An analysis of referral patterns for dizziness in the primary care setting. (1/421)

BACKGROUND: The majority of balance disorders are non life-threatening and symptoms will resolve spontaneously. However, some patients require further investigation and many disorders may benefit from specialist treatment it is unclear whether appropriate identification and referral of this group of patients presently occurs. AIM: To review the management of patients with symptoms of dizziness within primary care. METHOD: A retrospective review of the management of 503 patients who visited their general practitioner (GP) complaining of dizziness between August 1993 and July 1995. Management was then compared with local criteria. RESULTS: On average, 2.2% of patients per year at the practices studied consulted their GP about dizziness, amounting to 0.7% of all consultations. The most common GP diagnosis was of an ear, nose, and throat (ENT) disorder (33.8%). Similarly, many of the 16% referred were directed to ENT (36%) specialists. The proportion of patients referred was significantly higher in those seeing their GP at least twice, those with symptoms lasting a year or more, or where there were additional symptoms associated with the dizziness, indicative of a cardiac, ENT, or neurological disorder. Compared with the local criteria, 17% of management decisions were deemed inappropriate. The major failing was not referring appropriate patients. This group comprised patients with chronic, non-urgent symptoms, and were significantly older than those appropriately referred. CONCLUSION: Patients with chronic symptoms of dizziness, particularly the elderly, are under-referred for specialist consultation and, therefore, do not have access to appropriate treatment regimes. This suggests a need for further training of GPs and evaluation of therapeutic needs of elderly dizzy patients.  (+info)

Combination of calcium channel blockers and beta-adrenoceptor blockers for patients with exercise-induced angina pectoris: a double-blind parallel-group comparison of different classes of calcium channel blockers. Netherlands Working Group on Cardiovascular Research (WCN). (2/421)

AIMS: The combination of calcium channel blockers and beta-adrenoceptor blockers is more effective for the treatment of exercise-induced angina pectoris than beta-adrenoceptor blocker monotherapy. As ischaemia in exercise-induced angina is preceded by increase in heart rate, calcium channel blockers with negative chronotropic properties may perform better for this purpose than nonchronotropic compounds. METHODS: A 335 patient double-blind parallel-group study comparing 14 day treatment with amlodipine 5 and 10 mg, with diltiazem 200 and 300 mg, and mibefradil 50 and 100 mg added to baseline beta-adrenoceptor blocker treatment was performed. Exercise testing (ETT) was performed by bicycle ergometry. RESULTS: Although none of the calcium channel blockers improved duration of exercise or amount of workload, all significantly delayed onset of 1 mm ST-segment depression on ETT (P<0.001 for any treatment vs baseline). In addition, mibefradil, both low and high dose treatment, produced the longest delays (low dose: different from diltiazem and amlodipine by 24.1 and 29.8 s, respectively, P<0. 003 and <0.001; high dose: different from diltiazem and amlodipine by 33.7 and 37.0 s, respectively, P<0.001 and <0.001). These effects were linearly correlated with the reduction in rate pressure product (RPP). Serious symptoms of dizziness occurred significantly more frequently on mibefradil (P<0.05), and 19 patients on mibefradil withdrew from trial. CONCLUSIONS: Calcium channel blockers with negative chronotropic properties provide greater delay of ischaemia in patients with exercise-induced angina, but the concomitant risk of intolerable dizziness attenuates this benefit.  (+info)

The influence of CYP2D6 activity on the kinetics of propafenone enantiomers in Chinese subjects. (3/421)

