Background: Patients after myocardial infarction (MI) are at greater risk of sudden cardiac death (SCD) than people in the overall population. The aim of this study was to detect mutations, including intronic ones, in the KCNQ1 gene coding for proteins of cardiac potassium channels and evaluate their possible effects on the clinical course in patients after MI.
Methods: The study group was composed of 100 Polish patients after MI, which included 27 women (mean age 69 years) and 73 men (mean age 67 years). All patients underwent clinical examinations and genetic tests. The genetic test results have been correlated with the clinical data. The following parameters have been chosen as endpoints for this survey: sudden cardiac arrest (SCA) or SCD, complex ventricular arrhythmia, QT interval and QT dispersion values assessed during 24-hour Holter ECG monitoring in relation to ventricular arrhythmias as well as the minimum and maximum heart rate (HR) observed during the examination.
Results: Six new mutations in the KCNQ1 gene: C2505734T, A2753831C in exons and C2505846A, G2753881A, T2755854C, T2755875G in introns. Detected intronic mutations in patients after MI were related to a worse clinical course and frequent occurrence of SCA.
Conclusions: The novel intronic mutations may have a significant influence on the clinical course of the disease. (Cardiol J 2008; 15: 252-260)