The relation between QT intervals and heart rate in young healthy males using an incremental head-up tilt protocol

The relationship between the QT interval and the preceding RR interval is often described by a simple formula with 1 or 2 parameters like, e.g., Bazett's correction formula or an exponential formula. These formulas may perform adequately in large groups of people, but not in individuals. The authors describe an incremental head-up tilt protocol to obtain QT intervals at a large range of different heart rates in individuals within 3 hr under minimal changes in conditions. The resulting QT-RR relationship is complex and differs for each individual, but all curves share some common characteristics.