SMART Identification of Ventricular Tachycardia Isthmus
SMART Identification of Ventricular Tachycardia Isthmus
Context :

 Ventricular tachycardia (VT) are serious heart rhythm disorders which can lead to sudden
 death. A curative treatment for these abnormalities in the cardiac electrical conduction
 system is possible through an interventional electrophysiology procedure. A catheter is
 inserted, generally via a femoral access, and is introduced in the heart ventricles in order
 to collect various 3D electro-anatomical maps.

 The pace-mapping technique developed in Nancy (de Chillou et al, Heart Rhythm 2014) allows
 the reentrant circuit underlying the VT to be identified, as well as a definition of the
 target zones to be ablated, using radiofrequency energy with the catheter. The pace-mapping
 technique consists of stimulating the ventricle from various sites within its internal
 surface, in order to generate different activation pathways of the myocardium. When an
 activation pathway is similar to the VT pathway, this means that the stimulation site is
 located near the pathologic zone to be ablated. The surface electrocardiogram (ECG) is used
 to compare activation pathways. A 3D correlation ma is then generated: the zones with high
 correlation (>90%) indicated the exit of the reentrant circuit, while rapid transition zones
 (several %/mm) indicate the entrance of the VT circuit. The pace-mapping technique has
 several limitations: (i) it requires an ECG recording of the clinical VT of the patient
 (spontaneous or induced at the beginning of the procedure), however it is not always possible
 to induce it; (ii) sometimes several VT circuits may be present, rendering the procedure of
 identification and ablation non-exhaustive.

 The aim of this study is to analyze retrospectively electroanatomical data collected during
 the intervention, in order to develop a new method for identifying target zones to be
 ablated, and to compare the results with the conventionally used method.

 Hypothesis :

 The investigators hypothesize that alternative methods to analyze electroanatomical data
 (surface ECG and spatial coordinates of the pacing sites) could provide information
 equivalent to conventional methods (e.g. VT correlation map, VT activation maps etc…) without
 the need for a reference recording of the clinical VT of the patient.
Inclusion Criteria:

 -  Ventricular tachycardia ablation between October 2014 and April 2021

 -  Patient for whom electroanatomical data are available.

 -  Ischemic cardiomyopathy / previous myocardial infarction

 -  At least 30 points of pace-mapping during the VT procedure

 Exclusion Criteria:

 -  Incomplete data

 -  Poor quality ECG recordings

 -  Absence of ventricular tachycardia isthmus identified during the procedure