Figure
1: Panel A shows the 12-lead ECG intrinsic LBBB with QRS duration of
196ms (the precordial leads were placed on the right side due to
dextroposition of the heart chambers); Panel B shows the 12-lead ECG
after His-CRT with QRS duration of 146ms and correction of the LBBB;
Panel C shows the cardiac CT scan demonstrating the ‘Scimitar’ vein –
anomalous drainage of the right pulmonary vein into the IVC. RA = right
atrium, RV = right ventricle, LV = left ventricle, PA = pulmonary
artery, IVC = inferior vena cava, SV = Scimitar vein.
Figure 2: Panel A shows the CARTOSEG™ modality wherein the
Cardiac CT was integrated onto the CARTO™ electro-anatomical mapping
system. Note the perpendicular orientation of the interventricular
septum at RAO 20; Panels B and C show the geometries created by an
electrophysiology catheter which was integrated with the cardiac CT
scan. His bundle (yellow marker) was tagged (white arrow). Panel D and E
show the intracardiac electrograms observed with the lead. The distal
H-V was 58ms. Pacing at this site resulted in correction of the LBBB; AP
= antero-posterior, RAO = right anterior oblique, LAO = left anterior
oblique, TA = tricuspid annulus, CS = coronary sinus, RA = right atrium,
RAA = right atrial appendage, RV = right ventricle, RVOT = right
ventricular outflow tract, LV = left ventricle, PA = pulmonary artery,
IVC = inferior vena cava.