Grimm R A, Chandra S, Klein A L, Stewart W J, Black I W, Kidwell G A, Thomas J D
Department of Cardiology, Cleveland Clinic Foundation, Ohio 44195-5064, USA.
Am Heart J. 1996 Aug;132(2 Pt 1):286-96. doi: 10.1016/s0002-8703(96)90424-x.
The aim of this study was to characterize left atrial appendage mechanical function in atrial fibrillation and flutter by Fourier analysis to analyze frequency and regularity of flow. Left atrial appendage function is central to a patient's risk for thromboembolism. Although the function of the appendage can be analyzed by Doppler echocardiography in sinus rhythm, its mechanical function in atrial fibrillation and flutter has not been well characterized. This lack of adequate definition is caused by the complexity and temporal variability of the Doppler flow profiles. We assessed left atrial appendage function in 21 cases of atrial fibrillation (n - 11) and flutter (n = 10) and five in sinus rhythm with transesophageal Doppler echocardiography. Doppler profiles were examined by Fourier analysis, and the power spectra compared and analyzed between patients with atrial fibrillation and flutter. Left atrial appendage Doppler flow in atrial fibrillation produced Fourier spectra over a narrow band of frequencies with a peak frequency of 6.2 +/- 1.0 Hz, significantly higher than in atrial flutter (3.9 +/- 0.6 Hz, p < 0.00001). Additionally, a significant difference in subharmonic modulation (spectral power below the peak frequency) was observed between atrial appendage flow in atrial fibrillation and flutter, because 37% +/- 16% of the total spectral power was achieved before the dominant frequency in atrial fibrillation compared with 20% +/- 14% in atrial flutter (p = 0.02). Conversely, patients in sinus rhythm exhibited broad-banded Fourier spectra with most of the power in discrete frequency spikes at harmonics above the fundamental frequency with very little subharmonic modulation (1% +/- 0.05%). Left atrial appendage function in atrial fibrillation and flutter can be well characterized by Fourier analysis of Doppler flow. Atrial fibrillation has higher dominant frequencies and greater subharmonic modulation compared with flutter. Moreover, atrial fibrillation demonstrated quasiperiodic contraction patterns typically found in chaotic systems. Fourier analysis of left atrial appendage contraction patterns may therefore have significant promise in providing insights into mechanisms of atrial fibrillation and thromboembolism.
本研究的目的是通过傅里叶分析来表征心房颤动和心房扑动时左心耳的机械功能，以分析血流的频率和规律性。左心耳功能对于患者发生血栓栓塞的风险至关重要。虽然在窦性心律时可通过多普勒超声心动图分析心耳功能，但其在心房颤动和心房扑动时的机械功能尚未得到充分表征。这种缺乏充分定义的情况是由多普勒血流频谱的复杂性和时间变异性导致的。我们采用经食管多普勒超声心动图评估了21例心房颤动（n = 11）和心房扑动（n = 10）患者以及5例窦性心律患者的左心耳功能。通过傅里叶分析检查多普勒频谱，并比较和分析心房颤动和心房扑动患者之间的功率谱。心房颤动时左心耳多普勒血流产生的傅里叶频谱频率范围较窄，峰值频率为6.2±1.0 Hz，显著高于心房扑动（3.9±0.6 Hz，p < 0.00001）。此外，观察到心房颤动和心房扑动时心耳血流的次谐波调制（峰值频率以下的频谱功率）存在显著差异，因为心房颤动时总频谱功率的37%±16%在主导频率之前达到，而心房扑动时为20%±14%（p = 0.02）。相反，窦性心律患者表现出宽带傅里叶频谱，大部分功率集中在基频以上谐波的离散频率尖峰处，次谐波调制非常小（1%±0.05%）。通过对多普勒血流进行傅里叶分析，可以很好地表征心房颤动和心房扑动时的左心耳功能。与心房扑动相比，心房颤动具有更高的主导频率和更大的次谐波调制。此外，心房颤动表现出通常在混沌系统中发现的准周期性收缩模式。因此，对左心耳收缩模式进行傅里叶分析可能在深入了解心房颤动和血栓栓塞机制方面具有重要前景。
