Symptomatic intermittent ventricular pre-excitation in adult: a monocentric retrospective study

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. Backgorund: Intermittent ventricular pre-excitation was considered a low-risk marker for sudden death. However, to date some studies do not exclude the existence of accessory pathways (APs) with high-risk intermittent antegrade conductive properties. High-risk features of APs are: ERP/SPERRI ≤250 msec (in basal or during adrenergic stimulus), inducibility of atrioventricular reciprocating tachycardias (AVRT), inducibility of pre-excited atrial fibrillation (AF), multiple APs. For these catheter ablation is recommended. PURPOSE: The aim of this retrospective study was to evaluate the existence of a statistically significant difference in the risk characteristics between patients with intermittent pre-excitation (IPX) and with persistent pre-excitation (PPX), from a sample of adults with symptomatic ventricular pre-excitation (Wolff-Parkinson-White Syndrome). METHODS: Between August 2005 and December 2015, 293 adults (age ≥18 years) [males: 183 (62.5%)], without structural heart disease, with signs of ventricular pre-excitation and symptomatic for palpitations underwent an EP study [IPX: 51 (17.4%), males: 31 (60.8%); PPX: 242 (82.6%), males: 152 (62.8%)]. The APs were submitted to catheter ablation if EP study showed inducibility of arrhythmias (AVRT/AF) and, in case of non-inducibility of arrhythmias, if ERP ≤250 msec, in basal or during intravenous infusion of isoproterenol. Additionally, the presence of multiple accessory pathways was assessed during the test. RESULTS: The 2 groups of patients did not show statistically significant differences in age at the time of EP study [IPX: mean age 37.23±16.89 years Vs PPX: mean age 39.03±16.19 (P-value>0.05)] and gender (IPX male: 60.8% Vs PPX male: 62.8%; P-value>0.05). When measured, there were no statistically significant differences regarding ERP [IPX: mean ERP 260±45.8msec Vs PPX: mean ERP 267.7±59.6msec; P-value>0.05]. The inducibility of arrhythmias (AVRT/AF) was 59.3% in the IPX group (27 patients) vs 38% in the PPX group (92 patients), showing statistically significant differences (P-value<0.05). Multiple accessory pathways were found in 2 patients of the IPX group (3.9%), both females (100%), and in 6 patients of the PPX group (2.5%), of which 2 females (33.3%), not showing statistically significant differences (P-value>0.05). CONCLUSION: In our study, patients with IPX did not shown statical significant differences in clinical and electrophysiological features Vs PPX partients. Thus, intermittent ventricular pre-excitation could not absolutely be considered a marker of lower arrhythmic risk. [Figure: see text]