Evaluation of the Relationship between Corrected QT Interval and the Development of Coronary Slow flow in Patients with ST-elevation Myocardial Infarction

Objective: Corrected thrombolysis in myocardial infarction frame count (CTFC) is a quantitative angiographic method for assessing coronary flow after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). Corrected QT interval (QTc) is associated with myocardial ischemia and adverse cardiovascular outcomes; however, its relationship with CTFC remains unclear. This study evaluated the relationship between QTc interval and CTFC in patients with STEMI undergoing primary PCI. Methods: This retrospective study included 133 STEMI patients who underwent successful primary PCI. Clinical, laboratory, electrocardiographic, and angiographic data were analyzed. QTc interval was calculated from admission electrocardiograms, and coronary flow was assessed by post-procedural CTFC. Correlations between CTFC and study variables were analyzed using Spearman correlation analysis. Results: The mean age was 56±12 years, and 80.5% were male. The mean QTc interval was 457.46±55.92 ms, and the mean CTFC value was 35.78±22.99. No significant relationship was observed between QTc interval and CTFC (r=-0.020; p=0.816). Among laboratory parameters, only neutrophil count showed a positive correlation with CTFC (r=0.177; p=0.042), whereas lymphocyte count showed a negative correlation with CTFC (r=-0.178; p=0.040). No significant relationship was found between CTFC and other clinical, laboratory, or procedural variables. Conclusion: This finding suggests that the QTc interval may not be a reliable indicator of post-procedural coronary flow as assessed by CTFC. However, the association of neutrophil and lymphocyte counts with CTFC supports the role of inflammation in coronary microvascular perfusion.