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Outcome of an integrated approach to the investigation of dizziness, falls and syncope in elderly patients referred to a 'syncope' clinic.

Introduction

There are problems in the classification of causes of falls and syncope among elderly people |1-5~. Studies of syncope have frequently excluded unexplained falls when no history of loss of consciousness was evident |6-9~. None the less, a recent paper which addressed the investigation of unexplained falls and/or syncope identified carotid sinus syndrome as a cause of symptoms in 20% of patients. Furthermore, retrograde amnesia for syncope was present in a third, emphasizing the relevance of syncope to falls by elderly people |10, 11~.

We currently run a 'syncope clinic' for elderly patients with falls, dizziness and syncope. In this selected patient group, an integrated approach to the investigation of symptoms has a high diagnostic yield. The purpose of this paper is to present the first six months' experience of the clinic.

Patients and Methods

A consecutive series of 65 patients over 65 years who were referred to the syncope clinic between October 1990 and March 1991 were studied. All were secondary or tertiary referrals for investigation of unexplained falls, syncope or dizziness.

Baseline evaluation of patients: A standard evaluation form was designed before the study was started. For all patients we obtained (a) a complete history, physical and neurological examination, (b) details of witness account of symptoms, (c) lying and standing blood-pressure measurements (standard mercury sphygmomanometer), (d) baseline laboratory evaluation including blood count, urinalysis, electrolytes, urea, creatinine and glucose, (e) 12-lead surface electrocardiograph, (f) ambulatory electrocardiographic monitoring of at least 24 hours' duration, (g) results of carotid sinus massage and (h) of prolonged head-up tilt study (70%).

Abnormal historical or physical findings were further investigated by more specific tests: echocardiography (M mode and two-dimensional; 17%), treadmill exercise stress testing (6%), intracardiac electrophysiological study (3%), electroencephalography (26%) and head CT scan (15%).

Carotid sinus massage: Patients were tested in the supine and tilted upright (70 |degrees~) position with the neck slightly extended. Massage was applied over the point of maximum carotid impulse medial to the sternomastoid muscle at the level of the upper border of the thyroid cartilage. Longitudinal massage was applied for 5 s. The test was initially performed on the right side and after 1 min on the left side. Continuous electrocardiography recorded the heart rate response to massage. Continuous non-invasive beat-to-beat blood pressure was measured using a digital artery cuff (finger plethysmography: Finapres). If a cardioinhibitory response of greater than 1.5 s asystole was present, intravenous atropine was routinely given in 600 |Mu~g to 1200 |Mu~g bolus doses to abolish heart rate slowing and define a pure vasodepressor response.

Head-up tilt: In 45 patients for whom syncope remained undiagnosed or the history was suggestive of vasovagal syncope or carotid sinus syncope, prolonged head-up tilt (Akrow table) to 70 |degrees~ for 45 min was carried out with simultaneous continuous heart rate and non-invasive phasic arterial blood pressure monitoring.

Diagnostic Criteria

Diagnostic criteria were defined at the beginning of the study and assignment of a cause was based on strict adherence to these criteria. Definitions of diagnoses were based on previously published data |6, 12, 13~.

1. Carotid sinus syndrome: A 3-s or greater episode of asystole (cardioinhibitory) or a 50 mmHg fall in systolic blood pressure in the absence of diagnostic cardioinhibition (vasodepressor) following carotid sinus massage for 5 s. Symptom reproduction was not necessary to make the diagnosis. Responses were grouped into predominantly cardioinhibitory, predominantly vasodepressor or a mixed response; the latter if patients had a significant cardioinhibitory response and vasodepressor response independent of cardioinhibition.

2. Orthostatic hypotension: A 20 mmHg fall in systolic or a 10 mmHg fall in diastolic pressures on active standing or tilting associated with symptoms or a fall in systolic blood pressure to 90 mmHg or less on standing.

3. Vasovagal syncope: A classical history of a precipitating event with hypotension and/or bradycardia induced by prolonged head-up tilt and reproduction of presenting symptoms.

4. Arrhythmia: Sinus pauses of greater than 2 s, prolonged sinus bradycardia, slow atrial fibrillation, supraventricular tachycardia, frequent ventricular ectopic beats or ventricular tachycardia associated with symptoms which improved with appropriate therapy or, in the case of drug-induced bradyarrhythmias, with cessation of treatment.

