Reduced mechanical efficiency of rat papillary muscle related to degree of hypertrophy of cardiomyocytes

2010 ◽  
Vol 298 (4) ◽  
pp. H1190-H1197 ◽  
Author(s):  
Yeun Ying Wong ◽  
M. Louis Handoko ◽  
Koen T. B. Mouchaers ◽  
Frances S. de Man ◽  
Anton Vonk-Noordegraaf ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Mechanical Efficiency ◽  
Isometric Tension ◽  
Cross Sectional Area ◽  
Cardiomyocyte Hypertrophy ◽  
Papillary Muscles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Length Changes ◽  
The Right

Isolated rat papillary muscles of the right ventricle were used to discover the origin of reduced myocardial efficiency in chronic heart failure. Right ventricular hypertrophy was induced by monocrotaline injection, causing pulmonary hypertension. Control ( n = 7) and hypertrophied ( n = 11) papillary muscles were subjected to sinusoidal length changes at 37°C and 5 Hz with a peak-to-peak amplitude of 15% of the length giving maximum force ( Lmax) after being stretched to 92.5% of Lmax. Isometric tension at Lmax was similar in control and hypertrophied muscles. Work was assessed from the area encompassed by force-length loops. Work per loop was 0.93 ± 0.11 and 0.84 ± 0.11 μJ/mm3 (means ± SE) for control and hypertrophied muscles, respectively ( P = 0.591). Suprabasal O2 uptake per work loop was 5.7 ± 0.7 pmol/mm3 in control muscles and 8.7 ± 1.7 pmol/mm3 in hypertrophied muscles ( P = 0.133). Net mechanical efficiency was calculated from the ratio of work output and suprabasal O2 uptake. The efficiency of hypertrophied muscles was 29.1 ± 3.7% and was smaller than in control muscles (43.7 ± 2.2%, P = 0.016). The right ventricular cardiomyocyte cross-sectional area increased from 272 ± 17 μm2 in control muscles to 396 ± 31 μm2 in hypertrophied muscles ( P < 0.003). Mechanical efficiency correlated negatively with right ventricular wall thickness and cardiomyocyte cross-sectional area [Spearman rank correlation coefficients of −0.50 ( P = 0.039) and −0.53 ( P = 0.024), respectively]. We conclude that efficiency decreases with increasing cardiomyocyte hypertrophy. Thus, the reduced efficiency of diseased whole hearts can be at least partly explained by reduced efficiency at the cardiomyocyte level.

scholarly journals Impact of tricuspid annular size reduction on right ventricular function, geometry and strain†

2019 ◽  
Vol 56 (2) ◽  
pp. 400-408 ◽  
Author(s):  
Marcin Malinowski ◽  
Tomasz Jaźwiec ◽  
Matthew Goehler ◽  
Jared Bush ◽  
Nathan Quay ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Ventricular Function ◽  
Cross Sectional Area ◽  
Free Wall ◽  
Sectional Area ◽  
Tricuspid Annulus ◽  
Cross Sectional ◽  
Area Reduction ◽  
The Right ◽  
Rv Function

Abstract OBJECTIVES Restrictive tricuspid annuloplasty is a clinically accepted approach to treat functional tricuspid regurgitation. We set out to investigate the effect of varying degrees of tricuspid annular reduction on the right ventricular (RV) function, geometry and strain. METHODS Eight, healthy sheep (45 ± 4 kg) had 6 sonomicrometry crystals implanted around the tricuspid annulus and 20 onto the epicardium of the right ventricle defining 3 free wall regions: basal, mid and lower. A polypropylene annuloplasty suture was placed around the tricuspid annulus and externalized to an epicardial tourniquet. Simultaneous echocardiographic, haemodynamic and sonomicrometry data were acquired at baseline and during 5 consecutive annular reduction steps (TAR 1–5) with successive (5–7 mm) suture cinching. RV free wall circumferential, longitudinal and areal cardiac and interventional strains, RV radius of curvature (ROC), cross-sectional area and tricuspid annular dimensions were calculated from 3-dimensional crystal coordinates. RESULTS TAR 1–5 resulted in 19 ± 15%, 35 ± 15%, 51 ± 15%, 60 ± 15% and 68 ± 13% tricuspid annular area reduction, respectively. TAR 1 and 2 had minimal influence on the RV function, RV-ROC and strains. TAR 4 and 5 decreased RV-ROC in basal and mid-regions, but reduced the RV cross-sectional area change (from 19 ± 4% at baseline to 14 ± 3% and 13 ± 2%, respectively, P < 0.001) and circumferential and areal strains. TAR 3 significantly decreased free wall RV-ROC from 44.0 ± 1.5 to 42.6 ± 2.4 mm P < 0.001 at the RV base but maintained the regional ventricular function and strains. CONCLUSIONS In healthy ovine hearts, a tricuspid annular area reduction of ∼50% provides optimal conditions for reducing RV-ROC while maintaining regional RV function and strain patterns.

scholarly journals Sonographic Measurement of Cross-sectional Area of the Median Nerve in Academic Dentists Without Symptoms or Signs of Carpal Tunnel Syndrome

