Duration of diastole and its phases as a function of heart rate during supine bicycle exercise
Duration of diastole and its phases as a function of heart rate during supine bicycle exercise
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DOI：
10.1152/ajpheart.00404.2004
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发表时间：
2004-11-01
影响因子：
4.8
通讯作者：
Kovács, SJ
中科院分区：
文献类型：
--
作者：
Chung, CS;Karamanoglu, M;Kovács, SJ
舒张期的持续时间可以根据机械事件来定义。机械舒张持续时间 (MDD) 由早期快速充盈（E 波）、舒张期和晚期心房充盈（A 波）三个阶段组成。心率 (HR) 对舒张期持续时间的影响可以通过运动学模型和已知的细胞生理学来预测。为了确定每个阶段的 MDD 和速度时间积分 (VTI) 对 HR 的依赖性，在健康志愿者的仰卧自行车运动期间记录了同步经动脉多普勒血流速度和心电图。使用三角近似法测量 E 波和 A 波形状的持续时间、峰值和 VTI。 MDD 定义为从 E 波开始到 A 波结束的间隔，通过 MDD = BMDD + M-LMDD.HR + M-IMDD/HR 拟合为 HR 的代数函数，可从第一原理导出，其中 B-MDD 是常数，M-LMDD 和 M-IMDD 是线性和反 HR 相关项的常数系数。观察到极好的相关性（r(2) = 0.98）。研究发现，E 波和 A 波持续时间几乎与 HR 无关：HR 增加 100% 仅导致 E 波持续时间减少 18%，A 波持续时间减少 16%。同样，VTI 几乎独立于 HR。舒张期持续时间与 MDD 密切相关，是 HR 的函数。我们得出的结论是，消除分离以及几乎固定持续时间的 E 波和 A 波的合并主要控制 MDD 的变化。这些观察结果支持这样的观点：E 波和 A 波持续时间主要受机械振荡规则的控制，而机械振荡规则与 HR 的依赖性最小。
The duration of diastole can be defined in terms of mechanical events. Mechanical diastolic duration (MDD) is comprised by the phases of early rapid filling ( E wave), diastasis, and late atrial filling ( A wave). The effect of heart rate (HR) on diastolic duration is predictable from kinematic modeling and known cellular physiology. To determine the dependence of MDD of each phase and the velocity time integral (VTI) on HR, simultaneous transmitral Doppler flow velocities and ECG were recorded during supine bicycle exercise in healthy volunteers. Durations, peak values, and VTI using triangular approximation for E- and A-wave shape were measured. MDD, defined as the interval from the start of the E wave to end of the A wave, was fit as an algebraic function of HR by MDD = BMDD + M-LMDD.HR + M-IMDD/HR, derivable from first principles, where B-MDD is a constant, and M-LMDD and M-IMDD are the constant coefficients of the linear and inverse HR dependent terms. Excellent correlation was observed (r(2) = 0.98). E- and A-wave durations were found to be very nearly independent of HR: 100% increase in HR generated only an 18% decrease in E- wave duration and 16% decrease in A-wave duration. VTI was similarly very nearly independent of HR. Diastasis duration closely tracked MDD as a function of HR. We conclude that the elimination of diastasis and merging of E and A waves of nearly fixed durations primarily govern changes in MDD. These observations support the perspective that E- and A-wave durations are primarily governed by the rules of mechanical oscillation that are minimally HR dependent.