortality among these men was relatively high whether or not VPB appeared on the short sample ECG.

Adult↗
PubMedDate not supplied

Cardiovascular monitoring in the coronary care unit.

The present status of cardiovascular monitoring in the coronary care unit is reviewed. Major emphasis is placed on electrocardiographic monitoring, the only form of monitoring used on most patients who have suffered recent myocardial infarction. The capabilities and limitations of computer systems to perform electrocardiographic monitoring are reviewed, as are present techniques for hemodynamic monitoring and computerized integration of electrocardiographic, hemodynamic, and other patient data.

Arrhythmias, Cardiac↗
PubMedDate not supplied

A 60x computer-based Holter tape processing system.

Since its introduction in 1968, the basic algorithm for automatic recognition of ventricular ectopic depolarizations, developed at Worcester Polytechnic Institute, has been implemented and modified by a number of investigators. The modified multi-template algorithm is conceptually similar to the original algorithm except that there are eight templates stored for each patient. A new template is stored whenever the match with each of the old templates yields a correlation coefficient less than 0.79. The system reads a Holter tape at 60 x real time for heart rates of 80 beats per minute, with relatively few false positives.

Arrhythmias, Cardiac↗