A case of Wolff-Parkinson-White syndrome: conduction through the Kent bundle seems to depend on the serum potassium level.

A 72-year-old man with Wolff-Parkinson-White syndrome and sick sinus syndrome had colon cancer, suggesting that the conduction of the Kent bundle depends on the serum potassium level. Because of severe diarrhea or furosemide administration, the serum potassium level in this patient was sometimes low. When it was less than 3.0 mEq/l delta wave or re-entrant tachycardia via the Kent bundle occurred. These were suppressed by the administration of potassium. On the other hand, when the serum potassium level was normal or high, neither effect was noted, and electrophysiological studies, done when the level was 3.2 mEq/l, showed no evidence of conduction by the accessory pathway. This suggests that conduction through the Kent bundle depends on the serum potassium level.