Paroxysmal atrioventricular block induced during head-up tilt testing in an apparently healthy man.
BACKGROUND
Prolonged asystole during head-up tilt testing has been reported, but the occurrence of paroxysmal AV block appears to be rare.


RESULTS
A 25-year-old man with no history of syncope underwent head-up tilt testing. After 11 minutes of 80 degrees 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.


CONCLUSIONS
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.
Sumiyoshi
M
M
Department of Cardiology, Juntendo University Izunagaoka Hospital, Shizuoka, Japan.
Nakata
Y
Y
Mineda
Y
Y
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D018660:Blood Pressure Monitoring, Ambulatory; D005080:Exercise Test; D006327:Heart Block / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D013575:Syncope / Q000503:physiopathology; D018667:Tilt-Table Test