Background

Cardiac optical mapping enables direct and high spatio-temporal resolution recording of action potential (AP) morphology. Temporal alterations in AP morphology are both predictive and consequent of arrhythmia. Here we sought to test if methods that quantify regularity of recorded waveforms could be applied to detect and quantify periods of temporal instability in optical mapping datasets in a semi-automated, user-unbiased manner.

Methods and results

We developed, tested and applied algorithms to quantify optical wave similarity (OWS) to study morphological temporal similarity of optically recorded APs. Unlike other measures (e.g. alternans ratio, beat-to-beat variability, arrhythmia scoring), the quantification of OWS is achieved without a restrictive definition of specific signal points/features and is instead derived by analysing the complete morphology from the entire AP waveform.

Using model datasets, we validated the ability of OWS to measure changes in AP morphology, and tested OWS mapping in guinea pig hearts and mouse atria. OWS successfully detected and measured alterations in temporal regularity in response to several proarrhythmic stimuli, including alterations in pacing frequency, premature contractions, alternans and ventricular fibrillation.

Conclusion

OWS mapping provides an effective measure of temporal regularity that can be applied to optical datasets to detect and quantify temporal alterations in action potential morphology. This methodology provides a new metric for arrhythmia inducibility and scoring in optical mapping datasets.

中文翻译：

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使用波形态相似性对光学动作电位进行时间不规则量化和映射。

背景

心脏光学映射能够直接和高时空分辨率记录动作电位 (AP) 形态。AP 形态的时间变化既可以预测心律失常，也可以预测心律失常的结果。在这里，我们试图测试是否可以应用量化记录波形规律性的方法以半自动、用户无偏见的方式检测和量化光学映射数据集中的时间不稳定性周期。

方法和结果

我们开发、测试和应用算法来量化光波相似性 (OWS)，以研究光学记录 AP 的形态时间相似性。与其他测量方法（例如交替比、逐搏变异性、心律失常评分）不同，OWS 的量化是在没有对特定信号点/特征的限制性定义的情况下实现的，而是通过分析整个 AP 波形的完整形态而得出。

使用模型数据集，我们验证了 OWS 测量 AP 形态变化的能力，并测试了豚鼠心脏和小鼠心房中的 OWS 映射。OWS 成功地检测和测量了响应几种促心律失常刺激的时间规律性变化，包括起搏频率、过早收缩、交替和心室颤动的变化。

结论

OWS 映射提供了一种有效的时间规律性测量方法，可应用于光学数据集以检测和量化动作电位形态的时间变化。该方法为光学映射数据集中的心律失常诱导和评分提供了新的指标。