Cardiac hypertrophy in response to dynamic conditioning in female athletes

1978 ◽  
Vol 44 (6) ◽  
pp. 849-852 ◽  
Author(s):  
S. M. Zeldis ◽  
J. Morganroth ◽  
S. Rubler
Keyword(s):  
Athletic Performance ◽  
Female Athletes ◽  
Treadmill Exercise ◽  
Maximal Oxygen Consumption ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Male Athletes ◽  
Posterior Wall Thickness ◽  
Hockey Players ◽  
Dynamic Conditioning

Ten female field hockey players were studied to determine if prolonged dynamic conditioning results in an increased left ventricular internal dimension at end diastole (LVIDD) and if this increase correlates with maximal oxygen consumption (VO2max). At peak season, echocardiograms were obtained and VO2max determined during maximal treadmill exercise. VO2max, LVIDD index (LVIDD/body surface area (BSA)), and ventricular septal and posterior wall thickness were compared to agematched nonathletic women. Mean LVIDD index was significantly greater in athletes than in controls: 29.3 +/- 0.9 mm/m2 vs. 26.3 +/- 0.6, P less than 0.005. Echocardiographic wall measurements did not differ significantly in the two groups. Mean VO2max for the athletes was significantly greater than controls: 51.7 +/- 4.0 ml O2.kg-1.min-1 vs. 41.2 +/- 2.1, P less than 0.001. VO2max correlated significantly with LVIDD index; r = 0.92, P less than 0.001. Female athletes show an increased LVIDD in response to dynamic conditioning similar to that seen in male athletes. The proficiency of athletic performance as measured by VO2max may be related to the heart's ability to increase LVIDD since there is a high correlation between VO2max and LVIDD index.

scholarly journals Cardiac remodeling indicators in adolescent athletes

2017 ◽  
Vol 63 (5) ◽  
pp. 427-434 ◽  
Author(s):  
Joaquim Castanheira ◽  
João Valente-dos-Santos ◽  
Daniela Costa ◽  
Diogo Martinho ◽  
Jorge Fernandes ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Basketball Players ◽  
Mean Values ◽  
Septal Thickness ◽  
Posterior Wall Thickness ◽  
Comparison Results ◽  
Hockey Players ◽  
Judo Athletes

Summary Objective: The idea that different sports and physical training type results in different cardiac adaptations has been widely accepted. However, this remodelling process among different sport modalities is still not fully understood. Thus, the current study aims to investigate the heart morphology variation associated with a set of different modalities characterized by distinct models of preparation and different methods and demands of training and completion. Method: The sample comprises 42 basketball players, 73 roller hockey players, 28 judo athletes and 21 swimmers. Anthropometry was assessed by a single and experienced anthropometrist and the same technician performed the echocardiographic exams. Analysis of variance was used to study age, body size and echocardiograph parameters as well as different sport athlete's comparison. Results: Basketball players are taller (F=23.448; p<0.001; ES-r=0.553), heavier (F=6.702; p<0.001; ES-r=0.334) and have a greater body surface area (F=11.896; p<0.001; ES-r=0.427). Basketball and hockey players have larger left auricle diameters compared with judo athletes (F=3.865; p=0.011; ES-r=0.316). Interventricular end-diastolic septal thickness (F=7.287; p<0.001; ES-r=0.347) and left ventricular posterior wall thickness (F=8.038; p<0.001; ES-r=0.362) of the judokas are smaller compared to the mean values of other sports participants. In addition, relative left parietal ventricular wall thickness is lower among swimmers compared with judokas (F=4.127; p=0.008; ES-r=0.268). Conclusion: The major contributors to changes in heart morphology are for the most part associated with sport-specific training and competition and the specific dynamics and adaptive mechanisms imposed by each sport.

scholarly journals Abnormal left ventricular geometry in female collegiate swimmers

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
Y K Taha ◽  
C A Rambart ◽  
F Reifsteck ◽  
R Hamburger ◽  
J R Clugston ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Female Athletes ◽  
Interventricular Septum ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Relative Wall Thickness ◽  
Left Ventricular Geometry ◽  
Ventricular Geometry ◽  
Posterior Wall Thickness ◽  
Lv Mass

