ACC
: American College of Cardiology
ACE
: angiotensin-converting enzyme
ACS
: acute coronary syndrome
AF
: atrial fibrillation
AGNES
: Arrhythmia Genetics in the Netherlands
AHA
: American Heart Association
AMIOVIRT
: AMIOdarone Versus Implantable cardioverter-defibrillator:

/pdf/2015-esc-guidelines-for-the-management-of-patients-with-3hzn8vw0c4.pdf

2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC)

2015 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

/pdf/2015-esc-guidelines-for-the-management-of-patients-with-4lhfmy4xir.pdf

2015 ESC Guidelines for the Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death.

Genetic factors contribute to the risk of sudden death from cardiac arrhythmias. Here, positional cloning methods establish KVLQT1 as the chromosome 11-linked LQT1 gene responsible for the most common inherited cardiac arrhythmia. KVLQT1 is strongly expressed in the heart and encodes a protein with structural features of a voltage-gated potassium channel. KVLQT1 mutations are present in affected members of 16 arrhythmia families, including one intragenic deletion and ten different missense mutations. These data define KVLQT1 as a novel cardiac potassium channel gene and show that mutations in this gene cause susceptibility to ventricular tachyarrhythmias and sudden death.

Positional cloning of a novel potassium channel gene: KVLQT1 mutations cause cardiac arrhythmias.

Background The congenital long-QT syndrome (LQTS) is caused by mutations on several genes, all of which encode cardiac ion channels. The progressive understanding of the electrophysiological consequences of these mutations opens unforeseen possibilities for genotype-phenotype correlation studies. Preliminary observations suggested that the conditions ("triggers") associated with cardiac events may in large part be gene specific. Methods and results We identified 670 LQTS patients of known genotype (LQT1, n=371; LQT2, n=234; LQT3, n=65) who had symptoms (syncope, cardiac arrest, sudden death) and examined whether 3 specific triggers (exercise, emotion, and sleep/rest without arousal) differed according to genotype. LQT1 patients experienced the majority of their events (62%) during exercise, and only 3% occurred during rest/sleep. These percentages were almost reversed among LQT2 and LQT3 patients, who were less likely to have events during exercise (13%) and more likely to have events during rest/sleep (29% and 39%). Lethal and nonlethal events followed the same pattern. Corrected QT interval did not differ among LQT1, LQT2, and LQT3 patients (498, 497, and 506 ms, respectively). The percent of patients who were free of recurrence with ss-blocker therapy was higher and the death rate was lower among LQT1 patients (81% and 4%, respectively) than among LQT2 (59% and 4%, respectively) and LQT3 (50% and 17%, respectively) patients. Conclusions Life-threatening arrhythmias in LQTS patients tend to occur under specific circumstances in a gene-specific manner. These data allow new insights into the mechanisms that relate the electrophysiological consequences of mutations on specific genes to clinical manifestations and offer the possibility of complementing traditional therapy with gene-specific approaches.

Genotype-Phenotype Correlation in the Long-QT Syndrome Gene-Specific Triggers for Life-Threatening Arrhythmias

HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes: document endorsed by HRS, EHRA, and APHRS in May 2013 and by ACCF, AHA, PACES, and AEPC in June 2013.

Background The genes for the long QT syndrome (LQTS) linked to chromosomes 3 (LQT3) and 7 (LQT2) were identified as SCN5A, the cardiac Na+ channel gene, and as HERG, a K+ channel gene. These findings opened the possibility of attempting gene-specific control of ventricular repolarization. We tested the hypothesis that the QT interval would shorten more in LQT3 than in LQT2 patients in response to mexiletine and also in response to increases in heart rate. Methods and Results Fifteen LQTS patients were studied. Six LQT3 and 7 LQT2 patients were treated with mexiletine, and its effects on QT and QTc were measured. Mexiletine significantly shortened the QT interval among LQT3 patients (QTc from 535±32 to 445±31 ms, P<.005) but not among LQT2 patients (QTc from 530±79 to 503±60 ms, P=NS). LQT3 patients (n=7) shortened their QT interval in response to increases in heart rate much more than LQT2 patients (n=4) and also more than 18 healthy control subjects (9.45±3.3 versus 3.95±1.97 and 2.83±1.33, P<.05; data e...

Long QT syndrome patients with mutations of the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate : implications for gene-specific therapy

Erratum: Long QT syndrome patients with mutations on the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate: Implications for gene-specific therapy (Circulation (1995) 92 (3381-3386))

Long QT syndrome patients genetically linked to defective genes on chromosomes 11, 7 and 3 present differential response to changes in heart rate

As non-canonical nucleic acid secondary structures consisting of cytosine-rich nucleic acids, i-motifs can form under certain conditions. Several i-motif sequences have been identified in the human genome and play important roles in biological regulatory functions. Due to their physicochemical properties, these i-motif structures have attracted attention and are new targets for drug development. Herein, we reviewed the characteristics and mechanisms of i-motifs located in gene promoters (including c-myc, Bcl-2, VEGF, and telomeres), summarized various small molecule ligands that interact with them, and the possible binding modes between ligands and i-motifs, and described their effects on gene expression. Furthermore, we discussed diseases closely associated with i-motifs. Among these, cancer is closely associated with i-motifs since i-motifs can form in some regions of most oncogenes. Finally, we introduced recent advances in the applications of i-motifs in multiple areas.

/pdf/emerging-roles-of-i-motif-in-gene-expression-and-disease-2a3z0mse.pdf

Ling Sing K. Chen

Papers

Long QT syndrome patients with mutations of the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate : implications for gene-specific therapy

Erratum: Long QT syndrome patients with mutations on the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate: Implications for gene-specific therapy (Circulation (1995) 92 (3381-3386))

Long QT syndrome patients genetically linked to defective genes on chromosomes 11, 7 and 3 present differential response to changes in heart rate

Emerging roles of i-motif in gene expression and disease treatment