Vasopressin release during orthostatic hypotension after cardiac transplantation

At the time of cardiac transplantation all nerves from the donor ventricles are cut. These nerves may regrow, but there is no method of measuring any regrowth. Arginine vasopressin (AVP) release was studied during hypotension induced by head-up tilt and lower body negative pressure (LBNP) in transplant recipients and in normal controls. Subjects were tilted to 60 degrees for up to 60 min or until symptomatic. Lower body negative pressure (40 mmHg) was applied for 10 min after 30 min rest. Seven of 17 transplant recipients and 11 of 12 controls became symptomatic during tilt testing, and 9 of 12 controls and 9 of 17 transplant recipients became symptomatic after 10 min of LBNP. Symptoms during tilt did not predict symptoms during LBNP. Resting AVP levels were similar but osmolality was greater in transplant recipients. Resting haematocrit was reduced, and atrial natriuretic peptide increased in transplant recipients, suggesting increased plasma volume. In symptomatic subjects, changes in humoral concentrations were similar when compared between transplant recipients and normals, except that the rise in AVP at the time of symptoms was reduced in transplant recipients, with a comparable drop in blood pressure consistent with persistent cardiac afferent denervation in a subset of transplant recipients.

Syncope: driving advice is frequently overlooked

Consecutive referrals to a syncope clinic were asked about the frequency of enquiries about driving status by referring general practitioners and/or hospital specialists. Although 40% were drivers, only 13% of patients had been previously asked about driving, and 12% of drivers had experienced symptoms whilst driving. This represents an important oversight on the part of referring doctors.

Falls presenting to the accident and emergency department: types of presentation and risk factor profile

The aim of this study was to evaluate the type and frequency of falls presenting to an inner city casualty department, and to identify modifiable risk factors in these patients. A prospective descriptive study evaluated those over 65 years presenting to an inner city casualty department with falls. Over a 4-week recruitment period, all consenting subjects completed a semi-structured questionnaire regarding their falls and cognitive status. Those with unexplained (UF) or recurrent falls (RF) underwent a more detailed assessment: history and examination, gait and balance assessment, visual acuity measurement and neurocardiovascular investigations (including orthostatic blood pressure, carotid sinus massage and head-up tilt testing). Of 200 patients with falls, 188 were interviewed; 29% could recall a reason for falling (accidental) and 30% had UF or RF. A cohort of 26 cognitively normal patients with UF and RF was fully investigated. In 23/26 patients risk factors for falls were found (median: three risk factors). These included: culprit medication (10), gait abnormalities (9) and carotid sinus hypersensitivity (19). Falls are a common presenting complaint yet a fall is readily explained in less than one-third of cases. Investigation of RF and UF has a high yield for possibly modifiable cardiac and non-cardiac risk factors. Targeted multi-disciplinary rapid assessment of patients attending the Accident and Emergency Department because of a fall might reduce the number of hospital admissions.

Reproducibility of orthostatic hypotension in symptomatic elderly

PURPOSE

Variations in the reported prevalence of orthostatic hypotension (4% to 33%) are attributed to population selection and varied criteria used to define orthostatic hypotension. Variation in the reproducibility of hemodynamic responses to orthostasis could be a further confounding variable. The purpose of this study was to evaluate reproducibility of orthostatic blood pressure changes in patients with documented symptomatic orthostatic hypotension.

PATIENTS AND METHODS

Forty outpatients (mean age 77+/- 8 years; 24 women) were recruited after initial presentation to a morning outpatient clinic with postural symptoms of dizziness (92%), falls (67.5%), or syncope (30%). Patients had a symptomatic drop in orthostatic systolic blood pressure of >20 mm Hg documented in clinic. Subsequent cardiovascular assessment included autonomic function tests, carotid sinus massage (supine and erect), and prolonged head-up tilt tests. Blood pressure and heart rate measurements were repeated during standing and head-up tilt on two further attendances in the morning.

RESULTS

A total of 67.5% patients had a drop in systolic blood pressure of >20 mm Hg on both visits during orthostatic stimuli; in the remainder, the response was not reproducible, and 5% had no significant orthostatic drop at either attendance. In 19 patients autonomic function tests were abnormal; orthostatic hypotension was reproducible in 79% of this group. In patients with normal autonomic function tests, 57% had reproducible orthostatic hypotension, of which only 60% were reproducible in those patients when further assessed in the afternoon.

CONCLUSIONS

Orthostatic blood pressure responses may not be reproducible in patients with documented symptomatic orthostatic hypotension, particularly if autonomic function is normal and measurements are taken in the afternoon. Repeated systolic blood pressure measurements in the morning may be necessary to make a diagnosis in older patients with suspected orthostatic hypotension.

