Daniel E. Forman

Reproducibility of Peak Oxygen Uptake and Other Cardiopulmonary Exercise Testing Parameters in Patients With Heart Failure (from the Heart Failure and A Controlled Trial Investigating Outcomes of exercise traiNing)

Peak oxygen uptake (pVo2) is an important parameter in assessing the functional capacity and prognosis of patients with heart failure. In heart failure trials, change in pVo2 was often used to assess the effectiveness of an intervention. However, the within-subject variability of pVo2 on serial testing may limit its usefulness. This study was designed to evaluate the within-subject variability of pVo2 over 2 baseline cardiopulmonary exercise tests. As a substudy of the HF-ACTION trial, 398 subjects (73% men, 27% women; mean age 59 years) with heart failure and left ventricular ejection fraction < or =35% underwent 2 baseline cardiopulmonary exercise tests within 14 days. Mean pVo2 was unchanged from test 1 to test 2 (15.16 +/- 4.97 vs 15.18 +/- 4.97 ml/kg/min; p = 0.78). However, mean within-subject absolute change was 1.3 ml/kg/min (10th, 90th percentiles 0.1, 3.0), with 46% of subjects increasing and 48% decreasing on the second test. Other parameters, including the ventilation-to-carbon-dioxide production slope and Vo2 at ventilatory threshold, also showed significant within-subject variation with minimal mean differences between tests. In conclusion, pVo2 showed substantial within-subject variability in patients with heart failure and should be taken into account in clinical applications. However, on repeated baseline cardiopulmonary exercise tests, there appears to be no familiarization effect for Vo2 in patients with HF. Therefore, in multicenter trials, there is no need to perform >1 baseline cardiopulmonary exercise test.

Neurocognitive functioning and improvement in quality of life following participation in cardiac rehabilitation

We investigated the relationship between neurocognitive functioning and quality of life/self-perceived health status (QOL) among cardiac rehabilitation (CR) patients to determine whether level of neurocognitive functioning is related to baseline QOL and improvement following CR. CR patients (n = 35) were given a neurocognitive screening before participation in CR, and also completed a behavioral inventory (SF-36) before and after CR to measure QOL associated with medical illness. At baseline, CR patients obtained relatively low SF-36 scores compared with published norms, and as reported previously, demonstrated inferior neurocognitive performance compared with healthy controls. Furthermore, neurocognitive performance was strongly positively correlated to SF-36 scores. Significant improvements were evident on many of the SF-36 subscales following rehabilitation. These improvements were relatively greater among SF-36 indexes of physical health status compared with SF-36 indexes of mental health status. Baseline neurocognitive performance also correlated strongly to the degree of improvement in SF-36 scores following rehabilitation. These findings indicate a strong relationship between baseline neurocognitive functioning and QOL before CR, and the degree to which QOL improves following this intervention.

Determining the Preferred Percent-Predicted Equation for Peak Oxygen Consumption in Patients With Heart Failure

Background—Peak oxygen consumption (Vo2) is routinely assessed in patients with heart failure undergoing cardiopulmonary exercise testing. The purpose of the present investigation was to determine the prognostic ability of several established peak Vo2 prediction equations in a large heart failure cohort. Methods and Results—One thousand one hundred sixty-five subjects (70% males; age, 57.0±13.8 years; ischemic etiology, 43%) diagnosed with heart failure underwent cardiopulmonary exercise testing. Percent-predicted peak Vo2 was calculated according to normative values proposed by Wasserman and Hansen (equation), Jones et al (equation), the Cooper Clinic (below low fitness threshold), a Veteran’s Administration male referral data set (4 equations), and the St James Take Heart Project for women (equation). The prognostic significance of percent-predicted Vo2 values derived from the 2 latter, sex-specific equations were assessed collectively. There were 179 major cardiac events (117 deaths, 44 heart transplantations, and 18 left ventricular assist device implantations) during the 2-year tracking period (annual event rate, 10%). Measured peak Vo2 and all percent-predicted peak Vo2 calculations were significant univariate predictors of adverse events (&khgr;2≥31.9, P<0.001) and added prognostic value to ventilatory efficiency (VE/Vco2 slope), the strongest cardiopulmonary exercise testing predictor of adverse events (&khgr;2=150.7, P<0.001), in a multivariate regression. The Wasserman/Hansen prediction equation provided optimal prognostic information. Conclusions—Actual peak Vo2 and the percent-predicted models included in this analysis all were significant predictors of adverse events. It seems that the percent-predicted peak Vo2 value derived from the Wasserman/Hansen equations may outperform other expressions of this cardiopulmonary exercise testing variable.

Cardiac Morphology and Function in Senescent Rats: Gender-Related Differences

OBJECTIVES We sought to better understand the effects of aging and gender on left ventricular (LV) structure and function. BACKGROUND Cardiovascular disease in older persons is associated with increased mortality and morbidity. The influence of gender on age-related cardiac changes is incompletely characterized. METHODS We studied 34 senescent, male and female, normotensive Fischer rats with transthoracic Doppler echocardiography and morphometric and histopathologic analyses. RESULTS Male rats were larger (396 +/- 31 g vs. 282 +/- 35 g), and LV mass in males was greater (1.04 +/- 0.22 g vs. 0.67 +/- 0.13 g). However, wall and chamber dimensions normalized to body weight revealed proportionately thicker anterior and posterior walls in females. Relative wall thickness ratio (2 [Diastolic posterior wall thickness]/Diastolic LV internal chamber diameter) was greater in females, but abnormal fractional shortening and diastolic filling (E/A ratio) patterns were more common in males. Significant mitral regurgitation (MR) was sevenfold more common among males (88% vs. 12%, p < 0.001). Histopathologic analysis showed that the cardiac myocytes were larger, and there was greater LV fibrosis in males (both p < 0.001). CONCLUSIONS Gender-related morphologic and functional differences are important to consider in cardiovascular assessment. Very old rats show significant gender differences in LV size and function. Male rat hearts are larger, thinner and more fibrotic and have indexes of diminished performance. The high prevalence of MR in male rats may play a crucial role in these gender differences.

