Is a preoperative QT prolongation a risk factor for tachyarrhythmia and hospital mortality after arterial switch operation?

Oleg Y. Kornoukhov, Asiya A. Valitova, Maria M. Belyaeva, Svetlana R. Birukova, Vladimir N. Ilyin

Filatov Childrens Hospital, Moscow, Russia

Date, time and location: 2018.05.25 13:30, Exhibition area, 1st Floor. Zone – B

Abstract

OBJECTIVES: Long QT syndrome is defined as a disorder presenting with QT prolongation that is often associated with life-threatening arrhythmias and sudden death. We reviewed our hospital data with regard to arterial switch operation (ASO) for transposition of the great arteries to investigate an influence of a preoperative QTc value to postoperative tachyarrhythmia events and hospital mortality.

METHODS: 128 patients who underwent ASO from 2008 to 2016 were included in this retrospective study. The preoperative QTc was calculated for every patient. Two postoperative outcomes were analyzed: 1) tachyarrhythmia required a specific therapy; 2) early death. Pearson’s correlation coefficient was calculated to measure the statistical strength of a linear relationship between paired data. The t-test was used for normal continuous variables.

RESULTS: The mean preoperative QTc value was 404±41 msec. There were 16.4% (n=21) of patients with QTc more than 440 msec; 9.3% (n=12) of patients with postoperative tachyarrhythmia episodes; nine early deaths. Correlation analysis demonstrated the statistical significant positive relationships between the QTc value and postoperative arrhythmias (r=0.17; p=0,03) and between QTc and early postoperative death (r=0.147; p=0,048). The mean QTc values were significantly longer in group of patients with arrhythmia episodes (426±59 versus 402±38 msec, p<0.016) and in those who died after ASO (426±62 versus 403±38 msec, p<0.017).

CONCLUSIONS: The data of our study suggest that in this consecutive series of patients the preoperative QTc value had a positive correlation with postoperative tachyarrhythmia episodes and hospital mortality. Further work is needed to refine a cutoff value of QTc that could predict the risk of adverse events and death after ASO.