5. Epilepsy: A witnessed account of the seizure usually but not necessarily confirmed by EEG findings with improvement on anticonvulsant therapy.

6. Benign positional vertigo: Classified by (a) episodic vertigo, (b) of less than 1 min in duration and (c) provoked by rapid positional changes such as turning over in bed, bending over or straightening up. A positive Hall Pike manoeuvre was additionally helpful in diagnosis.

7. Cerebrovascular: Documented transient ischaemic episode or cerebrovascular accident occurring at the time of symptoms.

8. Drop attack: A sudden, unexpected fall to the ground, usually while standing or walking, often following head or neck turning with difficulty standing again in an otherwise well individual who denied loss of consciousness and had no symptom reproduction during carotid sinus massage.

9. Conversion reaction: Diagnosed by a psychiatrist in the absence of any other identifiable cause.

Follow-up

Postal questionnaires were sent to patients after 6 months. Patients were asked about the number, frequency and duration of dizziness, syncope or falls since the last outpatient review: a minimum of 2 weeks and a maximum of 2 months since last review.

Results

Patient characteristics: The study group comprised 65 consecutive patients aged over 65 years (41 women), of mean age 78 (range 67-92) years referred to the syncope clinic. The referral source was a general practitioner for 39%, the accident and emergency department for 18%, and 43% were referred by medical or surgical consultants. Seventy-five per cent of patients were reviewed as outpatients and 25% as inpatients.

Presenting symptoms were dizziness alone in 12%, falls alone in 11% and syncope alone in 20%. The remainder had overlap of symptoms. The mean duration of dizziness was 49 months (range 1-240 months; median 21 months), and of falls or syncope 58 months (range 1-240 months; median 21 months). Patients had had a mean of 13 syncopal episodes or falls (range 1-240, median 3). Nine patients had experienced only one syncopal episode.

A witness account of events was available for 60%. Three patients complained of dizziness alone and denied syncope, but witness accounts confirmed syncopal episodes in all. In a further four patients who denied loss of consciousness, syncope was reproduced during upright carotid sinus massage with retrograde amnesia for this event. Thirty-six (55%) patients had sustained injuries during falls or syncope, fracture in 15 and superficial trauma in 21. Forty-five who complained of syncope or falls could recall events prior to their attack and of these 58% had not experienced a prodrome. Of those who had sustained a fracture, only 9% experienced prodromal symptoms.

Diagnoses: The most frequent diagnoses were carotid sinus syndrome in 45%, orthostatic hypotension in 32% and arrhythmia in 21%. Other diagnoses are summarized in the Table. Twenty-nine had carotid sinus syndrome. Of these, three patients had a predominantly cardioinhibitory response, 17 had a predominantly vasodepressor response and nine a mixed response. The cardioinhibitory response was right-sided in six, left-sided in four and bilateral in two. Duration of asystole was 4.7 |+ or -~ 1.3 seconds. For those with a predominant vasodepressor response, this was right-sided in 12, left-sided in seven and bilateral in seven. The mean vasodepressor response was 60 |+ or -~ 11 mmHg. The maximum response occurred at 18 |+ or -~ 3 s after massage and systolic blood pressure had returned to baseline by 46 |+ or -~ 15 s. Ischaemic heart disease, cerebrovascular disease, hypertension or peripheral vascular disease was present in 62% of patients with an abnormal response to carotid sinus massage.
Table. Final diagnoses after integrated investigation programme
Diagnosis                         n              %
Carotid sinus syndrome           29             45
Orthostatic hypotension          21             32
Vasodepressor syndrome            7             11
Cardiac arrhythmia               14             21
Epilepsy                          6              9
Cerebrovascular                   4              6
Unexplained                       5              8
Cough syncope                     1              2
Benign positional vertigo         5              8
Drop attack                       1              2
Conversion reaction               1              2


Twenty-one patients had orthostatic hypotension, idiopathic in 10, drug-related in eight and associated with diabetes mellitus in four. For seven patients for whom syncope remained unexplained, prolonged head-up tilt for 45 min to 70 |degrees~ reproduced syncope thus confirming a diagnosis of vasovagal syncope. The mean time to syncope after tilting was 24 |+ or -~ 6 min; four had hypotension with associated bradycardia and three had hypotension with either no heart rate change or a tachycardia. For 21% of patients, symptoms were attributed to arrhythmia; sick sinus syndrome in six, ventricular arrhythmia in four, supraventricular arrhythmia in one and drug-induced bradycardia in three. Six patients had epilepsy. Electroencephalography confirmed epileptiform discharges in three. CT head scan identified cerebral infarction as a focus for epilepsy in two and a parietal tumour was present in one. Five patients had benign positional vertigo. Hall Pike's manoeuvre was positive in two.

