Upright tilt-table testing in patients with syncope.
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Humans↗
Biomedical subjects
R A Kenny
Publications and source records attributed to R A Kenny.
Carotid sinus syndrome--clinical characteristics in elderly patients.
Carotid sinus massage was carried out on 130 consecutive patients referred for investigation of dizziness, syncope or unexplained falls. Carotid sinus syndrome was diagnosed in 33 for whom no other cause of symptoms was identified. Right-sided hypersensitivity was more frequent than left-sided. Thirty per cent identified a prodrome before syncope and 30% had retrograde amnesia for the event. In 52%, symptoms were precipitated by head movement and in 48% by vagal stimuli. Seven described 'drop attacks' but symptoms were reproduced with carotid sinus massage during head-up tilt. Injuries, including fractured neck of femur, were sustained by the majority. Carotid sinus massage should be performed routinely on all elderly patients who have symptoms of unexplained dizziness, falls or syncope. Cardiac pacing relieves syncopal symptoms in those with a predominant cardio-inhibitory response and recurrent syncope.
Aged↗
The incidence of malignant vasovagal syndrome in patients with recurrent syncope.
We reviewed 322 patients with recurrent syncope between 1984 and 1988. Investigation included limited intracardiac electrophysiological study in all cases with programmed extra-stimulus studies in 48 cases. In 93 patients (29%), all investigations were normal, (including negative extrastimulus in 30). In the other 229 cases syncope was explained by AV-block (n = 111, 34%), sinus node disease (n = 68, 21%), carotid sinus syndrome (n = 32, 10%) and inducible sustained tachyarrhythmia (n = 18, 6%). Prolonged 60 degrees head-up tilt was performed in 71 out of 93 patients with unexplained syncope, and reproduced vasovagal syncope and presenting symptoms in 53 (75%), or 16% of the whole population reported. These patients were diagnosed as having malignant vasovagal syndrome. Positive tilts were significantly less common in a group of 27 subjects of similar age without a history of syncope (7%), and a random sample of 37 patients with atrioventricular block (n = 16), sick sinus syndrome (n = 18) and inducible tachyarrhythmia (n = 3), (19%, 11% and 0% respectively, P less than 0.01). From this retrospective review it appears, therefore, that tilt testing is a valuable provocative tool for vasovagal syncope and may reduce the number of syncopal patients that remain undiagnosed, although these early observations do not allow an exact appraisal of the sensitivity and specificity of the tilt test.
Arrhythmias, Cardiac↗
Carotid sinus massage in carotid sinus syndrome.
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Aged↗
Benefits of dual chamber pacing in sick sinus syndrome.
The effects of DDD (fully automatic) and VVI (ventricular demand) pacing modes on exercise tolerance, symptom diary cards, and Holter monitoring were investigated in a randomised double blind crossover study of 16 patients who had had DDD pacemakers implanted because of frequent syncope. Eight patients presented with sick sinus syndrome and, with one exception, retrograde atrioventricular conduction and eight age and sex matched patients presented with 2:1 or complete atrioventricular block. Maximal symptom limited exercise in those with atrioventricular block was significantly higher after one month of DDD pacing than after VVI pacing. In those with sick sinus syndrome, however, maximal effort tolerance was not significantly different for the two pacing modes. In all but one patient with sick sinus syndrome sinus rhythm developed during exercise in VVI pacing. For both VVI and DDD modes maximal atrial rates were significantly lower in those with sick sinus syndrome. Palpitation and general wellbeing were significantly improved during DDD pacing in the eight patients with sick sinus syndrome. Shortness of breath was improved by DDD pacing in the eight patients with atrioventricular block but not in those with sick sinus syndrome. Holter monitoring showed that sick sinus syndrome patients remained in paced rhythm, either DDD or VVI, for most of the 24 hour period. DDD pacing was better than VVI pacing in sick sinus syndrome with retrograde atrioventricular conduction. Despite their ability to show sinus rhythm and inhibit their pacemakers on exercise patients with sick sinus syndrome are just as likely to have symptomatic benefit from DDD pacing as patients with atrioventricular block.
