Case Report
An 84-year-old woman was referred to our hospital due to heart failure
with wide QRS tachcardia associated with AF. She was diagnosed as
Wolf-Parkinson-White syndrome in 1996, however catheter ablation of the
right posterolateral accessary pathway at that time was unsuccessful
under fluoroscopy. She was not taking anticoagulants because her AF had
not been noted. After administration of medication for heart failure and
oral anticoagulant, transoesophageal echocardiography showed the
presence of a thrombus in the left atrium. We decided to perform
catheter ablation under AF.
An electrophysiological study (EPS) was performed under local
anaesthesia, and the position of the tricuspid valve was mapped using
the CARTO (Biosense Webster, Diamond Bar, CA) ICE catheter (Sound Star
Biosense Webster) to evaluate the functional tricuspid anulus (TA). The
functional TA was significantly deviated to the right ventricular side
(Figure 1-A-1). The location of the functional TA was tagged using ICE
(Figure 1-A-2,3). After insertion of the His-RV catheter, a high-density
mapping catheter (penta-ray Biosense Webster) and a ablation catheter
(ThermoCool Smarttouch Surroundflow catheter (STSFc), Biosense Webster)
were advanced into the right atrium and right ventricle, and activation
maps were generated using an electroanatomical mapping system (CARTO 3
System Version 7, Biosense Webster). Mapping was done under AF and both
ventricular and atrial electrogram were recorded on the tricuspid
annulus. The activation timing was automatically annotated using a local
activation time (LAT) annotation tool integrated in the CARTO system.
Activation mapping was performed concerning the body surface advanced
referenced annotation (ARA) algorithm. The window of interest was set to
cover the earliest V-wave of the endocardial ECG. Because of the mixture
of narrow QRS via atrioventricular node and wide QRS complex with
pre-excitation (Figure 2), the CARTO3 Confidence Module with pattern
matching was used to acquire the points of the QRS automatically. The
QRS morphology of maxmum pre-excitation was acquired, and the
correlation threshold was set to ≥0.97. Position stability was set to 3
mm, and the mapping density was set to maximum. One thousand eight
hundred forty-three points of maximum prepexcitation patterns were
mapped in 15 min. Since the AF electrogram was recorded simultaneously,
the earliest ventricular activity could not be detected by mapping using
a LAT map (Figure3-A). We used 3D intra-cardiac electrograms
visualisation (Ripple map (RM) module), which does not require
annotation of the timing of excitation and reflects all excitations on
the map even if there are multiple excitations in the window of
interest. The RM clearly visualized the consistent propagation around TA
via the accessary pathway (Figure3-B, supplemental movie). The fusion
point of the ventricular and atrial activity was more to the right
atrial side than the functional anulus mapped using ICE (Figure 1 B-2)
and coincided with the location of the earliest ventricular activity
expressed by RM (Figure 3 B-1,2,3). When the the fusion point was
energised at a maximum of 35W, the wide QRS wave disappeared, and only
the irregular narrow QRS beats were observed after 5 seconds of ablation
(Figure 1 B-1). Postoperative echocardiography showed improvement in
left ventricular ejection fraction, and the patient was confirmed with
an Ebstein anomaly on transbusturacic echocardiography.