Analysis of the amplified p-wave enables identification of patients with atrial fibrillation during sinus rhythm

Figures

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  FIGURE 1. Study flowchart. EPS, electrophysiology study; ECG, electrocardiography; Echo, echocardiography; Standard PWD, duration of standard (non-amplified) p-wave; APWD, duration of amplified p-wave.

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  FIGURE 2. Illustration of PWD measurement in standard and amplified scaling. Panel (A) illustrates the results of p-wave duration from the same digital 12-lead ECG measured at standard scaling (10 mm/mV, 25 mm/s) and amplified scaling (60 mm/mV, 100 mm/s) using digital calipers. PWD was measured from the earliest p-wave onset until latest p-wave ending in any of the 12 leads at respective scaling. The noise level of annotated by the red dashed lines. Panel (B,C) illustrate the difference between control and AF cohorts in internal and external validation using standard PWD (reference model) and APWD (basic model), respectively. PWD, p-wave duration; standard PWD, duration of standard p-wave; APWD, duration of amplified p-wave; ****p < 0.001.

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  FIGURE 3. Development of diagnostic models from the training set. Panel (A) illustrates the data collection in the training set in the current study, different parameters from echocardiography, 12-lead ECG and other baseline characteristics are collected. Every ECG was measured at both standard setting (25 mm/s, 10 mm/mV) and amplified setting (100 mm/s, 60–120 mm/mV) to acquire the standard PWD and amplified PWD, respectively. Panel (B) depicts the steps in developing models. Amplified PWD and standard PWD were compared regarding their AUC in discriminative power to identify patients with AF. The one with higher AUC value is used as the basic model and proceed to further steps whereas the one with lower AUC value is used as the reference model. Basic model, along with other echo and baseline parameters are selected by univariate and subsequent multivariate parameters. The integrated model consists of all the significant parameters from the logistic analysis. Additionally, in order to create an alternative model with less variables and more oriented at ECG parameters, a PWI-based model is developed by excluding echo parameters (if any) from the integrated model. AUC, area under the curve;…

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  FIGURE 4. ROC and DCA curves. In internal (upper panel) and external validation (lower panel), ROC curves of reference model (red), basic model (blue), PWI-based model (brown) and integrated model (yellow) are plotted (A,C) with model components and AUC value annotated at right side. DCA (B,D) illustrates the clinical impact (net benefit) of diagnostic model with reference curves of “Treat All” and “Treat None”. “Treat All” and “Treat None” described the impact of intervention for “All” and “None” of individuals for target outcome (AF) respectively, when diagnostic model is not applied. ROC, receiver operating characteristics; AUC, area under the curve; DCA, decision curve analysis; PWD, p-wave duration.

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  FIGURE 5. Nomograms for identification of AF patients. Nomogram of PWI-based model (upper panel) and Integrated model (lower panel). Each value from respective scale corresponds to a specific value at the top points scale, and the total points correspond to the estimated risk (bottom scale) for AF by respective model. APWD, duration of amplified p-wave; aIAB, advanced inter-atrial block; BSA, body surface area; LAD, left atrial diameter.