Observations on midodrine in a case of vasodepressor neurogenic syncope

A 43-year-old man presented with recurrent syncope and dizziness after he had a dual chamber pacemaker fitted for presumed sino-atrial disease. Head-up tilt produced vasodepressor neurocardiogenic syncope, despite appropriate heart rate support during pacing, and reproduced symptoms. Symptoms were not improved by disopyramide. A double-blind cross-over trial of midodrine, an alpha-receptor agonist, was effective in reducing symptoms: it abolished syncope and reduced frequency and severity of dizziness, coupled with improved haemodynamic responses to head-up tilt.

Service provision and use of anticoagulants in atrial fibrillation

Several large trials have shown that the risk of stroke in patients with non-valvar atrial fibrillation is reduced by treatment with warfarin. Implementing this research evidence requires not only an understanding of the trials' results and of the changes that they imply for clinicians' treatment decisions but also an appreciation of the organisation, quantity, and quality of services required to support these changes. Understanding of these implications is crucial for developing services that allow changes in practice to produce reductions in stroke incidence while minimising the risks of treatment. This article considers the developments in service provision that will probably be required to support the changes in clinical practice suggested by the trials' results. These services will be provided largely by doctors, and their development has implications for doctors in both primary and secondary care.

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.

Intravenous cannulation alters the specificity of head-up tilt testing for vasovagal syncope in elderly patients

Prolonged head-up tilt is increasingly used as a diagnostic test for vasovagal syncope. Its sensitivity is reported to increase with the concurrent administration of intravenous isoprenaline. False-positive responses are common in young controls particularly following intravascular instrumentation. We studied the influence of intravenous cannulation alone on responses to head-up tilt in ten healthy elderly subjects. All remained asymptomatic during tilt when non-cannulated whilst five developed symptomatic hypotension following cannulation. Thus, intravascular instrumentation influences responses to held-up tilt in elderly subjects; the significance of positive responses obtained using intravenous isoprenaline in this age group requires further evaluation.

Vasodepressor reactions after orthotopic cardiac transplantation: relationship to reinnervation status

Ventricular vagal nerve endings are thought to trigger vasodepressor syncope. Reports of vasodepressor reactions associated with donor bradycardia after cardiac transplantation have led to speculation that vagal reinnervation occurs. We assessed reinnervation status in seven patients 23-36 months (median 24 months) post-transplantation. Heart rate responses to vagal manoeuvres (respiration, Valsalva) and sympathetic stimuli (exercise and injection of tyramine into the coronary artery supplying the sinus node) were measured. All patients underwent 60 min of 60 degrees head-up tilt with foot plate support. During tilt four of the seven had vasodepressor reactions with a fall in mean arterial pressure of 20-90 mmHg. During vasodepression two patients had falls in donor heart rate of 13 and 40% relative to peak heart rate during tilt. These two patients had evidence of functional sympathetic reinnervation. By contrast the two patients without donor bradycardia during vasodepression had only limited or no evidence of sympathetic reinnervation. No patient had consistent evidence of parasympathetic reinnervation as judged by the heart rate response to vagal manoeuvres. Head-up tilt can thus produce vasodepressor reactions with donor bradycardia after cardiac transplantation in the absence of consistent evidence of vagal reinnervation. Left ventricular nerve endings may not be the only mediators of tilt-induced vasodepressor reactions in man. Donor bradycardia during vasodepression may reflect sympathetic withdrawal and not vagal reinnervation.

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.

Heart rate and blood pressure responses to carotid sinus massage in healthy elderly subjects

The purpose of the study was to define heart rate and blood pressure responses to supine and upright carotid sinus massage in healthy elderly subjects and thus to establish the validity of current diagnostic criteria for carotid sinus syndrome in this age group. Twenty-five healthy asymptomatic subjects (61-87 years) had carotid sinus massage carried out following a standardized technique employing previously defined criteria for abnormal heart rate and blood pressure responses: 3 s asystole and a 50 mmHg fall in systolic blood pressure independent of any heart rate slowing (after intravenous atropine). No cardioinhibitory responses of greater than 3 s were documented. The mean maximal cardioinhibitory response was 1038 +/- 195 msec. Right-sided responses were more marked than left when upright (1040 +/- 202 vs. 946 +/- 135 msec; p < 0.01) but not when supine (1094 +/- 215 vs. 1073 +/- 194 msec; NS). After atropine three subjects (12%) had a significant vasodepressor response when upright, but none when supine. The mean maximal vasodepressor response was 21 +/- 14 mmHg. Right-sided blood pressure responses were more marked than left (p < 0.01). There was no fixed relationship between maximum heart rate slowing and the degree of vasodepression during massage (range 2-80 msec/mmHg). The diagnostic criteria for heart rate and blood pressure responses in carotid sinus syndrome are appropriate for supine carotid sinus massage in elderly subjects. Asymptomatic vasodepressor responses occur in a small proportion of healthy elderly when upright.