2018 ◽  
Vol 35 (2) ◽  
pp. 105-111
Author(s):  
Akram Asbeutah ◽  
Mohsen Dashti ◽  
Abdullah AlMajran ◽  
Aref Ghayyath
Keyword(s):  
Median Nerve ◽  
Statistical Significance ◽  
Working Hours ◽  
Cross Sectional Area ◽  
Dominant Hand ◽  
Sectional Area ◽  
Cross Sectional ◽  
Increased Risk ◽  
Bone Level ◽  
The Right

The objective was to evaluate the distribution of the cross-sectional area (CSA) and flattening ratio (FR) of the median nerve (MN) in asymptomatic academic dentists using ultrasonography (US). Fifty academic dentists underwent US of the MN in transverse section at the pisiform bone level and the CSA (mm2) and FR were measured bilaterally. A CSA of <10 mm2 was considered normal. Paired t-test showed no statistical significance between either hand for CSA and FR ( P> .05). Two independent t-tests showed significant statistical differences ( P= .023) between males and females in the right dominant hand for CSA. Linear correlation analysis showed no significant correlation between CSA and FR for number of years of experience or number of working hours per day in either hand ( P>.05). The CSA was abnormal in the right dominant hand in 20 (40%) of the subjects. These male academic dentists were at increased risk of having an enlarged MN without symptoms.

Total parenteral nutrition does not improve diaphragm development in premature baboons

1994 ◽  
Vol 77 (1) ◽  
pp. 43-50 ◽  
Author(s):  
L. C. Maxwell ◽  
T. J. Kuehl ◽  
K. Meredith ◽  
D. R. Gerstmann ◽  
R. A. Delemos
Keyword(s):  
Parenteral Nutrition ◽  
Total Parenteral Nutrition ◽  
Fiber Type ◽  
Isometric Tension ◽  
Cross Sectional Area ◽  
Diaphragm Muscle ◽  
Lower Percentage ◽  
Force Frequency ◽  
Sectional Area ◽  
Cross Sectional

We hypothesized that total parenteral nutrition accelerates growth and development of diaphragm muscle (DPH) in prematurely delivered baboons (140 days gestation). For 10 days after delivery by cesarean section, we administered parenteral nutrition containing glucose, electrolytes, and water or total parenteral nutrition containing lipids, amino acids, glucose, vitamins, and electrolytes. After 10 days of care, dorsolateral and ventrolateral (VL) costal DPH were sampled for histochemically determined mean fiber area (MFA) and fiber type percentages. We determined isolated bundle isometric tension (normalized for cross-sectional area), time to peak tension, half-relaxation time, force-frequency relationship, and fatigability. Neither sex nor nutritional treatment affected contractile properties. Differences among sexes and muscle sites, but not among nutritional treatments, were observed for histochemical characteristics. In females, the VL DPH had a lower percentage of type IIo fibers and a greater MFA of type IIc fibers than the dorsolateral DPH and a lower percentage of type IIo fibers and greater MFA of type IIc and IIo fibers than the VL DPH in males. Mean fiber cross-sectional area of VL DPH was significantly greater in females than males. The larger fibers in females than males suggest a stronger DPH in females. Earlier growth of type II fibers in females could contribute to a better outcome for female than male premature infants with hyaline membrane disease.

scholarly journals Influence of malformation of right coronary artery originating from the left sinus on the hemodynamic environment

2020 ◽  
Author(s):  
Mengyang Cong ◽  
Xingming Xu ◽  
Jianfeng Qiu ◽  
Shun Dai ◽  
Chuanzhi Chen ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Arteries ◽  
Right Coronary Artery ◽  
Clinical Symptoms ◽  
Element Model ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross ◽  
The Right

Abstract Background: The Anomalous origin of the Right Coronary Artery (RCA) from the Left Coronary artery sinus(AORL) is one of the abnormal origins of the coronary arteries. Most of these issues seldom have effects on human health, but some individuals may have symptoms such as myocardial ischaemia or even sudden death. Recently, researchers are studying AORL through clinical cases, but study based on computational fluid dynamics (CFD) is rarely seen. In this study, haemodynamic changes between normal origin of the RCA and AORL are compared according to numerical simulation results.Methods: Realistic three-dimensional models of 16 normal right coronary arteries and 26 abnormal origins of the right coronary arteries were reconstructed, respectively. The blood flow was numerically simulated using software ANSYS. This study involves one-way fluid-solid coupling finite element model in which the blood is assumed to be incompressible Newtonian fluid, and the vessel is assumed to be isotropic, linear elastic material.Results: The differences of the cross-sectional area at the inlet between the normal group and the abnormal group was significant ( P <0.0001). There were significant differences in the volumetric flow ( P <0.0001) and the pressure ( P =0.0001). There were positive correlations with the ratio of the cross-sectional area of the RCA to the inlet area of the ascending aorta (AAO) and the ratio of the inlet volumetric flow of the RCA to the volumetric flow of the AAO, in both the normal ( P =0.0001, r=0.8198) and abnormal ( P =0.0199, r=0.4925) group.Conclusion: This study shows that the cross-sectional area of the inlet of AORL may cause ischaemia symptoms, and the results may contribute to the further understanding of the clinical symptoms of AORL based on the haemodynamics.

