Elevated plasma fatty acid concentrations prolong cardiac repolarization in healthy subjects

High fatty acid concentrations have been shown to stimulate sympathetic nervous system activity, which may modify ventricular repolarization and thus the Q-T interval on electrocardiogram recordings.

The aim of this study was to investigate whether acute elevations of plasma fatty acid concentrations influence the corrected Q-T interval (Q-Tc), Q-Tc dispersion, and sympathetic nervous system activity in healthy nonobese subjects.

Thirty-two healthy subjects (x +/- SD: 48+/-7 y of age) received an infusion of 10% triacylglycerol emulsion plus heparin (a bolus of 200 U followed by 0.2 U min(-1) * kg body wt(-1) for 180 min); on another occasion and in random order, the same subjects received a saline infusion.

Compared with the saline infusion, infusion of 10% triacylglycerol emulsion increased plasma fatty acids (P<0.001) and was associated with an increase in mean blood pressure (P<0.05), heart rate (P<0.05), Q-Tc (P<0.01), Q-Tc dispersion (P<0.01), and plasma epinephrine (P<0.005). Furthermore, individual changes in plasma epinephrine correlated with changes in Q-Tc (r = 0.60, P<0.001) and Q-Tc dispersion (r = 0.53, P< 0.02) even after adjustment for age, sex, and body mass index (P<0.03 for all correlations). Only changes in plasma fatty acids (P = 0.04) and plasma epinephrine (P = 0.006) concentrations were significantly and independently associated with the lengthening of the Q-T interval.

Our study showed that elevated plasma fatty acid concentrations might affect cardiac repolarization, at least in part because of an increase in plasma catecholamines.