Neuropsychological Functioning Among Cardiac Rehabilitation Patients

PURPOSE The underlying pathophysiology contributing to coronary heart disease also predisposes patients to cerebrovascular disease and associated cognitive disorders. Although prior studies have focused on the neuropsychological sequelae of specific cardiac problems, few have examined the associated cognitive capacities and limitations of typical cardiac patients. The current study was designed to examine neuropsychological functioning among a sample of cardiac rehabilitation (CR) patients. METHODS Using neuropsychological instruments, patients were compared in a CR program to age-matched outpatient control subjects who had no known history of cardiac or neurologic disease. Cardiac rehabilitation patients were then divided into dichotomous subgroups based on whether they had undergone coronary artery bypass grafting, had experienced a myocardial infarction, had hypertension, or had impaired ejection fraction. Neuropsychological functioning was examined relative to each of these factors. RESULTS Cardiac rehabilitation patients had poorer neuropsychological test performance than did control subjects, with subtle relative deficits on measures of response generation, memory, and verbal abstraction, and particularly verbal fluency. Low ejection fraction, hypertension, and prior coronary artery bypass graft were associated with greater relative neuropsychological impairments. CONCLUSIONS Although CR patients were not grossly neuropsychologically impaired as a group, it appears highly likely that many within a given program exhibit some degree of neuropsychological dysfunction. Including neuropsychological screening as part of pre-CR testing would help to identify such patients. This information may help staff to impart health care information in a manner that is most effective for the individual patient and may also be useful in the formation of realistic goals.

Increased Walking Variability in Elderly Persons with Congestive Heart Failure

OBJECTIVES: To determine the effects of congestive heart failure on a persons ability to walk at a steady pace while ambulating at a self‐determined rate.

Utility of beta-blockade treatment for older postinfarction patients

OBJECTIVE: The prevalence of myocardial infarction (MI) in older people is high. Whereas use of beta‐blockers after MI is known to lower MI mortality in younger adults, its efficacy for adults more than 75 years of age remains less clear. We hypothesized that use of beta‐blockers after MI in older adults would improve clinical outcomes.

Inspiratory muscle training in heart disease and heart failure: A review of the literature with a focus on method of training and outcomes

Evidence to date strongly suggests that poor inspiratory muscle performance is associated with dyspnea, poor exercise tolerance and poor functional status in patients with heart failure (HF). A growing body of literature has examined the effects of inspiratory muscle training (IMT) in HF patients with the majority of studies reporting favorable effects on several of the above limitations and a substantial number of related deficiencies due to inadequate inspiration and inspiratory muscle strength and endurance. The domains and manifestations of HF, which were significantly improved by IMT in one or more of the 18 out of 19 studies of IMT, included dyspnea, quality of life, balance, peripheral muscle strength and blood flow, peripheral muscle sympathetic nervous activity, heart rate, respiratory rate, peak VO2, 6-min walk test distance, ventilation, VE/VCO2 slope, oxygen uptake efficiency, circulatory power, recovery oxygen kinetics and several indices of cardiac performance. This paper will also review the available IMT literature with a focus on methods of IMT and clinical outcomes. Key differences between available IMT methods will be highlighted with a goal to improve IMT efforts and decrease the pathophysiological manifestations of heart disease and HF.

Validation of a Cardiopulmonary Exercise Test Score in Heart Failure

Background—Cardiopulmonary exercise test (CPX) responses are strong predictors of outcomes in patients with heart failure. We recently developed a CPX score that integrated the additive prognostic information from CPX. The purpose of this study was to validate the score in a larger, independent sample of patients. Methods and Results—A total of 2625 patients with heart failure underwent CPX and were followed for cardiovascular (CV) mortality and major CV events (death, transplantation, left ventricular assist device implantation). Net reclassification improvement (NRI) for the score and each of its components were determined at 3 years. The VE/VCO2 slope was the strongest predictor of risk and was attributed a relative weight of 7, with weighted scores for abnormal heart rate recovery, oxygen uptake efficiency slope, end-tidal CO2 pressure, and peak VO2 having scores of 5, 3, 3, and 2, respectively. A summed score of >15 was associated with an annual mortality rate of 12.2% and a relative risk >9 for total events, whereas a score of <5 was associated with an annual mortality rate of 1.2%. The composite score was the most accurate predictor of CV events among all CPX responses considered (C indexes, 0.70 for CV mortality and 0.72 for the composite outcome). Each component of the score provided significant NRI compared with peak VO2 (category-free NRI, 0.61–0.77), and the score provided significant NRI above clinical risk factors for both CV events and mortality (NRI, 0.63 and 0.65 for CPX score compared with clinical variables alone). Conclusions—These results validate the application of a simple, integrated multivariable score based on readily available CPX responses.

Evaluating the use of angiotensin-converting enzyme inhibitors for older nursing home residents with chronic heart failure.

BACKGROUND: Despite their well noted therapeutic benefits for heart failure (HF), angiotensin‐converting enzyme (ACE) inhibitors may be underprescribed and underdosed among older nursing home patients.