Introduction
Outflow
tract ventricular
arrhythmia
(OTVA) is one of the most common subgroups of
idiopathic
ventricular
arrhythmia
(VA) that typically occurs in healthy patients without any structural
heart diseases. Radiofrequency catheter ablation (RFCA) is considered
the curative therapy for OTVA, with a high success rate. Further, with
the development of new techniques, the success rate is extremely high in
experienced centers (>95%)[1]. Therefore, RFCA is
suggested as Class I, level B for VA arising from the
right
ventricular outflow tract (RVOT), and Class IIa, level B for that
arising from the
left
ventricular outflow tract (LVOT)[2]. Notably, it is clinically
important to accurately predict OTVA origin before ablation as it
reduces the risk of exposure to radiation, duration of the ablation, and
the number of vascular access sites. Further, timely identification of
the origin of the OTVA can improve the safety and efficacy of the
ablation procedure. By accurately predicting OTVA origin, the physician
can customize the ablation strategy to accurately target the arrhythmia
source, thereby improving patient outcomes. Typically, VA originating in
the RVOT manifests as a left bundle branch block (LBBB) configuration.
In contrast, VA originating in the LVOT usually manifests either as a
right bundle branch block or an LBBB. Considering the overlap between
precordial transition lead and morphological similarity, it is difficult
to
determine
the origin of OTVAs. Rapid developments in the past two decades have
resulted in the identification of several ECG parameters to distinguish
between the origins of RVOT and LVOT. However, the use of these
mentioned parameters may lead to
different
predictions of the VA origin and confuse the physician. To the best of
our knowledge, this is the first study to systematically investigate the
accuracy of these
parameters.
Further, we developed
the
algorithm
for reliably predicting OTVA origin and validated it in an additional
100 patients.