Atrial double potential associated with electrical connection between the coronary sinus musculature and the left atrium in a patient with Wolff-Parkinson-White syndrome.

We reported a case of Wolff-Parkinson-White syndrome with atrial double potential in coronary sinus (CS) electrograms during paroxysmal supraventricular tachycardia and ventricular pacing. The first component was low in frequency, and its timing was the same as atrial potential recorded by ablation catheter above the mitral annulus by transseptal approach; the second portion was high in frequency. The accessory pathway conduction was completely eliminated after ablation on the atrial site. We speculated that the discrete musculature connection between left atrium and CS was responsible for the pattern of double potential activation in the CS electrograms during paroxysmal supraventricular tachycardia and ventricular pacing.