Case description
A 65-year-old man with a history of a circumferential PV isolation for
paroxysmal atrial fibrillation (AF) and sick sinus syndrome underwent a
second ablation procedure for recurrent paroxysmal AF. Twelve-lead ECG
during sinus rhythm exhibited biphasic and split P-wave with a prolonged
duration, which called notched P-wave (NPW, Figure 1A). Echocardiography
revealed a normal LV systolic and diastolic function and an LA diameter
of 31 mm. Written informed consent was obtained before the procedure. An
electrophysiological study was conducted in the fasting state and under
deep conscious sedation. Although the first component of the NPW was
formed by the total atrial activation including that of the LA
appendage, the timing of the second component of the NPW was identical
to that of the coronary sinus (CS) activation (Figure 1B). Activation
mapping during distal CS pacing using an electroanatomical mapping
system (CARTO3, Biosense Webster Inc., Diamond Bar, CA, USA)
demonstrated 2 remote earliest activation sites in the LA near the
anterolateral mitral annulus and inferior mitral annulus, respectively
(Figure 2A). The shortest interval between the pacing stimulation spike
to the LA was 45 ms suggesting selective local capture of the CS
musculature (Figure 2B). Reconnections of the left superior PV and right
inferior PV were also noted. AF was spontaneously initiated by an
ectopic beat and repeated immediate recurrences occurred after
electrical defibrillation even after the achievement of the PV
isolation. Complex fractionated atrial electrograms were recorded at the
LA lateral wall, LA appendage, and CS. Therefore, additional ablation at
the mitral annulus and LA lateral wall was performed, however, it did
not terminate the AF. The second component of the NPW remained unchanged
after the ablation. Radio-frequency applications in distal portion of CS
terminated AF and eliminated the ectopic beats (Figure 3) along with the
disappearance of the second component of the P-wave (Figure 1B).
Eventually, sinus rhythm was maintained, and AF was no longer induced by
programmed stimulation with or without isoproterenol.