His bundle pacing guided by automated intrinsic morphology matching is feasible in patients with narrow QRS complexes

Figures

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  Figure 1. Intrinsic morphology matching. (A) Reference. The red ISI lines enclose the QRS morphology. (B) Intrinsic QRS compared with the reference. (C) S-HBP. The paced QRS complex (white color) is automatically compared with the stored template (gray shadow) and the degree of similarity indicated for every single lead (yellow numbers) and as IMS for all twelve leads (95%, not shown). Note that morphology comparison may be challenging for low amplitude signals, in this case in lead III. (D) NS-HBP, local myocardial capture, IMS 80%. (E) RVP, IMS 49%. (F) Points sorted by LAT. Positive LAT values indicate no capture or atrial capture beats. (G) No capture, IMS 99%, LAT positive. (H) Atrial capture, IMS 95%, LAT positive. 12-lead surface electrogram; ROV His, His lead.

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  Figure 2. Performance of the morphology match algorithm tested by comparing 354 intrinsic narrow QRS complexes with the stored intrinsic 12-lead ECG reference. The image was created with the sotware R: The R Project for Statistical Computing (r-project.org) version 3.6.2 (R Foundation, Vienna, Austria).

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  Figure 3. IMS-based automated classification of the pacing response. (A) Diagnostic mapping catheter and (B) His-lead pacing. IMS cutoff 0.889 for selective versus NS-HBP and 0.784 versus RVP. The image was created with the sotware R: The R Project for Statistical Computing (r-project.org) version 3.6.2 (R Foundation, Vienna, Austria).

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  Figure 4. Diagnostic pace mapping. (A) The distal electrodes of a steerable mapping catheter were positioned at the distal His area as indicated by the second intrinsic beat (*). Local pacing with reduced pacing amplitude from 10 mA@1 ms to 5 mA resulted in the transition from NS-His capture to S-HBP (†). By comparing the paced morphology with the intrinsic QRS complex beat to beat the AutoMap module, the loss of local myocardial capture (S-HBP) indicated a jump in the intrinsic morphology match score from 86% (not shown) to 97% (red box). Note that in addition to the “global” IMS for the 12-lead ECG, the algorithm calculates the morphology match for every single lead (‡). (B) IMS map using the cutoff values found in the study. The ECGs show an intrinsic beat during initially ineffective pacing followed by a paced morphology with an IMS of 92%, indicating S-HBP on the left (LAO) compared with NS-HBP on the right (postero-lateral view). 12-lead surface electrogram; ROV CS, mapping catheter, distal electrodes.

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  Figure 5. Morphology matching to guide HBP (left postero-lateral view). (A) Color-coded visualization of the IMS resulting from pace mapping within the His area differentiating the transition from selective (S) and NS-HBP (NS) to myocardial septal (RV) stimulation. The ECG below shows S-HBP classified by an IMS of 99% (red box). (B) Voltage map displaying the local bipolar voltage of the His bundle and the proximal RV conduction system peak to peak. Note the IMS of 99% for reference validation. (C) Fixed 3830 Select Secure lead connected to the EAM system, NS-HBP, IMS 87%. 12-lead electrogram; ROV CS, distal electrodes of the mapping catheter (A and B) and the His lead in (C).