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Biomedical subjects

Robert Shave

Publications and source records attributed to Robert Shave.

9 recordsLinked to original sources
PubMed2007

Impact of repeated prolonged exercise bouts on cardiac function and biomarkers.

PURPOSE: The present study examined the impact of repeated bouts of prolonged (< 60 min) exercise on left ventricular function and cardiac biomarkers. METHODS: Ten athletes completed a 15.3-mile hill run on three consecutive days and were assessed before, immediately after, 1 h after, and 20 h after each bout. Six of the athletes completed a fourth bout. Left ventricular (LV) function was examined echocardiographically using two-dimensional M-mode, Doppler, and flow propagation velocity (Vp). Venous blood samples were analyzed for cardiac biomarkers including cardiac troponin T (cTnT). RESULTS: Ejection fraction (EF) significantly decreased (P = 0.027) after the third exercise bout compared with baseline (mean +/- SD: 56.3 +/- 4.4 vs 51.3 +/- 5.9%), accompanied by a nonsignificant decrease in systolic blood pressure/end systolic volume (SBP/ESV) ratio. A sustained depression in systolic function 20 h after bout 3 also persisted in the subset who completed a fourth bout, yet this did not reach clinical levels. Significant (P < 0.01) reductions in early to late diastolic filling (E:A) ratio pre-to post-bout 1 (mean +/- SD: 1.9 +/- 0.5 vs 1.4 +/- 0.3) and pre- to post-bout 3(2.0 +/- 0.5 vs 1.3 +/- 0.4) normalized after each 20-h recovery period. A similar pattern of change was observed in Vp. Cardiac troponin T was elevated in four individuals 1 h after bout 1 (range: 0.013-0.125 microg.L(-1)) but was undetectable thereafter except in one athlete. CONCLUSION: Repeated bouts of prolonged exercise induce short-term reductions in diastolic filling and a cumulative decrease in systolic function, yet these alterations seem to have minimal clinical or functional impact. Elevated cTnT after the initial bout, but not thereafter, may represent an adaptive response to prolonged exercise.

Adult↗
PubMed2006

The impact of marathon running upon ventricular function as assessed by 2D, Doppler, and tissue-Doppler echocardiography.

The impact of prolonged exercise upon right ventricular (RV) function is poorly understood and to date no studies have utilized tissue-Doppler imaging (TDI). Thirty-five marathon runners (age range 18-50 years) volunteered for the study. Two-dimensional, pulsed Doppler, and TDI studies were performed one day before and immediately following race completion. Right and left ventricular (LV) longitudinal TDI myocardial velocities were acquired from the tricuspid annulus and mitral annulus, providing velocity data during systole (S'), early diastole (E'), and late diastole (A'). Transtricuspid and transmitral, early diastolic (E), and late diastolic (A) velocities and ratios were assessed using conventional pulsed-wave Doppler. RV and LV fractional area changes (FAC) were calculated from RV and LV end-diastolic and end-systolic areas recorded from 2D scans in a subsample (n = 23). RV myocardial velocities were unchanged pre-post race in S' (21.1 +/- 2.7 to 21.7 +/- 4.5 cm s(-1), P > 0.05), reduced in E' (23.3 +/- 3.5 to 19.9 +/- 5.3 cm s(-1), P < 0.05), increased in A' (19.1 +/- 3.6 to 23.7 +/- 6.8 cm s(-1), P < 0.05) with a resultant decline in E'/A' (1.28 +/- 0.36 to 0.94 +/- 0.45, P < 0.05). This pattern of data was mirrored in the LV. Similarly both pulsed-Doppler tricuspid and mitral E/A ratios decreased from pre- to postrace (P < 0.05). FAC for the RV and LV were unaltered postrace (P > 0.05). The impact of differing age, finishing time (173-330 min), hemodynamic loading and heart rate upon RV and LV function pre- to postrace was negligible. In conclusion, TDI and 2D data, for both the RV and LV demonstrated little change in systolic function after a marathon race. Conversely, a reduction in diastolic function was observed in both ventricles for which a mechanism has yet to be deduced.

