Benefits of fludrocortisone in the treatment of symptomatic vasodepressor carotid sinus syndrome

Dysautonomia: A Forgotten Condition - Part 1

Dysautonomia covers a range of clinical conditions with different characteristics and prognoses. They are classified as Reflex Syndromes, Postural Orthostatic Tachycardia Syndrome (POTS), Chronic Fatigue Syndrome, Neurogenic Orthostatic Hypotension (nOH) and Carotid Sinus Hypersensitivity Syndrome. Reflex (vasovagal) syndromes will not be discussed in this article. Reflex (vasovagal) syndromes are mostly benign and usually occur in patients without an intrinsic autonomic nervous system (ANS) or heart disease. Therefore, they are usually studied separately. Cardiovascular Autonomic Neuropathy (CAN) is the term most currently used to define dysautonomia with impairment of the sympathetic and/or parasympathetic cardiovascular autonomic nervous system. It can be idiopathic, such as multisystemic atrophy or pure autonomic failure, or secondary to systemic pathologies such as diabetes mellitus, neurodegenerative diseases, Parkinson's disease, dementia syndromes, chronic renal failure, amyloidosis and it may also occur in the elderly. The presence of Cardiovascular Autonomic Neuropathy (CAN) implies greater severity and worse prognosis in various clinical situations. Detection of Orthostatic Hypotension (OH) is a late sign and means greater severity in the context of dysautonomia, defined as Neurogenic Orthostatic Hypotension (nOH). It must be differentiated from hypotension due to hypovolemia or medications, called non-neurogenic orthostatic hypotension (nnOH). OH can result from benign causes, such as acute, chronic hypovolemia or use of various drugs. However, these drugs may only reveal subclinical pictures of Dysautonomia. All drugs of patients with dysautonomic conditions should be reevaluated. Precise diagnosis of CAN and the investigation of the involvement of other organs or systems is extremely important in the clinical suspicion of pandysautonomia. In diabetics, in addition to age and time of disease, other factors are associated with a higher incidence of CAN, such poor glycemic control, hypertension, dyslipidemia and obesity. Among diabetic patients, 38-44% can develop Dysautonomia, with prognostic implications and higher cardiovascular mortality. In the initial stages of DM, autonomic dysfunction involves the parasympathetic system, then the sympathetic system and, later on, it presents as orthostatic hypotension. Valsalva, Respiratory and Orthostatic tests (30:15) are the gold standard methods for the diagnosis of CAN. They can be associated with RR Variability tests in the time domain, and mainly in the frequency domain, to increase the sensitivity (protocol of the 7 tests). These tests can detect initial or subclinical abnormalities and assess severity and prognosis. The Tilt Test should not be the test of choice for investigating CAN at an early stage, as it detects cases at more advanced stages. Tilt response with a dysautonomic pattern (gradual drop in blood pressure without increasing heart rate) may suggest CAN. Treatment of patients at moderate to advanced stages of dysautonomia is quite complex and often refractory, requiring specialized and multidisciplinary evaluation. There is no cure for most types of Dysautonomia at a late stage. NOH patients can progress with supine hypertension in more than 50% of the cases, representing a major therapeutic challenge. The immediate risk and consequences of OH should take precedence over the later risks of supine hypertension and values greater than 160/90 mmHg are tolerable. Sleeping with the head elevated (20-30 cm), not getting up at night, taking short-acting antihypertensive drugs for more severe cases, such as losartan, captopril, clonidine or nitrate patches, may be necessary and effective in some cases. Preventive measures such as postural care; good hydration; higher salt intake; use of compression stockings and abdominal straps; portioned meals; supervised physical activity, mainly sitting, lying down or exercising in the water are important treatment steps. Various drugs can be used for symptomatic nOH, especially fludrocortisone, midodrine and droxidopa, the latter not available in Brazil. The risk of exacerbation or triggering supine hypertension should be considered. Chronic Fatigue Syndrome represents a form of Dysautonomia and has been renamed as a systemic disease of exercise intolerance, with new diagnostic criteria: 1 - Unexplained fatigue, leading to occupational disability for more than 6 months; 2 - Feeling ill after exercising; 3 - Non-restorative sleep; 4 - One of the following findings: cognitive impairment or orthostatic intolerance. Several pathologies today have evolved with chronic fatigue, being called chronic diseases associated with chronic fatigue. Postural orthostatic tachycardia syndrome (POTS), another form of presentation of dysautonomic syndromes, is characterized by sustained elevation of heart rate (HR) ≥30 bpm (≥40 bpm if <20 years) or HR ≥120 bpm, in the first 10 minutes in an orthostatic position or during the tilt test, without classical orthostatic hypotension associated. A slight decrease in blood pressure may occur. Symptoms appear or get worse in an orthostatic position, with dizziness, weakness, pre-syncope, palpitations, and other systemic symptoms being common.

