[Measurements of heart rate variability and baroreflex sensitivity].

BACKGROUND: Heart rate variability and baroreflex sensitivity are used to assess the activity in the autonomic nervous system. Heart rate variability is a measure of the tonic autonomic heart rate control, whereas baroreflex sensitivity measures the dynamic autonomic heart rate control. MATERIAL AND METHODS: On the basis of relevant literature and our own research, this article reviews the most commonly used techniques for measuring heart rate variability and baroreflex sensitivity, as well as results from selected studies. RESULTS: Reduced heart rate variability and reduced baroreflex sensitivity may be related to increased risk for malignant ventricular arrhythmias and sudden death in patients with coronary artery disease. These parameters are also distorted in patients with hypertension. Furthermore, heart rate variability has been suggested as a tool for monitoring anaesthesia depth. INTERPRETATION: Even though these methods are useful in pathophysiological studies of the autonomic nervous system, results from clinical studies have been diverging. Further investigation is required before these methods may be incorporated in clinical practice.