Search

Background Objective of this study was to evaluate the acute cardiovascular and respiratory effects of switching on the deep brain stimulation in the follow up of nine Parkinson's disease patients with subthalamic nucleus stimulation and six cluster headache patients with posterior hypothalamic area stimulation. Methods Systolic and diastolic blood pressure, heart rate, and respiratory rate were monitored continuously during supine rest in both groups. Each patient was assessed in two conditions: resting supine with stimulator off and with stimulator on. Results In supine resting condition switching on the DBS induced no significant changes ( p > 0.05) in systolic and diastolic blood pressure as well as in heart rate and respiratory rate, in both groups of patients, either taking 1 min or 10 heartbeats as a sample for analysis. Conclusions Switching on the DBS does not modify heart rate, blood pressure nor respiratory rate in both Parkinson and cluster headache patients under resting conditions.

Background According to expert opinion, orthostatic hypotension (OH) associated to a change in heart rate (ΔHR) less than 15 bpm suggests neurogenic OH (NOH). Recently, the ratio between HR and systolic blood pressure changes at 3 min of tilt test (ΔHR/ΔSBP) has been proposed as a better index than the ΔHR cut-off of 17 bpm. Our aim was to validate these indexes based on HR in an independent cohort of patients who performed cardiovascular reflex tests according to standardized procedures at our Institution. Methods We applied the HR indexes to all cardiovascular reflex tests that fulfilled the following criteria: (1) presence of classical OH at tilt test, (2) reliable Valsalva manoeuvre (VM), (3) absence of heart disease. We classified OH according to VM (absence of overshoot = NOH), and verified how many were correctly identified by ΔHR/ΔSBP (≤0.49 neurogenic) and ΔHR (≤17 and ≤15 neurogenic). Results We identified 369 tests with OH. Based on VM, 335 were NOH. The ΔHR/ΔSBP ≤ 0.49 identified NOH with a sensitivity of 91% and a specificity of 59%, the ΔHR ≤ 17 bpm with 88% sensitivity and 38% specificity, and the ΔHR ≤ 15 bpm with 84% sensitivity and 50% specificity. Conclusion In our cohort, the ΔHR/ΔSBP ratio had a good sensitivity but a limited specificity to identify NOH. This easily applicable test may represent a valuable screening tool in a clinical setting to identify patients who need further detailed autonomic testing to confirm the neurogenic origin of OH.

The autonomic nervous system is involved in function of organs and integrated systems that control blood pressure and body temperature in a variety of environments. It influences emotion and is essential for survival. It achieves this through a network of centers and pathways in the brain, spinal cord, and periphery. Autonomic disorders can occur at a variety of sites. Advances enable accurate evaluation of autonomic function. In the clinical setting these determine the degree of autonomic dysfunction, the site of lesion, and the mechanisms involved. Importantly, clinical autonomic testing aids therapeutic strategies that reverse or ameliorate the clinical problems.

Study objective Narcolepsy with cataplexy (NC) is associated with loss of hypocretin neurons in the lateral hypothalamus involved in the circadian timing of sleep and wakefulness, and many biologic functions including autonomic control. The authors investigated whether chronic lack of hypocretin signaling alters cardiovascular control during sleep in humans. Design Comparison of 24-hr circadian rhythms, day-night, time- and state-dependent changes of blood pressure (BP) and heart rate (HR) in drug-free patients with NC and control subjects. Setting University hospital. Patients or participants Ten drug-free patients with NC (9 men, 1 woman) and 12 control subjects (9 men, 3 women). Interventions N/A. Measurements and results Daytime BP was comparable in patients with NC and controls, but patients with NC displayed a nighttime nondipping BP pattern. The 24-hr circadian rhythmicity of BP and HR was normal in both groups. Systolic BP during nighttime rapid eye movement sleep was significantly increased in the NC group. The 24-hr HR was significantly higher in the NC group but the day-night and state-dependent HR modulations were intact. The nighttime BP pattern coupled in the NC group with increased sleep fragmentation and a higher prevalence of arousals, periodic limb movements in sleep (PLMS), and PLMS arousals. In an analysis of the sleep/cardiovascular interaction in the periods after sleep onset and preceding morning awakening, only PLMS were consistently associated with the blunted nighttime decrease in BP in the NC group. Conclusions Hypocretin deficiency in humans may couple with an altered nighttime BP regulation that can be associated with an increased cardiovascular risk. This finding may be the result not only of the hypocretinergic deficiency per se but also of the altered sleep/wake regulation characterizing NC.