Over half of the patients with vasodepressor carotid sinus hypersensitivity, vasovagal syncope or orthostatic hypotension had overlap for two or more of these diagnoses. Symptoms remained undiagnosed in five patients (8%).

Management: In patients with carotid sinus syndrome and vasovagal syndrome, factors which can precipitate syncope were explained to the patient, in particular tight collars, sudden head turning, looking up, wearing a cervical collar, warm atmospheres, prolonged standing, fasting, fatigue and dehydration. Those with a prodrome were advised to sit or lie at start of symptoms. Patients with orthostatic hypotension were additionally advised with respect to times of the day when blood pressures are lowest, postprandial dips in blood pressure, elevation of the head of the bed at night, TED stockings and increased caffeine consumption.

For those in whom diagnoses were related to medications, drugs were discontinued and patients and general practitioners informed with respect to the possible harmful effects of similar groups of drugs. Five patients with predominant cardioinhibitory carotid sinus syndrome and more than two syncopal episodes had dual chamber pacemakers implanted. Similarly, three patients with symptomatic sinus node disease had a pacemaker implant. Seven patients with supraventricular or ventricular tachycardia were given appropriate anti-arrhythmic treatment. Fludrocortisone is of benefit for vasodepressor carotid sinus syndrome |14~; 18 such patients were prescribed fludrocortisone 50-100 |Mu~g daily and 11 patients with orthostatic hypotension were similarly given fludrocortisone. Patients with epilepsy were prescribed anticonvulsant therapy (phenytoin or sodium valproate) and benign positional vertigo was treated with prochlorperazine or cinnarizine.

Benefits of diagnostic tests: In 61%, correct final diagnoses were suspected after the initial history and clinical examination; 24-hour electrocardiography identified an abnormality in 21% and carotid sinus massage in 45%. Of those who had head-up tilt, the investigation was diagnostic in 29% and CT scan was diagnostic in four of 11 patients.

Follow-up: In July 1991, (7 |+ or -~ 2 months after assessment) postal questionnaires were sent to 62 patients (three patients had died). Replies were received from 54. Symptoms had completely resolved in 20 patients, improved in 21, were unchanged in 11 and two reported an increase in symptom frequency and/or severity.

Discussion

To evaluate falls, investigators most often rely on the history of falling provided by patients and witnesses but poor recall of falls is not uncommon |10~. The patient's history is often inaccurate and witness accounts are frequently not available. Depending on the time period of recall, 13% to 32% of those with confirmed falls do not remember falling |10, 11~. Retrograde amnesia for loss of consciousness easily results in confusion between syncope and falls |11~. Because of the limited accuracy for recall of falls and for associated loss of consciousness, unexplained falls should be regarded as possible syncopal episodes in this age group. For this reason eligibility for referral of elderly patients to the syncope clinic includes symptoms of unexplained falls and/or syncope and/or dizziness.

Patients were a selected population of secondary and tertiary referrals from general practitioners, the accident and emergency department and consultant colleagues. Over half had syncope alone or syncope and dizziness and over 40% had recurrent unexplained falls and dizziness. Symptoms had been present for a long time, on average over four years, and patients had on average 13 syncopal episodes or unexplained falls prior to referral.

In only half of the patients was a witness account of symptoms available, and in 15% who denied loss of consciousness, syncope was reproduced during head-up tilt. Despite witnessed loss of consciousness these patients continued to deny syncope, demonstrating retrograde amnesia for the episodes and supporting previously published data |11~.

Before inclusion in the study, the diagnostic criteria for causes of dizziness and syncope were clearly defined and strictly adhered to. These were previously published and validated in other studies of syncope for all age groups |6~. By using these criteria and adopting an integrated investigation approach the diagnostic yield was high. However, long-term prospective studies are necessary to clarify the role of some of the diagnoses in symptomatic elderly people, in particular vasodepressor carotid sinus responses. Assessment and investigation required on average 3-4 hours for each patient. Unless this time is dedicated and appropriate facilities are available, the high diagnostic yield may not be forthcoming.