scholarly journals Novel body positioning maximizes femoral venous size in adults: An ultrasonographic evaluation

2018 ◽  
Vol 25 (6) ◽  
pp. 338-342
Author(s):  
Hong Joon Ahn ◽  
Jun Wan Lee ◽  
Seung Woo Yoo ◽  
Jee Hyun Kim ◽  
Kun Dong Kim ◽  
...  
Keyword(s):  
Body Position ◽  
Femoral Vein ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Vein Diameter ◽  
The Mean ◽  
The Right ◽  
Ultrasound Scanner ◽  
Leg Position

Introduction: Increased femoral vein size may lead to a higher first pass success rate during central venous cannulation. The aim of this study was to evaluate the effects of body position on femoral vein anatomy for cannulation. Methods: This prospective study examined the femoral vein of healthy volunteers by ultrasound scanner. The changes in cross-sectional area and diameter of the femoral vein were evaluated. Right-sided measurements were taken at four different leg positions: neutral, frog leg, back-up, and back-up/frog leg position. Results: A total of 50 subjects were enrolled in the study. The mean femoral vein cross-sectional area were 0.57 ± 0.29 cm2, 0.90 ± 0.26 cm2, 1.05 ± 0.33 cm2, and 1.47 ± 0.34 cm2, and the mean femoral vein diameter were 0.75 ± 0.20 cm, 1.05 ± 0.28 cm, 1.25 ± 0.21 cm, and 1.46 ± 0.25 cm in order of neutral, back-up, frog leg, and back-up/frog leg position (p < 0.001). Conclusion: Performing the right femoral vein catheterization in back-up and frog leg position is associated with a greater cross-sectional area of the femoral vein.

Multifidus Muscle Size and Symmetry in Ballroom Dancers with and without Low Back Pain

2018 ◽  
Vol 39 (08) ◽  
pp. 630-635 ◽  
Author(s):  
Alyssa Smyers Evanson ◽  
Joseph Myrer ◽  
Dennis Eggett ◽  
Ulrike Mitchell ◽  
A. Johnson
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Cross Sectional Area ◽  
Muscle Size ◽  
Low Back ◽  
Sectional Area ◽  
Multifidus Muscle ◽  
Cross Sectional ◽  
Significant Difference ◽  
The Right

AbstractThe incidence of low back pain (LBP) among elite ballroom dancers is high and understanding associations between muscle morphology and pain may provide insight into treatment or training options. Research has linked multifidus muscle atrophy to LBP in the general and some athletic populations; however, this has not been examined in ballroom dancers. We compared the lumbar multifidus cross-sectional area (CSA) at rest in 57 elite level ballroom dancers (age 23±2.4 years; height, 174±11 cm; mass, 64±10 kg) divided into one of three pain groups, according to their self-reported symptoms, 1) LBP group (n=19), 2) minimal LBP (n=17), and 3) no LBP (n=21). There were no significant difference in demographics between the groups (P>0.05). The LBP group demonstrated significant differences in reported pain and Oswestry Disability Index scores compared to the other two groups. There was no significant difference between groups in multifidus cross-sectional area (P=0.49). Asymmetry was found in all groups with the overall left side being significantly larger than the right (P<0.002). Pain associated with segmental decrease in multifidus CSA was not observed in ballroom dancers with LBP, suggesting other reasons for persistent LBP in ballroom dancers.

Cross-sectional area of the right and left internal jugular veins

1999 ◽  
Vol 13 (2) ◽  
pp. 136-138 ◽  
Author(s):  
Emilio B. Lobato ◽  
Cheri A. Sulek ◽  
Rodney L. Moody ◽  
Timothy E. Morey
Keyword(s):  
Cross Sectional Area ◽  
Sectional Area ◽  
Jugular Veins ◽  
Cross Sectional ◽  
The Right ◽  
Internal Jugular Veins

Isometric tension and myofilamental cross-sectional area in striated muscle

1962 ◽  
Vol 202 (5) ◽  
pp. 824-826 ◽  
Author(s):  
Einar Helander ◽  
Carl-Axel Thulin
Keyword(s):  
Striated Muscle ◽  
Protein Composition ◽  
Isometric Tension ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Total N ◽  
Calf Muscles

Isometric tension in tetanically stimulated calf muscles was examined in vivo in 3 rabbits and 18 cats. In two cats the gastrocnemius and soleus muscles were studied separately. After determination of the isometric tension the muscles were dissected and their water content, total N content, and protein composition were analyzed. On this basis it was possible to calculate that part of the cross-sectional area of the muscle fibers which consisted of myofilaments. The recorded maximum isometric tension was related to the myofilamental cross-sectional area. Under the given experimental conditions, the calf muscles developed a tension of 108 ± 5 g/mm2 cross-sectional area. Higher values resulted from tests of individual calf muscles than from combined muscles.

Sign in / Sign up

Export Citation Format

Share Document