Prognostic value of heart rate recovery in patients with heart failure

BACKGROUND: The rate in which heart rate recovers from exercise has recently been shown to be a strong predictor of mortality in patients suspected of having coronary disease, but its prognostic value in patients with heart failure (HF) has not been explored. We sought to assess the prognostic utility of heart rate recovery (HRR) in patients with HF. METHODS: Eighty-seven subjects diagnosed with compensated HF underwent cardiopulmonary exercise testing (CPX). Mean age and ejection fraction were 50.0 (+/-13.9) years and 28.1% (+/-13.6%), respectively. Heart rate at 1-minute post-CPX was subtracted from maximal heart rate during the exercise test to produce a measure of HRR1 in beats per minute. Subjects were followed for a combined death/hospitalization end point for 1-year after CPX. RESULTS: The mean peak respiratory exchange ratio, peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, and HRR1 were 1.06 (+/-0.11), 14.8 (+/-4.7) mL.kg(-1).min(-1), 36.6 (+/-8.6), and 11.0 (+/-10.4) beat/min, respectively. Although all three variables were significant univariate predictors of the composite end point (P 34.4) and HRR1 (< 6.5 beat/min) value was 9.2 (95% CI 4.5-18.5, P < .0001). CONCLUSIONS: These results indicate that HRR provides additional prognostic information in patients with HF undergoing CPX. Moreover, given the independent prognostic value of HRR, this variable alone may provide valuable clinical information when ventilatory expired gas analysis is not available

Prognostic characteristics of cardiopulmonary exercise testing in heart failure : comparing American and European models

BACKGROUND: Cardiopulmonary exercise testing (CPET) in the heart failure population is a standard of care in both American and European clinics, although the mode of exercise typically differs. The purpose of the present study was to compare the prognostic characteristics of peak oxygen consumption (VO2) and the minute ventilation-carbon dioxide production (VE/VCO2) slope between two independent heart failure groups. DESIGN AND METHODS: One hundred and two subjects underwent maximal exercise CPET using bicycle ergometry at San Paolo Hospital in Milan, Italy (SPH) and 105 subjects underwent treadmill CPET at Virginia Commonwealth University in Richmond, Virginia (VCU). Subjects were tracked for cardiac-related mortality for a 1-year period after CPET. RESULTS: There were 13 cardiac-related deaths over the 1-year tracking period in both groups. Optimal prognostic threshold values for peak VO2 were 12.9 ml O2/kg per min (sensitivity 81%, specificity 69%) in the SPH group and 12.0 ml O2/kg per min (sensitivity 74%, specificity 69%) in the VCU group. An optimal prognostic threshold value for the VE/VCO2 slope was 34.4 in the SPH (sensitivity 61%, specificity 85%) and 34.5 in the VCU (sensitivity 64%, specificity 93%) groups. DISCUSSION: The prognostic characteristics of peak VO2 and the VE/VCO2 slope were similar between the two centers. These results suggest that the mode of exercise does not greatly impact the prognostic utility of CPET responses in heart failure. They further suggest that prognostic guidelines for the application of CPET in heart failure may be applied globally, irrespective of differences in testing modality

Prognostic value of resting end-tidal carbon dioxide in patients with heart failure

Background: Cardiopulmonary exercise testing (CPET) variables provide valuable prognostic information in the heart failure (HF) population. The purpose of the present study is to assess the ability of resting end-tidal carbon dioxide partial pressure (PETCO2) to predict cardiac-related events in patients with HF. Methods: 121 subjects diagnosed with compensated HF under-went CPET on an outpatient basis. Mean age and ejection fraction were 49.3 years (+/- 14.7) and 28.4% (+/- 13.4), respectively. Resting P(ET)CO2 was determined immediately prior to the exercise test in the seated position. Peak oxygen consumption (VO2) and the minute ventilation-carbon dioxide production (VE/VCO2) slope were also acquired during CPET. Results: There were 41 cardiac-related hospitalizations and 9 cardiac-related deaths in the year following CPET. Mean resting PETCO2, peak VO2 and VE/VCO2 slope were 34.1 mmHg (+/- 4.6), 14.5 ml(.)kg(-1.)min(-1) (+/- 5.1) and 35.9 (+/- 8.7) respectively. Univariate Cox regression analysis revealed that resting PETCO2 (Chi-square=28.4, p < 0.001), peak VO2 (Chi-square=21.6, p < 0.001) and VE/VCO2 slope (Chisquare=54.9, p < 0.001) were all significant predictors of cardiac related events. Multivariate Cox regression analysis revealed resting PETCO2 added to the prognostic value of VE/VCO2 Slope in predicting cardiac related events (residual Chi-square=4.4, p=0.04). Peak VO2 did not add additional value and was removed (residual Chi-square=3.2, p=0.08). Conclusions: These results indicate a resting ventilatory expired gas variable possesses prognostic value independently and in combination with an established prognostic marker from the CPET. Resting PETCO2 may therefore be a valuable objective measure to obtain during both non-exercise and exercise evaluations in patients with HF

