ABSTRACT
BACKGROUND: Neurohormones and cytokines have been associated with poor prognosis in patients with congestive heart failure. However, direct comparisons between them are rare and the best predictor for worsening of heart failure remains to be elucidated. The aim of the study was to identify independent predictors for worsening of heart failure. METHODS: We studied 100 patients with congestive heart failure (LVEF Subject(s)
Heart Failure/blood
, Interleukin-6/blood
, Natriuretic Peptide, Brain/blood
, Angiotensin-Converting Enzyme Inhibitors/therapeutic use
, Disease Progression
, Female
, Heart Failure/drug therapy
, Humans
, Male
, Middle Aged
, Prognosis
, Proportional Hazards Models
, Regression Analysis
ABSTRACT
AIMS: The objective of the study was to test the relationship between isolated muscle strength and outcome, and its significance in the context of other exercise variables. METHODS AND RESULTS: 122 consecutive patients (LVEF 21+/-7%) were enrolled in the study. Isokinetic strength testing of the knee extensor and flexor muscles were performed. A subset of 51 patients underwent additional upright bicycle testing with gas exchange analysis. The outcome up to 60 months was defined by event-free survival (group A, n=59) or death (group B, n=34). Patients who had been transplanted were excluded from further analysis. The peak strength of the quadriceps muscle was comparable in both groups (N.S.). In contrast, the index (value adjusted for weight) did reveal significant differences (P<0.04), similar to the peak torque of the knee flexor muscle (P<0.04), whose index was even more significant with regard to differences (P<0.01). Multivariate analysis including muscle strength variables, pVO2 and workload into one model show that the flexor strength index is the only independent variable (x2=9 P<0.003). A cut-off point of 68 Nm x 100/kg in the strength index of the flexor muscles was used to establish a significant difference between groups with regard to outcome (P<0.01). Thus, the isokinetic strength of the knee flexor muscles is related to outcome. Moreover, this parameter is superior to variables such as peakVO2 and workload.
