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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Senior Consultant Ansgar Berg, Telemark Hospital Trust, Norway
- Second opponent: Professor Vibeke Elisabeth Hjortdal, University of Copenhagen, Denmark
- Third member and chair of the evaluation committee: Professor II Mona-Elisabeth Rootwelt-Revheim, University of Oslo
Chair of the Defence
Professor Emeritus Odd Ragnar Geiran, University of Oslo
Principal Supervisor
Senior Consultant Gaute Døhlen, Oslo University Hospital
Summary
Heart transplantation interrupts all autonomic nervous connections to the heart. The resulting pathologic regulatory state might over time be alleviated by regrowth of autonomic nerves into the transplanted heart (reinnervation).
Fifty heart transplant recipients were repeatedly examined during the first 36 months after surgery. Fifty healthy controls were studied once. A fixed set of tests were performed to evaluate the autonomic nervous system’s influence on the heart’s pacemaker cells located in the sinoatrial node. Heart rate, heart rate variability and blood pressure were recorded continuously at supine rest and head-up tilt, during the Valsalva maneuver and handgrip isometric exercise.
Low frequency heart rate variability and heart rate responses to induced physiological stress improved within 6 months after heart transplantation, indicating early onset sympathetic sinoatrial reinnervation. This is likely beneficial for exercise capacity.
High frequency heart rate variability and baroreceptor reflex sensitivity improved within 24 months, suggesting later onset parasympathetic sinoatrial reinnervation. The heart transplant recipients regained an ability to buffer blood pressure fluctuations with changes in heart rate.
The pathologic regulatory state present after heart transplantation is partially offset by time-dependent sinoatrial reinnervation. However, indices of reinnervation remained clearly subnormal at mid-term follow-up, indicating persistent autonomic dysfunction in most transplant recipients.
Additional information
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