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ABSTRACT: The significance of reduced right ventricular (RV) deformation reported in endurance athletes (EAs) is unclear, highlighting the ambiguities between physiologic RV remodeling and pathology. The aim of this study was to test the hypothesis that RV functional reserve would be normal in EAs despite reduced deformation measures at rest.
Forty EAs and 15 nonathletes (NAs) performed maximal incremental exercise with simultaneous echocardiographic measures of RV function. Two-dimensional (2D) and color-coded Doppler acquisitions were used to quantify peak systolic strain and strain rate (SRs) for the basal, mid, and apical RV free wall. A second surrogate of contractility, the RV end-systolic pressure-area relationship, was calculated from the tricuspid regurgitant velocity and the RV end-systolic area. Changes in multiple measures obtained throughout exercise were used to assess the affect of exercise on RV contractility.
Compared with NAs at rest, basal RV strain and SRs were reduced in EAs, with good agreement between 2D and Doppler methods. During exercise, there was a strong linear correlation between heart rate and global SRs (r = -0.74 and r = -0.84 for Doppler and 2D methods, respectively, P < .0001), which was similar for EAs and NAs (P = .21 and P = .97 for differences in mean regression slopes by Doppler and 2D echocardiography, respectively). Exercise-induced increases in the RV end-systolic pressure-area relationship were also similar for EAs and NAs (P = .42). There was a strong correlation between RV global SRs and the RV end-systolic pressure-area relationship during exercise (r = 0.71, P < .0001).
Comparable RV contractile reserve for EAs and NAs suggests that the lower resting values of RV in EAs may represent physiologic changes rather than subclinical myocardial damage.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 12/2011; 25(3):253-262.e1. · 2.98 Impact Factor
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ABSTRACT: Endurance training may be associated with arrhythmogenic cardiac remodelling of the right ventricle (RV). We examined whether myocardial dysfunction following intense endurance exercise affects the RV more than the left ventricle (LV) and whether cumulative exposure to endurance competition influences cardiac remodelling (including fibrosis) in well-trained athletes.
Forty athletes were studied at baseline, immediately following an endurance race (3-11 h duration) and 1-week post-race. Evaluation included cardiac troponin (cTnI), B-type natriuretic peptide, and echocardiography [including three-dimensional volumes, ejection fraction (EF), and systolic strain rate]. Delayed gadolinium enhancement (DGE) on cardiac magnetic resonance imaging (CMR) was assessed as a marker of myocardial fibrosis. Relative to baseline, RV volumes increased and all functional measures decreased post-race, whereas LV volumes reduced and function was preserved. B-type natriuretic peptide (13.1 ± 14.0 vs. 25.4 ± 21.4 ng/L, P = 0.003) and cTnI (0.01 ± .03 vs. 0.14 ± .17 μg/L, P < 0.0001) increased post-race and correlated with reductions in RVEF (r = 0.52, P = 0.001 and r = 0.49, P = 0.002, respectively), but not LVEF. Right ventricular ejection fraction decreased with increasing race duration (r = -0.501, P < 0.0001) and VO(2)max (r = -0.359, P = 0.011). Right ventricular function mostly recovered by 1 week. On CMR, DGE localized to the interventricular septum was identified in 5 of 39 athletes who had greater cumulative exercise exposure and lower RVEF (47.1 ± 5.9 vs. 51.1 ± 3.7%, P = 0.042) than those with normal CMR.
Intense endurance exercise causes acute dysfunction of the RV, but not the LV. Although short-term recovery appears complete, chronic structural changes and reduced RV function are evident in some of the most practiced athletes, the long-term clinical significance of which warrants further study.
