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Biomedical subjects

M H Luria

Publications and source records attributed to M H Luria.

17 recordsLinked to original sources
PubMed1992

Day vs night ECG and heart rate variability patterns in patients without obvious heart disease.

The day vs night values of variables that may be related to the autonomic nervous system were compared in 50 individuals without obvious heart disease. Using ambulatory electrocardiographic monitoring and heart rate variability analysis, it was found that in contrast to daytime, nocturnal heart rate and total heart rate variability were reduced and low (0-0.05 Hz) and high (0.2-0.35 Hz) frequency power of nocturnal heart rate variability were increased, whereas mid-frequency (0.05-0.2 Hz) power was reduced. In addition, nocturnal episodes of trapezoidal-shaped waveforms of heart rate increase were present primarily at night and ST was elevated to a greater extent at night. Many of these factors were related to age and tentatively, despite the small sample size, reflect an age-related diminished autonomic nervous system response. These results serve to establish a circadian basis for comparison when evaluating disease states such as ischemic heart disease and its prognosis.

Adult↗
PubMed1991

Cardiovascular risk factor clustering and ratio of total cholesterol to high-density lipoprotein cholesterol in angiographically documented coronary artery disease.

High levels of cardiac risk factors tend to cluster together and act synergistically. To develop a suitable and practical marker for clustering, we evaluated 380 consecutive patients at the time of coronary angiography. Analyses of lipid, rheologic, clinical and arteriographic profiles indicated a variety of interwoven relations. Because the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol (total/HDL cholesterol) was closely related to both the presence and extent of greater than or equal to 50% diameter reduction of greater than or equal to 1 coronary arteries, it was used to divide patients into quartiles. Clustering of high- and low-level risk factors was demonstrated in the highest and lowest quartiles of total/HDL cholesterol, respectively (p less than 0.001). The highest quartile may be characterized by an only moderately elevated total cholesterol level but patients in this quartile may have a very low HDL cholesterol level, high triglycerides, a tendency toward high hemoglobin and fibrinogen levels, a history of smoking, previous myocardial infarction and multivessel disease. These results suggest that total/HDL cholesterol serves as a marker not only for obstructive coronary disease but also for a cluster of potentially modifiable risk factors.

Angiography↗
PubMed1990

Atherosclerosis: the importance of HDL cholesterol and prostacyclin: a role for niacin therapy.

Niacin reduces the incidence of non-fatal myocardial way infarction, confers a significant long-term survival benefit after recovery from myocardial infarction, and has had many years of study and usage by the medical community. Recent evidence suggests that via mechanisms which elevate HDL cholesterol and also release endogenous prostacyclin, niacin should be a potent agent in the long-term treatment of atherosclerosis.

Animals↗
PubMed1989

Influence of ethanol on the delivery of intravenous nitroglycerin solutions.

In order to evaluate the surface tension lowering effect of ethanol in intravenous nitroglycerin solutions of varying concentrations, drop size was measured in intravenous transfusion sets that should deliver 60 drops/ml. Ethanol 5% solutions led to a significant decrease in drop volume and a concomitant increase in the number of drops per unit volume, up to 79 drops/ml were observed. The surface tension lowering effect may account for decreases of up to 25% in delivered nitroglycerin when drop counting infusion pumps are used, and may be a factor in the development of apparent tolerance to intravenous nitroglycerin.

Ethanol↗
PubMed1988

Effect of low-dose niacin on high-density lipoprotein cholesterol and total cholesterol/high-density lipoprotein cholesterol ratio.

Niacin significantly alters blood lipid concentrations but its use has been limited because of clinically disturbing side effects. In an attempt to circumvent these drawbacks, 55 patients with cardiovascular disease were given low-dose long-acting niacin, 1 g/d. Treatment was continued for a mean of 6.7 months and lipid values were compared with a non-treated group of 17 patients followed for a mean of 6.3 months. Lipid values did not change in the nontreated group. In the niacin-treated group total cholesterol and triglyceride levels also did not significantly change. High-density lipoprotein (HDL) cholesterol level rose 31% from 1.01 +/- 0.31 mmol/L to 1.32 +/- 0.31 mmol/L and total cholesterol/HDL cholesterol ratio was reduced 27% from 6.4 +/- 1.9 to 4.7 +/- 1.3. Despite these results, 40% of the patients left the study mainly because of side effects. Apart from one patient who developed overt diabetes, of questionable relationship to niacin, no patient developed serious side effects such as jaundice or peptic ulcer as seen with much higher doses of the drug. Although often difficult to administer to patients, niacin, particularly in low dose, deserves consideration as an inexpensive agent especially useful for elevating HDL cholesterol level and altering the total cholesterol/HDL cholesterol ratio.

