Clinical Application of an Integrated 3-Phase Mapping Technique for Localization of the Site of Origin of Idiopathic Ventricular Tachycardia

Abstract

Background-Radiofrequency (RF) catheter ablation provides curative treatment for idiopathic ventricular tachycardia (VT). Methods and Results-Nineteen consecutive patients with an idiopathic VT underwent RF catheter ablation. An integrated 3-phase mapping approach was used, consisting of the successive application of online 62-lead body surface QRS integral mapping, directed regional paced body surface QRS integral mapping, and local activation sequence mapping.Mapping phase 1 was localization of the segment of VT origin by comparing the VT QRS integral map with a database of mean paced QRS integral maps. Mapping phase 2 was body surface pace mapping during sinus rhythm in the segment localized in phase 1 until the site at which the paced QRS integral map matched the VT QRS integral map was identified (ie, VT exit site). Mapping phase 3 was local activation sequence mapping at the circumscribed area identified in phase 2 to identify the site with the earliest local endocardial activation (ie, site of VT origin). This site became the ablation target. Ten VTs were ablated in the right ventricular outflow tract, 2 at the basal LV septum, and 7 at the midapical posterior left ventricle. A high long-term ablation success (mean follow-up duration, 14Ϯ9 months) was achieved in 17 of the 19 patients (89%) with a low number of RF pulses (mean, 3.3Ϯ2.2 pulses per patient). Conclusions-This prospective study shows that integrated 3-phase mapping for localization of the site of origin of idiopathic VT offers efficient and accurate localization of the target site for RF catheter ablation. (Circulation. 1999;99:1300-1311.)

Software design for analysis of multichannel intracardial and body surface electrocardiograms

“…For example, if analysis of BSM recordings is used on-line to guide catheter ablation of an arrhythmia, a computer program can perform all computations, but the physician has to select the QRS complex of interest [5,6]. An interactive system is also desired if data is processed off-line but with input from a human expert.…”

“…It includes basic, established, and experimental algorithms. Among the implemented routines are various filters, zeroth-and first-order baseline correction, QRS detection [20], arrhythmia localisation by body surface mapping using either databases [5,21] or a continuous algorithm [6], a configurable activation-detection algorithm, computation of nondipolar content [22,23], signal alignment and signal averaging, and various display methods discussed above. As mentioned in Section 3, we shall not go into details about the algorithms.…”

Continuous Localization of Ventricular Tachycardia Exit Sites in Patients With Previous Myocardial Infarction

“…The procedure may be shortened by utilizing body surface mapping to quickly identify the target area by first determining the exit site of the VT, from where a suitable ablation site can be found by a short local activation sequence mapping procedure [1]. A database of paced body surface QRS integral maps (QRSI's) corresponding to known pacing positions is helpful for localization of the VT exit site.…”

Guidance for catheter ablation of ventricular arrhythmia

“…The goal is to find the earliest activated site. This is a time-consuming procedure, during which the patient has to be kept in VT. To gain time, the exit site found by pace mapping can be used as a starting point [3]. When catheter ablation became mainstream, in the early 1990s, difficulties encountered included the need for radiography to find out where the catheter was, and the need to rapidly infer from a standard 12-lead ECG where it should be going.…”

“…Atlases of paced BSMs were created, which linked potential patterns to segments of the myocardium [1,3]. This approach had a resolution similar to that of inverse models, but it was much faster and did not require an accurate anatomic model.…”