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[Cardiac hypertrophy and coronary reserve in endurance athletes]
M Toraa1, F Pouillard, P Merlet
1ADDMS 94, Centre Département de Médecine du Sport, Créteil, France.
Insights
Intensive training-induced left ventricular hypertrophy (LVH) in athletes does not impair coronary reserve (CR). This adaptive LVH is associated with increased coronary blood flow capacity, unlike pathological LVH.
Area of Science:
- Cardiology
- Sports Medicine
- Physiology
Background:
- Left ventricular hypertrophy (LVH) from valvular heart disease or hypertension is linked to impaired coronary reserve (CR).
- The effects of adaptive LVH from intensive training on myocardial blood flow (MBF) and CR are not well understood.
Purpose of the Study:
- To investigate whether adaptive LVH in highly trained athletes alters myocardial blood flow (MBF) and coronary reserve (CR).
Main Methods:
- Compared 8 elite triathletes with echocardiographic LVH to 6 control subjects.
- Assessed MBF and CR using Positron Emission Tomography (PET) with H2O15 at rest and during pharmacologic hyperemia (dipyridamole).
- Measured left ventricular mass via 2-D echocardiography.
Main Results:
- Triathletes with LVH exhibited normal resting MBF compared to controls (0.74 +/- 0.1 vs 0.8 +/- 0.2 ml/ml/min).
- Athletes demonstrated significantly increased CR (6.1 +/- 1.9) compared to controls (3.8 +/- 0.7).
- LVH in athletes did not impair CR, contrasting with findings in pathological LVH.
Conclusions:
- LVH resulting from intensive physical training is not associated with impaired coronary reserve.
- Adaptive LVH in athletes may enhance coronary blood flow capacity.
Abstract:
Impaired coronary reserve (CR) with angiographic coronary arteries has been demonstrated in patients with left ventricular hypertrophy (LVH) in response to valvular heart disease or hypertension. To determine if adaptive LVH induced by intensive training may alter myocardial blood flow (MBF) and CR, 8 highly trained endurance tri- athletes (29.6 +/- 4.0 yrs, with echographic LVH) were compared with 6 control subjects (33.0 +/- 7.9 yrs, with a normal echographic examination). Triathletes entered the study if they had a left ventricular mass >120 g/m2 at 2-D echocardiographic measurements (mean = 148.6 +/- 19.8 g/m2). MBF was assessed using positron emission tomography (PET) with H2O15. Subjects underwent an intravenous bolus of 17- 25 mCi of H2)15 at baseline and after intravenous infusion of 0.80 mg/kg of dipyridimole; H2O15 examination was followed by an F18-fluorodeoxyglucose (FDG) myocardial imaging. CR was determined as the ration of maximal to basal myocardial blood flow. In comparison with controls, triathletes with LVH showed normal MBF values (0.74 +/- 0.1 vs 0.8 +/- 0.2 ml/ml/min, p = 0.2), but an increased CR (3.8 +/- 0.7 vs 6.1 +/-1.9, p < 0.05). In contrast with other forms of LVH, CR is not altered in LVH due intense physical training. These results suggest that LVH due to intensive physical training is associated with an increase in coronary blood flow capacity.