Abstract Background There is a paucity of data describing left ventricular geometry changes in female athletes. While some studies suggest that female athletes participating in dynamic sports exhibit higher prevalence of eccentric left ventricular hypertrophy (LVH) when compared to men, a recent study suggested more concentric geometry changes in female basketball athletes. We were unable to identify studies describing the left ventricular geometry of female collegiate swimmers. Objectives To describe LV geometry changes in a cohort of female collegiate swimmers. Methods We analyzed a cohort of female collegiate swimmers who had a pre-participation cardiac evaluation by 12-lead ECG and 2-dimensional echocardiography. Left ventricular (LV) geometry was assessed based on relative wall thickness (RWT) (defined as: 2 x posterior wall thickness (PWT) divided by LV end-diastolic diameter (LVEDD)) and LV mass (LVM) (Devereux's formula: LVM = [0.8 x 1.04 [(LVEDD + interventricular septum + posterior wall thickness)3 − (LVEDD)3]] + 0.6g) and was indexed to body surface area (BSA).LVH was defined as LV mass index &gt;95 g and was defined as concentric when associated with a relative wall thickness (RWT) &gt;0.42 and as eccentric when RWT was ≤0.42. Concentric remodeling was defined as normal LVM index and increased RWT. Results A total of 83 female collegiate swimmers were included. Their age was 18.5±0.5 years (mean ± standard deviation, SD), 74 (89.2%) were White, BSA was 1.78±0.11 m2, height 173±6.3 cm, weight 66.2±7.2 K. Their interventricular septum diameter was 0.89±0.14 cm, PWT 0.92±0.15 cm, LVEDD 4.9±0.5 cm and LV end-systolic diameter (LVESD) 3.2±0.4 cm. Left atrium diameter ranged from 2.6 to 4.3 cm (mean 3.4 cm ± 0.4 cm). Aortic root diameter ranged from 1.9 to 3.5 cm (mean 2.7±0.3 cm) (Figure 1). LVH was present in 27 swimmers (32.5%). Eccentric LVH was present in 17 athletes (20.5%), concentric hypertrophy in 10 athletes (12%), and concentric remodeling in 12 (14.5%) (Figure 2). No athletes with LVH or concentric remodeling had borderline or abnormal ECG findings based on international criteria. Only two women with normal LV geometry had abnormal ECG findings: prolonged QT interval and abnormal T wave inversion. There was a linear correlation between BSA with LVEDD, LVESD and LV mass (r=0.40, 0.35, and 0.48 with P&lt;0.001,0.002 and &lt;0.001, respectively). However, there was no statistically significant difference between LV geometry groups based on BSA or blood pressure. Conclusion Our data document a high incidence of eccentric hypertrophy among female collegiate swimmers. Concentric remodeling and hypertrophy were also relatively high. Differentiating physiologic from pathologic cardiac remodeling in these athletes is critical to prevent potential complications such as sudden cardiac death, arrhythmias, and other adverse outcomes. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): This work was supported in part by the American Medical Society for Sports Medicine (AMSSM) Foundation Research Grant 2016 awarded to KE, and the University of Florida REDCap uses the NIH National Center for Advancing Translational Sciences (NCATS) grant UL1 TR001427. Figure 1 Figure 2. LV geometry in female swimmers

Combination of Huangqi Granule and Rosuvastatin Improves the Cardiac Function in Heart Failure

2020 ◽  
Vol 19 (2) ◽  
pp. 181-187
Author(s):  
Jing Li ◽  
Yun Zhang ◽  
Weizhong Huangfu ◽  
Yuhong Ma
Keyword(s):  
Heart Failure ◽  
Left Ventricular Ejection Fraction ◽  
Ejection Fraction ◽  
Wall Thickness ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Model Group ◽  
Ventricular Ejection Fraction ◽  
Posterior Wall Thickness

Using rat models of heart failure, we evaluated the effects of rosuvastatin and Huangqi granule alone and in combination on left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, left ventricular posterior wall thickness at end-diastole, and left ventricular posterior wall thickness at end-systole. Results showed that left ventricular end-diastolic dimension, left ventricular end-systolic dimension in the rosuvastatin + Huangqi granule group were significantly decreased (P ‹ 0.01), while left ventricular ejection fraction, left ventricular posterior wall thickness at end-diastole and left ventricular posterior wall thickness at end-systole were significantly increased (P ‹ 0.05). The serum IL-2, IFN-β, and TNF-α in rosuvastatin + Huangqi granule group were significantly lower than those in model group (P ‹ 0.05). However, the levels of S-methylglutathione and superoxide dismutase in rosuvastatin + Huangqi granule group were significantly higher, while nitric oxide was significantly lower than that in the model group (P ‹ 0.05). Also, compared to the model group, the apoptosis rate, and the autophagy protein LC3-II in the cardiomyocytes of rosuvastatin + Huangqi granule group was significantly decreased (P ‹ 0.01), while the level of p62 protein was significantly increased (P ‹ 0.01). The levels of AMPK and p-AMPK in cardiomyocytes were significantly lower in rosuvastatin + Huangqi granule group; however, the levels of mTOR and p-mTOR showed an opposite trend (P ‹ 0.05). To sum up, rosuvastatin + Huangqi granule could improve the cardiac function, decrease the level of oxidative stress, and inflammatory cytokines in rats with HF. The possible underlying mechanism might be inhibition of autophagy and reduced apoptosis in cardiomyocytes by regulating AMPK-mTOR signaling pathway.

