BACKGROUND: The identification of the molecular-genetic substrate underlying the various forms of the congenital long-QT syndrome (LQTS) has sparked studies into possible genotype-phenotype correlations with the aim of developing genotype-tailored therapy. The onset of torsade de pointes (TdP) may differ among LQTS patients, being pause dependent in some but not all. This disparity may point to different arrhythmia mechanisms and may affect therapy strategies. We studied whether the proportion of pause-dependent TdP onset varies among LQTS genotypes. METHODS AND RESULTS: We studied all LQT1 (n=10), LQT2 (n=34), and LQT3 (n=6) patients from 4 centers for whom ECGs of TdP onset were available and analyzed whether pauses preceded TdP onset (first available ECG per patient). Pauses preceded TdP significantly more often in LQT2 (68%) than in LQT1 (0%), and the interval immediately before TdP (pause interval) was significantly longer in LQT2 than in LQT1. The proportion of pause dependence in LQT3 (33%) appeared intermediate, but this group was too small for statistical analysis. CONCLUSIONS: Pause dependence of TdP onset is predominant in LQT2 but absent or rare in LQT1. It is suggested that disparities in pause dependence of TdP onset may reflect different arrhythmia mechanisms.
BACKGROUND: The identification of the molecular-genetic substrate underlying the various forms of the congenital long-QT syndrome (LQTS) has sparked studies into possible genotype-phenotype correlations with the aim of developing genotype-tailored therapy. The onset of torsade de pointes (TdP) may differ among LQTS patients, being pause dependent in some but not all. This disparity may point to different arrhythmia mechanisms and may affect therapy strategies. We studied whether the proportion of pause-dependent TdP onset varies among LQTS genotypes. METHODS AND RESULTS: We studied all LQT1 (n=10), LQT2 (n=34), and LQT3 (n=6) patients from 4 centers for whom ECGs of TdP onset were available and analyzed whether pauses preceded TdP onset (first available ECG per patient). Pauses preceded TdP significantly more often in LQT2 (68%) than in LQT1 (0%), and the interval immediately before TdP (pause interval) was significantly longer in LQT2 than in LQT1. The proportion of pause dependence in LQT3 (33%) appeared intermediate, but this group was too small for statistical analysis. CONCLUSIONS: Pause dependence of TdP onset is predominant in LQT2 but absent or rare in LQT1. It is suggested that disparities in pause dependence of TdP onset may reflect different arrhythmia mechanisms.
Authors: Jonathan Buber; Jehu Mathew; Arthur J Moss; W Jackson Hall; Alon Barsheshet; Scott McNitt; Jennifer L Robinson; Wojciech Zareba; Michael J Ackerman; Elizabeth S Kaufman; David Luria; Michael Eldar; Jeffrey A Towbin; Michael Vincent; Ilan Goldenberg Journal: Circulation Date: 2011-05-31 Impact factor: 29.690
Authors: Chunyan Shao; Yan Lu; Mohan Liu; Qi Chen; Yunfeng Lan; Yan Liu; Min Lin; Yang Li Journal: J Huazhong Univ Sci Technolog Med Sci Date: 2011-12-16
Authors: Josef Halamek; Jean-Philippe Couderc; Pavel Jurak; Vlastimil Vondra; Wojciech Zareba; Ivo Viscor; Pavel Leinveber Journal: Ann Noninvasive Electrocardiol Date: 2012-08-13 Impact factor: 1.468
Authors: Larissa Fabritz; Dierk Damke; Markus Emmerich; Susann G Kaufmann; Kathrin Theis; Andreas Blana; Lisa Fortmüller; Sandra Laakmann; Sven Hermann; Elena Aleynichenko; Johannes Steinfurt; Daniela Volkery; Burkhard Riemann; Uwe Kirchhefer; Michael R Franz; Günter Breithardt; Edward Carmeliet; Michael Schäfers; Sebastian K G Maier; Peter Carmeliet; Paulus Kirchhof Journal: Cardiovasc Res Date: 2010-01-28 Impact factor: 10.787