Department of Medicine, Division of Cardiology, Columbia University Medical Center, NY, USA.
Comput Biol Med. 2013 Dec;43(12):2127-35. doi: 10.1016/j.compbiomed.2013.08.027. Epub 2013 Oct 10.
Measurements of both the dominant frequency (DF) and the time series morphology of complex fractionated atrial electrograms (CFAE) are useful to distinguish persistent from paroxysmal atrial fibrillation (AF). In this study, an algorithm was devised to extract morphologic components according to frequency, and its usefulness for distinguishing CFAE was shown.
CFAE of length 16s were obtained at two sites each from the four pulmonary vein ostia (PV), and from anterior and posterior left atrial free wall (FW), in nine paroxysmal and 10 longstanding persistent AF patients. The DF was computed for each of two 8s CFAE segments in each 16s recording. Each CFAE segment was then transformed into a set of basis vectors, which represent electrogram morphology at each frequency. The dominant morphology (DM) is defined as the ensemble average of sequential signal segments, with the segment length equal to the period at the DF. The DMs of the two 8s pairs were correlated. Normalized correlation coefficients were tabulated for all data, and separately for PV and FW. The means and coefficients of variation of the DM correlation coefficients were then plotted, and a linear discriminant function was used to classify persistent versus paroxysmal AF data. For comparison with DM results, CFE-mean and interval confidence level (ICL) were also calculated for persistent versus paroxysmal AF data.
Mean correlation of the DM, 1st 8s versus 2nd 8s data, was 0.62+0.22 for persistent versus 0.50+0.19 for paroxysmal CFAE for all recording sites (p<0.001). At single anatomical locations, correlation was greater in persistents than paroxysmals at all sites, but achieved significance only at the left superior (p<0.001) and right superior (p<0.05) PV. Spatial variation in correlation coefficient was greater in paroxysmal than persistent AF (not significant). Using the means of DF correlation coefficients, 17/19 patients were classified correctly. The CFE-mean parameter averaged 89.01±20.99 ms in persistents versus 93.96±33.81 ms in paroxysmals (p<0.05), while ICL averaged 94.54±18.52 deflections/8s for persistents versus 90.70±19.28 deflections/8s for paroxysmals (p<0.05).
In CFAE recordings, the DM parameter was found to have greater temporal morphologic variation in paroxysmal as compared with persistent AF data (p<0.001). In contrast, only moderate significance between paroxysmal versus persistent AF data was found when using the of CFE-mean and ICL parameters (p<0.05). The DM parameter may thus be useful as a new measure to discern both temporal and spatial variations in CFAE in paroxysmal versus persistent AF recordings.
测量主导频率（DF）和复杂碎裂心房电图（CFAE）的时程形态有助于区分持续性和阵发性心房颤动（AF）。本研究设计了一种根据频率提取形态成分的算法，并证明其对区分 CFAE 的有用性。
在 9 例阵发性和 10 例持续性 AF 患者的四个肺静脉口（PV）的每一处和左心房前壁和后壁的每一处获得长度为 16s 的 CFAE。为每个 16s 记录中的两个 8s CFAE 段计算 DF。然后，将每个 CFAE 段转换为一组基向量，代表每个频率的心电图形态。主导形态（DM）定义为连续信号段的集合平均值，段长等于 DF 的周期。比较两个 8s 对的 DM。为所有数据以及 PV 和 FW 分别列出归一化相关系数表。然后绘制 DM 相关系数的均值和变异系数图，并使用线性判别函数对持续性与阵发性 AF 数据进行分类。为了与 DM 结果进行比较，还计算了持续性与阵发性 AF 数据的 CFE-均值和间隔置信度水平（ICL）。
持续性与阵发性 CFAE 的所有记录部位的 1st 8s 与 2nd 8s 数据的 DM 平均相关性分别为 0.62+0.22 和 0.50+0.19（p<0.001）。在单个解剖部位，持续性的相关性大于阵发性，但仅在左上（p<0.001）和右上（p<0.05）PV 处具有统计学意义。阵发性 AF 的相关系数空间变异性大于持续性（无统计学意义）。使用 DF 相关系数的均值，17/19 例患者的分类正确。持续性的 CFE-均值平均为 89.01±20.99ms，阵发性为 93.96±33.81ms（p<0.05），而 ICL 持续性为 94.54±18.52 个偏转/8s，阵发性为 90.70±19.28 个偏转/8s（p<0.05）。
在 CFAE 记录中，与持续性 AF 数据相比，阵发性 AF 数据的 DM 参数具有更大的时间形态变化（p<0.001）。相比之下，仅当使用 CFE-均值和 ICL 参数时，才发现阵发性与持续性 AF 数据之间具有中度显著性差异（p<0.05）。因此，DM 参数可作为区分阵发性和持续性 AF 记录中 CFAE 的时间和空间变化的新指标。
