Cardiovascular Functioning Features in Individuals with Connective Tissue Dysplasia Engaged in Sports for the...

Connective tissue dysplasia (CTD) is associated with disorders of collagen synthesis and is widely spread among the healthy population and people with disabilities. In the heart, primarily in the left ventricle (LV), CTD manifests itself as the formation of false tendons (LVFTs) to maintain close-to-normal LV pump function. This exploratory work is devoted to the search for general patterns of cardiac response to physical activity in athletes with disabilities, CTD, and LVFTs. The extent to which "the type of sports or the type of disability" determines the involvement of the heart's functional reserve is the main testable question of the proposed research.

The group under this study included 610 individuals with disabilities aged from 6 to 60 years with at least two transverse and/or oblique FTs per LV. Participants represented different sports disciplines (n = 10) and various forms of disabilities (n = 4). Cardiovascular indicators were obtained by means of standard TTE, impedance cardiography for hemodynamic monitoring in active orthotest, resting, and stress 12-lead ECG. Exercise testing of the athletes was performed with the use of appropriate methods of physical loading. In total, 141 parameters of cardiorespiratory function and exercise performance per participant were recorded. Statistical analysis of the dataset obtained across sports types or disability types was performed using one-way ANOVA or the Kruskal-Wallis test, depending on the assumptions of normality and homogeneity of variance.

Most importantly, it was found that only maximum relative oxygen consumption (VO₂max, mL·kg^-1·min^-1) as a reliable indicator of the heart's functional reserve and the corrected QT (QTc, ms) interval as an integral measure of the heart's electrical activity demonstrated statistically significant differences across the sports specialization or the disability type. In particular, significance values (P) for VO₂max across athletic disciplines and nosology categories were equal to 0.00063 and 0.01028 (one-way ANOVA), while for QTc they were 0.00001 and 0.02185 (Kruskal-Wallis), respectively. Furthermore, the type of disability had a lower impact on VO₂max and QTc than the type of athletic activity.

In athletes with disabilities and CTD, sport specialization may involve the heart's functional reserve to a greater extent than the type of disability. To prescribe training loads for people with disabilities and CTD, individual cardiology screening with an emphasis on VO₂max and QTc is necessary.