PMC10235778_01
Index electrocardiogram from patient's presentation to the hospital showed narrow complex tachycardia with a short RP interval at a rate of 163 bpm. Star denotes p waves in V1 and lead II.
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F1
Her initial electrocardiogram showed a regular and narrow complex tachycardia with a rate of 163 bpm with a short RP relationship (Figure 1). The patient continued to have paroxysms of SVT during the hospitalization (other electrocardiograms and telemetry tracings shown in Supplementary Figures S1A,B).
Representative electrocardiograms and intracardiac electrograms from electrophysiology study prior to ablation. (A) Tracings during tachycardia from theright atrial septum. (B) Tracings during tachycardia from the non-coronary sinus of Valsalva. (C) Tracings during tachycardia from the left atrial septum.
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F2
We did position our catheter slightly higher in order to be adjacent to the prior lesions from the right atrium and noted atrial electrograms -17 ms ahead of the surface p wave (Figure 2B shows electrograms during tachycarida, Supplementary Figure S2B shows same site during sinus rhythm). Mapping of the atrial septum was performed which revealed earlier (-29 ms relative to surface p wave) and fractionated signals near the left side of the superior limbus (Figure 2C shows electrograms during tachycarida, Supplementary Figure S2C shows same site during sinus rhythm) and close to the right superior pulmonary vein along the roof (directly adjacent to the area where right atrial ablation was performed).
Intracardiac (ICE) echocardiography of ablation sites (arrow: ablation catheter, RA, right atrium; NC, non-coronary sinus of Valsalva; LA; atrial septum; IAS, interatrial septum). *Images are placeholders for videos which are attached. (A) Right atrial septum. (B) Non-coronary sinus of Valsalva. (C) Left atrial septum.
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F3
The earliest atrial signals were -27 ms ahead of the surface p wave and appeared to be along the septum, approximately 11:30 along the tricuspid annulus and around the superior limbus which appeared thick on imaging (Figure 3A). Watts with 30 cc/minute flow for 30-90 s per lesion. We noted almost immediate suppression of the tachycardia with ablation (Figure 3A shows catheter position during ablation with intracardiac echocardiography; Supplementary Figure S3A shows corresponding fluoroscopic position). We then performed additional lesions around this region, in particular targeting the muscle bundle opposing the non-coronary aortic sinus of Valsalva and superior limbus. Radiofrequency lesions were performed in this region at 30-40 Watts and 30 cc/min flow for 30-60 s per lesion (Figure 3B and Supplementary Figure S3B shows corresponding intracardiac echocardiography and fluoroscopic position of ablation catheter). Watts and 30 cc/min flow for 30-60 s per lesion (Figure 3C shows corresponding ablation catheter position with intracardiac echocardiography; Supplementary Figure S3C shows corresponding fluoroscopic position). We noted temporary suppression and slowing of the tachycardia.