An Organized Approach to the Localization, Mapping, and Ablation of Outflow Tract Ventricular Arrhythmias

Abstract

The outflow tract (OT) regions of the right and left ventricles, common sites of origin for idiopathic ventricular arrhythmias (VA), have complex three-dimensional anatomical relationships. The understanding of in situ or "attitudinal" relationships not only informs the electrocardiographic interpretation of VA site of origin, but also facilitates their catheter-based mapping and ablation strategies. By viewing each patient as his or her own "control," the expected changes in ECG morphology (i.e., frontal plane QRS axis and precordial transition) between adjacent intracardiac structures (e.g., RVOT and aortic root) can be reliably predicted. Successful mapping of OT VAs involve a combination of activation and pacemapping guided by fluoroscopy, electroanatomical mapping, and intracardiac echocardiography. The purpose of this manuscript is to provide a simple, reliable strategy for catheter based mapping and ablation of OT VAs. We also discuss 2 specific challenges in OT VA mapping: (1) differentiating posterior RVOT from right coronary cusp VA origin; and (2) mapping VAs originating from the LV summit.

Catheter Ablation of Idiopathic Ventricular Arrhythmias Arising From the Cardiac Outflow Tracts – Recent Insights and Techniques for the Successful Treatment of Common and Challenging Cases –

“…Activation mapping originating from the distinct RVOT typically shows simultaneous activation in bipolar and unipolar activation and a QS morphology in the unipolar recording in patients without previously extensive ablation (Figure 2A). 19 However, the activation in bipolar and unipolar recordings may be not simultaneous in patients with a previous ablation ( Figure 2B). In patients with infrequent spontaneous VA, pace mapping is initially performed after reconstruction of the RV anatomy.…”

“…Power delivery should be initiated at 20 W and carefully titrated to a maximum of 40 W for a maximum of 120 s. Early suppression of the VA during energy delivery has been suggested as a possible indicator of successful RFCA whereas late suppression may be associated with recurrence. 19 However, it is sometimes difficult to judge the observation that RFCA response with similar QRS morphology to that of clinical VA is frequently observed during ablating the RVOT below the PV. The QRS morphology of the original PVC may slightly change after initial ablation at the RVOT ( Figure 2C).…”

“…19 Structures with an anterior location within the LVOT, such as the RCC of the ASV, present with an LBBB morphology and R/S transition Only the anterior and lateral LVOT comprise myocardium. The posterior part consists of fibrous tissue that extends from the fibrous skeleton of the heart across the anterior leaflet of the mitral valve and supports the aortic valve leaflets at the aortomitral continuity.…”

“…The PV is positioned 1-2 cm superior to and offset 90° from the aortic valve in the horizontal plane. 19 The pulmonary root is the most superior part of the RVOT and supports the semilunar leaflets of the PV. The leaflets have distal attachments at the sinotubular junction, which separates the PSCs from the tubular component of the PA trunk.…”

Kamrai tachycardiák katéterablatiós kezelése

“…Ezekben az esetekben a pontról pontra történő elektroanatómiai térképezés az általában használatos technika. Az ablatiós katéter bipoláris (>1,5 mV) és unipoláris (éles QRS mély, negatív defl exióval) nem fragmentált jelei az irányadóak, amelyek a felszíni QRS-t 10-60 msmal előzik meg [32]. Gyakran pace-térképezést is végez-nek kiegészítésként, különösen azokban az esetekben, ha a célrégió spontán aktivitása a beavatkozás alatt nem jelentkezik.…”