Moran Sagiv

Wingate Institute

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Left Ventricular Contractility in Response to Upright Isometric Exercise in Heart Transplant Recipients and Healthy Men

Journal of Cardiopulmonary Rehabilitation and Prevention (2008)

Moran Sagiv Offer Amir Ehud Goldhammer David Ben‐Sira Ruthie Amir

We evaluated left ventricular contractility during upright isometric exercise, in heart transplant recipients (HTRs) and in healthy controls, using ejection fraction and end-systolic pressure/volume ratio indexes.Fifteen healthy men (40 +/- 13 years) and 10 HTRs (42 +/- 12 years) underwent dead lift (DL) test at 30% of maximal effort for 3 minutes. Echocardiographic variables were measured during the final 45 seconds.During DL test, HTRs were significantly different (P < .01) from controls in all parameters except end-diastolic volume. DL test had lower mean values of ejection fraction (49.9% +/- 8.3% vs 67.0% +/- 4.3%, respectively) and left ventricular end-systolic pressure/volume ratio (3.5 +/- 0.7 vs 5.5 +/- 1.2, respectively) whereas higher values of end-systolic volume (51.0 +/- 9.4 mL vs 34.1 +/- 5.3 mL, respectively). Importantly, an intergroup effect was found in end-systolic pressure/volume ratio, further signifying differential response of HTRs. End-systolic pressure/volume ratio increased consistently (P < .001) in both groups, whereas the overall main effect of ejection fraction response was not significant.Left ventricular function during upright isometric exercise displays differential pattern of response in HTRs in comparison with healthy controls. However, cardiac contractility in HTRs remained stable at peak systolic blood pressure produced by the isometric DL exercise. Results suggest that both ejection fraction and end-systolic pressure/volume ratio indexes can be used for assessment of ventricular function in patients after heart transplantation.

Contractility

End-systolic volume

10.1097/01.hcr.0000311503.64645.85

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Citations (9)

Author Index Vol. 53, 2007

Gerontology (2007)

Carolyn Unsworth Yvonne Wells Shane Thomas Hal Kendig Colette Browning

10.1159/000131889

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Citations (0)

AT1R Polymorphism Is Associated with Increased Mortality in Chronic Systolic Heart Failure Patients

Journal of Cardiac Failure (2007)

Offer Amir Ruthie E. Amir Hagar Paz Moran Sagiv R Amar

10.1016/j.cardfail.2007.06.424

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NRF2 intron 3 A/G polymorphism is associated with endurance athletes’ status

Journal of Applied Physiology (2009)

Nir Eynon Moran Sagiv Yoav Meckel José Alberto Duarte Alberto J. Alves

The aim of this study was to determine the frequency distribution of nuclear respiratory factor 2 (NRF2) intron 3 A/G polymorphism (rs7181866) among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy controls. Results showed that there was a significantly higher proportion of the AG genotype, rather than the AA genotype, in the group of endurance athletes compared with the sprinters (P = 0.014) and controls (P = 0.0008). However, the sprinters' genotype and allele frequencies were similar to those of the control group (P = 0.62 for genotype distribution percentage). These results were even more pronounced when we compared between the subgroups of 20 elite endurance athletes (those who had represented Israel in a world track-and-field championship or in the Olympic Games) and 54 national-level endurance athletes. In the group of elite endurance athletes the G allele was more frequent than in the national-level endurance athletes (P = 0.047). We conclude that 1) in Israeli athletes the NRF2 AG genotype is more frequent in elite endurance athletes than in sprinters, and 2) within the endurance group the NRF2 AG genotype and the G allele are more frequent in elite athletes, suggesting a positive association between the AG genotype, and possibly the G allele, and the likelihood of being an elite endurance athlete.

