Relationship between frontal QRS-T angle and coronary slow flow phenomenon

Abstract

Background/Aim: Coronary slow flow phenomenon (CSFP) is termed as slow passage of contrast dye to distal portion of the coronary arteries, and can provoke angina pectoris, serious arrhythmias, or even sudden death. Previous reports suggested that frontal QRS-T angle (fQRSTa), measured by surface ECG may associate with ventricular arrhythmias and cardiac death. In this study, we aimed to assess the relationship between fQRSTa and CSFP. Methods: In this case-control study, we retrospectively included 76 patients with CSFP [85.5% male; mean age 58.4 (9.2) years] and 50 patients with normal coronary flow (control group) [86.6% male; mean age 56.5 (10.1) years] between July 2017 and March 2019. CSFP was identified by TIMI frame count (TFC) method. Demographic, clinical and ECG characteristics were obtained from hospital records. Results: The groups were similar concerning co-morbid cardiac conditions. Mean QTc interval and median fQRSTa were significantly greater in CSFP group compared with the controls [416.2 (34.5) vs 401 (36.3), P=0.020 and 51° (11° to 132°) vs 27° (4° to 92°), P<0.001; respectively]. Conclusion: The findings may suggest a possible distortion in cardiac electrical micropathways and indicate an increased likelihood of arrhythmia.