title: Cardiac drift during prolonged exercise with echocardiographic evidence of reduced diastolic function of the heart.
abstract: This study examined whether, in 16 male subjects, a continuous increase in heart rate (HR) during 4 h of ergometry cycling relates to cardiac fatigue or cardiomyocyte damage. Serum cardiac troponin T (cTnT) was determined and echocardiographic assessment was carried out prior to and after 2 h of exercise, within 15 min of completing exercise and after 24 h. Left ventricular contractile function (end-systolic blood pressure-volume relationship [SBP/ESV]) and diastolic filling (ratio of early to late peak left ventricular filling velocities [E:A]) were calculated. During exercise HR was 132+/-5 beats min(-1) after 2 h and increased to 141+/-5 beats min(-1) (mean +/- SD; P<0.05), but there was no evidence of altered LV contractile function (SBP/ESV 39.0+/-5.1 mmHg cm(-1) to 36.5+/-5.2 mmHg cm(-1) and SBP/ESV was not correlated to maximal oxygen uptake (r(2)=0.363). In contrast, E:A decreased (1.82+/-0.32 to 1.48+/-0.30; P<0.05) and returned towards baseline after 24 h (1.78+/-0.28), and individual changes were correlated to maximal oxygen uptake (r(2)=0.61; P<0.05). Low levels of cTnT were detected in two subjects after 4 h of exercise that had normalised by 24 h of recovery. During prolonged exercise cardiovascular drift occurred with echocardiographic signs of a reduced diastolic function of the heart, especially in those subjects with a high maximal oxygen uptake.
authors.affiliation: Centre for Clinical and Biophysical Research in Human Movement, Manchester Metropolitan University, Hassall Road, Alsager, ST7 2HL, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Dawson
authors.forename: R
authors.initials: R
authors.lastname: Shave
authors.forename: K
authors.initials: K
authors.lastname: George
authors.forename: G
authors.initials: G
authors.lastname: Whyte
authors.forename: D
authors.initials: D
authors.lastname: Ball
authors.forename: D
authors.initials: D
authors.lastname: Gaze
authors.forename: P
authors.initials: P
authors.lastname: Collinson
mesh_terms: D000328:Adult; D003326:Coronary Circulation; D003971:Diastole; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D009206:Myocardium / Q000378:metabolism; D013599:Systole; D013997:Time Factors; D020107:Troponin T / Q000097:blood* / Q000378:metabolism; D016277:Ventricular Function, Left
chemical_list: D020107:Troponin T