Syncope: Case Studies

Syncope, or the sudden loss of consciousness, is a common presenting symptom for evaluation by neurologists. It is not a unique diagnosis but rather a common manifestation of disorders with diverse mechanisms. Loss of consciousness is typically preceded by a prodrome of symptoms and sometimes there is a clear trigger. This article discusses several cases that illustrate the various causes of syncope. Reflex syncope is the most common type and includes neurally mediated, vasovagal, situational, carotid sinus hypersensitivity, and atypical forms. Acute and chronic autonomic neuropathies and neurodegenerative disorders can also present with syncope.

Carotid sinus syndrome

Carotid sinus hypersensitivity, first described less than 65 years ago, is an important and often undiagnosed cause of syncope in the elderly. Its pathophysiology is complex and certain aspects are not completely understood. The timely diagnosis and treatment of this condition can improve morbidity and prevent complications in the elderly. In this article, the prevalence, risk factors, pathophysiology, diagnosis, aspects of carotid sinus massage, and treatment options for the different kinds of carotid sinus hypersensitivity are discussed.

Management of vasovagal syncope: 2004

Vasovagal syncope is a common disorder that affects at least 20% of people at some time in their lives. Probably half of these patients faint recurrently; for many this causes physical trauma, a substantial reduction in quality of life, and difficulties with driving, employment and education. The last 15 years have seen striking advances in diagnostic approaches and prognostic understanding. A number of physiological, pharmacological and electrical therapies have been developed and tested to various degrees in patients. These include counterpressure manoeuvres, salt and fluid recommendations, and attempted treatment with fludrocortisone, midodrine, beta-blockers, serotonin reuptake inhibitors, and permanent pacemakers. This review highlights the most important of these advances and suggests strategies for managing this often difficult problem.

Autonomic dysfunction in older people

The autonomic nervous system comprises the sympathetic, parasympathetic and enteric nervous systems and plays an integral role in homeostasis. This includes cardiovascular and temperature control, glucose metabolism, gastrointestinal and reproductive function and increasing evidence to support its involvement in the inflammatory response to infection and cancer. Ageing is associated with autonomic dysfunction, and many clinical syndromes associated with older adults are due to inadequate autonomic responses to physiological stressors. The aim of this review is to explore the relationship between autonomic dysfunction and ageing illustrated with examples of maladaptive autonomic responses in a variety of different clinical syndromes including an exploration of autonomic cellular changes. Appropriate investigation and management strategies are outlined, recognizing the fine balance needed to improve symptoms without creating further medical complications.

Evaluation and Management of Syncope

Context

Syncope is a commonly encountered by primary care physicians and cardiologists. Etiology is frequently not apparent, and patients may undergo unnecessary tests. Treatment must be tailored to the likely etiology. Complexities of diagnosis and treatment often warrant referral to a specialist.

Objective

To highlight the evolving recommendations for managing syncope in a clinically and cost effective manner.

Evidence Acquisition

An electronic literature search was undertaken of the Medline database from January 1996 to April 2006, using the Medical Subject Heading syncope, defibrillators, pacemakers, echocardiogram, cardiomyopathy, long QT syndrome, Arrhythmogenic right ventricular dysplasia, and Brugada syndrome. Abstracts and titles were reviewed to identify English-language trials. Bibliographies from the references as well as scientific statements from the Heart Rhythm Society, American Heart Association, and American College of Cardiology were reviewed.