Endurance Training

10.1152/japplphysiol.00310.2009

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Citations (30)

Genotype-phenotype associations between chymase and angiotensin—converting enzyme gene polymorphisms in chronic systolic heart failure patients

Genetics in Medicine (2008)

Ruthie E. Amir Offer Amir Hagar Paz Moran Sagiv Roi Mor

Chymase

Etiology

10.1097/gim.0b013e3181804b9c

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Citations (16)

Factors defining oxygen uptake at peak exercise in aged people

European Review of Aging and Physical Activity (2010)

Moran Sagiv Ehud Goldhammer David Ben‐Sira Ruthie Amir

Maximum oxygen uptake (VO2max) is defined as the highest rates at which oxygen can be taken up and utilized by the body during severe exercise indicating the cardiopulmonary fitness of the individual. It is one of the main variables in the field of exercise physiology and is frequently used to indicate the cardio-respiratory fitness of an individual [1]. Consequently, there has been great interest in identifying the physiological factors that limit VO2max and determining the role of this variable in endurance and anaerobic performances. Today, it is universally accepted that there is a physiological upper limit to the body's ability to consume oxygen. In the scientific literature, an increase in VO2max is the most common method of demonstrating a training effect. In addition, VO2max is frequently used in the development of an exercise prescription in health and disease. Given these applications of VO2max, there has been great interest in identifying the physiological factors that limit VO2max and determining the role of this variable in endurance performance. Aging-related changes occur mainly in the cardiopulmonary and skeletal muscles, bringing about a reduction in physical performance [7]. Such myocardial and peripheral functional changes include a decline in the maximum heart rate, stroke volume, and contractility, and an increase in peripheral vascular resistance. Consequently, the maximal VO2max decreases. The primary aging process, itself genetically associated, occurs both independently of lifestyle and in the absence of disease [4]. Accordingly, one may expect maximal cardiac output to decrease with aging irrespective of lifestyle because of genetic factors. Reduced arteriovenous oxygen difference at maximal effort [6] is the second factor associated with decrease with aging of VO2max. Incremental exercise is characterized by exposing the subjects to a high degree of load which may alter the left ventricular contractility and function [5]. This has the effect of placing a large load on the left ventricular which might have significant effects on oxygen delivery to the working muscles. Thus, oxygen delivery to the working muscle may be reduced, and since metabolic demand during incremental exercise is increased over time to maximum, elderly subjects may maintain the energy supply due to the balance between O2 delivery and extraction. Untrained and trained elderly can increase the response of the central factors i.e., cardiopulmonary without a significant reduction in peripheral ability to extract oxygen at the muscle level. It was found that in elderly subjects, skeletal muscle mitochondrial capacity, tissue blood flow capacity, and oxygen exchange capacity appear to be wellmatched. It seems that intrinsic mitochondrial function and regulation are not altered significantly. Values for cardiac output at peak aerobic exercise are low in the untrained compared to the trained at maximal aerobic exercise. The lower cardiac output in the untrained elderly at peak exercise is related to the limited heart rate reserve, stroke volume, contractility, and to the inappropriate adjustment of the circulation [3, 5]. The augmentation in maximal oxygen uptake in the trained elderly in response to M. Sagiv (*) :D. Ben-Sira : R. Amir Sports Medicine and Rehabilitation Division, Zinman College of Physical Education and Sport Sciences Wingate, Netany, Israel 42902 e-mail: sagiv-moran@wincol.ac.il

Endurance Training

Exercise prescription

Contractility

10.1007/s11556-010-0061-x

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Citations (7)

LEFT VENTRICULAR SYSTOLIC FUNCTION DURING TREADMILL WALKING WITH LOAD CARRIAGE IN ADOLESCENTS

DOAJ (DOAJ: Directory of Open Access Journals) (2006)

Moran Sagiv Michael Sagiv Ruthie Amir David Ben‐Sira

Treadmill

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ACE ID genotype affects blood creatine kinase response to eccentric exercise

Journal of Applied Physiology (2007)

