Hardman S M, Noble M I, Seed W A
Academic Unit of Cardiovascular Medicine, Charing Cross and Westminster Medical School, London.
Circulation. 1992 Oct;86(4):1223-32. doi: 10.1161/01.cir.86.4.1223.
Beat-to-beat variations in the pulse during atrial fibrillation (AF) have conventionally been attributed to time-dependent changes in filling. We have explored the possibility that they are dependent on the intrinsic myocardial interval force relation.
Left ventricular (LV) contractility (maximum rate of rise of pressure, LV dP/dtmax) and ascending aortic blood velocity were measured during cardiac catheterization in 15 patients with AF. Beats preceded by an interval of less than 500 msec were excluded from analysis to reduce the confounding influence of incomplete mechanical restitution. The LV dP/dtmax was then related to the prepreceding interval. An inverse relation consistent with postextrasystolic potentiation was obtained in all 15 patients (Spearman's rank correlations, -0.56 to -0.86; p less than or equal to 0.0001). This relation was confirmed in three patients during pacing that overrode the AF and introduced single-interval variations into steady-state pacing. The ECG sequences from six of the AF patients were used to drive isometrically contracting guinea pig papillary muscle and human right ventricular tissue (n = 7); the same inverse relation was demonstrated. On a beat-by-beat basis, the maximum rate of rise of force in the isolated muscle correlated well with LV dP/dtmax in the patients (r = 0.50-0.86, p less than or equal to 0.0001). The relation of the integral of aortic velocity (AVI, proportional to stroke volume) to prepreceding interval was also inverse, whereas important correlations were demonstrated between LV dP/dtmax and AVI (Spearman's rank correlations, 0.27-0.95; p less than or equal to 0.0001).
This study demonstrates that postextrasystolic potentiation contributes to the characteristic beat-to-beat variation of the pulse in AF.
心房颤动（AF）期间脉搏逐搏变化传统上归因于充盈的时间依赖性变化。我们探讨了它们依赖于心肌内在间期力关系的可能性。
在15例AF患者的心导管检查期间测量左心室（LV）收缩力（压力最大上升速率，LV dP/dtmax）和升主动脉血流速度。分析中排除了间期小于500毫秒的搏动，以减少不完全机械恢复的混杂影响。然后将LV dP/dtmax与前一个间期相关联。在所有15例患者中均获得了与早搏后增强一致的反比关系（Spearman等级相关系数，-0.56至-0.86；p≤0.0001）。在三名患者的起搏过程中证实了这种关系，该起搏过程抑制了AF并将单间期变化引入稳态起搏。使用6例AF患者的心电图序列驱动等长收缩的豚鼠乳头肌和人右心室组织（n = 7）；证实了相同的反比关系。在逐搏基础上，分离肌肉中的最大力上升速率与患者的LV dP/dtmax密切相关（r = 0.50 - 0.86，p≤0.0001）。主动脉速度积分（AVI，与每搏量成正比）与前一个间期的关系也是反比关系，而LV dP/dtmax与AVI之间显示出重要的相关性（Spearman等级相关系数，0.27 - 0.95；p≤0.0001）。
本研究表明早搏后增强有助于AF中脉搏的特征性逐搏变化。