Adult↗
Reduced plasma renin activity in elderly subjects in response to vasovagal hypotension and head-up tilt.
The sympathoadrenal and renin-angiotensin systems play an important role in the cardiovascular responses induced by head-up tilt. In young people, hypotension and postural changes induced by tilt produce significant increases in plasma renin activity. The response of plasma renin activity to prolonged tilt and subsequent vasovagal hypotension has not been assessed in the elderly. Seventeen elderly subjects (10 with carotid sinus syndrome and seven age-matched controls) were studied during 45 minutes of recumbency and 120 minutes of head-up tilt to 40 degrees. Intra-arterial systolic blood pressure and heart rate were monitored continuously and plasma renin activity was measured at frequent intervals. Ten subjects developed vasovagal syncope during tilt (at 32 +/- 18 min). Systolic blood pressure and heart rate fell by 70 +/- 20 mmHg and 20 +/- 7 beats . min-1 (P less than 0.001 and P less than 0.01, respectively). Plasma renin activity did not change in syncopal subjects and remained unchanged up to 60 min after syncope. In seven subjects who completed 120 min of tilt without symptoms, heart rate rose during tilt but plasma renin activity remained unchanged. Plasma renin activity is not influenced by marked hypotension or prolonged head-up tilt in the elderly.
Aged↗
Enhanced vagal activity and normal arginine vasopressin response in carotid sinus syndrome: implications for a central abnormality in carotid sinus hypersensitivity.
The relation between arginine vasopressin and vagal activity in carotid sinus syndrome was studied in 10 patients and 17 age matched controls using head up tilt as a stimulus. Of the controls, seven had unexplained syncope and 10 were healthy elderly subjects with no previous history of syncope. Subjects were studied supine for 45 min and thereafter during 120 min head up tilt to 40 degrees. Phasic arterial pressure and heart rate were monitored throughout. Serum was sampled at frequent intervals to measure arginine vasopressin, noradrenaline, and adrenaline concentrations. Seventy per cent of carotid sinus patients had vasovagal syncope at (mean(SD)) 25(4) min after tilt compared with 43% of subjects with unexplained syncope and one healthy elderly control. The maximum (mean(SD)) fall in systolic blood pressure and heart rate was 70(20) mmHg and 20(7) beats.min-1 (p less than 0.001 and p less than 0.01 respectively). Arginine vasopressin, noradrenaline, and adrenaline concentrations rose significantly in syncopal subjects (p less than 0.001, p less than 0.01, and p less than 0.05 respectively). Changes in systolic blood pressure, heart rate, and hormone concentrations were similar for patients with carotid sinus syndrome and control subjects. For those who completed the tilt period without the development of symptoms, systolic blood pressure and arginine vasopressin and adrenaline concentrations were unchanged, whereas noradrenaline concentrations and heart rate rose significantly. Vasovagal activity is thus appreciably increased in carotid sinus syndrome. Furthermore, the afferent limb of the carotid sinus reflex appears to be intact in patients with carotid sinus syndrome since the pattern of arginine vasopressin release was not different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Head-up tilt: a useful test for investigating unexplained syncope.
Head-up tilt, a recognised stimulus to vasovagal syncope, was used to investigate syncope that remained unexplained despite full clinical and electrophysiological assessment in fifteen patients, mean age 65 +/- 10 years, who had had 15 +/- 19 episodes of unexplained syncope over periods of a week to 26 years. After overnight fast systolic blood pressure and heart rate were continuously monitored during 40 degrees head-up tilt for 60 min. Ten control subjects with no history of syncope were studied similarly. In ten patients (67%) and one control vasovagal syncope developed after 29 +/- 19 min (p less than 0.001). In symptomatic patients systolic blood pressure fell from 150 +/- 32 to 56 +/- 9 mm Hg (p less than 0.001) and heart rate from 62 +/- 9 to 38 +/- 12 beats per min (p less than 0.01). In each case symptoms during the test reproduced those previously experienced. No clinical findings predicted development of syncope during tilt. Baseline systolic blood pressure and heart rate did not differ significantly between patients and controls. Pacemakers were implanted in seven patients who have remained symptom-free since implant (follow-up 10 +/- 3 mo).
