Correlation between dispersion of repolarization and heart rate variability in patients with acute myocardial infarction

Recently some studies have hypothesized that variation in autonomic tone may be responsible for QT dispersion, so we studied the correlation between QT dispersion and heart rate variability (SDNN) in a group of patients after AMI, In this prospective double blind study 52 of a total of 80 consecutive patients with a definite diagnosis of AMI entered the study. Corrected QTd (QTcd) was manually measured on days 1,2 and at 1-month follow-up, A 24-hour ambulatory ECG recording and a time domain based analysis for heart rate variability (SDNN values in ms) was performed in 45 patients, A statistically significant difference in dispersion values was noticed on day 2 between patients with SDNN less than or equal to 50 and those with SDNN >100 ms with p< 0.001 with a significant negative correlation (Pearson correlation coefficient r= -0,62, p<0,01). Regional autonomic tone of myocardium is known to influence SDNN values, Its strong negative correlation with QT dispersion strengthens the hypothesis that autonomic tone of the myocardium exerts a similar strong influence on this parameter.