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- Title
Abnormal Response to Exercise, Face Immersion, and Isoproterenol in Children with the Long QT Syndrome.
- Authors
Katagiri-Kawade, Mayumi; Ohe, Tohru; Arakaki, Yoshio; Kurita, Takashi; Shimizu, Wataru; Kamiya, Tetstsuro; Orii, Tadao
- Abstract
The present study was performed to observe the change of QT interval by sympathetic stimulations in patients with the long QT syndrome (LQTS). The study group consisted of 6 children with LQTS and 6 healthy children without QT prolongation. All LSQTS patients had syncopal episodes. The QTc and ΔQTc% (1QTc interval after examination - QTc interval at rest/QTc interval at rest × 100) by treadmill testing, face immersion, and isoproterenol were examined. One minute after peak exercise of treadmill testing, the changes in the QTc interval were not significant in either group, but ΔQTc% was larger in the LQTS group than in the control group (+11.0 ± 12.1% vs -2.6 ± 3.2%;P = 0.02). The QTc interval at the shortest RB interval during face immersion was prolonged in the LQTS group (0.47 ± 0.01 s to 0.51 ± 0.04 s; P = 0.02), but there were no significant changes in the control group (0.40 ± 0.03 s to 0.41 ± 0.03 s: P = NS). ΔQTc% was larger in the LQTS group than in the control group (+ 10.0 ± 7.3% vs + 1.1 ± 5.5%; P = 0.04). In the LQTS group, the BR interval was shortened (P = 0.009) and QTc interval was prolonged (P = 0.0008) after isoproterenol infusion. These sympathetic stimulations amplified the TU abnormality in the LQTS group. By observing the TU changes caused by face immersion, we hoped to find a possible new method with which to diagnose LQTS. The combination of these examinations may be helpful in screening the borderline cases of TU abnormalities.
- Subjects
EXERCISE physiology; LONG QT syndrome; ARRHYTHMIA in children; EXERCISE tests; HEART diseases; SICK sinus syndrome in children; PEDIATRIC cardiology
- Publication
Pacing & Clinical Electrophysiology, 1995, Vol 18, Issue 12, p2128
- ISSN
0147-8389
- Publication type
Article
- DOI
10.1111/j.1540-8159.1995.tb04637.x