Objective To test the autonomic control of cardiovascular reflexes and heart rate variability (HRV) at rest and during orthostatic stress in narcolepsy with cataplexy (NC). Methods Ten NC patients with a hypocretin deficit and 18 control subjects underwent head-up tilt test (HUTT), Valsalva manoeuvre, deep breathing and cold face under controlled laboratory conditions. Heart rate variability (HRV) was analysed during supine rest and HUTT considering the normalized unit of LF and HF power (LFnu; HFnu), using autoregressive (AR) and fast Fourier transform (FFT) algorithms. Results Cardiovascular changes during HUTT, Valsalva manoeuvre, deep breathing, isometric handgrip and cold face were normal and comparable in the two groups. AR and FFT analysis showed an increased LF/HF ratio in NC patients during supine rest. As expected, LFnu increased and HFnu decreased in the control group during HUTT, but did not change in narcoleptics being comparable to values in the supine condition. Conclusions NC patients showed an increased sympathetic drive on heart rate (HR) in the supine condition that did not further increase during HUTT. Significance These results suggest the proper functioning of cardiovascular reflexes in NC but support an impairment of HR modulation at rest in favour of an enhanced sympathetic activity.

The objective of this study was to determine the cardiovascular effects of chronic stimulation of the posterior hypothalamic area (PHA) in cluster headache (CH) patients. Systolic and diastolic blood pressure (SBP, DBP), cardiac output, total peripheral resistance (TPR), heart rate (HR) and breathing were monitored at supine rest and during head-up tilt test (HUTT), Valsalva manoeuvre, deep breathing, cold face test and isometric handgrip in eight drug-resistant chronic CH patients who underwent monolateral electrode implantation in the PHA for therapeutic purposes. Autoregressive power spectral analysis (PSA) of HR variability (HRV) was calculated at rest and during HUTT. Each subject was studied before surgery (condition A) and after chronic deep brain stimulation (DBS) of PHA (condition B). Baseline SBP, DBP, HR and cardiovascular reflexes were normal and similar in both conditions. With respect to condition A, DBP, TPR and the LF/HF obtained from the PSA of HRV were significantly (P < 0.05) increased during HUTT in condition B. In conclusion, chronic DBS of the PHA in chronic CH patients is associated with an enhanced sympathoexcitatory drive on the cardiovascular system during HUTT.

Objective To evaluate whether a battery of cardiovascular autonomic tests (Ewing's battery, EB) performed with a new integrated instrumental approach is useful in differentiating multiple system atrophy with predominant parkinsonism (MSA-P) from Parkinson's disease (PD) at an early stage. Methods We retrospectively analyzed EB tests of all the patients (n = 99) with a parkinsonian syndrome referred to our clinic who performed EB during the first diagnostic workup and were subsequently evaluated at least once a year until a final diagnosis of MSA-P (n = 34) or PD (n = 65). Thirty-eight controls matched for age and sex were included. EB consisted of head-up tilt test (HUTT), Valsalva manoeuvre (VM), deep breathing, and sustained handgrip whose correct execution and results were checked and obtained automatically. Results were compared between groups. Discriminant analysis was performed to identify MSA-P or PD patients. Results Orthostatic hypotension was found in 22 MSA-P and 3 PD patients. Cardiovascular reflexes indices were significantly more affected in MSA-P compared to PD and controls. EB presented a 91% sensitivity and 94% specificity in the differentiation of MSA-P and PD. HUTT + VM presented a 91% sensitivity and 92% specificity. Conclusions Our results suggest that EB or HUTT + VM performed with an integrated instrumental approach and analyzed with the discriminant procedure may distinguish MSA-P from PD at an early stage and might improve the accuracy of current diagnostic criteria. However, a validation in separate samples and prospective studies is needed.

