title: Left Ventricular Mechanics in Untrained and Trained Males with Tetraplegia.
abstract: Reduced left ventricular (LV) function is common in tetraplegia, yet it is unknown whether intrinsic myocardial function is attenuated. This study examined the effect of SCI and exercise-training status on LV mechanics (intrinsic function) and LV systolic/diastolic function by comparing untrained (UT) and trained (TT) individuals with tetraplegia and able-bodied (AB) individuals. Individuals with tetraplegia had a traumatic, chronic, motor-complete cervical spinal cord injury. Nine UT males (40 ± 10 years), 8 TT males (30 ± 5 years), and nine AB males (37 ± 9 years) participated in the study. LV indices were assessed using two-dimensional transthoracic echocardiography, with speckle-tracking analysis for the determination of LV mechanics. For systolic function, stroke volumes were lower in both UT (59 ± 9 mL; p < 0.001) and TT (63 ± 9 mL; p < 0.001) relative to AB (82 ± 11 mL), whereas systolic mechanics were similar across groups. Diastolic function was only reduced in UT, including a lower ratio of early-to-late transmitral filling velocity (1.55 ± 0.28) relative to TT (2.07 ± 0.42; p < 0.05) and AB (2.44 ± 0.61; p < 0.01) and longer isovolumetric relaxation times in UT (101 ± 7 ms) relative to TT (88 ± 11 ms; p < 0.05) and AB (85 ± 6 ms; p < 0.01). Diastolic mechanics (apical circumferential strain rate) were significantly enhanced in TT (3.03 ± 0.83 s-1) compared to AB (1.85 ± 0.65 s-1; p < 0.05). There was a trend (p = 0.062) for a between-group difference in apical radial diastolic strain rate (UT: -2.51 ± 0.83 s-1; TT: -3.92 ± 1.96 s-1; AB: -1.84 ± 0.46 s-1). In tetraplegia, attenuated LV systolic function is not attributed to intrinsic dysfunction, whereas exercise-training status appears to improve both global LV diastolic function and LV mechanics.
authors.affiliation: 1 International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Katharine D
authors.initials: KD
authors.lastname: Currie
authors.affiliation: 1 International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .|2 School of Kinesiology, Faculty of Education, University of British Columbia , Vancouver, British Columbia, Canada .
authors.forename: Christopher R
authors.initials: CR
authors.lastname: West
authors.affiliation: 3 Discipline of Physiology & Health, Cardiff School of Sport, Cardiff Metropolitan University , Cardiff, United Kingdom .
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Stöhr
authors.affiliation: 1 International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .|4 Division of Physical Medicine and Rehabilitation, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .|5 G.F. Strong Rehabilitation Center , Vancouver, British Columbia, Canada .
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Krassioukov
mesh_terms: D000328:Adult; D056352:Athletes; D006801:Humans; D008297:Male; D008875:Middle Aged; D064797:Physical Conditioning, Human / Q000502:physiology*; D011782:Quadriplegia / Q000175:diagnosis / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology; D016037:Single-Blind Method; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: echocardiography; exercise; spinal cord injury; strain rate