Maximal dyspnea on exertion during cardiopulmonary exercise testing is related to poor prognosis and echocardiography with tissue Doppler imaging in heart failure

This study tested the hypothesis that increasing levels of maximal dyspnea on exertion (DOE) during cardiopulmonary exercise testing (CPX) is associated with heart failure (HF) disease severity and worsening prognosis. Three hundred seventy-six HF patients underwent CPX where ventilatory efficiency (minute ventilation/carbon dioxide production; VE/VCO2 slope), peak oxygen consumption (VO2), and maximal DOE were determined. A subgroup of 243 patients underwent echocardiography with tissue Doppler imaging to measure the ratio between mitral early (E) to mitral annular (E\u2032) velocity as well as other variables. Maximal DOE was significantly correlated with E/E\u2032 (rs=.49; P<.001). In the multivariate Cox regression, the VE/VCO2 slope was the strongest prognostic marker obtained from CPX (Multivariate chi-square, 48.0; P<.001) while maximal DOE (residual chi-square, 17.4; P<.001) and peak VO2 (residual chi-square, 7.5; P=.006) added predictive value. These results suggest that increasing DOE reflects the degree of disease severity and adds prognostic value to established CPX variables

The prognostic value of the initial heart rate increase during progressive exercise testing in heart failure

The increase in heart rate during the first minute of a progressive exercise test (HR1) has been shown to be prognostically significant in a large cohort at risk for or diagnosed with cardiovascular disease. This issue, however, has not been specifically investigated in patients diagnosed with heart failure (HF). We assessed the hypothesis that HR1 would possess prognostic value in a large HF cohort. Three-hundred and ninety two subjects diagnosed with HF (207 ischemic/185 non-ischemic, 279 male/113 female, age: 57.2 \ub113.2 years, ejection fraction: 33.4 \ub112.5) underwent cardiopulmonary exercise testing. Two-hundred and thirty three subjects were prescribed a beta-blocking agent at the time of testing. The difference between resting HR and HR after the first minute of exercise was defined as HR1. Ventilatory efficiency (VE/VCO2 slope), the presence of oscillatory ventilation (EOV) and peak oxygen consumption (VO2) were also determined. Subjects were tracked for major cardiac events following exercise testing. There were 93 major cardiac events (82 deaths, 8 heart transplants, 3 left ventricular assist device implantations) during the 24.5 \ub121.2 month tracking period (annual event rate: 10.5%). A HR1 threshold of >13 beats per minute was a significant univariate predictor of adverse events in the overall group (Hazard ratio: 6.5, 95% CI: 3.6\u201311.4, p13, chi-square: 53.5, p14 mlO2\ub7kg\u20131\ub7min\u20131, residual chi-square: 0.42, p=0.52) was not. Others have postulated that a greater HR1 reflects a more rapid withdrawal of parasympathetic stimulus during exercise and a higher vagal tone at rest. These results demonstrate HR1 during a progressive exercise test is prognostically valuable in patients with HF. Consideration of HR1 for prognostic purposes may therefore be warranted in patients with HF during both submaximal and maximal exercise testing

Prognostic usefulness of the functional aerobic reserve in patients with heart failure

Background: Peak oxygen consumption derived from cardiopulmonary exercise (CPX) testing provides important prognostic information in patients with heart failure (HF). The oxygen consumption at the ventilatory threshold (VT) has also been shown to be prognostic. However, the VT cannot always be detected in patients with HF. Other variables such as the difference between peak oxygen consumption and oxygen consumption at the VT (termed the functional aerobic reserve [FAR]) may also provide prognostic information. The purpose of this study was to determine the prognostic value of an undetectable VT and FAR. Methods: Eight hundred seventy-four patients with chronic, systolic HF (70% male, age 54 \ub1 14 years, ejection fraction 29% \ub1 12%) underwent CPX and were tracked for 2 years for major events (death, transplant, and left ventricular assist device implantation). Results: Patients were divided into 2 subgroups based on whether VT could be detected or not. There were 141 major events during the 2-year follow-up. Kaplan-Meier analysis for the 2 VT subgroups demonstrated worse prognoses for patients with a nondetectable VT versus those with a detectable VT (P 3 mlO2 kg-1 min-1 (sensitivity/specificity 69%/60%). Cox regression analysis identified the FAR as a significant univariate predictor of risk and was retained in multivariate analysis. Conclusion: In conclusion, these data reveal that an undetectable VT and the FAR during CPX testing can provide useful prognostic information in patients with HF