Algorithmic detection of the beginning and end of bipolar electrograms: Implications for novel methods to assess local activation time during atrial tachycardia

详细信息    查看全文

• 作者：Milad El Haddad ; Richard Houben ; Rol ; Stroob ; t ; Frederic Van Heuverswyn ; Rene Tavernier ; Mattias Duytschaever
• 关键词：AT ; atrial tachycardia ; B-EGM ; bipolar electrogram ; CL ; cycle length ; CNT ; counter ; CoM ; center-of-mass ; CS ; coronary sinus ; HQ ; high quality ; LAT ; local activation time ; LQ ; low quality ; ROC ; receiver operating characteristic ; SNR ; signal-to-noise ratio ; U-EGM ; unipolar electrogram
• 刊名：Biomedical Signal Processing and Control
• 出版年：November, 2013
• 年：2013
• 卷：8
• 期：6
• 页码：981-991
• 全文大小：3010 K

文摘

Activation mapping is required to effectively ablate atrial tachycardia (AT). Conventional tools to assess local activation time (LAT) are based upon the peak of the bipolar electrogram (B-EGM, LAT_Peak) and the maximal negative slope of the unipolar electrogram (U-EGM, LAT_Slope). Bipolar electrograms are influenced by wavefront direction, bipole orientation, and inter-electrode spacing causing ambiguity in peak detection, whereas unipolar electrograms are disturbed by the presence of far-field signals. We developed a new algorithm to detect the beginning and end of bipolar electrograms (t_begin and t_end). Then, we introduced new LAT methods related to the onset of B-EGMs (LAT_Onset), the center of mass of B-EGMs (LAT_CoM), and the slope of U-EGMs within a pre-defined window (LAT_Slope-hybrid).

In total 3752 recordings from 31 AT patients were retrospectively analyzed. The signal-to-noise ratio (SNR) for B-EGMs was calculated to differentiate algorithmically high from low quality electrograms (HQ and LQ). In a subset of 328 B-EGMs, five experts validated the t_begin as determined by the algorithm by visual rating. The newly developed LAT methods were compared to the conventional LAT methods and to one another (Bland-Altman plots) in both HQ (n = 3003) and LQ EGMs (n = 749).

The t_begin algorithm was accurate (deviation < 卤10 ms) in 96 卤 4% of HQ and 91 卤 8% of LQ B-EGMs. BA plots revealed the following difference (bias) and variation in HQ and LQ EGMs respectively: (1) LAT_Onset vs. LAT_Peak: 27 卤 30 ms and 24 卤 62 ms; (2) LAT_CoM vs. LAT_Peak: 0 卤 16 ms and 2 卤 38 ms; (3) LAT_Slope-hybrid vs. LAT_Slope: 1 卤 32 ms and 15 卤 110 ms; (4) LAT_Onset vs. LAT_CoM: 22 卤 24 ms and 18 卤 22 ms; (5) LAT_Onset vs. LAT_Slope-hybrid: 16 卤 18 ms and 13 卤 22 ms; and (6) LAT_CoM vs. LAT_Slope-hybrid: 5 卤 20 ms and 4 卤 18 ms.

In the present study, we introduced three new methods to assess local activation time in AT, based upon an algorithm detecting accurately the beginning and end of the B-EGM complex. BA analysis of the new methods showed similar variation in high and low quality EGMs, suggesting that they introduce less ambiguity than the conventional peak method. LAT_Onset consistently yielded an earlier activation moment. LAT_Slope-hybrid - by blanking far-field potentials - seems to be the optimal method for detection of the maximal negative slope in U-EGMs. Interestingly, LAT_CoM in B-EGMs coincided with the maximal negative slope in U-EGMs, suggesting its physiological sense and future use. The new LAT methods can be implemented in real-time mapping applications.