Modulation of Left Ventricular Diastolic Filling During Exercise in Persons with Cervical Motor Incomplete Spinal Cord Injury

Eur J Appl Physiol, 2019 · DOI: 10.1007/s00421-019-04249-9 · Published: December 1, 2019

Spinal Cord Injury Physiology Rehabilitation

Simple Explanation

This study looks at how the heart's ability to fill with blood changes during exercise in people with incomplete spinal cord injuries in their neck, compared to people without such injuries. The researchers measured how much blood the heart could hold (end-diastolic volume) and how quickly it filled (early diastolic filling ratio) during arm exercises. The study found that people with spinal cord injuries had a reduced ability for their hearts to fill with blood during exercise, potentially due to limitations in muscle pumping and possible stiffness in the heart walls.

Study Duration

5 months

Participants

8 males with cervical incomplete spinal cord injury (icSCI; C5-C7: age 39 ± 14 yrs) versus 8 able-bodied males (CON: age 38 ± 13 yrs)

Evidence Level

Cross-sectional study

Key Findings

1
End-diastolic volume (EDV) was significantly reduced in icSCI compared to CON at peak exercise and at isomax.
2
Early diastolic filling ratio (EDFR) was significantly reduced in icSCI compared to CON at peak exercise and at isomax.
3
Stroke volume (SV) was significantly decreased in the subjects with icSCI compared to CON.

Research Summary

The study characterized left ventricular diastolic filling and volume during an exercise challenge in adults with incomplete cervical spinal cord injury (icSCI). The subjects with icSCI in this study had reduced LV end-diastolic volume and diastolic filling ratio compared to able-bodied controls, even after adjusting for the effects of inotropic, chronotropic conditions. This study provides evidence of impaired diastolic function in response to increases in exercise workload in individuals who have icSCI.

Practical Implications

Physiological Implications

Impaired diastolic filling in people with icSCI, likely resulting from partial de-efferentation and diminished muscle pump capacity, may contribute to overall limitations on cardiac function and oxygen delivery.

Practical Implications for Cardiac Function

Increases in left ventricular stiffness, myocardial thickness and elasticity in the subjects with icSCI could be neither confirmed nor ruled out by the methods used in this study thus leaving the contribution of altered LV compliance and cardiac energetics open for consideration.

Future Research

Further research is needed to determine if interventions that target improvements in muscle pump function or ventricular compliance can improve cardiac function in individuals with icSCI.

Study Limitations

1
Use of a convenience sample due to the lack of a large database.
2
Sample size was insufficient for assurance of representation with respect to the icSCI population at large.
3
Women and participants with complete spinal cord injury were not included in this study creating a degree of gender bias.

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