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Biomedical subjects

M Nejat

Publications and source records attributed to M Nejat.

14 recordsLinked to original sources
PubMed2001

Left ventricular function and perfusion in elderly endurance athletes.

PURPOSE: To study the extent to which lifelong physical training can affect cardiovascular capacity, left ventricular function, and myocardial perfusion in elderly men. METHODS AND RESULTS: Ten healthy male veteran endurance athletes aged 73 +/- 3 yr (mean +/- SD) and a control group of 12 sedentary or moderately physically active healthy subjects aged 75 +/- 2 yr were studied. Echocardiographic examinations at rest and exercise stress tests were performed. Gated blood pool scans and myocardial perfusion scintigraphy were recorded at rest and during exercise. Maximal VO2 was 41 +/- 7 mL.kg-1.min-1 in the athletes and 26 +/- 5 mL.kg-1.min-1 in the controls (P < 0.001). Echocardiographic measures of systolic and diastolic function at rest were better in the athletes. The ejection fraction during exercise was also higher in the athletes (P = 0.003). Seven of the 10 athletes, but none of the controls, had pathological myocardial perfusion findings. CONCLUSIONS: By endurance training, a high level of physical capacity can be maintained late in life. The superior cardiovascular function in the veteran athletes, compared with the untrained controls was due to both better systolic and diastolic left ventricular function. Myocardial perfusion defects in athletes should be judged with caution, as this finding is common both in veteran athletes and as previously shown, in young athletes.

Aged↗
PubMed1999

Myocardial sestamibi uptake in healthy subjects is related to age, gender and habitus.

The object of this study was to evaluate the effect of gender, age and anthropometric data on regional isotope uptake in myocardial perfusion scintigraphy using 99mTc-MIBI-SPECT (myocardial sestamibi single-photon emission technique). Seventy-one healthy, non-smoking subjects, 42 men and 29 women between 40 and 80 years of age, with less than 5% likelihood of having coronary artery disease were studied. All subjects underwent a maximal exercise and rest MIBI-SPECT using a 2-day protocol and a 180 degrees anterior circular rotation. No correction for scatter or attenuation was made. Normalized regional activity was different in men and women in the anterior and inferior regions, with higher values anteriorly in men and inferiorly in women. Regional activity also differed with age in both women and men with higher relative activity in the anterior regions in the oldest age groups. Higher activities were seen in the basal parts of the left ventricle at rest compared with stress in both men and women. Regional isotope uptake was significantly affected by habitus expressed as body mass index (BMI) and thoracic circumference. Different protocols for stress and rest seem to be needed for men and women in different age groups, and for stress and rest when performing semiquantitative MIBI-SPECT and comparing data with a normal file of healthy subjects. Furthermore, such anthropometric data as BMI and/or thoracic circumference should be considered in order to minimize the risk for false-positive or false-negative scintigraphic results.

Adult↗
PubMed1998

Left ventricular function in endurance runners during exercise.

Left ventricular function in elite runners and controls was compared by means of nuclear angiocardiography. Fifteen middle- or long-distance runners and a control group of 10 sedentary to moderately physically active subjects were studied at rest and during semi-sitting incremental exercise. Ejection fraction was higher in the runners than the controls both at rest and during exercise. At the transition from rest to exercise left ventricular end-diastolic volume initially increased similarly in runners and controls by an average of 14 and 12%, respectively, with an increase in stroke volume by approximately 25 and 23%. The parallel increase in stroke volume and left ventricular end-diastolic volume could at least partly be because of the Frank-Starling mechanism. With increasing workloads, left ventricular end-diastolic volume and ejection fraction remained fairly constant, resulting in an unchanged stroke volume from the lowest to the highest exercise intensity. This was in the runners accomplished by a 41% increase in peak filling rate and a 38% increase in peak emptying rate with similar changes observed in the controls. This has to be due to increased myocardial contractility paralleling the systolic shortening with increasing heart rate. We conclude that endurance-trained athletes have a better systolic function expressed as higher ejection fraction both at rest and during exercise than untrained subjects reflecting an enhanced myocardial contractility contributing to the maintenance of a large stroke volume during exercise. The regulatory mechanisms however, appear to be similar for athletes and healthy controls.

Adult↗
PubMed1998

Factor V Leiden, activated protein C resistance, and retinal vein occlusion.