Adolescent↗
PubMed2005

Mitral annular myocardial velocity assessment of segmental left ventricular diastolic function after prolonged exercise in humans.

We assessed segmental and global left ventricular (LV) diastolic function via tissue-Doppler imaging (TDI) as well as Doppler flow variables before and after a marathon race to extend our knowledge of exercise-induced changes in cardiac function. Twenty-nine subjects (age 18-62 year) volunteered to participate and were assessed pre- and post-race. Measurements of longitudinal plane TDI myocardial diastolic velocities at five sites on the mitral annulus included peak early myocardial tissue velocity (E'), peak late (or atrial) myocardial tissue velocity (A') and the ratio E'/A'. Standard pulsed-wave Doppler transmitral and pulmonary vein flow indices were also recorded along with measurements of body mass, heart rate, blood pressures and cardiac troponin T (cTnT), a biomarker of myocyte damage. Pre- to post-race changes in LV diastolic function were analysed by repeated measures ANOVA. Delta scores for LV diastolic function were correlated with each other and alterations in indices of LV loading. Diastolic longitudinal segmental and mean TDI data were altered post-race such that the mean E'/A' ratio was significantly depressed (1.51 +/- 0.34 to 1.16 +/- 0.35, P < 0.05). Changes in segmental and global TDI data were not related to an elevated post-race HR, a decreased post-race pre-load or an elevated cTnT. The pulsed wave Doppler ratio of peak early transmitral flow velocity (E)/peak late (or atrial) flow velocity (A) was also significantly reduced post-race (1.75 +/- 0.46 to 1.05 +/- 0.30, P < 0.05); however, it was significantly correlated with post-race changes in heart rate. The lack of change in E/E' from pre- to post-race (3.4 +/- 0.8 and 3.3 +/- 0.7, respectively) suggests that the depression in diastolic function is likely to be due to altered relaxation of the left ventricle; however, the exact aetiology of this change remains to be determined.

Adolescent↗
PubMed2005

Impact of marathon running on cardiac structure and function in recreational runners.

The present study examined the relationship between LV (left ventricular) function, markers of cardiac-specific damage and markers of oxidative stress in recreational runners following a marathon. Runners (n=52; 43 male and nine female; age, 35+/-10 years; height, 1.74+/-0.08 m; body mass, 75.9+/-8.9 kg) were assessed pre- and immediately post-marathon. LV function was assessed using standard M-mode two-dimensional Doppler echocardiography and TDI (tissue-Doppler imaging) echocardiography. Serum was analysed for cTnT (cardiac troponin-T), TEAC (Trolox equivalent antioxidant capacity; a measure of total antioxidant capacity), MDA (malondealdehyde) and 4-HNE (4-hydroxynonenal). A strong relationship was observed between standard and TDI echocardiography for all functional measures. Diastolic function was altered post-marathon characterized by a reduction in E (peak early diastolic filling: 0.79+/-0.11 compared with 0.64+/-0.16 cm/s; P<0.001), an increase in A (peak late diastolic filling: 0.48+/-0.11 compared with 0.60+/-0.12 cm/s; P<0.001) and a resultant decrease in E/A (ratio of E to A; 1.71+/-0.48 compared with 1.10+/-0.31; P<0.001). Ejection fraction remained unchanged post-marathon. Thirty-two runners presented with cTnT values above the lower limit of detection for the assay (0.01 microg/l), and 20 runners presented post-marathon with cTnT values above the acute myocardial infarction cut-off value (0.05 microg/l). No significant correlations were observed between cTnT and any functional measurements. MDA (2.90+/-1.58 compared with 3.59+/-1.47 micromol/l) and TEAC (1.80+/-0.12 compared with 1.89+/-0.21 mmol/l) were significantly increased post-marathon, but were unrelated to changes in function or cTnT. In conclusion, the present study demonstrated a reduction in diastolic function and widespread evidence of minimal cardiac damage following a marathon in recreational runners. The mechanism(s) underpinning the altered function and appearance of cTnT appear unrelated to reactive oxygen species.

