Author + information
- Published online April 18, 2018.
- Jae-Hyeong Park, MD, PhD,
- Jin Kyung Oh, MD,
- Kye Hun Kim, MD PhD∗ (, )
- Jae Yeong Cho, MD,
- Goo-Yeong Cho, MD, PhD,
- Jae-Hwan Lee, MD, PhD,
- In-Whan Seong, MD, PhD,
- Lawrence Rink, MD, PhD† (, )
- Kyle Hornsby, MD,
- Myung Ho Jeong, MD, PhD,
- Jeong Gwan Cho, MD, PhD and
- Jong Chun Park, MD, PhD
- ↵∗Echocardiography and Cardiac Imaging Laboratory, Chonnam National University Hospital, 42 Jebong-ro, Dong-gu, Gwangju 61469, South Korea
- ↵†Center for Sports Medicine and Technology, Indiana University School of Medicine, Indiana University Sports Medicine, 550 Landmark Avenue, Bloomington, Indiana 47403
Left ventricular (LV) strain values measured by 2-dimensional speckle tracking echocardiography (2DSTE) represent global and regional myocardial functions. These values can give prognostic information, detect subclinical LV changes, and distinguish physiologic adaptation from pathologic hypertrophy. Because highly trained athletes can have altered cardiac structures, it is difficult to differentiate normal adaptation from pathologic changes. In this regard, 2DSTE can be a useful tool for the screening of athletes (1). Because the differences in myocardial deformation according to sex and classifications of sports have been poorly studied in university athletes, we investigated the impact of sex and classifications of sports on LV deformation in 1,120 (22 ± 2 years of age; 649 men) young athletes during the 2015 Gwangju Summer Universiade. Sports were divided according to cardiovascular demand into lowest demand (LD) (including riflery and golf), low moderate demand (LMD) (including baseball and table tennis), moderate demand (MD) (including running and soccer), high moderate demand (HMD) (including basketball and swimming), and highest demand (HD) (including rowing and triathlon) (2).
Left ventricular ejection fraction (LVEF) was 63.4 ± 6.3%, and left ventricular mass index (LVMi) was 77.3 ± 21.8 g/m2. Left ventricular global longitudinal peak systolic strain (LVGLS) and left ventricular global longitudinal strain rates (LVGLSR-S) were −20.1 ± 2.1% and −1.19 ± 0.17 s−1, respectively. Women had lower LV volumes and LVMi (67.6 ± 15.9 g/m2 vs. 83.6 ± 21.7g/m2, respectively; p < 0.001) and higher LVEF (64.5 ± 6.2% vs. 62.5 ± 6.3%, respectively; p < 0.001) than men, although classifications of sports and training times were similar. Along with the increase in cardiovascular demand, body surface area, body mass index, LV volumes, and LVM were increased, whereas LVGLS and LVGLSR-S were decreased (p < 0.001) (Figure 1).
The main findings of this study are significant sex differences in strain values, even though these values were within normal limits from the previous meta-analysis (3). Women had significantly higher LVGLS (−20.7 ± 2.1% vs. −19.7 ± 2.0%, respectively; p < 0.001) and LVGLSR-S (−1.23 ± 0.17 s−1 vs. −1.17 ± 0.17 s−1, respectively; p < 0.001) than men. The effect of sex hormones, especially estrogen, on cardiac function would be a possible explanation for these sex differences (4).
This study also demonstrated that LVGLS and LVGLSR-S values significantly decreased along with the increase in cardiovascular demand of sports disciplines. Athletes with HD had the lowest values of LVGLS and LVGLSR-S. Cardiac geometric changes from repeated exercise would be a possible explanation. Because LVMi showed significant negative correlations with LVGLS (r = −0.211; p < 0.001) and LVGLSR-S (r = 0.298; p < 0.001), LVMi may be a confounder of strain values in different types of sports. However, classification of sports showed significant correlations with LVGLS and LVGLSR-S, even after adjusting for LVMi. Unlike the study by D’Ascenzi et al. (5), we reported results showing that exercise training leads to lower (more positive) strain values. Further studies will be needed to clarify this issue. Systolic blood pressure and heart rate were significantly different according to the type of sport in this study, and these may also affect the strain values. After adjustment for systolic blood pressure and heart rate, classification of sports was as significantly associated with LVGLS and LVGLSR-S as ever (p < 0.001 and p < 0.001, respectively). Because there were significant ethnic differences among groups according to their sport types, these differences might have affected the correlations in this study. However, the statistical significance remained evident after the adjustment for ethnicity (p < 0.001 for LVGLS and p < 0.001 for LVGLSR-S).
In conclusion, female university athletes had lower LV volumes, mass, and higher LVEF and strain values than men. LVGLS and LVGLSR-S were significantly decreased along with the increase of cardiovascular demands. The present study demonstrated that there are sex or sports discipline differences in LV mechanics as measured by 2DSTE in highly trained university athletes. Because this was a cross-sectional study, further long-term follow-up studies will be needed to determine whether the reduced strain values reflect subtle myocardial damage and its clinical significance.
Please note: This research was supported by Chonnam National University Hospital Biomedical Research Institute grant CRI 13904-21, the International University Sports Federation, and the Organizing Committee of the 2015 Gwangju Summer Universiade. The authors have reported that they have no relationships with industry relevant to the contents of this paper to disclose.
- 2018 American College of Cardiology Foundation