Evidence Synthesis

A methodical approach to syncope can improve diagnosis, limit testing, and identify patients at risk of fatal outcome. A thorough history, physical exam and electrocardiogram are critical to the initial diagnosis. Presence of heart disease determines the extent of work-up and treatment. A trans-thoracic echocardiogram should be performed in patients with an unclear diagnosis and a positive cardiac history or an abnormal ECG. Ventricular arrhythmias are the most common cause of syncope in patients with structural heart disease. Patients with an ejection fraction less than 30 percent should receive an implantable defibrillator with few exceptions. An electrophysiology study may assist risk stratification in syncopal patients with borderline ventricular function. In patients without structural heart disease, the presence of a well defined arrhythmia syndrome consistent with a genetically determined risk of sudden death must be sought. The 12-lead electrocardiogram, family history and clinical presentation will identify most high-risk patients. Patients without structural heart disease can often be managed conservatively with well defined strategies for preventing neurocardiogenic syncope.

Conclusions

Managing syncope requires a methodical approach. An understanding of the limitations of the diagnostic tools and treatments is important. Lethal causes of syncope make it imperative to recognize the appropriate timing of referring patients to specialists.

Neurocardiogenic syncope: latest pharmacological therapies

Neurocardiogenic syncope is a neurally mediated disorder and is a common cause of syncope. The goal of treatment is to prevent recurrences with the aim of improving quality of life and reducing morbidity. Reassurance, in some cases, may suffice. In others, augmenting central blood volume by increasing fluid and/or salt intake is effective. The role of non-pharmacological physical manoeuvres is increasingly recognised, given the increasing clinical trial data supporting their efficacy. This review summarises the clinical evidence for a variety of pharmacological agents. Of these, midodrine appears to have yielded the most consistent favourable outcome. Its use, however, should be reserved for patients with recurrent and refractory syncope.

Seizure versus syncope

One of the most common but difficult management problems in medicine is that of patients who present with a paroxysmal loss of consciousness. All too often the underlying diagnosis remains elusive. This has a cost both in terms of mortality and ongoing morbidity and in terms of the financial burden associated with hospitalisation and repeated investigations. We describe a practical approach to this clinical dilemma, which is rooted in adherence to basic principles of history taking and examination, formulation of a reasonable differential diagnosis, followed by an intelligent use of specific investigations and selection of an appropriate treatment. We also discuss the effect of sudden unexpected death in epilepsy and sudden cardiac death. Despite a careful and thorough approach to the patient with a "seizure versus syncope" problem, many will require repeated assessment before a diagnosis is made.

Treatment of vasodepressor carotid sinus syndrome with midodrine: a randomized, controlled pilot study

OBJECTIVES

To evaluate the efficacy of treatment of the vasodepressor form of carotid sinus hypersensitivity (carotid sinus syndrome (CSS)) with midodrine.

DESIGN

A prospective, double-blind, randomized, controlled trial of crossover design.

SETTING

A dedicated outpatient facility with access to tilt-table, digital arterial photoplethysmography, and 24-hour ambulatory blood pressure (BP) monitoring equipment.

PARTICIPANTS

Ten older adults (4 male, 6 female, mean age 75, range 66-86 years) with a history of unexplained syncope who displayed an asymptomatic decrease in systolic BP (SBP) of more than 50 mmHg or a symptomatic decrease of more than 30 mmHg within 30 seconds of carotid sinus massage (CSM).

MEASUREMENTS

Symptom reproduction and BP and heart rate changes were evaluated after CSM in supine and semierect positions on the right and then left sides. These measurements were performed on the final day of placebo and active-treatment phases. Ambulatory 24-hour BP monitoring took place on the penultimate and final days of each treatment phase.

RESULTS

Eight patients were symptomatic after their initial CSM. The mean+/-standard deviation SBP decrease after initial CSM was 54+/-22 mmHg. Initial mean 24-hour ambulatory BP was 127/70+/-7/5 mmHg. Eight patients reported symptoms after CSM at the end of the placebo phase. The mean SBP decrease at the end of the placebo phase was 49+/-12 mmHg. The mean 24-hour ambulatory BP was 127/69+/-9/7 mmHg. One patient reported symptoms after CSM at the end of the active-treatment phase. The mean SBP decrease at the end of the active-treatment phase was 36+/-9 mmHg. The mean 24-hour ambulatory BP at the end of the treatment phase was 133/75+/-7/6 mmHg. The differences in symptom reporting and mean SBP decrease after CSM were both significant (P<.01 and P=.03, respectively).

