Associations of serum n-6 polyunsaturated fatty acid concentrations with heart rate-corrected QT and JT intervals in middle-aged males.

Although n-6 polyunsaturated fatty acids (PUFAs), particularly the main n-6 PUFA linoleic acid (LA), have been shown to be inversely related to cardiovascular disease (CVD) risk, their associations with ventricular repolarization, a marker of ventricular arrhythmias, remain unclear. This study examined the relationships between serum n-6 PUFA concentrations and heart rate-corrected QT (QTc) and JT (JTc) intervals. This cross-sectional study included 1,420 Finnish males (aged 42-60 years) free of CVD from the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD). Fasting serum n-6 PUFA concentrations were determined by gas chromatography, and electrocardiographic intervals were automatically derived. QTc and JTc intervals were calculated using Bazett's formula. Associations were analyzed using multivariable-adjusted ANCOVA and logistic regression. Higher serum total n-6 PUFA concentrations were associated with shorter QTc and JTc intervals (QTc: extreme-quartile difference = -3.36 ms; 95% CI -6.69, -0.41; P-trend = 0.02; JTc: extreme-quartile difference = -3.38 ms; 95% CI -6.79, -0.27; P-trend = 0.03). Similar inverse associations were found for serum LA (QTc: -4.64 ms; 95% CI -8.00, -1.27; P-trend = 0.009; JTc: -3.99 ms; 95% CI -7.44, -0.54; P-trend = 0.02). The other n-6 PUFAs gamma-linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid showed no significant associations. Higher serum total n-6 PUFA and LA concentrations were associated with shorter QTc and JTc intervals, suggesting a potential protective effect on ventricular arrythmias.