AIMS: To determine role of CYP2D6 activity in the pharmacokinetics of propafenone (PPF) enantiomers in native Chinese subjects. METHODS: Sixteen extensive metabolizers (EMs) and one poor metabolizer (PM), whose phenotype had been previously assessed with dextromethorphan metabolic phenotyping, were enrolled. Blood samples (0 approximately 15 h) were taken after oral administration of a single dose (400 mg) of racemic-propafenone hydrochloride. A reverse-phase h.p.l.c. method with pre-column derivatization was employed to quantitate enantiomeric concentrations of propafenone in plasma. RESULTS: For the EM subjects, S-PPF was less rapidly metabolized and had higher peak plasma concentrations than R-PPF (413+/-143 vs 291+/-109 ng ml-1, P<0.001). The AUC was markedly higher for S-PPF than for R-PPF (2214+/-776 vs 1639+/-630 microg h l-1, P<0.001), whereas the clearance of S-PPF was significantly lower than that of R-PPF (96.0+/-39.0 vs 138+/-78 l h-1, P<0.01). There were no differences in t1/2, and Cmax between the two isomers (P >0.05). In the one PM subject, not only did S-PPF appear to undergo less rapid metabolism than R-PPF, but the subject also showed 2 approximately 3 fold differences in Cmax, CL and AUC compared with EMs. The correlation coefficients (rs ) between dextromethorphan metabolic ratio (lg MR) and pharmacokinetic parameters (Cmax, CL and AUC) were 0.63, -0.87, 0.87 for S-PPF and 0. 57, -0.73, 0.86 for R-PPF, respectively. CONCLUSIONS: Our results suggest that CYP2D6 activity contributes to the pharmacokinetic variability of propafenone enantiomers in Chinese subjects.  (+info)

Outcome of symptoms of dizziness in a general practice community sample. (4/421)

BACKGROUND: Dizziness is commonly experienced in the community, but little is known about the long-term progression of the condition. OBJECTIVE: We aimed to assess over 18 months the outcome of symptoms of dizziness in a sample of patients identified from London general practices. METHOD: We followed up at 18 months a cohort of patients who reported symptoms of dizziness with or without anxiety, panic reactions or avoidance of situations that provoked the symptoms. The subjects completed a structured questionnaire both at baseline and at 18 months. RESULTS: At 18 months, 24% (95% CI = 23.5-34.8%) were more handicapped and 20% (95% CI = 15.2-25.2%) had recurrent dizziness, while 20% (95% CI = 14.9-24.8%) had improved. Patients with significant dizziness were more likely to consult their GP (OR = 14.4, 95% CI = 7.0-29.1) and were more likely to receive treatment (OR = 7.8, 95% CI = 3.2-22.4) or be referred to hospital (OR = 8.4, 95% CI = 3.2-22.4). The independent predictors of handicapping dizziness at 18 months were a history of fainting (OR = 2.4, 95% CI = 1.2-4.7), vertigo (OR = 2.6, 95% CI = 1.3-5.0) and avoidance of a situation that provoke dizziness (OR = 4.8, 95% CI = 2.5-9.0). CONCLUSION: Four per cent of all patients registered with a GP suffer persistent symptoms of dizziness and at least 3% are severely incapacitated by their symptoms. The presence of vertigo, fainting and avoidance in a person with dizziness is predictive of chronic handicapping dizziness. Further research is required on the progressions of symptoms of dizziness in a sample of GP attenders and those in the community.  (+info)

Effects of sibutramine alone and with alcohol on cognitive function in healthy volunteers. (5/421)

