Paroxysmal atrioventricular block induced during head-up tilt testing in an apparently healthy man

Abstract

Introduction: Prolonged asystole during head-up tilt testing has been reported, but the occurrence of paroxysmal AV block appears to be rare. Methods and Results: A 25-year-old man with no history of syncope underwent head-up tilt testing. After 11 minutes of 80°tilting, he developed syncope with paroxysmal AV block and asystole lasting 10.5 seconds. However, this response was not reproduced during a subsequent tilt test 4 weeks later. Treadmill exercise testing and Holter monitoring showed no abnormalities. Power spectral analysis of heart rate variability revealed a marked increase in sympathetic activity several minutes before the induction of paroxysmal AV block. Conclusion: We report a case of paroxysmal AV block that occurred during head-up tilt testing but did not recur on a subsequent test in an apparently healthy young man.