Comparison of clock drawing with Mini Mental State Examination as a screening test in elderly acute hospital admissions

Clock drawing is a quick, easy to remember test that is well received by patients. It is a good screening test for Alzheimer's disease in the outpatient setting. We evaluated its usefulness compared with the standard Mini Mental State Examination (MMSE) in elderly acute medical and surgical hospital admissions. Within 48 hours of admission, 117 patients over 70 years old were administered the MMSE and asked to draw a clock. Using the MMSE as the standard, clock drawing had a sensitivity of 77% and a specificity of 87%. Patients with discrepant scores were then further evaluated. The findings suggest that normal clock drawing ability reasonably excludes cognitive impairment or other causes of an abnormal MMSE in elderly acute medical and surgical hospital admissions, where cognitive impairment is common and frequently missed.

Clinical characteristics of vasodepressor, cardioinhibitory, and mixed carotid sinus syndrome in the elderly

PURPOSE

Carotid sinus syndrome (CSS) is frequently overlooked as a cause of syncope in the elderly. It is diagnosed when carotid sinus massage (CSM) produces asystole exceeding 3 seconds (cardioinhibitory CSS), a reduction in systolic blood pressure exceeding 50 mm Hg independent of heart rate slowing (vasodepressor CSS), or a combination of the two (mixed CSS). Most published data pertain to the cardioinhibitory subtype. The recent availability of noninvasive phasic blood pressure monitoring has allowed accurate routine assessment of the vasodepressor response to CSM. The aim of this study was to assess the clinical characteristics of vasodepressor, cardioinhibitory, and mixed CSS.

PATIENTS AND METHODS

CSM was carried out on 132 consecutive patients over 65 years referred for investigation of dizziness, falls, or syncope. Massage was performed both supine and upright with continuous electrocardiographic and phasic blood pressure monitoring. Patients exhibiting greater than 1.5-second asystole were given 600 micrograms of intravenous atropine to abolish heart rate slowing and allow assessment of the pure vasodepressor response.

RESULTS

Carotid sinus hypersensitivity was documented in 64 patients (mean age 81 +/- 7 years, 31 male). The response was vasodepressor in 37%, cardioinhibitory in 29%, and mixed in 34%. Thirty-six patients had recurrent syncope, 17 presented with unexplained falls, and the remainder had dizziness alone. Symptoms had been present for a median of 24 months, and the median number of syncopal episodes was four. Twenty-five percent had sustained a fracture and, of these, 93% had not experienced a prodrome. Head movement precipitated symptoms in 47% and vagal stimuli in 73%. Episodes were unwitnessed in two thirds of patients. Twelve patients who presented with falls denied syncope but had witnessed loss of consciousness during CSM. Mean cardioinhibition was 5 +/- 2 seconds and mean vasodepression 61 +/- 9 mm Hg. The blood pressure nadir occurred rapidly at 18 +/- 3 seconds after massage, and baseline values were regained at 30 +/- 6 seconds. The clinical characteristics of patients with vasodepressor, cardioinhibitory, and mixed responses were similar.

CONCLUSION

CSS is an underdiagnosed cause of dizziness, falls, and syncope in the elderly. The vasodepressor form occurs more frequently than previously reported and has clinical characteristics similar to those of the cardioinhibitory and mixed subtypes. Elderly patients with this condition may deny syncope and present with recurrent unexplained falls. CSM, ideally with noninvasive phasic blood pressure monitoring, should be routinely performed in elderly patients with unexplained bradycardic or hypotensive symptoms.

Non-starch polysaccharide/dietary fibre supplementation using small meals in long-stay frail elderly patients

Small meals of high non-starch polysaccharide (NSP)/dietary fibre cakes were offered to clinically stable continuing-care elderly patients, replacing the standard provision of low NSP/dietary fibre commercial cakes in an attempt to improve their well being. The study design was comprised of a 4 week control period, a 4 week intervention period, when modified cakes were offered, and finally a second 4 week control period. During intervention, an additional 33% NSP or 23% dietary fibre was offered, but only 7.7% and between 3.5% and 5.6% were consumed, respectively. Anthropometric measurements and bowel frequency did not change throughout the study but a decrease in aperient use was noted. From this study it was concluded that more comprehensive changes in food provision are required to achieve the current recommended consumption of NSP/dietary fibre in continuing-care elderly patients.