Carotid sinus syndrome was present in 45% of patients. Right-sided massage resulted more frequently in abnormal responses of both heart rate and blood pressure than did left-sided massage. A significant vasodepresor response was recorded whilst supine in only half of the patients and massage during head-up tilt was required for diagnosis in the remainder. Arterial cannulation results in altered autonomic tone and because the carotid sinus response is mediated via the vagus nerve, cannulation with consequent enhanced vagal tone is inappropriate for study of this patient group |15, 16~. In the present study, the maximum vasodepressor response occurred within 18 s of stimulus and blood pressure returned to baseline measurements in less than 1 min, highlighting the rapidity of this response and the necessity for phasic arterial monitoring; standard sphygmomanometry or automated digital sphygmomanometr would not identify these rapid changes. Alternatively, the digital artery cuff (Finapres) records phasic arterial pressures by an extrinsic plethysmographic technique without cannulation and under standard laboratory conditions the technique is valid and reproducible |17, 18~. Routine use of carotid sinus massage, with recordings during supine and erect posture, and continuous phasic blood pressure measurements before and after atropine, has not been previously reported for symptomatic elderly patients. The diagnostic yield is high, but whether symptoms can exclusively be attributed to these diagnoses needs to be established in longer follow-up.

Of interest is the diagnostic overlap between orthostatic hypotension, vasodepressor carotid sinus syndrome and vasovagal syndrome. For those with vasodepressor carotid sinus hypersensitivity, 60% had either vasovagal syncope and/or postural hypotension. This finding has not been previously reported and suggests a possible common aetiology for these three diagnostic groups which may in part explain the beneficial effects of fludrocortisone in vasodepressor carotid sinus hypersensitivity |14~.

Over a short-term follow-up period, the majority of patients received symptom benefit from education about their diagnosis, simple instructions to avoid precipitating factors, cardiac pacing, modification of medications and, in some instances, specific drug therapy. The long-term benefits of this diagnostic approach have not been studied. Awareness of the possible contribution of carotid sinus syndrome and, in particular, vasodepressor carotid sinus hypersensitivity to syncope and falls greatly enhances the diagnostic yield.

Acknowledgements

Dr Shona McIntosh is in receipt of a grant from Research into Ageing.

References

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10. Cummings SR, Nevitt MC, Kidd S. Forgetting falls: the limited accuracy of recall of falls in the elderly. J Am Geriatr Soc 1988;36:613-16.

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12. Almquist A, Gornick C, Benson DW, Dunnigan A, Benditt DG. Carotid sinus hypersensitivity: evaluation of the vasodepressor component. Circulation 1985;71:927-36.

13. Kenny RA, Bayliss J, Ingram A, Sutton R. Head-up tilt: a useful test for investigating unexplained syncope. Lancet 1986;i:1352-4.

14. Da Costa D, McIntosh SJ, Kenny RA. Benefits of fludrocortisone in the treatment of symptomatic vasodepressor carotid sinus syndrome in the elderly. (In press).

15. Morley CA, Dehn TCB, Perrins EJ, Chan SL, Sutton R. Baroreflex sensitivity measured by the phenylephrine pressor test in patients with carotid sinus syndrome and sick sinus syndrome. Cardiovasc Res 1984;18:752-61.

16. Van Lieshout JJ, Wieling W, Wesseling KH, Karemaker JM. Pitfalls in the assessment of cardiovascular reflexes in patients with sympathetic failure but intact vagal control. Clin Sci 1989;76:523-8.

17. Imholz BPM, Settells JJ, Van de Meiracken AH, Wieling W. Cardiovascular reflex testing with Finapres: non-invasive beat to beat finger blood pressure responses to changes of posture compared to invasive measurements. Cardiovasc Res 1990;24:214-21.

18. Imholz BPM, Wieling W, Langewoutens GJ, Montfraus GA. Continuous finger arterial pressure; utility in the cardiovascular laboratory. Clin Auton Res 1991;1:43-53.
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Author:McIntosh, Shona; Da Costa, David; Kenny, Rose Anne
Publication:Age and Ageing
Date:Jan 1, 1993
Words:2978
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