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Terminal QRS Distortion in ST Elevation Myocardial Infarction as a Prediction of Mortality: Systematic Review and Meta-Analysis.

Background
Terminal QRS distortion reflects advanced stage and large myocardial infarction predisposing the heart to adverse outcomes. Recent studies suggest that terminal QRS distortion is associated with morbidity and mortality in ST elevation myocardial infarction (STEMI). However, a systematic review and meta-analysis of the literature have not been done.


Objective
We assessed the association between terminal QRS distortion in patients with STEMI and mortality by a systematic review of the literature and a meta-analysis.


Methods
We comprehensively searched the databases of MEDLINE and EMBASE from inception to September 2017. Included studies were published prospective or retrospective cohort studies that compared all-cause mortality in subjects with STEMI with QRS distortion versus those without QRS distortion. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals.


Results
Fifteen studies from January 1993 to May 2015 were included in this meta-analysis involving 7,479 subjects with STEMI (2,906 QRS distortion and 4,573 non-QRS distortion). QRS distortion was associated with increased mortality (pooled risk ratio = 1.81, 95% confidence interval: 1.37-2.40, p < 0.000, I2 = 41.6%). Considering the introduction of clopidogrel in 2004, we performed subgroup analyses before and after 2004, and the associated with higher mortality was still present (before 2004, RR 1.75, 95% CI 1.08-2.82, p = 0.022, I2 = 66.1%; after 2004, RR 1.96, 95% CI 1.44-2.65, p < 0.001, I2 = 0%).


Conclusions
Terminal QRS distortion increased all-cause mortality by 81%. Our study suggests that terminal QRS distortion is an important tool to assess the risk in patients with STEMI.