European Heart Journal 12/2011; 33(8):998-1006. · 10.48 Impact Factor
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ABSTRACT: Pre-participation screening of all competitive athletes is recommended in some countries and mandated in others to prevent sudden cardiac death in predisposed athletes. Whilst the prevalence of some conditions, which are screened for such as coronary artery anomalies and long QT syndromes, are stable across different populations, the prevalence of underlying conditions such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia shows considerable geographic variability. Evidence exists that screening reduces sudden death, but the potential negative impact of exclusion from sport has not been quantified. Australia has a high rate of participation in sport and needs to consider whether screening is feasible, effective and affordable. It is difficult to make this decision currently as there is little information about the scope of the problem in Australia and whether the prevalence of underlying conditions which predispose to sudden cardiac death is similar or different to that in other countries. We review the evidence for and against screening and propose that systematic collection of Australian data is required before routine pre-participation screening can be introduced in Australia.
Heart Lung & Circulation 10/2011; 20(10):629-33. · 1.20 Impact Factor
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ABSTRACT: Training induces changes in cardiac structure and function which improves cardiac output (CO) and oxygen delivery during exercise. It is unclear whether it is cardiac structure or function which is of greatest importance in determining maximal oxygen consumption (VO(2max)). In 55 subjects (15 non-athletes, 32 amateur and 8 elite athletes), left and right ventricular (LV and RV) volumes and mass were assessed by magnetic resonance imaging (CMR). Comprehensive traditional and novel echocardiographic measures included colour-coded Doppler echocardiography to assess myocardial velocities, strain and strain rate at rest and maximal exercise in both ventricles. Measures of cardiac size and function were assessed as univariate and multivariate predictors of VO(2max). LV and RV mass correlated strongly with VO(2max) (r = 0.79 and r = 0.65, respectively, p < 0.0001), as did LV and RV end-diastolic volumes (r = 0.68 and r = 0.75, p < 0.0001) and heart rate reserve (r = 0.60, p < 0.0001). Measures of myocardial function were not predictive of VO(2max) with the exception of RV diastolic velocities (r = 0.32 and r = 0.36 for rest and exercise, respectively, p < 0.05). On multivariate analysis, only RV end-diastolic volume, LV mass and heart rate reserve were independent predictors (beta = 0.28, 0.45 and 0.27 respectively, p < 0.0001) and together explained 73% of the variance in VO(2max). Measures of cardiac morphology are strongly associated with VO(2max) in healthy adults and well-trained athletes. A combination of ventricular volume, mass and heart rate reserve explains much of the variance in VO(2max), whilst measures of myocardial function do not further strengthen predictive models.
Arbeitsphysiologie 10/2011; 112(6):2139-47. · 2.15 Impact Factor
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ABSTRACT: There is evolving evidence that intense exercise may place a disproportionate load on the right ventricle (RV) when compared with the left ventricle (LV) of the heart. Using a novel method of estimating end-systolic wall stress (ES-σ), we compared the RV and LV during exercise and assessed whether this influenced chronic ventricular remodeling in athletes.
For this study, 39 endurance athletes (EA) and 14 nonathletes (NA) underwent resting cardiac magnetic resonance (CMR), maximal oxygen uptake (VO2), and exercise echocardiography studies. LV and RV end-systolic wall stress (ES-σ) were calculated using the Laplace relation (ES-σ = Pr/(2h)). Ventricular size and wall thickness were determined by CMR; invasive and Doppler echo estimates were used to measure systemic and pulmonary ventricular pressures, respectively; and stroke volume was quantified by Doppler echocardiography and used to calculate changes in ventricular geometry during exercise.
In EA, compared with NA, resting CMR measures showed greater RV than LV remodeling. The ratios RV ESV/LV ESV (1.40 ± 0.23 vs 1.26 ± 0.12, P = 0.007) and RV mass/LV mass (0.29 ± 0.04 vs 0.25 ± 0.03, P = 0.012) were greater in EA than in NA. RVES-σ was lower at rest than LVES-σ (143 ± 44 vs 252 ± 49 kdyn · cm, P < 0.001) but increased more with strenuous exercise (125% vs 14%, P < 0.001), resulting in similar peak exercise ES-σ (321 ± 106 vs 286 ± 77 kdyn · cm, P = 0.058). Peak exercise RVES-σ was greater in EA than in NA (340 ± 107 vs 266 ± 82 kdyn · cm, P = 0.028), whereas RVES-σ at matched absolute workloads did not differ (P = 0.79).
