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  • 1
    Electronic Resource
    Electronic Resource
    Role of Compact Node and Posterior Extension in Direction-Dependent Changes in Atrioventricular Nodal Function in Rabbit (2003)
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 14 (2003), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: AV nodal conduction properties differ in the anterograde versus the retrograde direction. The underlying substrate remains unclear. We propose that direction-dependent changes in AV nodal function are the net result of those occurring in the slow and fast pathways. Methods and Results: Anterograde and retrograde AV nodal properties were determined with a premature protocol before and after posterior extension (slow pathway) ablation, and before and after upper compact node (fast pathway) ablation. Each ablation was performed in a different group of six rabbit heart preparations. In control, nodal minimum conduction time (NCTmin) and effective refractory period (ERPN) typically were longer, and maximum conduction time (NCTmax) was shorter in the retrograde compared to the anterograde direction. Posterior extension ablation prolonged anterograde ERPN from 91 ± 10 ms to 141 ± 15 ms (P 〈 0.01) and shortened NCTmax from 150 ± 13 ms to 82 ± 7 ms (P 〈 0.01) but did not affect retrograde conduction. Thus, the posterior extension normally contributes to the anterograde but not retrograde recovery curve. Compact node ablation prolonged anterograde conduction (NCTmin increased from 57 ± 2 ms to 73 ± 7 ms, P 〈 0.01) but did not alter ERPN and NCTmax. This ablation abolished retrograde conduction in two preparations and resulted in retrograde slow pathway conduction in four, the latter being interrupted by posterior extension ablation. Thus, the compact node accounts for the baseline of the recovery curve in both directions. Ablation of the compact node results in anterograde slow pathway conduction over the entire cycle length range and may result in retrograde slow pathway conduction. Conclusion: Direction-dependent properties of the AV node arise from those of the compact node-based fast pathway and posterior extension-based slow pathway. Normal AV node has bidirectional dual pathways. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1342-1350, December 2003)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2003.03382.x
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  • 2
    Electronic Resource
    Electronic Resource
    Properties and Substrate of Slow Pathway Exposed with a Compact Node Targeted Fast Pathway Ablation in Rabbit Atrioventricular Node (2001)
    Oxford, UK : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 12 (2001), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Selective Slow Nodal Pathway Model. Introduction: The properties and substrates of slow and fast AV nodal pathway remain unclear. This applies particularly to the slow pathway (SP), which is largely concealed by fast pathway (FP) conduction. We designed a new FP ablation approach that exposes the SP over the entire cycle length range and allows for its independent characterization and ablation. Methods and Results: Premature stimulation was performed before and after FP ablation with 5.4 ± 1.9 lesions (300-μm diameter each; overall lesion size 1.4 ± 0.5 mm) targeting the junction between perinodal and compact node tissues in seven rabbit heart preparations. The resulting SP recovery curve and control curve had the same maximum nodal conduction time (165 ± 22 msec vs 164 ± 24 msec; P = NS) and effective refractory period (101 ± 10 msec vs 100 ± 9 msec; P = NS). The two curves covered the same cycle length range. However, the SP curve was shifted up with respect to control one at intermediate and long cycle lengths and thus showed a longer minimum nodal conduction time (81 ± 15 msec vs 66 ± 10 msec; P 〈 0.01) and functional refractory period (180 ± 11 msec vs 170 ± 12 msec; P 〈 0.05). The SP curve was continuous and closely fitted by a single exponential function. Small local lesions (2 ± 1) applied to the posterior nodal extension resulted in third-degree nodal block in all preparations. Conclusion: The posterior nodal extension can sustain effective atrial-His conduction at all cycle lengths and account for both the manifest and concealed portion of SP. Slow and FP conduction primarily arise from the posterior extension and compact node, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2001.00479.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of blind substitution of aspartame-sweetened for sugar-sweetened soft drinks on appetite and mood (1998)
    Bradford : Emerald
    British food journal 100 (1998), S. 254-259 
    Details
    ISSN: 0007-070X
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: It has been suggested that habitual consumers of sugar experience "cravings" when deprived. Subjects (n = 27) who habitually consumed sugar-sweetened drinks were placed on a seven-day regime receiving either sugar-sweetened drinks, or aspartame-sweetened alternatives. A between-subjects design was used to prevent subjects comparing the drinks, which were given blind with the cover story that the study was testing a new drink. In fact commercial carbonated beverages were given. At the end, subjects were unable to guess which they had received. Subjects completed a prospective food diary and rated mood daily using the Profile of Mood States, as well as before and after each test drink, using simple visual analogue scales. Compared to subsequent days, on the first day of the study subjects receiving aspartame-sweetened drinks ate fewer grams of carbohydrate and had fewer sugar episodes (where sugars, or sugar-fat, or sugar-alcohol mixtures were consumed). Overall energy intake for the day was unaffected. By day two, there were no differences between the groups in diet or mood. Body weight at seven days was unaltered from baseline. Blind substitution of aspartame-sweetened for sugar-sweetened soft drinks did not increase other sugar consumption and did not adversely affect mood. Any effects of this dietary change appear transient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00070709810221508
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    Paper (German National Licenses)
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