Chronotropic incompetence in coronary slow flow

Aims: Previous studies have associated coronary slow flow (CSF) and chronotropic incompetence (CI) with increased mortality. There is no established treatment protocol for CSF. In this study, we aimed to answer questions such as "Is there CI in patients with CSF? If so, is there an increase in the frequency of hospital admissions due to cardiac complaints in these patients?" Methods: The study included 29 patients with CSF detected according to Thrombolysis in Myocardial Infarction (TIMI) frame count during angiography and 27 healthy volunteers with normal coronary artery as a control group. The relationship between coronary slow flow and chronotropic incompetence between the patient and healthy control groups and the differences between these and healthy control individuals were compared. Results: The maximum heart rate reached during the treadmill exercise test was found to be statistically significantly lower in patients with coronary slow flow compared to the control group (p=0.045). The presence of chronotropic incompetence in the patient group with coronary slow flow was found to be statistically significantly higher than the control group (p=0.038). However, there was no significant difference between the chronotropic indexes (p=0.953). Duke treadmill scores (DTS) were found to be similar between the groups (p>0.05). Conclusion: Patients with coronary slow flow were found to have statistically significant higher chronotropic incompetence in the treadmill exercise test. However, no significant difference was observed between the groups in the chronotropic index values, which are an indicator of chronotropic incompetence. These results suggest the presence of autonomic dysfunction in coronary slow flow phenomenon and that chronotropic incompetence may be caused by coronary slow flow phenomenon and should be investigated in etiology.