The Morganroth hypothesis revisited: endurance exercise elicits eccentric hypertrophy of the heart

Lifestyle and Cardiac Structure and Function in Healthy Midlife Population

The association between lifestyle and cardiac structure and function measures, such as global longitudinal strain and diastolic function in a healthy midlife general population, is not well known. A subpopulation of the Northern Finland Birth Cohort 1966 took part in follow-up, including echocardiography (n = 1,155) at the age of 46. All antihypertensive medication users (n = 164), patients with diabetes (n = 70), subjects with any cardiac diseases (n = 24), and subjects with echocardiography abnormalities (n = 21) were excluded. Moderate to vigorous physical activity (MVPA) was recorded with a wrist-worn accelerometer over 14 days and categorized into high, moderate, and low MVPA groups. Similarly, alcohol consumption was categorized as low, moderate, and high-dose users of alcohol and smoking as nonsmokers, former, and current smokers. The total number of healthy subjects included in the study was 715 (44% males). Left ventricular mass index and left atrial end-systolic volume index were significantly higher in the high MVPA group compared with the low MVPA group (adjusted main effect p = 0.002 and p <0.001, respectively). Cardiac function did not differ among the physical activity groups. High alcohol consumption was associated with impaired global longitudinal strain and diastolic function (adjusted main effect p = 0.002 and p = 0.004, respectively) but not with any cardiac structure variables. Smoking was not associated with cardiac structure or function. In healthy middle-aged adults, MVPA was independently associated with structural changes in the heart but not with cardiac function. High alcohol consumption was associated with impaired modern cardiac function measures but not with cardiac structure.

The athlete's heart: insights from echocardiography

The manifestations of the athlete's heart can create diagnostic challenges during an echocardiographic assessment. The classifications of the morphological and functional changes induced by sport participation are often beyond 'normal limits' making it imperative to identify any overlap between pathology and normal physiology. The phenotype of the athlete's heart is not exclusive to one chamber or function. Therefore, in this narrative review, we consider the effects of sporting discipline and training volume on the holistic athlete's heart, as well as demographic factors including ethnicity, body size, sex, and age.

Functional and Morphological Adaptations in the Heart of Children Aged 12-14 Years following Two Different Endurance Training Protocols

This study investigated the cardiac functional and the morphological adaptations because of two endurance training protocols. Untrained children (N = 30, age: 12-14 years) were divided into three groups (N = 10/group). The first group did not perform any session (CONTROL), the second performed ventilatory threshold endurance training (VTT) for 12 weeks (2 sessions/week) at an intensity corresponding to the ventilatory threshold (VT) and the third (IT) performed two sessions per week at 120% of maximal oxygen uptake (VO2max). Two other sessions (30 min running at 55-65% of VO2max) per week were performed in VVT and IT. Echocardiograms (Left Ventricular end Diastolic Diameter, LVEDd; Left Ventricular end Diastolic Volume, LVEDV; Stroke Volume, SV; Ejection Fraction, EF; Posterior Wall Thickness of the Left Ventricle, PWTLV) and cardiopulmonary ergospirometry (VO2max, VT, velocity at VO2max (vVO2max), time in vVO2max until exhaustion (Tlim) was conducted before and after protocols. Significant increases were observed in both training groups in LVEDd (VTT = 5%; IT = 3.64%), in LVEDV (VTT = 23.7%; ITT = 13.6%), in SV (VTT = 25%; IT = 16.9%) but not in PWTLV and EF, after protocols. No differences were noted in the CONTROL group. VO2max and VT increased significantly in both training groups by approximately 9% after training. Our results indicate that intensity endurance training does not induce meaningful functional and morphological perturbations in the hearts of children.

Relationship between echocardiogram and physical parameters in experienced resistance trainers: a pilot study

BACKGROUND

A paucity of research exists concerning physiological factors influencing heart structure and function in strength athletes. This pilot study investigated whether body composition and muscle performance are associated with indices of cardiac structure and function in experienced resistance trainers.

METHODS

A cross-sectional study designed was employed to address the study aim. Seventeen males (median age 33.0 years) and eight females (median age 32.5 years) with backgrounds in bodybuilding and powerlifting participated in this study. Muscle performance, body composition and echocardiographic measures were performed. Mann-Whitney U-tests were used to examine differences between males and females. Spearman's Rho partial correlation analyses (adjusting for sex) were conducted to examine relationships between physical and echocardiogram parameters.

RESULTS

Moderate to strong positive correlations were found between fat-free mass and aortic root, right ventricular internal dimension, interventricular septum thickness, left ventricular posterior wall thickness, left atrium area, left ventricular end-diastolic volume, and left ventricular end-systolic volume (r: 0.43-0.76, P≤0.03). Moderate to strong positive correlations were found between leg press 1RM and aortic root, left ventricular internal dimension diastole, left atrium area, left ventricular end-diastolic volume, and left ventricular end-systolic volume (r: 0.49-0.67, P≤0.02).

CONCLUSIONS

Resistance trainers with greater fat-free mass and lower body strength appear to have larger cardiac structures. Changes in heart size and function are likely to result from long-term strenuous resistance training. Due to the suspected prevalence of performance enhancing drug use among powerlifters and bodybuilders, care is required to rule out pathological conditions.

