Effect of slow coronary flow on signal-averaged electrocardiogram

The slow flow coronary or decreased coronary TIMI flow rate is characterized by delayed pacification of coronary vessels in the absence of any evidence of obstruction coronary artery disease and is detected by coronary angiography. In the present study, we aimed to evaluate the effects of slow coronary artery flow on signal-averaged electrocardiogram (SAECG) as a possible indicator of increased risk for ventricular arrhythmias and sudden cardiac death. Methods The study included 43 patients with angiographically proven normal coronary arteries and slow coronary flow (mean age = 53.7 +/- 8.3 years), and 43 patients with angiographically proven normal coronary arteries without associated slow coronary flow (mean age = 52.8 +/- 8.5 years). Coronary flow rates of all subjects were documented by thrombolysis in myocardial infarction frame count (TIMI frame count). SAECG was performed for each subject and late potentials were measured. Results There was no statistically significant difference between the two groups in respect to age, gender, presence of hypertension, diabetes mellitus, opium addiction, cigarette smoking, typical angina, and positive exercise, blood sugar, white blood cell count and platelet count. There was a significant difference between the two groups in respect to the lipid profiles, uric acid level, body mass index, hemoglobin and positive CRP (P < 0.05). Abnormal SAECG was more frequent in SCF compared to control subjects (P=0.003). Conclusion Abnormal SAECG and late potentials, indicating increased risk for ventricular arrhythmias and cardiovascular mortality was found to be significantly higher in patients with slow coronary artery flow.