BACKGROUND: Resistance to activated protein C (APC resistance) is a thrombophilic abnormality characterized by a normal plasma level of protein C and an inherited defect in the coagulative response. This condition is believed to be caused by a point mutation in factor V, the so-called factor V Leiden, and is inherited as an autosomal dominant trait. PURPOSE: A case-control study was carried out to evaluate the prevalence of APC resistance and factor V Leiden in patients with retinal vein occlusion (RVO) and in control subjects. METHODS: Eighty-four consecutive RVO patients and 70 controls were tested for APC resistance with a commercial assay (Chromogenix). The first 30 patients and 47 controls were also studied for factor V Leiden. In addition, a repeat APC-resistance test was performed in 40 RVO patients and in 9 controls with a second-generation assay done to compare the reliability and reproducibility of the tests. RESULTS: Results of testing for APC resistance with the first-generation assay revealed positive results in 38 (45%) of the study patients and 6 (9%) of the controls. The difference in frequencies of APC resistance in patients and controls was statistically significant (P < 0.0001). In the patients tested for factor V Leiden, one (3%) was a heterozygous carrier of the Arg506GIn mutation and one (2%) of the controls was a heterozygous carrier. No homozygous individuals were identified in either the study or the control groups. The difference in frequencies of factor V Leiden in study patients and controls was not statistically significant (P = 1). The repeat APC-resistance assay using factor V-deficient plasma in 40 RVO patients and 9 controls did not show any significant difference between study patients and controls or an association between APC resistance and the determination of the factor V Leiden mutant. CONCLUSION: The first-generation commercial assay for APC resistance is not a useful screening test. The molecular test for factor V Leiden is the only definitive method. Furthermore, no significant association was found between factor V Leiden and retinal vein occlusion. Accordingly, routine testing for the presence of the factor V Leiden mutant is not advisable for patients with retinal vein occlusion.

Activated Protein C Resistance↗
PubMed1997

High incidence of scintigraphic myocardial uptake defects at rest and during exercise in male elite runners.

OBJECTIVE: To evaluate the usefulness of myocardial perfusion scintigraphy (MIBI-SPECT) as a diagnostic tool in well trained men. DESIGN: The study was prospective, involving 2 d stress-rest myocardial scintigraphy (MIBI-SPECT), polar map reconstruction with and without uniform attenuation correction, and comparison with a healthy male group (local Swedish) and with a commonly used reference group (American, Emory University Hospital). SETTING: University Hospital, Stockholm, Sweden. SUBJECTS: 16 healthy, male elite runners (mean (SD) age 26.1 (3.1) years). Peak oxygen uptake 73 (4) ml O2/kg/min. RESULTS: Uptake defects on polar maps were found in the majority of the runners compared with both reference groups (local Swedish 13/16, American 10/16). Most defects (91%) were fixed. Defects were located in the anterior, lateral, and posterior regions of the left ventricle. Application of a uniform attenuation correction algorithm enhanced rather than reduced perfusion defect size, probably because this correction method is imperfect in SPECT studies of the thoracic cavity. CONCLUSIONS: If myocardial perfusion scintigraphy is used for evaluating well trained men, existing normal reference files for semiquantitative evaluation appear to be inadequate.

Adult↗
PubMed1997

Atopy, asthma, and emphysema in patients with severe alpha-1-antitrypysin deficiency.

Bronchial asthma is characterized by episodic airway obstruction and associated with wheezing, a bronchodilator response, an elevation in total serum IgE, and atopy. To determine whether asthma is more common in subjects with severe alpha 1-antitrypsin deficiency (alpha 1-ATD) and airway obstruction, we compared 38 patients who had this condition (Group 1) with 22 control patients with chronic obstructive pulmonary disease (COPD) (Group 2) and with five subjects with alpha 1-ATD and normal spirometry (Group 3). Subjects were evaluated with a symptom questionnaire, pulmonary function testing, intradermal allergen testing, and serum IgE measurement. Self-reported wheezing was a common symptom in all patient groups, but attacks of wheezing with dyspnea were significantly more common in Group 1. Of those patients with airway obstruction, more than 50% showed a bronchodilator response whether suffering from alpha 1-ATD or not. Atopy was more common in Group 1 than in Group 2 (48% versus 27%). Mean serum IgE for all groups was similar but significantly greater in patients with atopy. We estimated the prevalence of asthma in the study groups on the basis of the criteria of attacks of wheezing, reversible airway obstruction, atopy, and that increased IgE. The proportion of patients with asthma in Group 1 was significantly greater than that in Group 2 (22% versus 5%, p < 0.05). Our study shows that with control for the degree of airway obstruction, asthma, as defined, is more common in patients with alpha 1-ATD than in those without it. We suggest that a lack of alpha 1-AT in airways increases the propensity to develop asthma.