Exercise induces a relative increase in RVES-σ which exceeds LVES-σ. In athletes, greater RV enlargement and greater wall thickening may be a product of this disproportionate load excess.
Medicine and science in sports and exercise 11/2010; 43(6):974-81. · 3.71 Impact Factor
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ABSTRACT: Pulmonary transit of agitated contrast (PTAC) occurs to variable extents during exercise. We tested the hypothesis that the onset of PTAC signifies flow through larger-caliber vessels, resulting in improved pulmonary vascular reserve during exercise. Forty athletes and fifteen nonathletes performed maximal exercise with continuous echocardiographic Doppler measures [cardiac output (CO), pulmonary artery systolic pressure (PASP), and myocardial velocities] and invasive blood pressure (BP). Arterial gases and B-type natriuretic peptide (BNP) were measured at baseline and peak exercise. Pulmonary vascular resistance (PVR) was determined as the regression of PASP/CO and was compared according to athletic and PTAC status. At peak exercise, athletes had greater CO (16.0 ± 2.9 vs. 12.4 ± 3.2 l/min, P < 0.001) and higher PASP (60.8 ± 12.6 vs. 47.0 ± 6.5 mmHg, P < 0.001), but PVR was similar to nonathletes (P = 0.71). High PTAC (defined by contrast filling of the left ventricle) occurred in a similar proportion of athletes and nonathletes (18/40 vs. 10/15, P = 0.35) and was associated with higher peak-exercise CO (16.1 ± 3.4 vs. 13.9 ± 2.9 l/min, P = 0.010), lower PASP (52.3 ± 9.8 vs. 62.6 ± 13.7 mmHg, P = 0.003), and 37% lower PVR (P < 0.0001) relative to low PTAC. Right ventricular (RV) myocardial velocities increased more and BNP increased less in high vs. low PTAC subjects. On multivariate analysis, maximal oxygen consumption (VO(2max)) (P = 0.009) and maximal exercise output (P = 0.049) were greater in high PTAC subjects. An exercise-induced decrease in arterial oxygen saturation (98.0 ± 0.4 vs. 96.7 ± 1.4%, P < 0.0001) was not influenced by PTAC status (P = 0.96). Increased PTAC during exercise is a marker of pulmonary vascular reserve reflected by greater flow, reduced PVR, and enhanced RV function.
Journal of Applied Physiology 11/2010; 109(5):1307-17. · 3.75 Impact Factor
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ABSTRACT: Quantification of left ventricular torsion may provide new indices of systolic and diastolic function. We sought to characterize the effect of acute manipulation of load on cardiac torsion, plecotropy in human subjects.
Simultaneous Millar LV pressure, micromanometry, and echocardiograms were performed on 18 patients (10 male, mean age 66 years) with normal systolic function. Loading was altered sequentially by the administration of glyceryl trinitrate (GTN) and saline fluid loading. Echocardiographic speckle tracking imaging was used to quantify LV torsion and event timing was recorded relative to mitral valve opening (MVO).
GTN administration decreased preload (LV end diastolic pressure: 15.7 vs 8.4 mmHg, P < 0.001), and afterload (wall stress: 140 vs 84 x10(3)dyn/cm(2), P < 0.02). Administration of fluid increased preload (LVEDP 11.3 vs 18.1 mmHg, P < 0.001) and increased wall stress, but to a lesser extent (102 vs 117 x10(3)dyn/cm(2), P < 0.003). GTN administration augmented peak torsion (8.4 vs 11.0 deg, P < 0.05), increased systolic torsion velocity (46.6 vs 65.3deg/sec, P < 0.01) and resulted in earlier onset of untwisting (-105 vs -127ms, P < 0.05). Fluid loading decreased the proportion of untwisting prior to MVO (39.0 vs 31.0%, P < 0.05), untwisting acceleration (-750 vs -592deg/sec/sec, P < 0.05) and delayed the timing of peak untwisting (-37.0 vs 9.1ms, P < 0.01), but did not affect systolic torsion parameters.
