@entity337 is a common feature in @entity1526 @entity1 . New methodologies are now available to evaluate the chronotropic response in different subsets. The chronotropic-metabolic index (CMI) is one of these new indexes and quantifies the relationship between the increment of heart rate and the maximal @entity26 consumption (VO2 max) during exercise testing. In normal subjects there is linear response and the index is round 1.0. The aim of the study was to evaluate the chronotropic response in healthy controls and @entity1526 @entity1 with and without @entity1002 , using CMI. Twenty-four controls and 171 @entity1526 @entity1 underwent a clinical protocol and maximal exercise testing. @entity1526 @entity1 were divided into two groups: Ch1= @entity1 with ejection fraction (EF) > 39% and Ch2 = EF < 40%. CMI was analyzed and calculated according to the Wilkoff method. @entity1526 @entity1 were older than controls and showed higher prevalence of @entity714 , as well as lower VO2 max during exercise. Both groups of @entity1526 @entity1 showed a less steep curve in the chronotropic-metabolic index (Ch1: 0.91+/-0.10, Ch2: 0.89+/-0.08) than controls (1.0+/-0.12, p < 0.001). @entity1526 @entity1 with and without @entity1002 chronotropic @entity337 may exhibit reduced chronotropic response to exercise, expressed by a less steep chronotropic-metabolic index.

[Chronotropic-metabolic index in XXXX ].

@entity1 :: ('9606', 'Species') :: ['patients'] @entity714 :: ('MESH:D002037', 'Disease') :: ['right bundle branch block'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity1526 :: ('MESH:D014355', 'Disease') :: ["Chagas' disease"] @entity337 :: ('MESH:D001022', 'Disease') :: ['Chronotropic incompetence', 'incompetence'] @entity1002 :: ('MESH:D018487', 'Disease') :: ['left ventricular dysfunction']
@entity1526 :: (MESH:D014355,Disease) :: ['Chagas' disease']