scholarly journals Superoxide production by NAD(P)H oxidase and mitochondria is increased in genetically obese and hyperglycemic rat heart and aorta before the development of cardiac dysfunction. The role of glucose-6-phosphate dehydrogenase-derived NADPH

2009 ◽  
Vol 297 (1) ◽  
pp. H153-H162 ◽  
Author(s):  
Sabrina Serpillon ◽  
Beverly C. Floyd ◽  
Rakhee S. Gupte ◽  
Shimran George ◽  
Mark Kozicky ◽  
...  
Keyword(s):  
Cardiac Dysfunction ◽  
Rat Heart ◽  
Mitochondrial Respiratory Chain ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Posterior Wall Thickness ◽  
Patients With Diabetes ◽  
Protein Kinase C Inhibitor ◽  
Glucose 6 Phosphate Dehydrogenase

Increased oxidative stress is a known cause of cardiac dysfunction in animals and patients with diabetes, but the sources of reactive oxygen species [e.g., superoxide anion (O2−)] and the mechanisms underlying O2− production in diabetic hearts are not clearly understood. Our aim was to determine whether NADPH oxidase (Nox) is a source of O2− and whether glucose-6-phosphate dehydrogenase (G6PD)-derived NADPH plays a role in augmenting O2− generation in diabetes. We assessed cardiac function, Nox and G6PD activities, NADPH levels, and the activities of antioxidant enzymes in heart homogenates from young (9–11 wk old) Zucker lean and obese (fa/fa) rats. We found that myocardial G6PD activity was significantly higher in fa/fa than in lean rats, whereas superoxide dismutase and glutathione peroxidase activities were decreased ( P < 0.05). O2− levels were elevated (70–90%; P < 0.05) in the diabetic heart, and this elevation was blocked by the Nox inhibitor gp-91ds-tat (50 μM) or by the mitochondrial respiratory chain inhibitors antimycin (10 μM) and rotenone (50 μM). Inhibition of G6PD by 6-aminonicotinamide (5 mM) and dihydroepiandrosterone (100 μM) also reduced ( P < 0.05) O2− production. Notably, the activities of Nox and G6PD in the fa/fa rat heart were inhibited by chelerythrine, a protein kinase C inhibitor. Although we detected no changes in stroke volume, cardiac output, or ejection fraction, left ventricular diameter was slightly increased during diastole and systole, and left ventricular posterior wall thickness was decreased during systole ( P < 0.05) in Zucker fa/fa rats. Our findings suggest that in a model of severe hyperlipidema and hyperglycemia Nox-derived O2− generation in the myocardium is fueled by elevated levels of G6PD-derived NADPH. Similar mechanisms were found to activate O2− production and induce endothelial dysfunction in aorta. Thus G6PD may be a useful therapeutic target for treating the cardiovascular disease associated with type 2 diabetes, if second-generation drugs specifically reducing the activity of G6PD to near normal levels are developed.

scholarly journals Left ventricular geometric patterns and cardiac function in patients with chronic renal failure undergoing hemodialysis

2005 ◽  
Vol 64 (1) ◽  
Author(s):  
Maria Teresa Manes ◽  
Manlio Gagliardi ◽  
Gianfranco Misuraca ◽  
Stefania Rossi ◽  
Mario Chiatto
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Diastolic Dysfunction ◽  
Cardiac Troponin ◽  
Ventricular Hypertrophy ◽  
Interventricular Septum ◽  
Myocardial Damage ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Posterior Wall Thickness ◽  
Significant Difference