Athletic Remodeling in Female College Athletes: The "Morganroth Hypothesis" Revisited

BACKGROUND

There is limited data regarding ventricular remodeling in college female athletes, especially when appropriate scaling of cardiac dimensions to lean body mass (LBM) is considered. Moreover, it is not well established whether cardiac remodeling in female athletes is a balanced process with proportional increase in left ventricular (LV) mass and volume or the right and LV size.

METHODS

During the preparticipation competitive screening, 72 female college athletes volunteered to undergo dual energy x-ray absorptiometry scan for quantification of LBM and comprehensive 2D echocardiography including assessment of longitudinal myocardial strain. The athletes were divided in 2 groups according to the intensity of the dynamic and static components of their sport categories, ie, a higher intensity dynamic and resistive group (n = 37 participating in rowing, water polo and lacrosse) and a lower intensity group (n = 35, participating in short distance running, sailing, synchronized swimming, and softball). In addition, we recruited a group of 31 age-matched nonathlete controls.

RESULTS

The mean age of the study population was 18.7 ± 1.0 years. When scaled to body surface area, the higher intensity group had 17.1 ± 3.6% (P < 0.001) greater LV mass when compared with the lower intensity group and 21.7 ± 4.0% (P < 0.001) greater LV mass than the control group. The differences persisted after scaling to LBM with 14.2 ± 3.2% (P < 0.001) greater LV mass in the higher intensity group. By contrast, there was no difference in any of the relative remodeling indices including the LV mass to volume ratio, right to LV area ratio, or left atrial to LV volume ratio (P > 0.50 for all). In addition, no significant difference was noted among the 3 groups in LV ejection fraction (P = 0.22), LV global longitudinal strain (P = 0.55), LV systolic strain rate (P = 0.62), or right ventricular global longitudinal strain (P = 0.61).

CONCLUSION

Female collegiate athletes participating in higher intensity dynamic and resistive sports have higher indexed LV mass even when scaled to LBM. The remodeling process does however appear to be a balanced process not only at the intraventricular level but also at the interventricular and atrioventricular levels.

Athlete's Heart: Diagnostic Challenges and Future Perspectives

Distinguishing between adaptive and maladaptive cardiovascular response to exercise is crucial to prevent the unnecessary termination of an athlete's career and to minimize the risk of sudden death. This is a challenging task essentially due to the substantial phenotypic overlap between electrical and structural changes seen in the physiological athletic heart remodeling and pathological changes seen in inherited or acquired cardiomyopathies. Stress testing is an ideal tool to discriminate normal from abnormal cardiovascular response by unmasking subtle pathologic responses otherwise undetectable at rest. Treadmill or bicycle electrocardiography, transthoracic echocardiography, and cardiopulmonary exercise testing are common clinical investigations used in sports cardiology, specifically among participants presenting with resting electrocardiographic abnormalities, frequent premature ventricular beats, or non-sustained ventricular arrhythmias. In this setting, as well as in cases of left ventricular hypertrophy or asymptomatic left ventricular dysfunction, stress imaging and myocardial tissue characterization by cardiovascular magnetic resonance show promise. In this review, we aimed to reappraise current diagnostic schemes, screening strategies and novel approaches that may be used to distinguish adaptive remodeling patterns to physical exercise from early phenotypes of inherited or acquired pathological conditions commanding prompt intervention.

Cardiac Magnetic Resonance Assessment of the Structural and Functional Cardiac Adaptations to Soccer Training in School-Aged Male Children

Physical training is associated with changes in cardiac morphology called the "athlete's heart", which has not been sufficiently studied in children. The aim of the study was to analyze cardiac adaptation to exercise in pre-adolescent soccer players. Thirty-six soccer players (mean age 10.1 ± 1.4 years) and 24 non-athlete male controls (10.4 ± 1.7 years) underwent cardiac magnetic resonance. Measurements of myocardial mass, end-diastolic and end-systolic volume, stroke volume and ejection fraction for left and right ventricle (LV, RV) were performed. Additionally, left and right atrial (LA, RA) areas and volumes were analysed. Relative wall thickness (RWT) was calculated to describe the pattern of cardiac remodeling. Interventricular wall thickness and LV mass were significantly higher in athletes, but remained within the reference (6.9 ± 0.8 vs. 6.2 ± 0.9 mm/√m², p = 0.003 and 57.1 ± 7.4 vs. 50.0 ± 7.1 g/m², p = 0.0006, respectively) with no changes in LV size and function between groups. The RWT tended to be higher among athletes (p = 0.09) indicating LV concentric remodeling geometry. Soccer players had significantly larger RV size (p < 0.04) with similar function and mass. Also, the LA volume (p = 0.01), LA area (p = 0.03) and LA diameter (p = 0.009) were significantly greater in players than in controls. Cardiac adaptations in pre-adolescent soccer players are characterized by an increased LV mass without any changes in LV size and systolic function, which is typical of resistance training with tendency to concentric remodeling. This is accompanied by increase of LA and RV size. It should be taken into account during annual pre-participation evaluation.