Adolescent↗
PubMed2004

Altered cardiac function and minimal cardiac damage during prolonged exercise.

PURPOSE: The purpose of the present study was to examine markers of cardiac function and cardiac damage during a simulated half-ironman triathlon in highly trained athletes. METHODS: Nine highly trained male triathletes volunteered for the study (mean +/- SD; age: 33 +/- 3 yr; height: 1.8 +/- 0.1 m; body mass: 77.7 +/- 3.2 kg). The subjects completed a half-ironman triathlon; 1.9-km swim in an indoor 20-m pool, followed by a laboratory-based 90-km cycle and 21.1-km run. Venous blood samples were drawn and echocardiographic assessment completed before the start of exercise, immediately after each stage, and 24 h postexercise. Serum was analyzed for total creatine kinase activity (CK), creatine kinase isoenzyme MB(mass) (CK-MB(mass)), and cardiac troponin T (cTnT). Left ventricular systolic (stroke volume, and systolic blood pressure/end systolic volume ratio (SBP/ESV)) and diastolic (ratio of early [E] to late [A], ventricular filling E:A) measurements were derived from echocardiographic assessment. RESULTS: The mean completion time of the half-ironman triathlon was 301 +/- 28 min. Left ventricular contractility (SBP/ESV) was significantly reduced after the half-ironman triathlon (P < 0.05). A significant reduction in E:A was observed after the run phase of the half-ironman triathlon (P < 0.05). Significant increases in CK and CK-MB(mass) were observed during and after the half-ironman triathlon (P < 0.05), and cTnT was elevated in four subjects over the course of the half-ironman triathlon. CONCLUSIONS: The physiologic stress imposed by the half-ironman triathlon resulted in a reduced left ventricular contractility and altered diastolic filling, coupled with minimal cardiac damage in a number of highly trained male triathletes. The mechanisms behind such altered cardiac function and cardiac damage after prolonged exercise are yet to be elucidated.

Adult↗
PubMed2004

The impact of prolonged exercise in a cold environment upon cardiac function.

PURPOSE: The purpose of the present study was to examine the impact of cold exposure coupled with prolonged exercise upon postexercise left ventricular (LV) function and markers of myocardial damage. METHODS: colon; Eight highly trained male athletes (mean +/- SD; age: 28.2 +/- 8.8 yr; height: 1.78 +/- 0.07 m; body mass: 74.9 +/- 7.6 kg; VO2max: 65.6 +/- 7.0 mL x kg(-1) x min(-1)) performed two 100-mile cycle trials, the first in an ambient temperature of 0 degrees C, the second in an ambient temperature of 19 degrees C. Echocardiographic assessment was completed and blood samples drawn before, immediately postexercise, and 24-h postexercise. Left ventricular systolic (stroke volume [SV], ejection fraction [EF], and systolic blood pressure/end systolic volume ratio [SBP/ESV]) and diastolic (early [E] to late [A] filling ratio [E:A]) parameters were calculated. Serum was analyzed for creatine kinase isoenzyme MB (CK-MBmass) and cardiac troponin T (cTnT). cTnT was analyzed descriptively whereas other variables were assessed using two-way repeated-measures ANOVA. RESULTS: No significant change was observed in systolic function across time or between trials. A significant difference between trials was observed in E:A immediately after exercise (1.4 +/- 0.4 [19 degrees C] vs 1.8 +/- 0.3 [0 degrees C]) (P < 0.05). CK-MBmass was significantly elevated immediately after exercise in both trials (P < 0.05). Positive cTnT concentrations were observed in two subjects immediately after the 19 degrees C trial (0.012 microg x L(-1) and 0.034 microg x L(-1)). CONCLUSIONS: Cycling 100 miles in an ambient temperature of 19 degrees C is associated with an acute change in diastolic filling that is not observed after prolonged exercise at 0 degrees C. Prolonged exercise is associated with minimal cardiac damage in some individuals; it appears that this is a separate phenomenon to the change in diastolic filling.

Adult↗
PubMed2004

Postexercise left ventricular function and cTnT in recreational marathon runners.

