Effects of a High Salt Intake and Potassium Supplementation on QT Interval Dispersion in Normotensive Healthy Subjects

64 normotensive healthy subjects (29 men, 35 women), ranging from 28 to 60 years of age (mean 47.8 years), from Mei County, Shaanxi Province, China. Excluded: severe cardiovascular disease, liver, kidney or other acute or chronic diseases, pregnant women, and those with frequent drinking habits.

Sequential dietary protocol: 7-day low-salt period (3 g/day NaCl), followed by 7-day salt loading period (18 g/day NaCl), followed by 7-day salt loading with potassium supplementation period (18 g/day NaCl + 4.5 g/day KCl).

Self-controlled (sequential comparison of baseline, low-salt, salt loading, and salt loading with potassium supplementation periods).

QT interval, QT interval dispersion (QTd), corrected QT interval dispersion (QTdc), and T peak-T end interval (Tp-Te) measured on 12-lead ECG on the last day of each period.surrogate