CONCLUSION

The results of this pilot study suggest that treatment of vasodepressor CSS with midodrine significantly reduced the rate of symptom reporting and attenuated SBP decreases after CSM but increased mean 24-hour ambulatory BP.

The management of patients with carotid sinus syndrome: is pacing the answer?

Carotid sinus syndrome (CSS) is an under recognized cause of recurrent unexplained syncope and potentially of recurrent falls in the elderly. The mechanisms that lead to syncope in patients with CSS remain debated. However, evidence for both peripheral and central alterations have been recently reported. The diagnosis of CSS is challenging and a high clinical suspicion is usually needed to make the diagnosis. Clinical presentation may be typical and characterized by a clear association between accidental manipulation of the carotid sinus and the presentation of syncope. On the other hand, recurrent unexplained syncope and unexplained falls may be the clinical presentation of patients with CSS without a specific trigger. Carotid sinus hypersensitivity documented by carotid sinus massage (CSM) may be the only finding indicating the possibility of CSS as the cause of syncope. In older patients with recurrent unexplained syncope and a negative diagnostic work-up, carotid sinus massage both in the supine and upright positions is recommended. CSS may present primarily as a cardioinhibitory response or a true vasodepressor response. Therapy should address any underlying pathology if present, and be directed to either prevent cardioinhibition, vasodepression or both alterations. A variety of medical therapies have been used with unclear effects. No appropriately designed controlled clinical trials have been performed comparing pacing with medical therapy. Nonetheless, available information indicates that pacing may have a strong beneficial effect and prevents recurrence of syncope in patients with CSS. The present paper critically reviews the latest insights in the pathophysiology, diagnosis and management of CSS.

Carotid sinus syndrome is common in dementia with Lewy bodies and correlates with deep white matter lesions

BACKGROUND

Carotid sinus syndrome (CSS) is a common cause of syncope in older persons. There appears to be a high prevalence of carotid sinus hypersensitivity (CSH) in patients with dementia with Lewy bodies (DLB) but not in Alzheimer's disease.

OBJECTIVE

To compare the prevalence of CSH in DLB and Alzheimer's disease, and to determine whether there is an association between CSH induced hypotension and brain white matter hyperintensities on magnetic resonance imaging (MRI).

METHODS

Prevalence of CSH was compared in 38 patients with DLB (mean (SD) age, 76 (7) years), 52 with Alzheimer's disease (80 (6) years), and 31 case controls (73 (5) years) during right sided supine carotid sinus massage (CSM). CSH was defined as cardioinhibitory (CICSH; >3 s asystole) or vasodepressor (VDCSH; >30 mm Hg fall in systolic blood pressure (SBP)). T2 weighted brain MRI was done in 45 patients (23 DLB, 22 Alzheimer). Hyperintensities were rated by the Scheltens scale.

RESULTS

Overall heart rate response to CSM was slower (RR interval = 3370 ms (640 to 9400)) and the proportion of patients with CICSH greater (32%) in DLB than in Alzheimer's disease (1570 (720 to 7800); 11.1%) or controls (1600 (720 to 3300); 3.2%) (p<0.01)). The strongest predictor of heart rate slowing and CSH was a diagnosis of DLB (Wald 8.0, p<0.005). The fall in SBP during carotid sinus massage was greater with DLB (40 (22) mm Hg) than with Alzheimer's disease (30 (19) mm Hg) or controls (24 (19) mm Hg) (both p<0.02). Deep white matter hyperintensities were present in 29 patients (64%). In DLB, there was a correlation between magnitude of fall in SBP during CSM and severity of deep white matter changes (R = 0.58, p = 0.005).

CONCLUSIONS

Heart rate responses to CSM are prolonged in patients with DLB, causing hypotension. Deep white matter changes from microvascular disease correlated with the fall in SBP. Microvascular pathology is a key substrate of cognitive impairment and could be reversible in DLB where there are exaggerated heart rate responses to carotid sinus stimulation.

