Blood Pressure and LV Remodeling Among American-Style Football Players

OBJECTIVES

This study sought to determine the relationships among American-style football (ASF) participation, acquired left ventricular (LV) hypertrophy, and LV systolic function as assessed using contemporary echocardiographic parameters.

BACKGROUND

Participation in ASF has been associated with development of hypertension and LV hypertrophy. To what degree these processes impact LV function is unknown.

METHODS

This was a prospective, longitudinal cohort study evaluating National Collegiate Athletic Association Division I football athletes stratified by field position (linemen: n = 30; vs. nonlinemen, n = 57) before and after a single competitive season, using transthoracic echocardiography. LV systolic function was measured using complementary parameters of global longitudinal strain (GLS) (using 2-dimensional speckle-tracking) and ejection fraction (EF) (2-dimensional biplane).

RESULTS

ASF participation was associated with field position-specific increases in systolic blood pressure (SBP) (a Δ SBP of 10 ± 8 mm Hg in linemen vs. a Δ SBP of 3 ± 7 mm Hg in nonlinemen; p < 0.001) and an overall increase in incident LV hypertrophy (pre-season = 8% vs. post-season = 25%, p < 0.05). Linemen who developed LV hypertrophy had concentric geometry (9 of 11 [82%]) with decreased GLS (Δ = -1.1%; p < 0.001), whereas nonlinemen demonstrated eccentric LV hypertrophy (8 of 10 [80%]) with increased GLS (Δ = +1.4%; p < 0.001). In contrast, LV ejection fraction in the total cohort, stratified by field position, was not significantly affected by ASF participation. Among the total cohort, lineman field position, post-season weight, SBP, average LV wall thickness, and relative wall thickness were all independent predictors of post-season GLS.

CONCLUSIONS

ASF participation at a lineman field position may lead to a form of sport-related myocardial remodeling that is pathologic rather than adaptive. Future study will be required to determine if targeted efforts to control blood pressure, minimize weight gain, and to include an element of aerobic conditioning in this subset of athletes may attenuate this process and translate into tangible downstream health benefits.

Exercise-Induced Left Ventricular Remodeling Among Competitive Athletes

Background—

Contemporary understanding of exercise-induced cardiac remodeling is based on cross-sectional data and relatively short duration longitudinal studies. Temporal progression of exercise-induced cardiac remodeling remains incompletely understood.

Methods and Results—

A longitudinal repeated-measures study design using 2-dimensional and speckle-tracking echocardiography was used to examine acute augmentation phase (AAP; 90 days) and more extended chronic maintenance phase (39 months) left ventricular (LV) structural and functional adaptations to endurance exercise training among competitive male rowers (n=12; age 18.6±0.5 years). LV mass was within normal limits at baseline (93±9 g/m 2 ), increased after AAP (105±7 g/m 2 ; P =0.001), and further increased after chronic maintenance phase (113±10 g/m 2 ; P <0.001 for comparison to post-AAP). AAP LV hypertrophy was driven by LV dilation (ΔLV end-diastolic volume, 9±3 mL/m 2 ; P =0.004) with stable LV wall thickness (ΔLV wall thickness, 0.3±0.1 mm; P =0.63). In contrast, chronic maintenance phase LV hypertrophy was attributable to LV wall thickening (Δ LV wall thickness, 1.1±0.4 mm; P =0.004) with stable LV chamber volumes (ΔLV end-diastolic volume, 1±1 mL/m 2 ; P =0.48). Early diastolic peak tissue velocity increased during AAP (−11.7±1.9 versus −13.6±1.3 cm/s; P <0.001) and remained similarly increased after chronic maintenance phase.

Conclusions—

In a small sample of competitive endurance athletes, exercise-induced cardiac remodeling follows a phasic response with increases in LV chamber size, early diastolic function, and systolic twist in an acute augmentation phase of exercise training. This is followed by a chronic phase of adaptation characterized by increasing wall thickness and regression in LV twist. Training duration is a determinant of exercise-induced cardiac remodeling and has implications for the assessment of myocardial structure and function in athletes.

Endurance Exercise-Induced Cardiac Remodeling: Not All Sports Are Created Equal

BACKGROUND

The term endurance sport (ES) is broadly used to characterize any exercise that requires maintenance of high cardiac output over extended time. However, the relative amount of isotonic (volume) versus isometric (pressure) cardiac stress varies across ES disciplines. To what degree ES-mediated cardiac remodeling varies, as a function of superimposed isometric stress, is uncertain. The aim of this study was to compare the cardiac remodeling characteristics associated with two common yet physiologically distinct forms of ES.

METHODS

Healthy competitive male long-distance runners (high isotonic, low isometric stress; n = 40) and rowers (high isotonic, high isometric stress; n = 40) were comparatively studied after 3 months of sport-specific exercise training with conventional and speckle-tracking two-dimensional echocardiography.

RESULTS

Rowers demonstrated dilated left ventricular (LV) volumes and elevated LV mass (i.e., eccentric LV hypertrophy), whereas runners demonstrated normal LV mass (runners, 88 ± 11 g/m(2); rowers, 108 ± 13 g/m(2); P < .001) despite comparatively larger LV volumes (runners, 101 ± 10 mL/m(2); rowers, 89 ± 13 mL/m(2); P < .001) consistent with eccentric LV remodeling. Increasing LV mass was associated with increased reliance on early diastolic filling (LV mass vs E'/A' ratio, R = 0.47, P < .001) indicating "mass-dependent" diastolic function. Right ventricular dilation of similar magnitude and LV systolic function, as assessed by numerous complementary indices, were similar in both groups.

CONCLUSIONS

Cardiac adaptations differ significantly as a function of ES discipline. Further work is required to determine the mechanisms for this differential adaptation, to develop definitive ES discipline-specific normative values, and to evaluate the optimal therapeutic use of specific ES disciplines among patients with common cardiovascular diseases.