Imbalance of heart rate regulation in cluster headache as based on continuous 24-h recordings.

An altered autonomic balance is considered to be a pathogenetic factor in cluster headache syndrome, although there is varying data on sympathetic and/or parasympathetic activation during attacks and/or attack-free intervals. The aim of the present study was to evaluate the day/night pattern of heart rate during the active and remission phases of cluster headache. In addition, the relationship between heart rate changes and the site of pain was investigated to determine if an autonomic imbalance was related to the lateralization of pain. Thirty-nine patients (34 with primary episodic cluster headache and five with primary chronic cluster headache and 30 healthy controls underwent 24-h Holter ECG recording. Nine cluster headache patients were monitored during both phases of the disease. The data obtained confirmed the existence of a disordered chrono-organization in cluster headache (phase-shift of approximately 1 h of heart rate rhythm during the cluster period) together with a low heart rate variability and a higher occurrence of arrhythmias in cluster headache patients with right-sided pain. Differences were also observed in the cluster headache patients when headache free, excluding the pain itself as a reason for the abnormality. The chronobiological data point out a transient rhythmic dysfunction, while heart rate variability changes, mostly related either to the phase of the disease or to the site of pain, probably reflects a central, site-related, dysfunction of the autonomic nervous system in cluster headache

Haemodynamic and neurohormonal responsiveness to different stress tests in mitral valve prolapse

In this study the blood pressure, heart rate, plasma noradrenaline and plasma adrenaline responses to various forms of sympatho-neural stress were evaluated in patients with mitral valve prolapse (MVP). Sympathetic reactivity in different subgroups of MVP were related to the degree of ventricular arrhythmia. Thirty-eight patients with mitral valve prolapse and 17 healthy controls were studied. All underwent 24-h ECG recording, 2-D echocardiography, head-up tilt to 60\ub0, pressor tests (sustained handgrip, mental arithmetic, cold pressor) and psychological assessment. The blood pressure, noradrenaline and adrenaline response to stress in patients without premature ventricular contraction were similar to those of the controls. In patients with unifocal premature ventricular contraction (PVC) less than 300/h, responses were similar to normal but were associated with higher plasma noradrenaline levels in the basal state and a diminished response to isometric stress. In patients with more than 300/h unifocal premature ventricular contraction, pairs of premature ventricular contraction, or runs of ventricular tachycardia there were lower blood pressure values in the basal state with reduced blood pressure, heart rate and plasma noradrenaline and adrenaline responses to head-up tilt and sustained handgrip, but marked increases in blood pressure, heart rate and plasma noradrenaline levels during the cold pressor test. Our data suggest different degrees of autonomic involvement in mitral valve prolapse which may be related to the various degrees of arrhythmia which seem to contribute to their symptoms