AIMS: To investigate the effects of sibutramine in combination with alcohol in a double-blind, randomised, placebo-controlled, four-way crossover study in 20 healthy volunteers. METHODS: On each study day each volunteer received either: sibutramine 20 mg+0.5 g kg-1 alcohol; sibutramine 20 mg+placebo alcohol; placebo capsules+0.5 g kg-1 alcohol; or placebo capsules+placebo alcohol. Alcohol was administered 2 h following ingestion of the study capsules. During each study day, assessments of cognitive performance were made prior to dosing, and at 3, 4.5, 6 and 10 h post dosing. Blood alcohol concentration was estimated using a breath alcometer immediately prior to each cognitive performance test session. Each study day was followed by a minimum 7 day washout period. RESULTS: Alcohol was found to produce statistically significant impairments in tests of attention (maximum impairment to speed of digit vigilance=49 ms) and episodic memory (maximum impairment to speed of word recognition=74 ms). Alcohol also increased body sway (maximum increase 17.4 units) and lowered self rated alertness (maximum decrease 13.6 mm). These effects were produced by an inferred blood alcohol level of 53.2 mg dl-1. Sibutramine was not found to potentiate any of the effects of alcohol. There was a small, yet statistically significant, interaction effect observed on the sensitivity index of the picture recognition task. In this test, the combined effects of sibutramine and alcohol were smaller than the impairments produced by alcohol alone. Sibutramine, when dosed alone, was associated with improved performance on several tasks. Sibutramine improved attention (mean speed of digit vigilance improved by 21 ms), picture recognition speed (improvement at 3=81) and motor control (tracking error at 3 h reduced by 1.58 mm). Also sibutramine improved postural stability (reducing body sway at 3 h by 14.2 units). Adverse events reported were unremarkable and consistent with the known pharmacology of sibutramine and alcohol. CONCLUSIONS: There was little evidence of a clinically relevant interaction of sibutramine with the impairment of cognitive function produced by alcohol in healthy volunteers. The single statistically significant interaction indicated a reduction, rather than a worsening, of alcohol-induced impairment when sibutramine is taken concomitantly. Sibutramine when administered alone is associated with improved performance on several tasks.  (+info)

The work by the developing primary care team in China: a survey in two cities. (6/421)

BACKGROUND: China is in the process of converting its existing primary care resources into general practice. The infrastructure is different from that of many other countries. OBJECTIVES: We surveyed patients' reasons for encounter (RFE) and the health providers' diagnoses in the general practice clinics of two large northern cities in order to assess the nature of the work of these practices. METHOD: Practices whose staff had a short course of training in the theory and practice of the International Classification of Primary Care (ICPC) were recruited to document the RFE and diagnoses of patient encounters in two separate winter weeks. RESULTS: The practices dealt mainly with chronic illness in older patients. Hypertension-related problems were the most frequent diagnoses, followed by upper respiratory tract infection. Patients also consulted very frequently for dizziness. Overall, there was good agreement between RFE and diagnosis in some organ systems. CONCLUSION: In their present form, the Chinese practices surveyed were delivering the full range of general practice care to a self-selected age group of patients. The ICPC was very useful for monitoring the work of general practice from the perspective of both the patients and the providers.  (+info)

Effect of sleep restriction on orthostatic cardiovascular control in humans. (7/421)

We hypothesized that sleep restriction (4 consecutive nights, 4 h sleep/night) attenuates orthostatic tolerance. The effect of sleep restriction on cardiovascular responses to simulated orthostasis, arterial baroreflex gain, and heart rate variability was evaluated in 10 healthy volunteers. Arterial baroreflex gain was determined from heart rate responses to nitroprusside-phenylephrine injections, and orthostatic tolerance was tested via lower body negative pressure (LBNP). A Finapres device measured finger arterial pressure. No difference in baroreflex function, heart rate variability, or LBNP tolerance was observed with sleep restriction (P > 0.3). Systolic pressure was greater at -60 mmHg LBNP after sleep restriction than before sleep restriction (110 +/- 6 and 124 +/- 3 mmHg before and after sleep restriction, respectively, P = 0.038), whereas heart rate decreased (108 +/- 8 and 99 +/- 8 beats/min before and after sleep restriction, respectively, P = 0.028). These data demonstrate that sleep restriction produces subtle changes in cardiovascular responses to simulated orthostasis, but these changes do not compromise orthostatic tolerance.  (+info)

Capture and fusion beats during atrial fibrillation and ventricular tachycardia. (8/421)

Two patients were presented, and two previously unreported observations were made. Patient 1, a 50 year old man with episodic palpitations and dizziness for 10 years, exhibited initiation of idiopathic ventricular tachycardia (VT) by atrial fibrillation (AF). Patient 2, a 43 year old woman with a structurally normal heart but recurrent palpitations for one year, demonstrated fusion and capture beats during simultaneous VT and AF. An explanation is given as to why the latter phenomenon is rarely observed.  (+info)