BACKGROUND: The congenital long-QT syndrome, caused by mutations in cardiac potassium-channel genes (KVLQT1 at the LQT1 locus and HERG at the LQT2 locus) and the sodium-channel gene (SCN5A at the LQT3 locus), has distinct repolarization patterns on electrocardiography, but it is not known whether the genotype influences the clinical course of the disease. METHODS: We determined the genotypes of 541 of 1378 members of 38 families enrolled in the International Long-QT Syndrome Registry: 112 had mutations at the LQT1 locus, 72 had mutations at the LQT2 locus, and 62 had mutations at the LQT3 locus. We determined the cumulative probability and lethality of cardiac events (syncope, aborted cardiac arrest, or sudden death) occurring from birth through the age of 40 years according to genotype in the 246 gene carriers and in all 1378 members of the families studied. RESULTS: The frequency of cardiac events was higher among subjects with mutations at the LQT1 locus (63 percent) or the LQT2 locus (46 percent) than among subjects with mutations at the LQT3 locus (18 percent) (P<0.001 for the comparison of all three groups). In a multivariate Cox analysis, the genotype and the QT interval corrected for heart rate were significant independent predictors of a first cardiac event. The cumulative mortality through the age of 40 among members of the three groups of families studied was similar; however, the likelihood of dying during a cardiac event was significantly higher (P<0.001) among families with mutations at the LQT3 locus (20 percent) than among those with mutations at the LQT1 locus (4 percent) or the LQT2 locus (4 percent). CONCLUSIONS: The genotype of the long-QT syndrome influences the clinical course. The risk of cardiac events is significantly higher among subjects with mutations at the LQT1 or LQT2 locus than among those with mutations at the LQT3 locus. Although cumulative mortality is similar regardless of the genotype, the percentage of cardiac events that are lethal is significantly higher in families with mutations at the LQT3 locus.
BACKGROUND: The congenital long-QT syndrome, caused by mutations in cardiac potassium-channel genes (KVLQT1 at the LQT1 locus and HERG at the LQT2 locus) and the sodium-channel gene (SCN5A at the LQT3 locus), has distinct repolarization patterns on electrocardiography, but it is not known whether the genotype influences the clinical course of the disease. METHODS: We determined the genotypes of 541 of 1378 members of 38 families enrolled in the International Long-QT Syndrome Registry: 112 had mutations at the LQT1 locus, 72 had mutations at the LQT2 locus, and 62 had mutations at the LQT3 locus. We determined the cumulative probability and lethality of cardiac events (syncope, aborted cardiac arrest, or sudden death) occurring from birth through the age of 40 years according to genotype in the 246 gene carriers and in all 1378 members of the families studied. RESULTS: The frequency of cardiac events was higher among subjects with mutations at the LQT1 locus (63 percent) or the LQT2 locus (46 percent) than among subjects with mutations at the LQT3 locus (18 percent) (P<0.001 for the comparison of all three groups). In a multivariate Cox analysis, the genotype and the QT interval corrected for heart rate were significant independent predictors of a first cardiac event. The cumulative mortality through the age of 40 among members of the three groups of families studied was similar; however, the likelihood of dying during a cardiac event was significantly higher (P<0.001) among families with mutations at the LQT3 locus (20 percent) than among those with mutations at the LQT1 locus (4 percent) or the LQT2 locus (4 percent). CONCLUSIONS: The genotype of the long-QT syndrome influences the clinical course. The risk of cardiac events is significantly higher among subjects with mutations at the LQT1 or LQT2 locus than among those with mutations at the LQT3 locus. Although cumulative mortality is similar regardless of the genotype, the percentage of cardiac events that are lethal is significantly higher in families with mutations at the LQT3 locus.
Authors: Jesaia Benhorin; Arthur J Moss; Matthew Bak; Wojciech Zareba; Elizabeth S Kaufman; Batsheva Kerem; Jeffrey A Towbin; Silvia Priori; Robert S Kass; Bernard Attali; Arthur M Brown; Eckhard Ficker Journal: Ann Noninvasive Electrocardiol Date: 2002-01 Impact factor: 1.468
Authors: Alon Barsheshet; Arthur J Moss; Scott McNitt; Slava Polonsky; Coeli M Lopes; Wojciech Zareba; Jennifer L Robinson; Michael J Ackerman; Jesaia Benhorin; Elizabeth S Kaufman; Jeffrey A Towbin; G Michael Vincent; Ming Qi; Ilan Goldenberg Journal: Circ Cardiovasc Genet Date: 2011-08-10
Authors: Martin Tristani-Firouzi; Judy L Jensen; Matthew R Donaldson; Valeria Sansone; Giovanni Meola; Angelika Hahn; Said Bendahhou; Hubert Kwiecinski; Anna Fidzianska; Nikki Plaster; Ying-Hui Fu; Louis J Ptacek; Rabi Tawil Journal: J Clin Invest Date: 2002-08 Impact factor: 14.808
Authors: Anant Khositseth; Jan Nemec; Joseph Hejlik; Win K Shen; Michael J Ackerman Journal: Ann Noninvasive Electrocardiol Date: 2003-07 Impact factor: 1.468
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