Relationship of the fourth heart sound to atrial systolic transmitral flow deceleration.
Relationship of the fourth heart sound to atrial systolic transmitral flow deceleration.
复制标题
第四心音与心房收缩期二尖瓣血流减速的关系。
DOI：
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发表时间：
1997
影响因子：
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通讯作者：
S. Kovacs
中科院分区：
文献类型：
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作者：
A. M. McGuire;M. Hagley;A. Hall;S. Kovacs
第四心音 (S4) 被认为是由心血振动引起的，由二尖瓣血流减速驱动，当心房收缩导致心室舒张末期压力（相对于舒张）不成比例地升高时，会发生心血振动，与心房收缩期充血量增加或心室壁僵硬相关。为了表征 S4 的产生，我们将心血系统建模为强制阻尼非线性谐振子。强迫项使用多普勒 A 波轮廓的封闭式表达式。我们同时记录了有或没有可听 S4 的受试者的经胸心音图和多普勒 A 波，并将 S4 幅度、频率和功率谱的模型预测与记录的 S4 的模型预测进行了比较。模型预测的振幅、持续时间、时间和功率谱与心音图 S4 的振幅、持续时间、时间和功率谱之间观察到极好的一致性。我们的结论是，对于正常的二尖瓣，在 A 波减速期间心血系统应该始终存在振荡。然而，振荡可能没有足够高的幅度、频率或与胸壁的耦合，无法在临床上听到 S4 声。
The fourth heart sound (S4) is thought to be due to cardiohemic vibrations, powered by deceleration of transmitral blood flow, that occur when atrial systole leads to a disproportionately high rise in ventricular end-diastolic pressure (relative to diastasis), associated with an enhanced atrial systolic blood filling volume or a stiff ventricular wall. To characterize S4 production, we modeled the cardiohemic system as a forced, damped nonlinear harmonic oscillator. The forcing term used a closed-form expression for the Doppler A-wave contour. We simultaneously recorded transthoracic phonocardiograms and Doppler A waves in subjects with and without audible S4 and compared model predictions for S4 amplitude, frequency, and power spectrum with those of the recorded S4. Excellent agreement was observed between the model-predicted amplitude, duration, timing, and power spectrum and those of the phonocardiographic S4. We conclude that, with a normal mitral valve, there should always be an oscillation of the cardiohemic system during A-wave deceleration. However, oscillations may not have high enough amplitude, frequency, or coupling to the chest wall to be clinically audible as an S4.