Yamin Chen Offer Amir Moran Sagiv Eric Attias Yoav Meckel

Unaccustomed exercise may cause muscle breakdown with marked increase in serum creatine kinase (CK) activity. The skeletal muscle renin-angiotensin system (RAS) plays an important role in exercise metabolism and tissue injury. A functional insertion (I)/deletion (D) polymorphism in the angiotensin I-converting enzyme (ACE) gene (rs4646994) has been associated with ACE activity. We hypothesized that ACE ID genotype may contribute to the wide variability in individuals' CK response to a given exercise. Young individuals performed maximal eccentric contractions of the elbow flexor muscles. Pre- and postexercise CK activity was determined. ACE genotype was significantly associated with postexercise CK increase and peak CK activity. Individuals harboring one or more of the I allele had a greater increase and higher peak CK values than individuals with the DD genotype. This response was dose-dependent (mean +/- SE U/L: II, 8,882 +/- 2,362; ID, 4,454 +/- 1,105; DD, 2,937 +/- 753, ANOVA, P = 0.02; P = 0.009 for linear trend). Multivariate stepwise regression analysis, which included age, sex, body mass index, and genotype subtypes, revealed that ACE genotype was the most powerful independent determinant of peak CK activity (adjusted odds ratio 1.3, 95% confidence interval 1.03-1.64, P = 0.02). In conclusion, we indicate a positive association of the ACE ID genotype with CK response to strenuous exercise. We suggest that the II genotype imposes increased risk for developing muscle damage, whereas the DD genotype may have protective effects. These findings support the role of local RAS in the regulation of exertional muscle injury.

Creatine kinase

10.1152/japplphysiol.00867.2007

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Citations (69)

Prevalence of Chymase and Angiotensin – Converting Enzyme Gene Polymorphisms and Relation to Clinical Findings in Patients with Heart Failure

Journal of Cardiac Failure (2007)

Ruthie E. Amir Offer Amir Hagar Paz Moran Sagiv Ronny Ammar

Chymase

10.1016/j.cardfail.2007.06.425

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Citations (0)

Left ventricular systolic function during treadmill walking with load carriage in adolescents.

PubMed (2006)

Moran Sagiv Michael Sagiv Ruthie Amir David Ben‐Sira

Backpack carriage occurs in day-to-day tasks and has applications in school, physical training, recreational activities and sports. Using metabolic cart and echocardiograph, this study determined and examined the effects of two different load carriages on left ventricular function during 30 min. of treadmill walking in healthy adolescent male subjects. Seventeen males (13.1 ± 0.5 yrs.) walked on a treadmill at a speed of 4 km·h(-1), each carrying a load relative to his body mass at 333 gr·kg(-1) body weight during one session and without weight during the other session. Significant (p < 0.05) differences were noted between the 333 gr·kg(-1) body weight and the no weights with regard to: VO2 13.6 ± 1.3 and 10.5 ± 1.1 ml·kg(-1)·min(-1); heart rate: 133.2 ± 7.1 and 121.4 ± 5.6 beats·min(-1); mean arterial blood pressure; 95. 4 ± 4.3 and 87.5 ± 3.8 mmHg and systolic blood pressure 147.7 ± 7.0 and 129.8 ± 7.1 mmHg respectively. No significant differences were noted between the two exercises with regard to left ventricular function variables. This study suggests that in adolescents as in adults, the vasodilatation mechanism dominates during combined dynamic and isometric exercises. Thus, the opposing force to the left ventricular ejection is reduced which in turn does not change the left ventricular global function. In addition, the vasodilatation mechanism enables oxygen supply to the contracting muscles via aerobic energy pathways. Key PointsThis study suggests that in adolescents as in adults, the vasodilatation mechanism dominates during combined dynamic and isometric exercises.Thus, the opposing force to the left ventricular ejection is reduced which in turn does not change the left ventricular global function.In addition, the vasodilatation mechanism enables oxygen supply to the contracting muscles via aerobic energy pathways.

Backpack

Treadmill

Ventricular pressure

Aerobic Exercise

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Citations (8)