Intermittent preexcitation indicates “a low‐risk” accessory pathway: Time for a paradigm shift?

Abstract

We report three patients with intermittent loss of the preexcitation pattern in the ECG that had undergone an electrophysiological study. Despite apparently poorly conducting accessory pathway (AP), in each case a fast anterograde conduction, either during spontaneous atrial fibrillation or during incremental atrial pacing (on isoproterenol) was documented; shortest preexcited RR intervals of 200-240 ms were observed. We review the literature and conclude that intermittent preexcitation observed on resting 12-lead ECG lacks sufficient specificity for the diagnosis of an AP with long refractory period and cannot be considered a substitute for electrophysiological study in patients with this electrocardiographical phenomenon.

Intermittent ventricular pre‐excitation in symptomatic adults: Always a marker of low risk?

“…So far we have made some speculations on the pediatric population on which we have considerable studies, which however are lacking on the adult population. For the latter, we have only reports showing cases of patients with intermittent ventricular pre‐excitation and APs with high‐risk characteristics or even cardiac arrest from VF 11–13 . And based on these data, as already mentioned at the beginning of the discussion, the recent European Guidelines have taken a step backward on the hot topic of intermittent ventricular pre‐excitation, on whose risk stratification they do not express themselves at all 14 …”

“…In addition, there are some recent data in the literature reporting IPX patients, both symptomatic and asymptomatic, with high-risk features. [11][12][13] For these reasons, current European Guidelines on the management of supraventricular arrhythmias do recognize IPX as an imperfect marker of a low-risk AP. 14 Given that current European Guidelines recommend APs ablation in case of fast antegrade conduction [defined as an effective refractory period/shortest pre-excited RR interval (ERP/SPERRI) ≤250 ms in baseline or during adrenergic stimulus], AVRT/pre-excited AF (spontaneous or triggered), or presence of multiple APs, 14 the aim of our monocentric retrospective study was to evaluate the existence of dif-ferences in the risk features between patients with IPX and those with persistent pre-excitation (PPX), from a sample of adults with ventricular pre-excitation evaluated for palpitations (Wolff-Parkinson-White syndrome).…”

“…Although IPX has been considered a predictor of poor antegrade AP conduction, 1,7–10 it has been observed on rare occasions in some patients with cardiac arrest. In addition, there are some recent data in the literature reporting IPX patients, both symptomatic and asymptomatic, with high‐risk features 11–13 . For these reasons, current European Guidelines on the management of supraventricular arrhythmias do recognize IPX as an imperfect marker of a low‐risk AP 14 …”

Management of Young Athletes with Asymptomatic Preexcitation—A Review of the Literature

“…However, the reliability of those tools has been questioned, as there are problems with general anaesthesia (often used in the paediatric population) affecting the conduction system, and there is no standardisation for the use of isoproterenol [ 19 ]. Sudden death and life-threatening arrhythmias can be the first manifestation of the condition, and they have also been reported in patients with intermittent preexcitation and properties of the AP believed to be benign [ 16 , 20 , 21 , 22 ]. In the literature, there are reports with low and high frequency of LTE in asymptomatic children [ 23 , 24 ].…”

Woman with alternating QRS in the emergency department: what is happening?

“…Intermittent pre-excitation does not exclude the risk of arrhythmia. Jastrzebski et al describes three cases with intermittent pre-excitation and tachyarrhythmias that had undergone an electrophysiological study4. I another study with 1007 patients with WPW syndrome, 7% with intermittent pre-excitation on resting ECG had sudden cardiac arrest.…”