Adult↗
PubMed1994

Are wall thickening measurements reproducible?

An early transesophageal echocardiography (TEE) study reported that there was high inter- and intraobserver variability in measurements of wall thickening (WT). This study reevaluated TEE for the measurement of WT in the transverse plane and, for the first time, evaluated it in the longitudinal plane. Ten patients were studied with a biplane TEE probe inserted and positioned to obtain a transverse short-axis (SA) view of the left ventricle at the midpapillary muscle level. A longitudinal transgastric long-axis (LA) view of the left ventricle was then obtained. This measurement sequence was performed four times in each patient. Off-line analysis was performed independently by two observers. In each tomographic cut of the ventricle, four locations for measurement were defined. WT was measured in three consecutive beats, and the results averaged (WT1). The observers repeated the measurements (WT2) 2 wk later, and the intra- and interobserver differences (mm) were calculated. Average differences for the intraobserver comparisons of wall thickening were small (0.08-0.24 mm), but the high standard deviations (1.17-2.44 mm) suggest significant variability between individual measurements. Thus it appears that measurements of wall thickening with small mean intraobserver bias may be possible, but to offset the potential for variability, multiple measurements are necessary. Also, careful standardization of location and edge definition is important to limit interobserver variability.

Aged↗
PubMed1993

Intraoperative transesophageal echocardiography for the detection of cardiac preload changes induced by transfusion and phlebotomy in pediatric patients.

BACKGROUND: Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume. METHODS: Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography of the midpapillary left ventricular short axis view and hemodynamics were recorded at baseline (T1), during withdrawal of blood until the systolic blood pressure decreased by 5 mmHg (T2) and 10 mmHg (T3), and after reinfusion of the blood (T4). The identical cycle of blood withdrawal and reinfusion was repeated after administration of calcium chloride (10 mg/kg; T5-T8). RESULTS: Manually traced transesophageal echocardiography images of the left ventricular end-diastolic area decreased from 4.64 +/- 1.50 cm2 at T1 to 4.03 +/- 1.25 cm2 at T2 to 3.78 +/- 1.35 cm2 at T3, and increased to 4.42 +/- 1.75 cm2 at T4. Nearly identical results were obtained at T5-T8. End-systolic areas significantly decreased from 1.96 +/- 0.86 cm2 at T1 to 1.52 +/- 0.73 cm2 at T2 to 1.41 +/- 0.62 cm2 at T3, and increased to 1.87 +/- 0.88 cm2 at T4. An experienced anesthesiologist-echocardiographer blinded to study events was able to identify mild reductions in blood volume (T2, T3, T6, T7) from recorded cine-loop video recordings with high sensitivity (80-95%) and specificity (80%). CONCLUSIONS: Transesophageal echocardiography is a potentially useful monitor of cardiac filling changes in pediatric patients.

Blood Transfusion↗
PubMed1986

Hypertrophic cardiomyopathy in the elderly. A frequently misdiagnosed disease.

In 20 elderly patients (mean age, 76 years; range, 70 to 86 years), hypertrophic cardiomyopathy was diagnosed echocardiographically. Although the disease was moderate to severe in all patients, the diagnosis was not suspected in 19 patients prior to echocardiography. Inappropriate therapy consisting of potentially harmful drugs, such as digitalis, nitrates, and diuretics, was commonly used, often for unclear indications. Since echocardiography can easily and accurately diagnose hypertrophic cardiomyopathy, an increased awareness of its occurrence in the elderly and use of echocardiography would reduce diagnostic and therapeutic errors.

Aged↗
PubMed1985

ST segment depression in acute anterior myocardial infarction.

We initiated a retrospective study to determine whether ST segment depression seen in inferior leads (II, III, and aVF) during acute anterior myocardial infarction (MI) is a reciprocal change or an independent sign of ischemia of additional myocardium. We selected 20 patients with anterior MI and attempted to compare findings of subsequent cardiac catheterization and the clinical course of 14 patients with ST segment depression (group A) and six without ST segment depression (group B). Patients in group A had a higher prevalence of right coronary artery disease (13 vs 0, P less than .01), multivessel disease (14 vs two, P less than .01), inferior wall motion abnormalities (seven vs 0, P less than .01), and ejection fraction of less than .50 (ten vs two, P greater than .05) than those in group B. A greater number of patients in group A had serious in-hospital and follow-up complications (12 vs two, P less than .05). We conclude that ST depression in leads II, III and aVF during acute anterior MI is not "reciprocal change" but a high-risk indicator.

Cardiac Catheterization↗