Comparison of Predicted Exercise Capacity Equations and the Effect of Actual versus Ideal Body Weight among Subjects Undergoing Cardiopulmonary Exercise Testing.

Background. Oxygen uptake at maximal exercise (VO2 max) is considered the best available index for assessment of exercise capacity. The purpose of this study is to determine if the use of actual versus ideal body weight in standard regression equations for predicted VO2 max results in differences in predicted VO2 max. Methods. This is a retrospective chart review of patients who were predominantly in active military duty with complaints of dyspnea or exercise tolerance and who underwent cardiopulmonary exercise testing (CPET) from 2007 to 2009. Results. A total of 230 subjects completed CPET on a bicycle ergometer with a male predominance (62%) and an average age of 37 ± 15 years. There was significant discordance between the measured VO2 max and predicted VO2 max when measured by the Hansen and Wasserman reference equations (P < 0.001). Specifically, there was less overestimation when predicted VO2 max was based on ideal body weight as opposed to actual body weight. Conclusion. Our retrospective analysis confirmed the wide variations in predicted versus measured VO2 max based on varying prediction equations and showed the potential advantage of using ideal body weight as opposed to actual body weight in order to further standardize reference norms.

A rare case of effusive constrictive cholesterol pericarditis: a case report and review.

Effusive constrictive cholesterol pericarditis is exceedingly rare. Most cases have an unclear etiology but can be associated with rheumatoid arthritis, tuberculosis infection, and hypothyroidism. The hallmark of the effusion is the distinctively high levels of cholesterol. We present the case of a 68-year-old male with prolonged symptoms of dyspnea with associated moderate pericardial effusion that were later determined to be constrictive effusive etiology, and the patient was referred for stripping with pathologic cholesterol crystal formation on pathology review.

Biomechanical efficiency is decreased in heart failure during low-level steady state and maximal ramp exercise.

BACKGROUND: Previous studies of biomechanical efficiency (external work/energy input--Watt/O(2) consumed) in heart failure (HF) using cardiopulmonary exercise testing (CPET) and magnetic resonance spectroscopy (MRS) have had discordant results with increased efficiency by CPET and decreased efficiency by MRS. AIMS: Compare biomechanical efficiency of HF subjects and normal controls during steady state (SS=35 W for 6 min) and ramp cycle ergometer exercise. The hypothesis was that HF subjects would have impaired biomechanical efficiency that correlated with HF symptoms. METHODS: Biomechanical efficiency used the actual Vo(2) during exercise and recovery. Gross (Vo(2) above zero), Net (Vo(2) above the resting Vo(2)) and Work (Vo(2) above the unloaded pedaling Vo(2)) efficiencies were calculated. RESULTS: HF subjects had an 18% higher Vo(2) during SS exercise (P=0.029). Biomechanical efficiency was reduced during SS exercise (gross -15%, P=0.019, net -15%, P=0.062, and work -35%, P=0.002). Gross Efficiency during SS exercise had the strongest correlation with HF symptoms (r=0.55). During ramp exercise gross (-26%), net (-10%) and work (-8%) biomechanical efficiency were all reduced (all P<0.05). The slope of the Vo(2)/Watt relationship during ramp exercise had the best correlation with HF symptoms (r=0.46). CONCLUSIONS: HF subjects have an increased O(2) cost/Watt during SS and ramp exercise that correlates with HF symptoms of fatigue and breathlessness. Methods to improve biomechanical efficiency in HF subjects by exercise training or medications may improve the symptoms and the impaired exercise capacity associated with HF.

Utility of magnetic resonance imaging in cardiac venous anatomic variants.

The incidence of persistent left superior vena cava (PLSVC) is approximately 0.5% in the general population; however, the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1-3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm, and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging. The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed.

Oxygen cost of exercise is increased in heart failure after accounting for recovery costs.

