Quality of life and exercise performance in patients in sinus rhythm versus persistent atrial fibrillation: a Veterans Affairs Cooperative Studies Program Substudy.

OBJECTIVES: The purpose of this study was to determine quality of life (QOL) and exercise performance (EP) in patients with persistent atrial fibrillation (AF) converted to sinus rhythm (SR) compared with those remaining in or reverting to AF. BACKGROUND: Restoration of SR in patients with AF improving QOL and EP remains controversial. METHODS: Patients with persistent AF were randomized double-blind to amiodarone, sotalol, or placebo. Those not achieving SR at day 28 were cardioverted and classified into SR or AF groups at 8 weeks (n = 624) and 1 year (n = 556). The QOL (SF-36), symptom checklist (SCL), specific activity scale (SAS), AF severity scale (AFSS), and EP were assessed. RESULTS: Favorable changes were seen in SR patients at 8 weeks in physical functioning (p < 0.001), physical role limitations (p = 0.03), general health (p = 0.002), and vitality (p < 0.001), and at 1 year in general health (p = 0.007) and social functioning (p = 0.02). Changes in the scores for SCL severity (p = 0.01), functional capacity (p = 0.003), and AFSS symptom burden (p < 0.001) at 8 weeks and in SCL severity (p < 0.01) and AF symptom burden (p < 0.001) at 1 year showed significant improvements in SR versus AF. Symptomatic patients were more likely to have improvement. The EP in SR versus AF was greater from baseline to 8 weeks (p = 0.01) and to 1 year (p = 0.02). The EP correlated with physical functioning and functional capacity except in the AF group at 1 year. CONCLUSIONS: In patients with persistent AF, restoration and maintenance of SR was associated with improvements in QOL measures and EP. There was a strong correlation between QOL measures and EP.     

Diameters of the common carotid artery and aorta change in different directions during acute asphyxia in the fetal lamb

The aim of this experimental ultrasound study on six fetal lambs was to evaluate how blood flow variables and vessel diameters of the descending aorta and the common carotid artery change during fetal asphyxia in the acute preparation. When acute asphyxia was induced by obstructing the maternal aortic blood flow all fetuses reacted with significant decrease in the aortic diameter and blood flow. In the common carotid artery vessel diameter and the blood flow increased significantly. The results support the theory of a brain sparing effect during fetal distress with significant changes of blood vessel diameters occurring in opposite directions in the aorta and the common carotid artery, thereby contributing to the centralisation of circulation.     

Fetal cardiac arrhythmias: Doppler assessment

Pregnancies in which fetal cardiac arrhythmias are present are associated with an elevated perinatal and neonatal mortality. In this group various major and minor fetal malformations, including heart malformations, are more common. FECG and phonocardiogram give some information on the type of arrhythmia in favorable cases. Real-time imaging detects fetal heart malformations and late signs of heart failure. Fetal echocardiogram is of great aid for the classification of the arrhythmia and for the detection of heart malformations. By applying combined real-time linear array and pulsed Doppler technique in cases of fetal cardiac arrhythmia, important information on the fetal circulatory state can be obtained. Estimations of the volume blood flow guide the clinician in the practical handling of these cases. Volume blood-flow estimations can probably detect imminent fetal heart failure. Therapeutic effects can be followed, and the timing of delivery can be optimized taking the circulatory state into account. Within the fetal heart rate range 50 to 250 beats/min adequate blood circulation is usually maintained in the fetus. The peak velocity, the acceleration, and the rising slope are all increased in the postextrasystolic beat, indicating the existence of postextrasystolic potentiation in the fetal heart. These three parameters can be related to the ventricular filling time, supporting the opinion that the fetal heart follows the rules of the Frank Starling relationship. Fetal arrhythmias constitute also an experimental model for the study of fetal cardiac physiology.     

Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model

OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2.     

Vestibular contribution to combined arm and trunk motion

Recent studies have shown that the hand-pointing movements within arm's reach remain invariant whether the trunk is recruited or not or its motion is unexpectedly prevented. This suggests the presence of compensatory arm-trunk coordination minimizing the deflections of the hand from the intended trajectory. It has been postulated that vestibular signals elicited by the trunk motion and transmitted to the arm motor system play a major role in the compensation. One prediction of this hypothesis is that vestibular stimulation should influence arm posture and movement during reaching. It has been demonstrated that galvanic vestibular stimulation (GVS) can influence the direction of pointing movements when body motion is restrained. In the present study, we analyzed the effects of GVS on trunk-assisted pointing movements. Subjects either moved the hand to a target or maintained a steady-state posture near the target, while moving the trunk forward with the eyes closed. When GVS was applied, the final position of the hand was deviated in the lateral and sagittal direction in both tasks. This was the result of two independent effects: a deviation of the trunk trajectory and a modification of the arm position relative to the trunk. Thus, the vestibular system might be directly involved not only in the control of trunk motion but also in the arm-trunk coordination during trunk-assisted reaching movements. Electronic Publication