Left ventricular torsion parameters are sensitive to acute changes in load and therefore need to be interpreted in the context of current loading conditions.
Echocardiography 04/2010; 27(4):407-14. · 1.24 Impact Factor
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Andrew T. Burns M.B, B.S. (Hons), B.Med.Sci., M.D., F.R.A.C.P,
Andre La Gerche M.B, B.S., F.R.A.C.P,
David L. Prior M.B.B.S., Ph.D., F.R.A.C.P., F.C.S.A.N.Z., F.A.C.C,
Andrew I. MacIsaac M.B.B.S., M.D., F.R.A.C.P., F.C.S.A.N.Z,
Andrew T. Burns,
Andre La Gerche,
David L. Prior, Andrew I. MacIsaac
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ABSTRACT: Background: Quantification of left ventricular torsion may provide new indices of systolic and diastolic function. We sought to characterize the effect of acute manipulation of load on cardiac torsion, plecotropy in human subjects. Methods: Simultaneous Millar LV pressure, micromanometry, and echocardiograms were performed on 18 patients (10 male, mean age 66 years) with normal systolic function. Loading was altered sequentially by the administration of glyceryl trinitrate (GTN) and saline fluid loading. Echocardiographic speckle tracking imaging was used to quantify LV torsion and event timing was recorded relative to mitral valve opening (MVO). Results: GTN administration decreased preload (LV end diastolic pressure: 15.7 vs 8.4 mmHg, P < 0.001), and afterload (wall stress: 140 vs 84 ×103dyn/cm2, P < 0.02). Administration of fluid increased preload (LVEDP 11.3 vs 18.1 mmHg, P < 0.001) and increased wall stress, but to a lesser extent (102 vs 117 ×103dyn/cm2, P < 0.003). GTN administration augmented peak torsion (8.4 vs 11.0 deg, P < 0.05), increased systolic torsion velocity (46.6 vs 65.3deg/sec, P < 0.01) and resulted in earlier onset of untwisting (–105 vs –127ms, P < 0.05). Fluid loading decreased the proportion of untwisting prior to MVO (39.0 vs 31.0%, P < 0.05), untwisting acceleration (–750 vs –592deg/sec/sec, P < 0.05) and delayed the timing of peak untwisting (–37.0 vs 9.1ms, P < 0.01), but did not affect systolic torsion parameters. Conclusions: Left ventricular torsion parameters are sensitive to acute changes in load and therefore need to be interpreted in the context of current loading conditions. (ECHOCARDIOGRAPHY 2010;27:407-414)
Echocardiography 03/2010; 27(4):407 - 414. · 1.24 Impact Factor
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ABSTRACT: Left ventricular (LV) strain and strain rate have been proposed as novel indices of systolic function; however, there are limited data about the effect of acute changes on these parameters.
Simultaneous Millar micromanometer LV pressure and echocardiographic assessment were performed on 18 patients. Loading was altered sequentially by the administration of glyceryl trinitrate (GTN) and saline fluid loading. Echocardiographic speckle tracking imaging was used to quantify the peak systolic strain (S) and peak systolic strain rate (SR S) and dp/dt max was recorded from the micromanometer data. GTN administration decreased preload (LV end diastolic pressure [LVEDP]: 15.7 vs. 8.4 mmHg, P < 0.001) and afterload (end systolic wall stress: 74 vs. 43 x 10(3)dyn/cm(2), P < 0.001). Administration of fluid increased preload (LVEDP: 11.3 vs. 18.1 mmHg, P < 0.001) and increased wall stress (53 vs. 62 x 10(3)dyn/cm(2), P < 0.003). Administration of GTN resulted in increased circumferential SR S (-1.2 vs. -1.7s(-1), P < 0.01) and longitudinal SR S (-0.9 vs. -1.0 s(-1), P < 0.001). The administration of fluid resulted in decreased circumferential SR S (-1.5 vs. -1.3s(-1), P < 0.01) and longitudinal SR S (-1.0 vs. -0.9s(-1), P < 0.01). As preload and afterload increased, decrease in circumferential SR S (r = 0.63, P < 0.001; r = 0.56, P<0.001) and longitudinal SR S were observed (r = 0.42, P < 0.003; r = 0.49 P < 0.001).