Aged↗
The natural history of sick sinus syndrome.
A literature review has addressed the two major factors in disease progression in sick sinus syndrome: atrioventricular block and atrial fibrillation. An incidence of atrioventricular block of 8.4 percent in a follow-up period of 34.2 months is considered clinically significant and sufficient to justify use of a ventricular lead in pacemaker management. Atrial fibrillation occurs much more commonly (22.3%) in ventricular pacing than with atrial demand pacing (3.9%) in a 2 1/2 year observation period. Coincident with the reduction in arrhythmia achieved by atrial demand pacing is a significant reduction in systemic embolism (1.6% vs. 13%). This is considered largely to be due to the improved rhythm control with AAI pacing but also possibly to the avoidance of retrograde atrioventricular conduction. The benefits of AAI pacing in terms of mortality in sick sinus syndrome have not yet been fully assessed. In the future, DDI pacing is recommended with, in some patients, the addition of another sensor to provide rate responsiveness on exercise.
Atrial Fibrillation↗
Optimum pacing mode for patients with angina pectoris.
A within patient double blind prospective study of symptoms and exercise tolerance was designed to determine the preferred pacing mode in 10 patients with programmable dual chamber pacemakers who also had angina pectoris. Patients were randomly allocated to one month in each of the following modes: ventricular pacing at 70 beats/min (VVI) or atrioventricular synchronous upper rate 150 beats/min (DDD 150) or 100 beats/min (DDD 100). Medications were unchanged throughout the study; none was taking beta blockers. At the end of each month patients underwent an exercise test. During each month patients recorded symptoms and their preferred pacing mode. DDD 100 was the preferred mode (seven patients). There was significantly less chest pain with this mode than with either of the other modes. There were significantly more episodes of dizziness in VVI, and two patients who developed pacemaker syndrome were unable to complete the pacing period. Three patients developed angina during exercise testing in DDD 150. Atrial synchronous ventricular pacing is better than ventricular pacing for the control of symptoms in patients with angina pectoris provided that the upper atrial tracking rate is limited.
Aged↗
A comparison of the erythrocyte sedimentation rate and serum C-reactive protein concentration in elderly patients.
Fifty-five consecutive admissions to an acute geriatric unit were studied prospectively. Individuals were classified according to the obvious presence or absence of an active disease process on admission and their serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were measured then and five days later. There was no significant difference between the ESR values in the two groups either on admission or at day 5, nor was there any significant change between admission and day 5. In contrast, CRP values were very significantly higher in the active than in the non-active group and there were marked changes over the 5-day period corresponding to changes in clinical condition. These results indicate that the serum CRP concentration is superior to the ESR as an objective, non-specific marker for disease activity in the elderly.
Aged↗
A prospective study between carbamazepine, phenytoin and sodium valproate as monotherapy in previously untreated and recently diagnosed patients with epilepsy.
One hundred and eighty one patients with previously untreated epilepsy were randomised to sodium valproate, phenytoin or carbamazepine as monotherapy and followed up for a median period which ranged from 14 to 24 months. All three drugs were highly effective in the control of generalised seizures but less effective for partial seizures. Excellent or good control was achieved with therapeutic levels of sodium valproate and carbamazepine, but with subtherapeutic levels of phenytoin.
Adolescent↗
The prolonged QT interval--a frequently unrecognized abnormality.
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Aged↗