Lack of nighttime blood pressure (BP) reduction by 10-20% from the mean daytime values (dipping) has been described as a distinguishing feature of essential hypertension and associated, also in normotensive subjects, with increased cardiovascular (CV) risk. Mechanisms involved in the loss of the nocturnal dip are still unclear, but involvement of autonomic nervous system (ANS) activity probably plays a crucial role. Sleep is fundamental in modulating ANS activity to maintain the physiological BP circadian rhythm, and for this reason its integrity has been widely investigated in hypertension. We investigated, under controlled conditions, the autonomic control of the CV system through an autonomic reflex screen in the awake condition and by assessment of circadian rhythm-, day-night-, time-, and state-dependent changes of BP and heart rate (HR) and associated sleep parameters in patients with a recent (≤1 yr) diagnosis of essential grade I hypertension naïve of therapy. Fourteen hypertensive patients (6 males, age: 43 ± 11 yrs; body mass index [BMI]: 24 ± 3 kg/m(2)) were compared with 28 healthy controls matched for sex, age, BMI (2 controls/patient) for cardiovascular reflex and to 8 different subjects from previous controls (6 males), comparable for age and BMI, for the day-night and nighttime CV profiles during two consecutive nights. The cardiovascular reflex screen data showed increased sympathetic effect in hypertensive patients, represented by higher overshoot of BP after Valsalva maneuver. Nighttime sleep architecture during the dark period in terms of duration, representation of sleep stages, sleep fragmentation, and incidence of arousals-periodic limb movements in sleep (PLMS) and PLMS arousals-was similar in patients and controls. Hypertensive patients displayed higher 24-h BP and HR values, but their sleep-related BP decrease was significantly reduced compared with controls. The circadian rhythms of BP and HR were intact and similar in patients and controls, coupling with the expected physiological peak time. BP and HR showed normal state-dependent modulation in hypertensive patients that, however, was higher in all sleep stages compared with controls. The lowering of systolic blood pressure (SBP) during non-rapid eye movement (NREM) sleep stages 1 and 2 and REM sleep, relative to daytime wake values, was significantly attenuated in the hypertensive group, whereas it was comparable to controls during slow-wave sleep. In hypertensive patients, analysis of sleep and CV parameters in the 90 min following sleep onset and preceding morning awakening showed normal depressor effect during the first part of the night after sleep onset and significantly higher BP rise in the hours preceding morning awakening. These findings were associated with comparable sleep architecture, sleep fragmentation, incidence of arousals, and PLMS and PLMS arousals in patients and controls. Our data suggest that drug-naïve essential grade I hypertension is associated with signs of increased vascular sympathetic response to standardized stress of the Valsalva maneuver during the awake condition, and during sleep with a non-dipping BP profile plus higher BP surge preceding morning awakening, assessable only by around-the-clock ambulatory BP monitoring, both representing additional CV risk already in early-stage hypertension and, therefore, requiring proper selection of pharmacological treatment.

Objective This study describes changes in heart rate (HR) and HR variability (HRV) related to clinical onset of seizures in nocturnal frontal lobe epilepsy (NFLE) in order to determine whether signs of autonomic activation precede onset of seizure motor manifestations, which was selected as seizure onset (SO). Further, to clarify the nature (epileptic or physiologic) of the changes in autonomic cardiac control presumed to precede SO, time-dependent variations in HR and HRV related to physiological cortical arousals associated with motor activity (phases of transitory activation, PAT) were also investigated. Methods HR and HRV spectral power, quantified by means of wavelet transform, were analyzed in relation to the onset of motor manifestations in 45 NFLE seizures and 45 PAT derived from whole night video-polysomnographic recordings of ten patients and of ten control subjects, respectively. Results Analysis of HRV showed a shift of sympathetic/parasympathetic cardiac control toward a sympathetic predominance in the 10 s immediately preceding SO, while changes in HR were evident only one second before SO. This sympathetic activation was not associated with a sleep-wake transition or changes in respiratory activity, both of which occurred concurrently with SO. Similar changes in HR and HRV were observed in the 10 s before the motor and electroencephalographic onset of PAT. Conclusions Our study demonstrates that a similar autonomic activation precedes the motor manifestations of NFLE seizures and physiological arousal. This autonomic activation could represent part of the arousal response, which could be implicated in the occurrence of both seizure and arousal motor manifestations.

Objective Reflex Syncope (RS) is a self-limited loss of consciousness due to systemic arterial hypotension resulting from widespread vasodilatation and/or bradycardia. Higher neural centres have been implicated in the pathophysiology of RS, particularly in blood/injury phobic patients. We investigated interictal central autonomic functions in non-phobic RS subjects compared to non-phobic controls evaluating their central and cardiovascular responses to emotional stimuli. Methods Cardiovascular responses to Valsalva Manoeuvre (VM), Deep Breathing (DB) and during presentation of 108 slides selected from the International Affective Picture System were assessed in 20 non-phobic RS subjects and 20 controls. Slide onset visual event-related potentials (ERPs) were also computed. Results No significant difference in cardiovascular responses and ERP amplitude were found in non-phobic RS subjects and controls at rest, in response to VM and DB or during picture presentation. Conclusions Non-phobic patients with RS not only have a normal interictal autonomic control of the cardiovascular system but also a normal modulation and adaptation of central and cardiovascular response to emotional processing, in our experimental setting. Significance Non-phobic patients with RS present normal interictal central and cardiovascular responses. Autonomic dysfunction observed in phobic RS patients could be related to mechanisms underlying the phobia itself rather than the mechanisms causing RS.