Neurocardiovascular instability in cognitive impairment and dementia

Neurocardiovascular instability (NCVI, neurally mediated disorders causing hypotension with or without bradycardia) represents abnormal neural control of the cardiovascular system and presents as dizziness, syncope, or falls. The mechanisms underpinning NCVI are incompletely understood. The three most common disorders are carotid sinus syndrome (CSS), orthostatic hypotension (OH), and vasovagal syndrome (VVS): CSS, cardioinhibition > 3 s and/or vasodepressor response > or = 50 mmHg drop in systolic pressure during carotid sinus stimulation; OH: fall in systolic blood pressure > 20 mmHg during standing; VVS: cardioinhibition > 3 s and/or vasodepressor response > 50 mmHg during prolonged head-up tilting. In fallers with cognitive impairment or dementia, the prevalence of NCVI is 70%. Multifactorial interventions, including treatment of NCVI, significantly reduce falls and syncope. The predominant components of NCVI in fallers with cognitive impairment and dementia are CSS and OH. In Lewy body and Alzheimer's dementia, the prevalence of NCVI is up to 60%, again predominantly CSS and OH. The prevalence of cardioinhibitory carotid sinus hypersensitivity is particularly high in Lewy body dementia-41% compared with 12% in Alzheimer's disease and 3% in case controls. In addition, patients with Lewy body dementia have greater heart rate slowing (>2 s) and falls in systolic blood pressure (>20 mmHg) than those with Alzheimer's disease or controls during carotid sinus stimulation. The extent of deep white matter hyperintensities on MRI correlates with systolic fall during carotid sinus stimulation (R = 0.58; p < 0.005), suggesting a possible causal association between bradyarrhythmia-induced hypotension and microvascular pathology. NCVI is common in patients with dementia and may be a reversible cause of falls and syncope. Repeated hypotensive episodes may exaggerate cognitive decline in these patients.

Diagnostic yield and development of a neurocardiovascular investigation unit for older adults in a district hospital

BACKGROUND

Dizziness, syncope, and falls are common occurrences in elderly people. Neurocardiovascular investigation units aim to detect those patients who fall due to disturbances of blood pressure control or cardiac conduction. Specialist units have a high diagnostic yield in the investigation of these problems. Does this translate to less specialized centers? We report on the diagnostic findings of a district general hospital neurocardiovascular investigation unit.

METHOD

A total of 120 consecutive patients over the age of 65 presenting to a single geriatrician were assessed. After a full history and physical examination, patients underwent neurocardiovascular investigation: blood pressure and heart rate response to active stand, carotid sinus massage, and 30-minute head-up tilt.

RESULTS

The 120 patients assessed had a mean age of 78 years (range 66-94 years); in this group, 85 were women. Of these patients, 23% presented with falls, 14% with blackouts, and 30% with dizziness. The remaining 33% had overlap of symptoms. Neurocardiovascular investigations produced a diagnosis in 57% of the patients: 22% had cardioinhibitory carotid sinus syndrome (CSS): 15% had vasodepressor CSS; 29% had orthostatic hypotension; and 3% had vasovagal syncope. Thirteen percent had more than one neurocardiovascular abnormality, and 18% had benign positional vertigo. Five patients had postural instability causing falls. Hyperventilation syndrome, aortic stenosis, dysrhythmia, cervical spondylosis, and epilepsy each accounted for one case. Seventeen percent of the subjects remained undiagnosed after integrated neurocardiovascular assessment.

CONCLUSION

Management of falls requires access to neurocardiovascular assessment. It is feasible to provide such a service in the district general hospital setting, with a comparable diagnostic yield to tertiary referral centers.

Role of carotid sinus syndrome and neurocardiogenic syncope in recurrent syncope and falls in patients referred to an outpatient clinic in a district general hospital

Carotid sinus syndrome (CSS) and neurocardiogenic syncope (NCS) are recognised as important causes of recurrent syncope and falls in the elderly. In this study the role of CSS (diagnosed with carotid sinus massage) and NCS (diagnosed with prolonged head-up tilt) in a district general hospital were investigated. Over 27 consecutive months carotid sinus massage was performed in 139 patients. Of these 29 (20.8%) patients (mean (SD) age of 78 (9) years) showed a positive response. Of these 18 (62%) patients showed a positive response only when carotid sinus massage was performed with 70( degrees ) head-up tilt. Thirteen (8.7%) of the 149 patients who had prolonged head-up tilt testing were found to have NCS. The mean (SD) age for patients with NCS was 59 (26) years and the mean (SD) time required to produce a positive response during prolonged head-up tilt was 12 (5) minutes. It is concluded that carotid sinus massage and head-up tilt testing are useful in patients presenting with unexplained syncope and falls in a district general hospital setting. Carotid sinus massage should be repeated upon head-up tilt if a negative response is obtained in the supine position.

