A non-invasively determined surrogate of cardiac power ('circulatory power') at peak exercise is a powerful prognostic factor in chronic heart failure.

This study was designed to assess the prognostic value of a new variable derived from a cardiopulmonary exercise test, the circulatory power, a surrogate of cardiac power, at peak exercise, in patients with chronic heart failure. Peak exercise cardiac power and stroke work are invasive parameters with recently proven prognostic value. It is unclear whether these variables have better prognostic value than peak oxygen uptake (VO(2)). The study population comprised 175 patients with chronic heart failure (ejection fraction <45%) who underwent a cardiopulmonary exercise test. Circulatory power and circulatory stroke work were defined as the product of systolic arterial pressure and VO(2) and oxygen pulse, respectively. Prognostic value was assessed by survival curves (Kaplan-Meier method) and uni- and multivariate Cox analyses. With a mean follow-up of 25+/-10 months, ejection fraction, heart rate, systolic arterial pressure, peak VO(2), VCO(2), the anaerobic threshold, minute ventilation, the ventilatory equivalents of oxygen and carbon dioxide, the half times of VO(2) and VCO(2) recoveries, and the circulatory stroke work and power predicted outcome. Multivariate analysis demonstrated that the peak circulatory power (chi-square=19.9, P<0.001) (but not peak circulatory stroke work) was the only variable predictive of prognosis. The prognostic value of cardiopulmonary exercise tests in heart failure patients can be improved by assessing a new variable, the circulatory power - a surrogate of cardiac power - at peak exercise.

Cohen-Solal A ，Tabet JY ，Logeart D ，Bourgoin P ，Tokmakova M ，Dahan M ... -  《EUROPEAN HEART JOURNAL》

Prognostic value of changes over time in exercise capacity and echocardiographic measurements in patients with chronic heart failure.

This study sought to examine the predictive values of changes over time in exercise capacity and echocardiographic measurements of ventricular dimensions or function in predicting mortality in patients with chronic heart failure. Sixty-two patients with chronic heart failure (58 men, mean [+/-SD] age 60+/-10 years, mean peak oxygen consumption (VO(2)) 18.2+/- 5.9 ml. kg(-1). min(-1), mean left ventricular ejection fraction 38.9+/-15. 8%) who underwent both treadmill exercise testing and echocardiographic examination on two occasions, separated by 19+/-15 months were followed-up for a mean of 17 months (interquartile range 9-30 months). During the follow-up period, 19 patients (30%) died and three (4.8%) underwent heart transplantation. Of measurements taken at a single time-point (visit 2) exercise duration, peak VO(2), ventilatory response to exercise (VE/VCO(2)), left atrial diameter and left ventricular ejection fraction were found, by Cox proportional-hazard analysis, to predict the outcome in these patients (all P<0.05). Of the changes in parameters between visit 1 to visit 2, only changes in peak VO(2)per year (P=0.026) predicted non-transplanted survival (independent of changes in left ventricular ejection fraction and VE/VCO(2)). In Kaplan-Meier survival analysis patients with increased peak VO(2)over time (n=28) showed a better prognosis at 2 years (cumulative survival 75% [95% confidence interval: 56-95%] than those with a decrease in peak VO(2)(n=34, cumulative survival 50% [95% confidence interval: 31-68%]). Although single estimates of peak VO(2), VE/VCO(2)and left ventricular ejection fraction have significant prognostic importance in patients with chronic heart failure, when monitoring changes over time only peak VO(2)remains a significant predictor of outcome.

Florea VG ，Henein MY ，Anker SD ，Francis DP ，Chambers JS ，Ponikowski P ，Coats AJ ... -  《EUROPEAN HEART JOURNAL》

Peak exercise cardiac power output; a direct indicator of cardiac function strongly predictive of prognosis in chronic heart failure.

This study assessed the prognostic value of peak cardiac power output, measured non-invasively during maximal cardiopulmonary exercise testing, against other exercise-derived haemodynamic variables in patients with chronic congestive heart failure. Two hundred and nineteen unselected, consecutive patients with congestive heart failure (166 men, mean (+/-SD) age of 56+/-13 years) who underwent maximal symptom limited cardiopulmonary treadmill exercise testing with non-invasive estimation of cardiac output using carbon dioxide re-breathing techniques, were followed-up for a mean period of 4.64 (4.47--4.82, 95% CI) years. Cardiac power output was calculated from the product of cardiac output and mean arterial blood pressure. All cause mortality was 12.3% (27 deaths). Peak and resting cardiac power output, peak mean arterial blood pressure, peak and resting cardiac output and peak VO(2)were all predictive of outcome on univariate analyses. Peak cardiac power output, either entered continuously or categorically with a cut-off value of 1.96 watts, was the only independent predictor of mortality (P=0.0004 for values < or >1.96 watts and P=0.001 for continuous values) using multivariate analysis. A relative risk ratio of 5.08 (1.94-13.3, 95% CI) was obtained for a cardiac power output <1.96 watts. Peak cardiac power output is an independent predictor of mortality that can be measured non-invasively using cardiopulmonary exercise testing. It can give further prognostic power to a peak VO(2)in the assessment of patients with congestive heart failure.

Williams SG ，Cooke GA ，Wright DJ ，Parsons WJ ，Riley RL ，Marshall P ，Tan LB ... -  《EUROPEAN HEART JOURNAL》

Cardiopulmonary exercise testing for prognosis in chronic heart failure: continuous and independent prognostic value from VE/VCO(2)slope and peak VO(2).

Chronic heart failure carries a poor prognosis. Cardiopulmonary exercise testing is useful in predicting survival. We set out to establish the prognostic value of peak VO(2)and VE/VCO(2)slope across a range of threshold values. Three hundred and three consecutive patients with stable chronic heart failure underwent cardiopulmonary exercise testing between 1992 and 1996. Their age was 59+/-11 years (mean+/-SD), peak VO(2)17. 8+/- 6.6 ml. kg(-1)min(-1), VE/VCO(2)slope 37+/-12. At the end of follow-up in January 1999, 91 patients had died (after a median of 7 months, interquartile range 3-16 months). The median follow-up for the survivors was 47 months (interquartile range 37-57 months). The areas under the receiver-operating characteristic curves for predicting mortality at 2 years were 0.77 for both peak VO(2)and VE/VCO(2)slope. With peak VO(2)and VE/VCO(2)slope viewed as continuous variables in the Cox proportional-hazards model, they were both highly significant prognostic indicators, both in univariate analysis and bivariate analysis (P<0.001 for VE/VCO(2)slope, P<0.003 for peak VO(2)). Lower peak VO(2)implies poorer prognosis across a range of values from 10 to 20 ml. kg(-1)min(-1), without a unique threshold. Gradations of elevation of the VE/VCO(2)slope also carry prognostic information over a wide range (30-55). The two parameters are comparable in terms of prognostic power, and contribute complementary prognostic information.

Francis DP ，Shamim W ，Davies LC ，Piepoli MF ，Ponikowski P ，Anker SD ，Coats AJ ... -  《EUROPEAN HEART JOURNAL》

Peak cardiac power output, measured noninvasively, is a powerful predictor of outcome in chronic heart failure.

Lang CC ，Karlin P ，Haythe J ，Lim TK ，Mancini DM ... -  《-》