PURPOSE: To assess the impact of prolonged exercise on left ventricular (LV) function and the appearance of cardiac troponin T (cTnT) in older and recreational athletes. METHODS: Heart rate (HR), blood pressures, and cTnT were recorded in 35 subjects (age range 22-57 yr, finishing time 157-341 min) pre- and postrace. Echocardiograms (N = 26) assessed stroke volume (SV), ejection fraction (EF), sBP/LV end-systolic volume (sBP/ESV), diastolic filling (E:A ratio) as well as preload (LV internal dimension at end-diastole [LVIDd]) and afterload (LV wall stress). HR and core temperature were recorded in-event. Prepost changes in LV function were analyzed by repeated measures t-test. Delta scores for LV function and cTnT data were correlated with each other, age, finishing time, alterations in loading, and in-event data. RESULTS: SV was significantly decreased postrace (109 +/- 31 vs 85 +/- 25 mL, P < 0.05) likely due to a significant decrease in LVIDd (5.3 +/- 0.4 vs 4.9 +/- 0.5 cm, P < 0.05; r = 0.80, P < 0.05). LV wall stress was unchanged postrace (90 +/- 25 vs 89 +/- 27 g x cm(-2), P > 0.05). EF (70 +/- 12 vs.70 +/- 10%, P > 0.05) and sBP/ESV (3.7 +/- 2.9 vs 4.0 +/- 2.0, P > 0.05) did not change prepost race and were not related to age or finishing time (P > 0.05). E:A ratio was significantly reduced postrace (1.73 +/- 0.38 vs 1.41 +/- 0.25, P < 0.05) and could not be explained by an increased HR (56 +/- 9 vs 84 +/- 10, P < 0.05; r = 0.08, P > 0.05), a reduced LVIDd (r = 0.11, P > 0.05), age, finishing time, or in-event data. Postrace 26/33 subjects presented cTnT values in the range 0.024-0.080 microg x L(-1) that were not related to changes in LV function, loading, age, finishing time, or in-event data. CONCLUSION: No evidence of load-independent depression in LV systolic function was reported. Changes in cTnT and E:A were not related, and their etiology is uncertain.

Adult↗
PubMed2002

The cardiospecificity of the third-generation cTnT assay after exercise-induced muscle damage.

PURPOSE: The purpose of the present study was to examine the cardiospecificity of cTnI and the new third-generation cTnT assay, in the presence of exercise-induced muscle damage in highly trained individuals, and to examine the impact of a maximal-ramping treadmill test on cardiac function. METHODS: Eight highly trained male triathletes (mean +/- SD; age: 29 +/- 9 yr; height: 1.79 +/- 0.10 m; body mass: 77 +/- 10 kg; .VO(2max): 67.4 +/- 6.3 mL.kg(-1).min(-1)) completed two bouts of exercise. On the first occasion, subjects completed a maximal-ramping treadmill test. On a separate occasion, the subjects completed 30 min of downhill running (15% gradient) at a speed equivalent to 70% of maximal running velocity attained during the maximal-ramping treadmill test. All subjects were assessed using ECG, echocardiography, and blood analysis. Measurements were taken at rest, immediately after, and 48 h postexercise for each bout of exercise. Echocardiographic analysis was used to determine left ventricular systolic and diastolic function. Blood samples were analyzed for markers of myocyte damage. RESULTS: Echocardiographic results indicated normal left ventricular function before and after both exercise bouts. Total CK and CKMB were significantly elevated 48 h after the downhill run. cTnT and cTnI were not elevated at any stage of the study. CONCLUSIONS: Neither the maximal-ramping treadmill test nor the 30-min downhill run produced cardiac dysfunction or myocardial damage in young, healthy trained subjects. The elevated total CK and CKMB within the downhill study are noncardiac in origin as demonstrated by the lack of cTnT and cTnI. The cTnI and new third-generation cTnT assays may be used to detect cardiac damage in the presence of elevated total CK and CKMB associated with exercise-induced skeletal muscle damage.

Adult↗