STUDY OBJECTIVES: The oxygen cost during exercise has been reported to be decreased in patients with congestive heart failure (CHF), implying an increased efficiency (lower oxygen uptake [VO(2)] per Watt [VO(2)/W]); however, these studies ignored the oxygen debt that is increased in heart failure. SUBJECTS: The primary aim of this research was to evaluate the total oxygen cost (work VO(2)/W) during exercise and recovery in patients with heart failure as compared with healthy adults. DESIGN AND PATIENTS: We performed a retrospective analysis comparing the exercise VO(2)/W, the recovery VO(2)/W, the work VO(2)/W, and the VO(2)/W relationship above and below the ventilatory threshold (VT) in 11 healthy control subjects and 45 patients with CHF. RESULTS: The exercise VO(2)/W was decreased by 29% (p < 0.0001) in patients with CHF; however, the recovery VO(2)/W was increased by 167% (p < 0.0001) and the work VO(2)/W was increased by 14% in patients with CHF (p = 0.014). The VO(2)/W slope increased above the VT (+ 27%, p = 0.0017) in both normal subjects and patients with CHF, suggesting a decrease in efficiency above the VT. There was an inverse correlation (r = 0.646, p < 0.0001) between exercise VO(2)/W and recovery VO(2)/W, implying that subjects with a low exercise VO(2)/W were not efficient but rather accumulated a large oxygen debt that was repaid following completion of exercise. CONCLUSIONS: Heart failure is associated with lower exercise VO(2)/W; however, the patient with heart failure is not efficient, but rather accumulating a large oxygen debt (recovery VO(2)/W) that is repaid following exercise. In addition, the work VO(2)/W (including both exercise and recovery) is increased in patients with heart failure in comparison to control subjects, and correlates inversely with the percentage of predicted VO(2). The large recovery VO(2)/W is likely due to impaired oxygen delivery to exercising muscle during exercise. The increase in the work VO(2)/W is probably due to changes in skeletal muscle fiber type that occur in patients with heart failure (type I to type IIb).

Research and commentary: Change in exercise tolerance, activity and sleep patterns, and quality of life in patients with cancer participating in a structured exercise program.

PURPOSE/OBJECTIVES: To investigate the feasibility of an exercise program patterned after a phase II cardiac rehabilitation program to improve selected physiologic and psychological parameters of health in patients with cancer. DESIGN: Prospective, repeated measures study. SETTING: Two major military medical centers in the southwestern United States. SAMPLE: 62 patients diagnosed with cancer within the previous two years. Ages ranged from 24-83 (meanX = 59). Half of the participants were male and half were female. Minorities made up 29% of the sample. Participants had a wide range of cancer diagnoses and all stages of cancer. Fifteen subjects were undergoing treatment when they enrolled in the study. More than half of the subjects exercised prior to their cancer diagnoses, but fewer than half were able to resume an exercise routine following their cancer diagnoses. METHODS: Subjects met two days each week for 12 weeks for exercise and education. MAIN RESEARCH VARIABLES: Exercise tolerance as measured with a graded exercise test, activity and sleep patterns as measured with a wrist actigraph, and quality of life (QOL) as measured with the Cancer Rehabilitation Evaluation System-Short Form. FINDINGS: Significant improvements were observed over time in exercise tolerance, selected activity and sleep patterns, and QOL among the 46 (74%) subjects who completed the program. CONCLUSIONS: Patients with various types and stages of cancer can safely exercise using a cardiac rehabilitation model and can realize significant improvements in exercise tolerance, selected activity and sleep patterns, and QOL. IMPLICATIONS FOR NURSING: Most people are aware that regular exercise is part of a healthy lifestyle. After cancer diagnosis and treatment, patients experience uncertainty regarding how to resume exercise or how to begin an exercise program as part of their rehabilitation. Participation in a structured exercise program can provide patients with a safe environment within which to exercise at an intensity appropriate to their individual needs.

The role of norepinephrine in exercise impairment in congestive heart failure.

Congestive heart failure is a disorder that includes a multitude of neurohormonal responses that become maladaptive over time. Chronic sympathetic stimulation adversely affects the well-being and survival of heart failure patients and contributes to the exercise intolerance frequently seen in these patients. Norepinephrine levels have been correlated with poorer survival in heart failure patients. Administration of norepinephrine has been shown to impair exercise responses in those with congestive heart failure, and the recent effort to incorporate beta blocker therapy into the standard management of heart failure patients addresses this abnormal neurohormonal process. Studies with central-acting sympatholytics have shown mixed results. The use of drugs such as clonidine has been suggested as potentially useful therapy in the long-term management of patients with heart failure, but definitive conclusions await further study. Regular exercise has been shown to reduce resting norepinephrine levels in heart failure subjects. This may serve as an additional rationale to recommend chronic exercise for these patients.