Challenging cardiac function post-spinal cord injury with dobutamine.

Area of Science:

• Cardiovascular Physiology
• Neurotrauma Research
• Cardiac Function Assessment

Background:

• Spinal cord injuries (SCI) above T6 alter cardiac sympathetic control, negatively impacting heart structure and function.
• Investigating cardiac responses under enhanced sympathetic activity is crucial for understanding SCI-related cardiac dysfunction.

Purpose of the Study:

• To investigate cardiac responses to dobutamine (DOB) stress echocardiography in a contusive SCI model.
• To assess the impact of SCI on systolic function and cardiac responses to DOB over time.

Main Methods:

• Utilized dobutamine (DOB) stress echocardiography in T2 contusive SCI and control groups.
• Echocardiography performed pre-SCI and at 1, 2, and 6 weeks post-SCI with increasing DOB doses.
• Parasternal-short axis imaging analyzed systolic function and changes in response to SCI and DOB.

Main Results:

• SCI reduced stroke volume (SV), end diastolic volume (EDV), cardiac output (CO), and ejection fraction (EF) compared to controls, persisting to 6 weeks.
• SCI led to increased collagen deposition at 6 weeks.
• Pre-SCI, DOB increased CO, EF, and heart rate (HR) but decreased EDV and did not change SV. Post-SCI, DOB increased CO, EF, HR, and notably, SV.

Conclusions:

• Impaired descending cardiac control directly contributes to reduced resting SV after SCI.
• The ability of DOB to increase SV post-SCI suggests that disrupted sympathetic pathways limit cardiac output.
• This study provides novel insights into DOB responses in a contusive SCI model with persistent cardiac impairments.