Figure legends:
Fig 1: Body surface ECG (I, II and V1) and intracardiac electrograms
during sinus rhythm (sinus cycle length, 1000 ms) (A) and during pacing
from the distal coronary sinus (pacing cycle length, 600 ms) (B) at a
sweep speed of 25 mm/s (A-1/B-1) and 100 mm/s (A-2/B-2).
RA indicates right atrium; LSPV, left superior pulmonary vein; CS p/m/d,
proximal/mid/distal coronary sinus; CL, cycle length.
Fig 2: Body surface ECG (I, II and V1) and intracardiac electrograms
during pacing from the distal coronary sinus (pacing cycle length, 750
ms) at a sweep speed of 25 mm/s (A) and 50 mm/s (B).
RA indicates right atrium; LSPV, left superior pulmonary vein; CS p/m/d,
proximal/mid/distal coronary sinus; CL, cycle length.
Fig 3: (A) Body surface ECG (I, II and V1) and intracardiac electrograms
during pacing from the distal coronary sinus [pacing cycle length
(CL), 750 ms] at a sweep speed of 150 mm/s. Arrows indicate the
earliest pulmonary vein (PV) potential of each beat. Asterisks represent
far-field signal from adjacent left atrial appendage. The numbers denote
cycle length (ms).
RA indicates right atrium; LSPV, left superior pulmonary vein; CS p/m/d,
proximal/mid/distal coronary sinus; CL, cycle length.
(B) Proposed mechanism of the intra-PV reentry causing the echoes.
Pink areas indicate atrial myocardium or myocardial sleeves. Purple
areas represent slow conduction zones. LA denotes left atrium.