Aged↗
PubMed1979

Survival after recovery from acute myocardial infarction. Two and five year prognostic indices.

A prognostic index for two year survival following recovery from acute myocardial infarction has been verified in an independent group of 105 patients. Five variables comprise the index: systolic blood pressure level on admission, highest blood urea nitrogen level in the cardiac care unit; atrial arrhythmias in the cardiac care unit; angina pectoris for more than three months or a previous myocardial infarction; and more than one ventricular ectopic beat per hour recorded on an 8 hour dynamic electrocardiogram during convalescence just prior to hospital discharge. One hundred twenty-six patients have also been followed for five or more years, and we now report a five year prognostic index. Discriminant analysis indicates that the same five variables, although weighted differently, continue to be significant for prognostic assessment and may be utilized in the identification of patients at high and lower risk.

Actuarial Analysis↗
PubMed1977

A-V block.

Explore the source record for details and available documents.

Atrioventricular Node↗
PubMed1976

Acute myocardial infarction: prognosis after recovery.

A prognostic index for 2-year survival after recovery from acute myocardial infarction was constructed from variables obtained during its course. One hundred ten of 143 patients survived 2 years, and 27 of 33 patients died of cardiac-related causes. Univariate analysis showed that 12 variables were significantly different between the surviving and nonsurviving groups. Discriminant analysis indicated five variables with meaningful predictive value to be included in a prognostic index: admission systolic blood pressure; highest blood urea nitrogen level in the cardiac care unit: atrial arrhythmias in the cardiac care unit; angina pectoris for more than 3 months or a previous myocardial infarction; and more than one ventricular ectopic beat per hour recorded on a dynamic electrocardiogram during the 17th to 24th hospital day. The prognostic index emphasizes the importance of extensive myocardial impairment and provides a means for identifying patients at risk of early mortality.

Angina Pectoris↗
PubMedDate not supplied

Computer processing of artifact and arrhythmias in heart rate variability analysis.

Analysis of heart rate variability (HRV) with Holter monitoring is often difficult due to excessive artifacts and arrhythmias. While short sudden surges are treated successfully by most methods, slow heart rate (HR) variations, nocturnal trapezoidally-shaped HR increases and special types of arrhythmias which are similar to normal HRV fluctuations may distort further time domain and spectral analysis. This paper examines the advantages and disadvantages of different methods for preprocessing of HR data. We have developed the following approach to the analysis of HRV. (1) A combination method based on the absolute difference between HR values and both the last normal HR value and an updated mean is used for removal of artifacts and arrhythmias. This method can detect both sudden surges in HR values as well as longer periods of noise combined with slow normal variations. An additional stage of wild point removal is then optionally applied. (2) Certain special problems such as large T-waves, bigeminal rhythm, slow HR variations and nocturnal trapezoidally-shaped HR increases are also identified. Although none of the algorithms can be applied successfully to all cases, the final computer analysis for preprocessing described in the present study has proved to be superior to the simplified methods which are usually used and provides more suitable data for HRV analysis.

Algorithms↗
PubMedDate not supplied

Left subclavian vein puncture for insertion of Swan-Ganz catheters.

A rapid, safe, and reliable method for insertion of Swan-Ganz flow-directed, balloon-tipped catheters using the left subclavian vein is described. Experience with this method in 24 consecutive patients indicates a distinct advantage over the antecubital fossa approach: A venous cutdown is not necessary, the pulmonary artery is readily entered, fluoroscopy is not required, the patient is free to move both arms, and thrombophlebitis and infection occur infrequently. With proper attention to landmarks such as the clavicular tubercle, the procedure may be performed with facility. The major complication, pneumothorax, is minimized if mechanical ventilators are briefly disconnected during the subclavian puncture.

Cardiac Catheterization↗
PubMedDate not supplied

A miniature segment-length strain gauge arch for the assessment of myocardial function.

A miniature myocardial segment-length strain gauge arch utilizing solid-state strain gauge elements is described. The arch weighs 0.25 g, has a frequency response flat to 30 Hz, requires simple circuitry, and is stable in situ for periods exceeding 6 hours. Its miniaturization and ease of insertion offer distinct advantages over similar devices previously described. Miniature arches have been applied simultaneously to multiple sites to assess left ventricular function in dogs. The response of these arches to a variety of interventions indicates that this device may be used to follow localized segment-length and velocity changes. The study also clearly demonstrates that the orientation of strain gauge arches with respect to muscle fiber direction in the ventricular wall qualitatively and quantitatively affects the recorded segment-length alterations.

Animals↗