The aim of this study was to estimate the impact and prevalence of left ventricular geometric alterations and systolic and diastolic dysfunction in hemodialysis patients, as well as the relationship with cardiac troponin as a marker of myocardial damage. Methods: 31 patients (pts), 19 males and 12 females, age 58.1±16.4 (26 on hemodialysis, 5 on peritoneal dialysis) and 31 healthy normal controls were enrolled. Echocardiography measurements were carried out according to the American Society of Echocardiography recommendations. Left ventricular mass was calculated, according to the Devereux formula and indexed to height and weight 2.7. Doppler echocardiography was performed to study diastolic function by measurements of isovolumetric relaxation period (IVRT), E wave deceleretion time (DTE) and E/A ratio. Cardiac troponin was measured by a third generation electrochemiluminescence immunoassay. Statistical analysis was performed using the t-test for between-group comparisons and the Pearson and Spearman’s tests to investigate correlations; p values of &lt;0.05 were considered statistically significant. Results: Eccentric hypertrophy was the most frequent pattern (n=17; 55%), followed by normal cardiac geometry (n=7; 23%), and concentric hypertrophy (n=5; 16%). Only 6% of pts (n=2) showed concentric remodelling. Systolic dysfunction was present in terms of endocardial parameters in 3 pts (9%) (fractional shartening &lt;25%, EF&lt;50%), but in terms of midwall myocardial shortening in 51% (n=16). Diastolic dysfunction was present in 87% (n=27) with a pattern of impaired relaxation (in 5 without left ventricular hypertrophy). E/A was negatively correlated with age (r=-0.41, p=0.02); DTE was positively correlated with posterior wall thickness (r=0.36, p=0.05) and interventricular septum thickness (r=0.45, p=0.01); cardiac troponin was positively correlated with age (r=0.50, p=0.00), left ventricular mass (r=0.41, p=0.02), posterior wall thickness (r=0.41; p=0.02) and interventricular septum thickness (r=0.39, p=0.03) but not with diastolic dysfunction parameters. No significant difference was found in terms of duration of dialysis between patients with normal left ventricular geometry and those with left ventricular hypertrophy, but a significant difference in age was found (p=0.03). Pts with diastolic dysfunction had more frequent hypotensive episodes during dialysis (p &lt;0.01). Conclusion: Impaired geometry and cardiac function is frequently observed in pts undergoing hemodialysis. Diastolic dysfuction is associated to a geometric pattern of left ventricular hypetrophy, although it can be an isolated initial manifestation of myocardial damage. Depressed midwall myocardial shortening can discriminate left ventricular dysfunction better than traditional endocardial systolic indexes.

scholarly journals The impact of obesity on left ventricular mass and left ventricular systolic function in children

2016 ◽  
Vol 45 (4) ◽  
pp. 171
Author(s):  
Ria Nova ◽  
Bambang Madiyono ◽  
Sudigdo Sastroasmoro ◽  
Damayanti R Sjarif
Keyword(s):  
Wall Thickness ◽  
Systolic Function ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Internal Diameter ◽  
Obese Children ◽  
Normal Children ◽  
Posterior Wall Thickness ◽  
Lv Mass ◽  
Lv Systolic Function

Background Obesity causes cardiovascular disturbances. Theincidence of cardiovascular disease is higher even in mildly obesepatients than in lean subjects.Objectives The purpose of this study was to compare left ven-tricular (LV) mass, LV internal dimensions, and LV systolic func-tion between obese and normal children; and to determine the as-sociation of the degree of obesity with LV mass and LV systolicfunction.Methods This cross-sectional study was conducted on elemen-tary school students in Jakarta from February to April 2003. Wemeasured the subjects’ body weight and height, and performedlipid profile and echocardiography examinations. Measurementsof LV mass, LV internal dimensions with regard to septum thick-ness, LV internal diameter, and LV posterior wall thickness; andLV systolic function as indicated by shortening fraction and ejec-tion fraction, were performed echocardiographically. The differ-ences in measurements between obese and normal children aswell as between obese children with and without lipid abnormalitywere analyzed. The correlation between the degree of obesity withLV size and systolic function was determined.Results Twenty-eight normal children and 62 obese children wereenrolled in the study. Mean LV mass was 35.7 (SD 5.16) g/cm 3 inobese children versus 24.0 (SD 3.80) g/cm 3 in normal children(P<0.0001). Mean septum thickness was 0.8 (SD 0.14) mm inobese children versus 0.6 (SD 7.90) mm in normal children (P<0.0001). Mean posterior wall thickness was 0.9 (SD 0.14) mm inobese children versus 0.6 (SD 9.97) mm in normal children(P<0.0001). Mean LV internal diameter was 4.0 (SD 0.34) mm inobese children versus 3.9 (SD 0.29) mm in normal children(P=0.300). There was strong correlation between the degree ofobesity and LV mass (r=0.838, P<0.0001). LV systolic function(shortening fraction) was 37.1 (SD 4.20) percent in obese childrenversus 35.8 (SD 4.99) percent in normal children (P=0.19). Ejec-tion fraction was 67.4 (SD 5.32) percent in obese children versus65.5 (SD 6.29) percent in normal children (P=0.13). There wasweak correlation between LV systolic function and the degree ofobesity (shortening fraction r=0.219, P=0.038; ejection fractionr=0.239, P=0.023).Conclusions Obese children had significantly greater LV mass,septum thickness, and posterior wall thickness than normal chil-Backgrounddren. Such significant difference was absent for LV internal diam-eter and measures of LV systolic function. There was no signifi-cant difference in LV mass and LV systolic function between obesechildren with or without abnormality of lipid profile. A strong corre-lation exists between the degree of obesity and LV mass, but thecorrelation between degree of obesity and LV systolic function wasweak

