PMID- 16500301
OWN - NLM
STAT- MEDLINE
DCOM- 20061013
LR  - 20161222
IS  - 1547-5271 (Print)
IS  - 1547-5271 (Linking)
VI  - 3
IP  - 3
DP  - 2006 Mar
TI  - Diurnal variation of ventricular repolarization in a large family with 
      LQT3-Brugada syndrome characterized by nocturnal sudden death.
PG  - 290-5
AB  - BACKGROUND: In patients with long-QT syndrome type 3 (LQT3), symptoms occur 
      particularly at rest or during sleep. As to the underlying mechanism, excessive 
      prolongation of the QT interval at slow heart rates probably plays a role. 
      OBJECTIVES: The purpose of the present study was to investigate QT interval 
      prolongation unrelated to heart rate comparing nighttime and daytime in a family 
      with features of both LQT3 and Brugada syndrome. METHODS: The study group 
      consisted of 38 carriers of the mutant gene (SCN5A, 1795insD) and 30 noncarrier 
      family members, who served as controls. Holter monitoring was performed with 
      beat-to-beat QT interval measurement. In addition, in a subset of subjects, an 
      exercise test and a pacing test (carriers only) with measurement of the RT 
      interval were performed. RESULTS: In carriers, the slope between heart rate and 
      QT interval was significantly steeper during nighttime (0:00 a.m. to 6:00 a.m.) 
      than during daytime (8:00 a.m. to 22:00 p.m.) (regression coefficient -6.18 and 
      -2.80, respectively), (p=0.03),no such effect being observed in the noncarriers. 
      Further, the RT interval was markedly shorter during recovery than during 
      exercise in carriers but not in noncarriers. In contrast, during AAI pacing in 
      the carriers, RT interval shortening along with increasing heart rate was 
      followed by a comparable prolongation of the RT interval along with subsequent 
      decreasing heart rate. CONCLUSIONS: In this large LQT3-Brugada syndrome family, 
      carriers of the mutant gene (SCN5A, 1795insD) are characterized by diurnal 
      variation of ventricular repolarization by exhibiting QT interval prolongation, 
      which is more pronounced during nighttime compared with daytime, even when taking 
      into account differences in heart rate. The autonomic nervous system appears to 
      play a role in mediating this effect. This observation may be of relevance for 
      explaining the high incidence of nocturnal sudden death in this family, but this 
      remains to be proven. In addition, whether our findings also apply to other 
      families with LQT3 is uncertain.
FAU - van den Berg, Maarten P
AU  - van den Berg MP
AD  - Department of Cardiology, University Medical Center Groningen, University of 
      Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands. 
      m.p.van.den.berg@thorax.umcg.nl
FAU - Haaksma, Jaap
AU  - Haaksma J
FAU - Veeger, Nic J G M
AU  - Veeger NJ
FAU - Wilde, Arthur A M
AU  - Wilde AA
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Heart Rhythm
JT  - Heart rhythm
JID - 101200317
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Autonomic Nervous System/physiology
MH  - Bundle-Branch Block/genetics/physiopathology
MH  - Cardiac Pacing, Artificial
MH  - Case-Control Studies
MH  - *Circadian Rhythm/physiology
MH  - Death, Sudden, Cardiac/*etiology
MH  - Electrocardiography, Ambulatory
MH  - Exercise Test
MH  - Female
MH  - Heart Rate/*physiology
MH  - Humans
MH  - Long QT Syndrome/*genetics/mortality/*physiopathology
MH  - Male
MH  - Mutation
EDAT- 2006/02/28 09:00
MHDA- 2006/10/14 09:00
CRDT- 2006/02/28 09:00
PHST- 2005/07/18 00:00 [received]
PHST- 2006/02/28 09:00 [pubmed]
PHST- 2006/10/14 09:00 [medline]
PHST- 2006/02/28 09:00 [entrez]
AID - S1547-5271(05)02357-X [pii]
AID - 10.1016/j.hrthm.2005.11.023 [doi]
PST - ppublish
SO  - Heart Rhythm. 2006 Mar;3(3):290-5. doi: 10.1016/j.hrthm.2005.11.023.