Fludrocortisone in the treatment of hypotensive disorders in the elderly

OBJECTIVE

To evaluate tolerance of fludrocortisone in older patients with hypotensive disorders.

DESIGN

Prospective case series.

SETTING

Syncope clinic.

PATIENTS

64 Consecutive patients over 65 years (mean age 80 years) with one or more hypotensive disorders (orthostatic hypotension, vasodepressor carotid sinus syncope, and/or vasodepressor neurocardiogenic syncope.

INTERVENTIONS

Fludrocortisone in daily doses of 100 micrograms [corrected] (72%), 50 micrograms [corrected] (27%), and 200 micrograms [corrected] (one patient).

MAIN OUTCOME MEASURES

Adverse events, treatment withdrawal.

RESULTS

During follow up 13 patients died of unrelated causes. Of the remainder 33% discontinued fludrocortisone at a mean of five months. Reasons for discontinuing treatment were hypertension, five; cardiac failure, four; depression, three; oedema, three; and unspecified, two. In those who continued treatment supine systolic and diastolic blood pressure did not differ significantly from baseline (follow up two to 21 months). Hypokalaemia developed in 24% at a mean of eight months; in no case was treatment withdrawn because of hypokalaemia.

CONCLUSION

Fludrocortisone, even in low doses, is poorly tolerated in the long term in older patients with hypotensive disorders.

Incidence of complications after carotid sinus massage in older patients with syncope

OBJECTIVE

To review the incidence of neurological complications occurring after carotid sinus massage performed for diagnostic purposes.

DESIGN

Case review and comparison with previously published work.

SETTING

Syncope Clinic, Royal Victoria Infirmary, Newcastle-upon-Tyne, and Chelsea and Westminster Hospital, London.

PARTICIPANTS

Patients undergoing investigation of dizziness, syncope, or unexplained falls.

METHODS

Carotid sinus massage performed for 5 seconds in both supine and erect postures, both before and after atropine. Contraindications to carotid sinus massage were the presence of carotid bruits, recent myocardial or cerebral ischemia, or previous ventricular tachyarrhythmias.

RESULTS

Two cases of neurological complications were reported from a total of 500 patients (2000 massage episodes) investigated in one center, giving an incidence of 0.1%. Combining this data with another center performing investigations in a similar fashion, seven neurological complications arose from a total of 5000 massage episodes, an incidence of 0.14%. Reported complications were pyramidal signs in five cases and visual field defects in two. Pyramidal weakness persisted in one case with a pre-existing stroke on the same side, and a visual field loss was permanent in one.

CONCLUSIONS

Neurological complications following carotid sinus massage for diagnosis of the carotid sinus syndrome are uncommon and usually transient. Contraindications to carotid sinus massage should be respected and the standardized technique used.

Pattern of inhibition of parasympathetic activity in response to incremental bolus doses of atropine in carotid sinus hypersensitivity

Patients with established reproducible cardioinhibitory carotid sinus hypersensitivity were studied to define the dose of atropine required to abolish the heart rate slowing in response to carotid sinus massage, the heart rate response to the Valsalva manoeuvre and salivary gland flow. Bolus doses of intravenous atropine were given to a cumulative dose of 700 mcg. Cardioinhibition was abolished in all patients with a total dose of 700 mcg. The heart rate ratio during the Valsalva manoeuvre did not vary significantly. The decline in salivary gland flow was evident earliest, at a dose of 75 mcg. In clinical studies, 700 mcg of atropine will abolish the diagnostic cardioinhibitory response to carotid sinus message in patients with the syndrome. This may not prevent syncope, as could occur in the key frequent vasodepressor form of carotid sinus hypersensitivity syndrome.