Chronotropic incompetence in patients without structural heart disease appears to be driven by impaired translation of sympathetic activation into heart rate increases, suggesting potential post-synaptic beta-adrenergic receptor pathway issues.
Our data suggested that CI in patients without structural heart disease was mainly caused by a pathophysiological condition in which sympathetic activation was not well translated into heart rate increase. Further study is needed to determine the post-synaptic sensitivity of the beta-adrenergic receptor pathway in relation to CI.
Kawasaki et al. (Fri,) studied this question.