Role of amiodarone in reducing atrial fibrillation after cardiac surgery in adults

Atrial fibrillation is a common occurrence after cardiac surgery and the source of financial expenditure and complications. A critical literature review was undertaken to examine the use of amiodarone therapy to prevent or manage atrial fibrillation after cardiac surgery. Evidence strongly suggests that perioperative treatment of cardiac patients with amiodarone may reduce the incidence of atrial fibrillation with minimal adverse effects. Further study is warranted to determine the optimal timing and dosing, for the drug's most cost-effective use.     

Measuring the functional status of patients in clinical trials using modern clinimetric methods

In clinical medicine numerous measurement instruments have been developed to assess the functional outcome of patients in clinical trials. The majority are questionnaires with multiple-choice items. The responses of the patients are used to calculate a sum score. However, there are some disadvantages associated with the use of sum scores. Modern clinimetric methods, based on item response theory (IRT) in combination with a calibrated item bank, can overcome these problems. When using this measurement technique, it is possible to arrange both the item difficulty and the patient's ability on a single, hierarchical linear scale. This allows the user to obtain a sufficiently detailed clinical picture using a small number of items. In addition to being efficient, this method makes it possible to present different sets of items to different groups of patients. Since all of the items are calibrated, the measurements remain comparable. The application of this innovative method of measuring is being studied in the ongoing 'Amsterdam linear disability score' (ALDS) project.     

Selective impairments in spatial memory after ischaemic stroke

There is evidence that object-location memory consists of three separate processes, that is, positional memory, binding of objects to locations, and a possible integration mechanism. A group of 26 patients with lesions following ischaemic stroke was studied to find evidence for selective impairments in these three processes using displays with pictures of everyday objects on different locations. Moreover, object-recognition memory and visuospatial construction was assessed. The Corsi Block-Tapping Task and Oxford Stylus Maze Test were included as standard spatial-memory tests. The results showed that of these 26 patients, 8 patients had selective impairments in the aforementioned object-location memory task conditions (both after immediate and delayed testing). These data further support the existence of separate cognitive processes within memory for object locations that can be selectively affected by cerebral dysfunction.     

Modulation of event-related potentials by prototypical and atypical faces

High-density event-related potentials (HD-ERPs) were recorded while adults passively viewed colour images of faces that artificially (Experiment I) or naturally (Experiment II) differed in configuration. In Experiment I, altering features of faces to make them less typical and less attractive did not affect the amplitude of N170, but did affect the amplitude of P1 and P2. In Experiment II, the P1 and N170 were larger for unattractive and atypical faces compared with attractive and typical faces, in the absence of P2 effects. The results show for the first time that variations in facial configuration modulate ERP activity as early as P1, but that modulation of later latency components depends on the nature of the stimuli and implicit task demands.     

Contractile properties and fatigue of quadriceps muscles in multiple sclerosis

Functional characteristics of electrically stimulated quadriceps muscles of patients with multiple sclerosis (MS) were determined to investigate whether adaptations in muscle properties contribute to the higher fatigability of these patients. The estimated maximal isometric force generating capacity of MS patients was only 11.2% (P < 0.05) lower than control subjects. However, the patients were only able to voluntarily exert 75 +/- 22% (n = 12) of their maximal capacity, against 94 +/- 6% (n = 7) for the control subjects. There were no differences in muscle speed, suggesting that muscle fiber distribution was not different in the MS patients due to reduced muscle usage. During a series of repeated contractions, greater decrements occurred in isometric force and in maximal rate of force rise in the MS patients (by 31.3 +/- 10.3% and 50.1 +/- 10.0%, respectively; n = 13) than control subjects (23.8 +/- 6.6% and 39.0 +/- 8.1%, n = 15), suggesting a lower oxidative capacity. The results indicate that increasing the mass of their muscles by training may help to reduce the excessive muscle fatigue of MS patients.     

Cerebral microbleeds in CADASIL

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary arteriopathy leading to recurrent cerebral infarcts and dementia. Intracerebral hemorrhage (ICH) has been described sporadically in patients with CADASIL, suggesting that the affected arteries in CADASIL are not bleed-prone. However, the presence of cerebral microbleeds, which often remain undetected on conventional MRI, has not been determined in CADASIL. OBJECTIVE: To determine whether cerebral vessels in patients with CADASIL are prone to microbleeding. METHODS: T2*-weighted gradient echo MRI, which is highly sensitive for visualizing microbleeds, was performed in patients with CADASIL and their family members (n = 63). Known risk factors for ICH were determined for all individuals. On an exploratory basis, the presence of cerebral microbleeds was correlated with demographic variables, vascular risk factors, disease progression, ischemic MR lesions, and genotype. RESULTS: Cerebral microbleeds were present in 31% of symptomatic CADASIL mutation carriers, predominantly in the thalamus. Vascular risk factors such as hypertension did not account for the microbleeds in these patients. Factors associated with microbleeds were age (p = 0.008), Rankin disability score (p = 0.017), antiplatelet use (p = 0.025), number of lacunae on MRI (p = 0.009), and the Arg153Cys Notch3 mutation (p = 0.017). After correction for age, only the Arg153Cys mutation remained significantly associated with the presence of microbleeds. CONCLUSION: Patients with CADASIL have an age-related increased risk of intracerebral microbleeds. This implies that they may have an increased risk for ICH, which should be taken into account in CADASIL diagnosis and patient management.