What is the typical resting heart rate response in individuals post-cardiac transplantation?

After cardiac transplantation, it is common for individuals to exhibit an increased resting heart rate. This phenomenon is primarily due to the denervation of the heart that occurs during the transplant procedure. The autonomic nervous system, which typically regulates heart rate through sympathetic and parasympathetic pathways, is disrupted, leading to a lack of normal autonomic control. Consequently, there is an increased resting heart rate since the heart rate is primarily influenced by circulating catecholamines, rather than by intrinsic nervous input.

In a healthy individual, the heart rate is typically modulated reflexively by the parasympathetic nervous system, primarily through the vagus nerve. However, in transplant recipients, this neural control is absent, which can lead to a greater degree of sensitivity to hormonal influences that generally promote a higher heart rate. Over time, some individuals may experience some normalization of heart rate, but the initial post-transplant period is characterized by this increased resting heart rate phenomenon.