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Updated: May 10, 2026
A Pre-Clinical Porcine Model of Orthotopic Heart Transplantation
Published on: April 27, 2019
Preserved left ventricular function during supine exercise in patients after orthotopic cardiac transplantation
Insights
Cardiac transplant recipients show altered heart rate responses during exercise due to denervation. However, their cardiac output and ejection fraction increase similarly to controls, indicating preserved cardiac function post-transplant.
Area of Science:
- Cardiology
- Exercise Physiology
- Transplantation Medicine
Background:
- Orthotopic cardiac transplantation results in cardiac denervation, potentially altering cardiovascular responses.
- Understanding these responses is crucial for managing exercise capacity in heart transplant recipients.
Purpose of the Study:
- To examine haemodynamic responses and left ventricular function during and after supine exercise in cardiac transplant patients.
- To compare these responses with those of normal healthy controls.
Main Methods:
- Seventeen heart transplant patients and six healthy controls underwent radionuclide ventriculography.
- Measurements were taken at rest, during leg elevation (volume loading), supine exercise, and recovery.
Main Results:
- Heart rate was significantly faster at rest in transplant patients.
- During exercise, heart rate increased slower in transplant patients, but cardiac output and ejection fraction increased similarly to controls.
- Heart rate, ejection fraction, and cardiac output declined slower during recovery in transplant patients.
Conclusions:
- Despite altered heart rate dynamics due to denervation, cardiac transplant recipients maintain comparable increases in cardiac output and ejection fraction during exercise.
- Left ventricular function appears preserved in these patients during physical exertion post-transplant.
Abstract:
Cardiac denervation may affect cardiovascular responses during exercise in patients after orthotopic cardiac transplantation. In 17 such patients, haemodynamic responses and left ventricular function were examined by radionuclide ventriculography during and after supine exercise, at an average of 17.1 +/- 2.6 months after surgery. Data were also obtained during 'volume loading' brought about by leg elevation before exercise. Results were compared with those of six normal controls. At rest, heart rate was significantly faster among transplant patients than among controls (P less than 0.0003). No significant inter-group differences in changes in cardiovascular parameters were found between the two groups during leg elevation. During exercise, heart rate in transplant patients rose at a significantly slower rate than controls (P = 0.0001), but similar increases in ejection fraction, stroke volume and cardiac output were observed among transplant patients and controls. Decline in heart rate (P = 0.0001), ejection fraction (P = 0.0007) and cardiac output (P = 0.0001) was significantly slower in transplant patients during recovery. Although there were differences in rates of increases in heart rate between transplant patients and controls during supine exercise, there were no inter-group differences in increases in cardiac output and ejection fraction and changes in haemodynamic responses and left ventricular volumes.
