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Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

ABSTRACT: OBJECTIVE:To investigate the possible causes of abnormal blood pressure control in light chain related (primary, AL) amyloidosis. DESIGN:Cardiovascular, autonomic, and respiratory response to passive tilting were investigated in 51 patients with primary amyloidosis (mean (SEM) age 56 (2) years) and in 20 age matched controls. Spontaneous fluctuations in RR interval, respiration, end tidal carbon dioxide, blood pressure, and skin microcirculation were recorded during supine rest and with tilting. The values were subjected to spectral analysis to assess baroreflex sensitivity and the autonomic modulation of cardiac and vascular responses. SETTING:Tertiary referral centre. RESULTS:Autonomic modulation of the heart and blood pressure was nearly absent in the patients with amyloidosis: thus baroreflex sensitivity and the low frequency (0.1 Hz) fluctuations in all cardiovascular signals were severely reduced (p < 0.01 or more), as were respiratory fluctuations in the RR interval, and no change was observed upon tilting. Despite reduced autonomic modulation, blood pressure remained relatively stable in the amyloid group from supine to tilting. End tidal carbon dioxide was reduced in the amyloid patients (p < 0.001) indicating persistent hyperventilation; the breathing rate correlated inversely with the fall in blood pressure on tilting (p < 0.05). CONCLUSIONS:In primary amyloidosis, pronounced abnormalities in arterial baroreflexes and cardiovascular autonomic modulation to the heart and the vessels may be partly compensated for by hyperventilation at a slow breathing rate.

SUBMITTER: Bernardi L

PROVIDER: S-EPMC1767452 | biostudies-literature | 2002 Dec

REPOSITORIES: biostudies-literature

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Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

Bernardi L L Passino C C Porta C C Anesi E E Palladini G G Merlini G G

Heart (British Cardiac Society) 20021201 6

<h4>Objective</h4>To investigate the possible causes of abnormal blood pressure control in light chain related (primary, AL) amyloidosis.<h4>Design</h4>Cardiovascular, autonomic, and respiratory response to passive tilting were investigated in 51 patients with primary amyloidosis (mean (SEM) age 56 (2) years) and in 20 age matched controls. Spontaneous fluctuations in RR interval, respiration, end tidal carbon dioxide, blood pressure, and skin microcirculation were recorded during supine rest an ...[more]

PMID: 12433892

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Project description:Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and has minimal risk for extrapyramidal symptoms. Therapeutic benefits, however, are accompanied by a myriad of cardiometabolic side-effects. The specific reasons for clozapine's high propensity to cause adverse cardiometabolic events remain unknown, but it is believed that autonomic dysfunction may play a role in many of these. Objective: This systematic review summarizes the literature on autonomic dysfunction and related cardiovascular side effects associated with clozapine treatment. Method: A search of the EMBASE, MEDLINE, and EBM Cochrane databases was conducted using the search terms antipsychotic agents, antipsychotic drug*, antipsychotic*, schizophrenia, schizophren*, psychos*, psychotic*, mental ill*, mental disorder*, neuroleptic*, cardiovascular*, cardiovascular diseases, clozapine*, clozaril*, autonomic*, sympathetic*, catecholamine*, norepinephrine, noradrenaline, epinephrine, adrenaline. Results: The search yielded 37 studies that were reviewed, of which only 16 studies have used interventions to manage cardiovascular side effects. Side effects reported in the studies include myocarditis, orthostatic hypotension and tachycardia. These were attributed to sympathetic hyperactivity, decreased vagal contribution, blockade of cholinergic and adrenergic receptors, reduced heart rate variability and elevated catecholamines with clozapine use. Autonomic neuropathy was identified by monitoring blood pressure and heart rate changes in response to stimuli and by spectral analysis of heart rate variability. Metoprolol, lorazepam, atenolol, propranolol, amlodipine, vasopressin and norepinephrine infusion were used to treat tachycardia and fluctuations in blood pressure, yet results were limited to case reports. Conclusion: The results indicate there is a lack of clinical studies investigating autonomic dysfunction and a limited use of interventions to manage cardiovascular side effects associated with clozapine. As there is often no alternative treatment for refractory schizophrenia, the current review highlights the need for better designed studies, use of autonomic tests for prevention of cardiovascular disease and development of novel interventions for clozapine-induced side effects.

Project description:Introduction: Syncope and orthostatic intolerance in paced patients constitute a common clinical dilemma. We, thus, aimed to determine the etiology of syncope and/or symptoms of orthostatic intolerance in paced patients. Methods: Among 1,705 patients with unexplained syncope and/or orthostatic intolerance that were investigated by cardiovascular autonomic tests, including Valsalva maneuver, active standing, carotid sinus massage, and tilt-testing, 39 patients (2.3%; age 65.6 years; 39% women) had a cardiac implantable electronic device (CIED). We explored past medical history, diagnoses found during cardiovascular autonomic tests, and the further clinical workup, in case of negative initial evaluation. Results: An etiology was identified during cardiovascular autonomic tests in 36 of the 39 patients. Orthostatic hypotension (n = 16; 41%) and vasovagal syncope (n = 12; 31%) were the most common diagnoses. There were no cases of pacemaker dysfunction. The original pacing indications followed guidelines (sick-sinus-syndrome in 16, atrioventricular block in 16, atrial fibrillation with bradycardia in five). Twenty-two of the 39 patients (56%) had experienced syncope prior to the original CIED implantation. Orthostatic hypotension was diagnosed in seven (32%) and vasovagal syncope in nine (41%) of these patients. Of the 17 patients that had not experienced syncope prior to the original CIED implantation, nine patients (53%) were diagnosed with orthostatic hypotension and vasovagal syncope was diagnosed in three (18%). Of the 39 patients, two had implantable cardioverter-defibrillators to treat malignant ventricular arrhythmias diagnosed after syncopal episodes. Conclusion: Cardiovascular autonomic tests reveal the etiology of syncope and/or orthostatic intolerance in the majority of paced patients. The most common diagnosis was orthostatic hypotension (40%) followed by vasovagal syncope (30%), whereas there were no cases of pacemaker dysfunction. Our results emphasize the importance of a complete diagnostic work-up, including cardiovascular autonomic tests, in paced patients that present with syncope and/or orthostatic intolerance.

Dataset Information

Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

Publications

Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

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