Discussion:
Anomalous coronary arteries with a malignant course are associated with
an increased risk of arrhythmias and sudden cardiac
death,4-6 though ventricular arrhythmias have not been
previously localized to the site of an anomalous coronary artery. This
is the first report associating a PVC to the site of an anomalous,
interarterial, intramural coronary artery.
PVC localization and surgical cryoablation were guided by the use of a
novel ECG mapping system. ECG data are imported into the computational
mapping system that then localizes and integrates the highest
probabilistic location for the PVC focus onto the patient’s CT 3D
reconstruction model. This algorithm is based on forward-solution
computational simulation libraries of arrhythmias including PVCs
originating from sites around the heart with or without scar. The
simulation libraries are based on 3D finite element models of monodomain
cardiac action potential propagation using the Continuity simulation
environment. The models consist of detailed descriptions of cardiac
geometry, myofiber orientation, and scar. The simulation library
incorporates >1 million simulated arrhythmia cycles.
There are many advantages to this technique. This method is less time
consuming than traditional invasive catheter-based mapping and is easy
to incorporate into any clinical workflow, including mapping in an
outpatient clinic using standard widely-available ECG equipment. It has
been shown to be a rapid and accurate technique, with a recent blinded
multicenter clinical trial showing segmental accuracy of 100%
[96-100%] and spatial accuracy of 11mm [5-22mm] for PVC
localization.8
The use of a non-invasive 12-lead ECG based mapping system to
successfully guide surgical ablation of ventricular arrhythmias is a
novel approach that can expand the indications for concomitant
arrhythmia ablation during cardiac surgery for other indications. The
familiarity of the 12-lead ECG to all physicians including cardiac
surgeons is attractive as it can be easily integrated into any clinical
pre-procedural workflow.