Evaluation of Cardiovascular Variables in a Calchaquí Population in the Middle and High Mountains of Tucumán

2021 ◽  
Vol 89 (1) ◽  
pp. 20-26
Author(s):  
Sebastián Galdeano ◽  
Damián Holownia ◽  
Darío Palavecino ◽  
José Daniel Abregú ◽  
María Silvina Rivas Jordan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiovascular Health ◽  
Posterior Wall ◽  
Left Ventricular ◽  
High Mountains ◽  
Urban Centers ◽  
Cross Sectional ◽  
The Third ◽  
Posterior Wall Thickness ◽  
Cardiovascular Morbidity And Mortality

Background: The Quilmes community includes 2,400 inhabitants of the middle and high mountains of Tucumán (1,800 to 4,000 meters above sea level). The purpose of the present study was to know their cardiovascular health status. Methods: A cross-sectional descriptive quantitative investigation was carried out in people belonging to the Quilmes community who voluntarily attended the planned evaluation on September 27-29, 2018. Results: Two hundred and two settlers were studied (125 women and 77 men; 48±1.4 years), 23% of them had hypertension (HTN); 14% were smokers; 4.9% had diabetes; 18% had dyslipidemia (DLP) and 25% usually consumed alcohol (1.0 ± 0.4 L/day). Also, 29% were overweight and 36% obese. High blood pressure (BP) was recorded in 48 individuals at the time of the study. Blood pressure decreased in the third compared to the first measurement, whereas heart rate increased in the third assessment (74±1 beats per minute vs. 77±1; p <0.01). Oxygen saturation (95.0±0.2%) was negatively correlated with age (Pearson r: -0.266; p <0.001). In individuals with normal BP, ultrasound E/ratio was higher (1.2±0.0) and left ventricular posterior wall thickness was lower (8.5±0.5 mm) than in those with elevated BP (0.92±0.1 and 9.0±0.3, respectively, p <0.001). Twenty-four percent of individuals had atherosclerotic plaques and 120 had DLP. Conclusions: The Quilmes population presents a prevalence of cardiovascular risk factors similar to that of urban centers, which could lead to an increase in cardiovascular morbidity and mortality in the coming years

scholarly journals Lung function and left ventricular hypertrophy in morbidly obese candidates for bariatric surgery

2015 ◽  
Vol 41 (5) ◽  
pp. 427-432
Author(s):  
Paulo de Tarso Müller ◽  
Hamilton Domingos ◽  
Luiz Armando Pereira Patusco ◽  
Gabriel Victor Guimarães Rapello
Keyword(s):  
Ventricular Hypertrophy ◽  
Relative Size ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Morbidly Obese ◽  
Small Airways ◽  
Systemic Arterial Hypertension ◽  
Posterior Wall Thickness ◽  
History Of ◽  
The Mean

