Myocardial ischemia and autonomic activity in dippers and non-dippers with coronary artery disease: assessment of normotensive and hypertensive patients

Abstract 

Objectives: The aim of this study was to assess the relations between the circadian variations of blood pressure (BP) and the pattern of ischemia and autonomic activity in normotensive and hypertensive patients with coronary artery disease (CAD). Patients and methods: On the basis of the results of ambulatory BP monitoring, 115 patients with stable CAD were divided into Group 1 (with arterial hypertension) and Group 2 (normotensives). Groups were subdivided into dippers and non-dippers. Holter monitoring was performed to assess the occurrence and circadian pattern of ischemic episodes. Time domain and frequency domain HRV analyses were performed to evaluate the autonomic activity. Results: The total number of ischemic episodes was similar in dippers and non-dippers. Non-dippers had a greater number of silent episodes and a different circadian pattern of ischemia with more night episodes. Among the time-domain HRV parameters, only SDNN was similar in dippers and non-dippers. Non-dippers had lower pNN50 and rMSSD—the parameters expressing parasympathetic activity. Differences between diurnal and nocturnal results of spectral HRV analysis were observed in dipper patients only. They presented an elevation of HF power and a decline of LF power at night. All differences between dippers and non-dippers were of similar significance in both hypertensives and normotensives. Conclusions: A lack of a nocturnal fall in BP is present in normotensive and hypertensive patients with CAD. Non-dippers with CAD had silent and nighttime ischemia more often. They also had an abnormal pattern of autonomic activity with higher sympathetic and lower parasympathetic modulation.

Keywords:  Dippers, Non-dippers, Coronary artery disease, Myocardial ischemia, Heart rate variability, Autonomic nervous system