Circumferential and longitudinal peak strain and systolic strain rate are sensitive to acute changes in load, an important factor that needs to be considered in their application as indices of systolic function.
European Heart Journal – Cardiovascular Imaging 12/2009; 11(3):283-9. · 2.32 Impact Factor
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ABSTRACT: We sought to establish the relationship between invasive measures of diastolic function and untwisting parameters measured with speckle tracking imaging.
Left ventricular (LV) diastolic function is determined by early diastolic relaxation (which creates suction gradients for LV filling) and myocardial stiffness. Assessment of LV torsion has shown that untwisting begins before aortic valve closure and, in animals, might be an important component of normal diastolic filling. Studies in human subjects using indirect indexes derived from right heart catheterization have suggested a relationship between tau and measures of untwisting, but the relationship between directly measured diastolic function indexes with micromanometer catheters and untwisting parameters has not been established in human subjects.
Simultaneous Millar micromanometer LV pressure and echocardiographic assessment was performed on 18 patients (10 male, mean age 66 years) with normal systolic function and a spectrum of diastolic function. Invasive rate of the rise of LV pressure, dp/dt minimum and tau were recorded as measures of active relaxation, and the LV minimum diastolic pressure was recorded as an index of diastolic suction. The LV stiffness constant and functional chamber stiffness were estimated from hybrid pressure-volume loops. Echocardiographic speckle tracking imaging was used to quantify torsion.
As relaxation was impaired, (prolonged tau) untwisting was delayed (r = 0.35, p < 0.01). There were nonsignificant associations between reduced untwisting and longer values of tau and lower dp/dt minimum. Reduction in the extent of untwisting before mitral valve opening was associated with increased LV minimum diastolic pressure (r = -0.30, p < 0.034). No relation was observed between the LV stiffness constant (beta: r = 0.11, p = NS) or the functional LV chamber stiffness (b: r = 0.11, p = NS) and untwisting.
Untwisting parameters are related to invasive indexes of LV relaxation and suction but not to LV stiffness. These data suggest that untwisting is an important component of early diastolic LV filling but not later diastolic events.
JACC. Cardiovascular imaging 06/2009; 2(6):709-16. · 14.29 Impact Factor
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ABSTRACT: Left ventricular torsion, resulting from the rotation of the base and apex of the ventricle in opposite directions, may be an important component of normal cardiac function both at rest and with exercise. The effect of exercise on torsion in the general population and the influence of aging on changes in torsion with exercise are not known.
Analysis of torsion, positive and negative torsion velocities, and negative torsion acceleration was performed using speckle tracking imaging on 33 stress echocardiograms using supine bicycle stress.
Resting and postexercise torsion could be assessed in 14 patients (42%). A total of 19 patients who were significantly older and larger (mean age 57 years, mean body mass index 28.2, both P < .03) were excluded as a result of inadequate frame rate and image quality after exercise. After exercise, significant increases in peak torsion (10.3 +/- 0.8 vs 13.3 +/- 1.3 degrees, P < .04), peak positive torsion (54.2 +/- 5.6 vs 113.6 +/- 12.3 degrees/s, P < .0001), and peak negative torsion (-56.3 +/- 7.9 vs -100.8 +/- 14.8 degrees/s, P < .03) velocities were observed. Ejection fraction correlated with torsion both at rest and after exercise (r = 0.63, P < .0004). At rest, torsion was greater in older individuals (8.9 +/- 0.6 vs 11.6 +/- 1.2 degrees, P < .04). With increasing age, exercise resulted in less augmentation of torsion (r = 0.59, P < .02) and positive torsion velocity (r = -0.79, P < .003), and decreased negative torsional acceleration (r = 0.60, P < .035).
