The ‘double transition’: a novel electrocardiogram sign to discriminate posteroseptal accessory pathways ablated from the right endocardium from those requiring a left-sided or epicardial coronary venous approach

Abstract

Aims The precise localization of manifest posteroseptal accessory pathways (APs) often poses diagnostic challenges considering that a small area may encompass AP that may be ablated from the right or left endocardium, or epicardially within the coronary sinus (CS). We sought to explore whether the QRS transition pattern in the precordial lead may help to discriminate the necessary ablation approach. Methods and results Consecutive patients who underwent a successful ablation of a single manifest AP over a 5-year period were included. Standard 12-lead electrocardiograms were reviewed. A total of 273 patients were identified. Mean age was 31 ± 15 years and 62% were male. Of the 110 identified posteroseptal AP, 64 were ablated from the right endocardium, 33 from the left endocardium, and 13 inside the CS. While a normal precordial QRS transition was most often observed, a subset of 33 patients presented an atypical ‘double transition’ pattern which specifically identified right endocardial AP. The combination of a q wave in V1 with a proportion of the positive QRS component in V1 < V2 > V3, predicted a right endocardial AP with a 100% specificity. In case of a positive QRS sum in V2, this ‘double transition’ pattern predicted a posteroseptal right endocardial AP with 99.5% specificity and 44% sensitivity. The positive predictive value was 97%. The only false positive was a midseptal AP. In the case of a negative or isoelectric QRS sum in V2, APs were located more laterally on the tricuspid annulus. Conclusion The combination of a q wave in V1 with a double QRS transition pattern in the precordial leads is highly specific of a right endocardial AP and rules out the need for CS or left-sided mapping.

3D transvenous radiofrequency ablation of manifest epicardial posterior-septal accessory pathways in children: Can technology innovations improve the outcome?

“…9 Regarding ECG characteristics of such epicardial accessory pathways, Arruda reported a negative delta wave in lead II as the typical ECG landmark of overt posteroseptal epicardial accessory pathways, 12 although, for other authors, this finding is absent in more than 30% of cases. 13 Differently from these studies, we found most of our patients with negative delta wave in III and aVF and all with positive delta wave in lead I. Interestingly, about 70% of the patients presented in V1 a "rS" morphology of the QRS.…”

Preprocedural Discrimination of Posteroseptal Accessory Pathways Ablated from the Right Endocardium from Those Requiring a Left-sided or Epicardial Coronary Venous Approach

“…[ 17 – 21 ] Epicardial APs requiring a coronary venous approach represent approximately 10–20% of inferior paraseptal APs, while the remaining APs can be successfully ablated on the septal mitral annulus. [ 4 , 16 , 19 – 21 ]…”

“…Only a limited number of studies have included in their analysis bypass tracts requiring ablation performed within the CS. [ 4 , 17 , 19 , 20 , 27 , 38 ] These algorithms have considered either the QRS polarity or the delta wave polarity, the latter being generally measured from the onset of the earliest delta wave observed in any of the peripheral leads. Direct comparison between studies is limited by the fact that the analysis of the delta wave polarity substantially differed between studies (see below).…”

“…Negative delta waves in at least two inferior leads , given that the delta wave in lead II less often displays a negative delta wave, and may be isoelectric or biphasic. [ 17 , 19 , 21 , 27 , 31 – 33 ] The delta wave polarity was variably defined: some studies considered the initial 20 ms, and some the initial 40 ms.[ 17 , 33 , 31 , 32 ] Isoelectric delta waves were also considered together with negative delta waves. [ 17 , 31 , 33 ] In our practice, we rather consider both the first and the second half of the 40 ms period, and would suspect an inferior paraseptal AP when a negative component is observed in either period.…”

“…[ 17 , 31 , 33 ] In our practice, we rather consider both the first and the second half of the 40 ms period, and would suspect an inferior paraseptal AP when a negative component is observed in either period. [ 19 ] We compared this method with the assessment of the initial 20 ms only. [ 19 ] As illustrated in Table 1 , considering only delta waves whose initial 20 ms are negative, the sensitivity to detect inferior paraseptal APs was notably reduced.…”