The Different Substrate Characteristics of Arrhythmogenic Triggers in Idiopathic Right Ventricular Outflow Tract Tachycardia and Arrhythmogenic Right Ventricular Dysplasia: New Insight from Noncontact Mapping

Abstract

BackgroundThe aim of this study was to investigate the different substrate characteristics of repetitive premature ventricular complexed (PVC) trigger sites by the non-contact mapping (NCM).MethodsThirty-five consecutive patients, including 14 with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC) and 21 with idiopathic right ventricular outflow tract tachycardia (RVOT VT), were enrolled for electrophysiological study and catheter ablation guided by the NCM. Substrate and electrogram (Eg) characteristics of the earliest activation (EA) and breakout (BO) sites of PVCs were investigated, and these were confirmed by successful PVC elimination.ResultsOverall 35 dominant focal PVCs were identified. PVCs arose from the focal origins with preferential conduction, breakout, and spread to the whole right ventricle. The conduction time and distance from EA to BO site were both longer in the ARVC than the RVOT group. The conduction velocity was similar between the 2 groups. The negative deflection of local unipolar Eg at the EA site (EA slope3,5,10ms values) was steeper in the RVOT, compared to ARVC patients. The PVCs of ARVC occurred in the diseased substrate in the ARVC patients. More radiofrequency applications were required to eliminate the triggers in ARVC patients.Conclusions/InterpretationThe substrate characteristics of PVC trigger may help to differentiate between idiopathic RVOT VT and ARVC. The slowing and slurred QS unipolar electrograms and longer distance from EA to BO in RVOT endocardium suggest that the triggers of ARVC may originate from mid- or sub-epicardial myocardium. More extensive ablation to the trigger site was required in order to create deeper lesions for a successful outcome.

Usefulness of three-dimensional echocardiography for the assessment of ventricular function in children: Comparison with cardiac magnetic resonance, with a focus on patients with arrhythmia

“…Contrary to the adult population, most cases of arrhythmia in children are classified as idiopathic because no link to cardiac morphology or evident haemodynamic dysfunction can be found [5][6][7][8]. In most cases the risk is low and general prognosis is good, patients do not usually require pharmacotherapy, even if extrasystole is common.…”

The use of a novel signal analysis to identify the origin of idiopathic right ventricular outflow tract ventricular tachycardia during sinus rhythm: Simultaneous amplitude frequency electrogram transformation mapping

“…[18,20–23] The earliest activation site of the VT might be identified by local unipolar electrogram with a QS pattern indicating that the vector of the depolarization is spreading away from the earliest activation site toward the surrounding peripheral area. [8] On the contrary, Man et al suggested that a QS pattern at local unipolar electrogram might not be accurate to identify the successful ablation site.…”

“…An anisotropic conduction pattern around the ventricular outflow tract has been reported to be due to low voltage areas distributed below the pulmonary artery valve and has been suggested to involve preferential conduction from the origin to the breakout site during the tachycardia as shown by high-density mapping. [ 18 , 20 – 23 ] The earliest activation site of the VT might be identified by local unipolar electrogram with a QS pattern indicating that the vector of the depolarization is spreading away from the earliest activation site toward the surrounding peripheral area. [ 8 ] On the contrary, Man et al suggested that a QS pattern at local unipolar electrogram might not be accurate to identify the successful ablation site.…”

“…Recurrence was defined as recurrence of sustained VT, nonsustained VT, or greater than 1000 ventricular PVCs, as confirmed by the morphology criteria using 24-hour Holter monitoring. [ 16 – 18 ]…”

Catheter Ablation of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

“…First, the electrophysiological study could yield the valuable information to differentiate idiopathic RVOT VT from ARVD/C. 27) The programmed electrical stimulation not only have a pivotal role to assess the vulnerability of ventricular tachyarrhythmias, but also provide clues for the diagnosis of ARVD/C. Denis et al 28) demonstrated that either the presence of polymorphic premature ventricular contractions with ≥1 couplet, sustained or non-sustained VT with left bundle branch block morphology after excluding RVOT VT by high dose isoproterenol (45 μg/min) infusion could help to diagnose ARVD/C in the early stage with a sensitivity of 91.4% and a specificity of 88.9%.…”