Related Experiment Video
Updated: May 31, 2026
A Pre-Clinical Porcine Model of Orthotopic Heart Transplantation
Published on: April 27, 2019
Chronotropic responses to exercise in heart transplant recipients: 1-yr follow-up
Kari Nytrøen1, Jonathan Myers, Khin Nyein Chan
1Department of Cardiology, Oslo University Hospital HF Rikshospitalet, Norway.
Objective:
Partial normalization of the heart rate (HR) response can take place some time after heart transplantation (HTx), but the extent to which this occurs, its time course, and functional significance remain unclear.
Design:
Seventy-seven heart transplantation patients underwent an exercise test at approximately 1, 6, and 12 mos after heart transplantation, consisting of a resting period, a submaximal exercise test, and a maximal exercise test with stair climbing, followed by a recovery period. An HR monitor was used for continuous surveillance of HR.
Results:
During the follow-up, HR at rest did not change, whereas all other HR parameters obtained during and after exercise improved, demonstrating a more rapid increase, a higher peak, and a more rapid decline in HR after stopping exercise. Age-predicted maximum HR at baseline was 73% ± 9%, improving to 83% ± 10% at 6 mos (P < 0.001) and to 90% ± 10% at 12 mos (P < 0.001), whereas the Chronotropic Response Index at baseline was 0.49 ± 0.15, improving to 0.67 ± 0.17 at 6 mos (P < 0.001) and to 0.81 ± 0.23 at 12 mos (P < 0.001).
Conclusions:
Partial normalization of HR was achieved by 71% of heart transplantation patients at 12 mos, with significant changes occurring within 6 mos in most subjects. These findings should contribute to reducing the exercise restrictions that apply to the denervated heart.
Related Concept Videos
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:28Kidney Transplant I: Introduction
01:29Heart Failure II: Pathophysiology