Palmieri Flavio, Gomis Pedro, Ferreira Dina, Pueyo Esther, Martinez Juan Pablo, Laguna Pablo, Ramirez Julia
IEEE Trans Biomed Eng. 2022 Sep;69(9):2787-2796. doi: 10.1109/TBME.2022.3153791. Epub 2022 Aug 19.
T-wave (TW) morphology indices based on time-warping ( d) have shown significant cardiovascular risk stratification value. However, errors in the location of TW boundaries may impact their prognostic power. Our aim was to test the hypothesis that a weighted time-warping function (WF) would reduce the sensitivity of d to these errors and improve their clinical significance.
The WFs were proportional to (i) the reference TW ( T), and (ii) the absolute value of its derivative ( D). The index d was recalculated using these WFs, and its performance was compared to the unweighted control case ( C) in four different scenarios: 1) robustness against simulated TW boundaries location errors; 2) ability to retain physiological information in an electrophysiological cardiac model; 3) ability to monitor blood potassium concentration changes ( ∆[K]) in 29 hemodialysis (HD) patients; 4) and the sudden cardiac death (SCD) risk stratification value of the TW morphology restitution (TMR) index, derived from d, in 651 chronic heart failure (CHF) patients.
The WFs led to a reduced sensitivity ( R) of d to TW boundary location errors as compared to C (median R=0.19 and 0.22 and 0.35 for T, D and C, respectively). They also preserved the physiological relationship between d and repolarization dispersion changes at ventricular level. No improvements in ∆[K] tracking were observed for the HD patients (Pearson's median correlation [ r] between ∆[K] and d was 0.86 ≤ r ≤ 0.90 for T, D and C). In CHF patients, the SCD risk stratification value of TMR was improved by applying T (hazard ratio, HAR, of 2.80), followed by D (HAR=2.32) and C (HAR=2.23).
The proposed WFs, with T showing the best performance, increased the robustness of time-warping based markers against TW location errors preserving their physiological information content and boosting their SCD risk stratification value. Results from this work support the use of T when deriving d for future clinical applications.
基于时间规整（d）的T波（TW）形态学指标已显示出显著的心血管风险分层价值。然而，TW边界位置的误差可能会影响其预后能力。我们的目的是检验以下假设：加权时间规整函数（WF）将降低d对这些误差的敏感性，并提高其临床意义。
WF与（i）参考TW（T）和（ii）其导数的绝对值（D）成比例。使用这些WF重新计算指标d，并在四种不同情况下将其性能与未加权的对照情况（C）进行比较：1）对模拟TW边界位置误差的稳健性；2）在心脏电生理模型中保留生理信息的能力；3）监测29例血液透析（HD）患者血钾浓度变化（∆[K]）的能力；4）在651例慢性心力衰竭（CHF）患者中，由d得出的TW形态恢复（TMR）指标的心脏性猝死（SCD）风险分层价值。
与C相比，WF导致d对TW边界位置误差的敏感性降低（T、D和C的中位R分别为0.19、0.22和0.35）。它们还保留了d与心室水平复极离散变化之间的生理关系。HD患者的∆[K]跟踪未观察到改善（T、D和C的∆[K]与d之间的Pearson中位相关性[r]为0.86≤r≤0.90）。在CHF患者中，应用T可提高TMR的SCD风险分层价值（风险比，HAR，为2.80），其次是D（HAR=2.32）和C（HAR=2.23）。
所提出的WF，其中T表现出最佳性能，提高了基于时间规整的标志物对TW位置误差的稳健性，保留了其生理信息内容，并提高了其SCD风险分层价值。这项工作的结果支持在未来临床应用中推导d时使用T。
