RESUMEN
Long-QT syndrome is a congenital cardiac disease resulting in ventricular arrhythmias and sudden death. Genetic mutations in two protein ion-channel genes, KCNQ1 and KCNH2. The mutations position in these genes provides additional information about the evaluation of the risk-stratification. In a Spanish family in whom previous repetitive syncope episodes, sudden death and pathological prolongation of the QT interval were documented, a novel heterozygous mutation in the KCNH2 gene (A1218>G) was identified. This mutation loading to amino acid substitution H420R in the S1 transmembrane domain of KCNH2. The new A1218>G mutation in the KCNH2 gene detected in this Spanish family causes arrhythmia manifestation in the carriers.
Asunto(s)
Sustitución de Aminoácidos/genética , Canales de Potasio Éter-A-Go-Go/genética , Síndrome de QT Prolongado/genética , Mutación Missense/genética , Adulto , Arginina/genética , Arritmias Cardíacas/genética , Canal de Potasio ERG1 , Femenino , Tamización de Portadores Genéticos , Histidina/genética , Humanos , Síndrome de QT Prolongado/diagnóstico , Síndrome de QT Prolongado/epidemiología , Masculino , Linaje , Estructura Terciaria de Proteína/genética , España/epidemiologíaRESUMEN
AIM: Myocardial performance index (MPI) is usually measured with pulsed wave Doppler (PWD). Our aim was to assess the degree of agreement between PWD and a method based on tissue Doppler imaging (TDI). METHODS AND RESULTS: Seventy-five patients with prior myocardial infarction and 20 healthy subjects underwent measurement of time intervals and MPI with PWD and pulsed TDI at septal and lateral sides of mitral annulus. MPI and TDI-MPI at septal side showed the best intraclass correlation coefficient (ICC=0.54; p<0.0005). Ninety-five percent interval of agreement ranged from -0.27 to 0.22. These differences were attributed to discrepancies in isovolumic contraction and relaxation times. In the healthy group the results were similar (ICC=0.44), although the 95% interval of agreement was lower (from -0.13 to 0.12). CONCLUSIONS: The agreement between PWD and TDI in the measurement of MPI is only moderate. This should be taken into account in the interpretation of studies in which TDI is used for this measurement.