Exercise results in increased cardiac plecotropy (the augmentation of torsion parameters in response to load or stimulus) but this effect is attenuated with aging. Further investigation is required to determine whether impairment of plecotropy contributes to the reduced exercise capacity associated with aging.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 05/2008; 21(4):315-20. · 2.98 Impact Factor
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European Heart Journal 04/2008; 29(6):825; author reply 825-6. · 10.48 Impact Factor
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ABSTRACT: Our aim was to study the independent effect of heart rate (HR) on parameters of diastolic function, particularly mitral annular velocities measured by tissue Doppler imaging (TDI), an effect which is not well understood.
Sixteen patients with dual chamber pacemakers attending for routine pacemaker review underwent detailed echocardiographic assessment during atrial pacing with intact atrioventricular conduction at baseline and accelerated HRs. Mitral inflow and annular tissue Doppler velocities and systolic strain parameters were compared.
Parameters of systolic function were unaffected by increased HR. When these parameters were compared at baseline (mean 67 bpm) and accelerated HR (mean 80 bpm), the following was observed: a significant decrease in early mitral inflow (E) wave (70.5 +/- 5.5 cm/s vs 63.5 +/- 4.9 cm/s, P < 0.02) and early mitral annular (E') velocities (7.0 +/- 0.5 cm/s vs 6.3 +/- 0.6 cm/s, P < 0.003) and a significant increase in mitral inflow A wave (70.3 +/- 4.5 cm/s vs 77.3 +/- 4.4 cm/s, P < 0.05) and late mitral annular (A') velocities (9.3 +/- 0.6 cm/s vs 10.8 +/- 0.5, P < 0.00004).
Changes in HR have previously unrecognized significant effects on tissue Doppler parameters of diastolic function. Further study is required to determine if tissue Doppler derived annular velocities should be corrected for HR.
Echocardiography 09/2007; 24(7):697-701. · 1.24 Impact Factor
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ABSTRACT: Idiopathic hypereosinophilic syndrome (HES) is an uncommon condition characterized by an unexplained elevation of absolute eosinophil count (AEC) to > or = 1.5 x 10(9)/l for at least six months, and is frequently associated with eosinophil-mediated end organ damage. Idiopathic HES, as with secondary HES and primary hypereosinophilic clonal hematopoietic disorders, has a high incidence of myocardial, pulmonary, neurological and other organ injury. Myocardial fibroelastosis and valvular lesions are common, and successful treatment with valve replacement or resection of fibrotic myocardium has been reported. The case is described of a patient with idiopathic HES and multi-organ complications including severe mitral valve disease, in whom a functionally obstructive thrombosis of a newly inserted prosthetic mitral valve occurred despite adequate anticoagulation, when the AEC was profoundly elevated. Recurrent thrombosis has not occurred over a substantial period following AEC reduction with corticosteroids, and subsequent maintenance at normal levels.
The Journal of heart valve disease 10/2006; 15(5):721-5. · 0.81 Impact Factor
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ABSTRACT: We describe two patients with severe aortic stenosis, coronary artery disease, severe left ventricular dysfunction and heart failure in which the calcium-sensitising agent, levosimendan was administered prior to aortic valve replacement and coronary artery bypass graft surgery. In both cases, drug infusion was well tolerated at the doses used, heart failure improved significantly prior to surgery and peri-operative management was relatively uncomplicated in cases that would traditionally be considered high risk. Further investigation of the use of levosimendan both for treating heart failure in the presence of severe aortic stenosis and as pre-operative therapy is warranted.
Heart Lung & Circulation 03/2006; 15(1):56-8. · 1.20 Impact Factor
