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Exercise response after cardiac transplantation: correlation with sympathetic reinnervation
Heart (British Cardiac Society)
|January 1, 1996
Summary
Sympathetic reinnervation in heart transplant recipients improves exercise heart rate response and recovery. This functional recovery is linked to better exercise capacity and workload completion.
Area of Science:
- Cardiology
- Transplantation immunology
- Autonomic nervous system function
Background:
- Cardiac transplantation involves denervation, impacting autonomic control of heart rate.
- Understanding sympathetic reinnervation is crucial for assessing post-transplant cardiac function.
Purpose of the Study:
- To investigate the relationship between sympathetic efferent reinnervation and chronotropic competence during exercise testing in heart transplant recipients.
Main Methods:
- Studied 25 long-term heart transplant recipients and 11 controls.
- Administered intracoronary tyramine to assess sympathetic response.
- Performed exercise tests to measure heart rate reserve and recovery.
Main Results:
- Heart transplant recipients showed significantly lower peak exercise heart rate reserve and slower heart rate recovery compared to controls.
- A positive correlation was found between sympathetic response to tyramine and improved heart rate reserve, recovery, and total workload.
Conclusions:
- Functional sympathetic reinnervation of the sinus node occurs in some heart transplant recipients.
- This reinnervation is associated with enhanced heart rate dynamics during and after exercise, and increased exercise capacity.