Sideris D A, Toumanidis S T, Thodorakis M, Kostopoulos K, Tselepatiotis E, Langoura C, Stringli T, Moulopoulos S D
Department of Clinical Therapeutics, Medical School of Athens University, Greece.
Eur Heart J. 1994 Nov;15(11):1585-9. doi: 10.1093/oxfordjournals.eurheartj.a060433.
In order to investigate the effect of atrial pressure on the propensity of the atria to fibrillate and the mechanism of this association, the right atrial pressure was changed acutely by transfusion-bleeding in 12 anaesthetized open-chest dogs. Under various atrial pressures the conduction time was measured between two pairs of hook electrodes positioned on the two atrial appendages respectively. The effective refractory period was measured by continuous pacing of the right atrium at a 250 ms cycle length at double threshold intensity and interpolating a progressively earlier stimulus after each eighth paced beat. The propensity of fibrillation was studied by rapid (450 min-1) pacing of the atria at double threshold intensity for 10 s at different atrial pressures. At a high (> or = 14 mmHg) atrial pressure the conduction time (45.7 +/- 14.2 ms) was significantly (P < 0.01) longer, the effective refractory period (157.9 +/- 15.2 ms) significantly (P < 0.01) longer and the atrial fibrillation (11/19 or 57.9%) significantly (chi 2 = 9.95, P < 0.001) more common than at a low (< or = 10 mmHg) pressure (35.2 +/- 11.6, 146.2 +/- 12.4, 3/24 or 12.5%, respectively). Analysis of variance showed that the probability of atrial fibrillation was significantly affected by the atrial pressure but not by either the conduction time or the effective refractory period. The findings suggest that an increase in right atrial pressure by acute volume overload prolongs the inter-atrial conduction time and right atrial refractoriness and increases the propensity of the atria to fibrillate by rapid atrial stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
为了研究心房压力对心房颤动倾向的影响及其相关机制,通过对12只麻醉开胸犬进行输血 - 放血操作来急性改变右心房压力。在不同的心房压力下,测量分别置于两个心耳上的两对钩状电极之间的传导时间。通过以250毫秒的周期长度、双倍阈值强度持续起搏右心房,并在每第八次起搏搏动后插入一个逐渐提前的刺激来测量有效不应期。在不同心房压力下,以双倍阈值强度对心房进行快速(450次/分钟)起搏10秒,研究颤动倾向。在高(≥14 mmHg)心房压力下,传导时间(45.7±14.2毫秒)显著(P<0.01)延长,有效不应期(157.9±15.2毫秒)显著(P<0.01)延长,心房颤动(11/19或57.9%)显著(χ2 = 9.95,P<0.001)比低(≤10 mmHg)压力时(分别为35.2±11.6、146.2±12.4、3/24或12.5%)更常见。方差分析表明,心房颤动的概率受心房压力显著影响,但不受传导时间或有效不应期影响。研究结果表明,急性容量超负荷导致的右心房压力升高会延长心房间传导时间和右心房不应期,并通过快速心房刺激增加心房颤动的倾向。(摘要截短于250字)