Chronotropic incompetence and survival in XXXX .

@entity1 @entity712 @entity1002
BACKGROUND: Failure of the heart rate to rise normally during an incremental exercise test is termed chronotropic incompetence (CI). It is common in @entity1 with @entity712 ( @entity712 ), and we wanted to explore the relation between CI and outcome in unselected @entity1 with @entity712 . METHODS: 411 @entity1 with @entity1002 who underwent cardiopulmonary exercise testing (CPET) were included. CI was defined as a failure to achieve 80% of the maximum predicted heart rate (HR). A CI index was also calculated: (Peak HR-Rest HR)/(220-age-Rest HR)   100. Cox regression was used to assess the univariate and multivariate relationship between variables and all-cause mortality. Survivors were followed for a median of 89months (IQR 62.8-98.6). The majority were male (81.4%) with a median age of 67years (IQR 60-73). A subgroup of 266 @entity1 had NT-proBNP values. RESULTS: CI was present in 42.3% of the population. The mean CI index was 65.7% (SD 41.3%). @entity1 without CI exercised for longer (510s) and had higher peak VO(2) values (21.1mL/kg/min) than those with CI (424 seconds and 18mL/kg/min). Only peak VO(2), age and b blocker use were independent prognostic variables. In the subset of @entity1 with NT-proBNP available, Log[NT-proBNP] was the most powerful predictor of mortality followed by peak VO(2) and b blocker use. CONCLUSIONS: @entity1 with CI had lower exercise time and peak VO(2). However CI was not a significant predictor of mortality in @entity1 with @entity712 undergoing CPET.