Objective: To look for correlations between lung function and cardiac dimension variables in morbidly obese patients, in order to test the hypothesis that the relative size of the small airways is independently correlated with left ventricular hypertrophy. Methods: This was a retrospective study involving 192 medical records containing a clinical protocol employed in candidates for bariatric surgery between January of 2006 and December of 2010. Results: Of the 192 patients evaluated, 39 (10 males and 29 females) met the inclusion criteria. The mean BMI of the patients was 49.2 ± 7.6 kg/m2, and the mean age was 35.5 ± 7.7 years. The FEF25-75/FVC, % correlated significantly with left ventricular posterior wall thickness and relative left ventricular posterior wall thickness, those correlations remaining statistically significant (r = −0.355 and r = −0.349, respectively) after adjustment for weight, gender, and history of systemic arterial hypertension. Stepwise multivariate linear regression analysis showed that FVC and FEV1 were the major determinants of left ventricular mass (in grams or indexed to body surface area). Conclusions: A reduction in the relative size of the small airways appears to be independently correlated with obesity-related cardiac hypertrophy, regardless of factors affecting respiratory mechanics (BMI and weight), gender, or history of systemic arterial hypertension. However, FEV1 and FVC might be important predictors of left ventricular mass in morbidly obese individuals.

Anatomical Accuracy of Echocardiographically Assessed Left Ventricular Wall Thickness

1979 ◽  
Vol 57 (s5) ◽  
pp. 55s-57s ◽  
Author(s):  
H. Larkin ◽  
D. C. Johnson ◽  
S. N. Hunyor ◽  
P. Caspari ◽  
R. Kaplan
Keyword(s):  
Direct Measurement ◽  
Wall Thickness ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Ventricular Wall ◽  
Left Ventricular Wall Thickness ◽  
Echocardiographic Measurement ◽  
Posterior Wall Thickness ◽  
Ventricular Wall Thickness

1. A comparison of direct measurement and M-mode echocardiography in the determination of posterior left ventricular wall thickness was performed in 26 subjects, of whom 21 underwent cardiac bypass surgery; the remainder came to necropsy. 2. In the surgical group a close correlation was demonstrated between direct measurement of posterior wall thickness and the echocardiographic end-diastolic dimension (r = 0·76, P &lt; 0·001). 3. The necropsy measurement of posterior wall thickness correlated with the echocardiographic end-systolic dimension (r = 0·99, P &lt; 0·001). 4. These findings confirm that the echocardiographic measurement of posterior wall thickness accurately reflects the anatomical dimension.

scholarly journals Chronic intermittent hypoxia increases left ventricular contractility in C57BL/6J mice

2009 ◽  
Vol 107 (3) ◽  
pp. 787-793 ◽  
Author(s):  
Jahan Naghshin ◽  
Kenneth R. McGaffin ◽  
William G. Witham ◽  
Michael A. Mathier ◽  
Lia C. Romano ◽  
...  
Keyword(s):  
Ejection Fraction ◽  
Intermittent Hypoxia ◽  
Posterior Wall ◽  
Left Ventricular ◽  
Heart Weight ◽  
Ventricular Contractility ◽  
Posterior Wall Thickness ◽  
Obstructive Sleep ◽  
Wide Range ◽  
Lv Ejection Fraction

Intermittent hypoxia (IH) commonly occurs in patients with obstructive sleep apnea and can cause a wide range of pathology, including reduced left ventricular (LV) ejection fraction in rats as determined by echocardiography, in rodent models. We utilized echocardiography and pressure-volume (PV) loop analyses to determine whether LV contractility was decreased in inbred C57BL/6J mice exposed to IH and whether blockade of β-adrenergic receptors modified the response to hypoxia. Adult male 9- to 10-wk-old mice were exposed to 4 wk of IH (nadir inspired O2 5–6% at 60 cycles/h for 12 h during the light period) or intermittent air (IA) as control. A second group of animals were exposed to the same regimen of IH or IA, but in the presence of nonspecific β-blockade with propranolol. Cardiac function was assessed by echocardiography and PV loop analyses, and mRNA and protein expression in ventricular homogenates was determined. Contrary to our expectations, we found with PV loop analyses that LV ejection fraction (63.4 ± 3.5 vs. 50.5 ± 2.6%, P = 0.015) and other measures of LV contractility were increased in IH-exposed animals compared with IA controls. There were no changes in contractile proteins, atrial natriuretic peptide levels, LV posterior wall thickness, or heart weight with IH exposure. However, cAMP levels were elevated after IH, and propranolol administration attenuated the increase in LV contractility induced by IH exposure. We conclude that, contrary to our hypothesis, 4 wk of IH exposure in C57BL/6J mice causes an increase in LV contractility that occurs independent of ventricular hypertrophy and is, in part, mediated by activation of cardiac β-adrenergic pathways.

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