Age- and sex-stratified normal values for circulatory and ventilatory power during ramp exercise derived from a healthy Japanese population.

Circulatory power (CP) and ventilatory power (VP), obtained by cardiopulmonary exercise testing (CPX), have been suggested to be excellent prognostic markers for heart failure. However, the normal values of these parameters in healthy Japanese populations remain unknown; thus, we aimed to investigate these values in such a population. A total of 391 healthy Japanese participants, 20-78 years of age, underwent CPX with a cycle ergometer with ramp protocols. Systolic blood pressure (SBP), heart rate, oxygen uptake ([Formula: see text]O2) at peak exercise, and the slope of minute ventilation ([Formula: see text]E) versus carbon dioxide ([Formula: see text]CO2) ([Formula: see text]E vs. [Formula: see text]CO2 slope) were measured. CP was calculated by multiplying the peak [Formula: see text]O2 and SBP values, and VP was calculated by dividing the peak SBP value by the [Formula: see text]E versus [Formula: see text]CO2 slope. For males and females, the average CP values were 6119 ± 1280 (mean ± standard deviation) and 4775 ± 914 mmHg·mL/min/kg, respectively (p < 0.001). The average VP values for males and females were 8.0 ± 1.3 and 6.9 ± 1.3 mmHg (p < 0.001). CP decreased with age in both sexes. VP increased with age in females, with no significant change in males. We calculated the normal values for CP and VP in a healthy Japanese population. The results can contribute to the evaluation of patients' CPX results as a reference.

Effects of cardiac rehabilitation with motion assistance from a wearable cyborg hybrid assistive limb on patients with chronic heart failure: a randomized controlled trial with a one-year follow-up.

[Purpose] We have recently reported that using a wearable cyborg hybrid assistive limb improved the isometric knee extensor muscle strength of patients with chronic heart failure. Here, we investigated the long-term effects of a lumbar-type hybrid assistive limb for patients with chronic heart failure. [Participants and Methods] A total of 28 hospitalized patients with chronic heart failure (mean age, 73.1 ± 13.8 years) were randomly assigned to two groups: the hybrid assistive limb group or the control group, in which they performed a sit-to-stand exercise with or without the hybrid assistive limb, respectively. The cardiac rehabilitation therapy included this intervention, which was performed as many times as possible for 5-30 minutes per day for 6-10 days. Clinical assessments like lower-limb muscle strength, walking ability, etc., were measured before and after the intervention. Cardiac events were followed up for up to a year after discharge. [Results] No adverse events occurred during the study period in either group. In terms of long-term effects, the incidence of cardiac events was 23% and 45% in the hybrid assistive limb and the control groups, respectively. [Conclusion] Hybrid assistive limb-assisted exercise therapy may be a safe and feasible cardiac rehabilitation tool in patients with chronic heart failure. The lumbar-type wearable cyborg hybrid assistive limb may have a positive effect on heart failure prognosis by adding long-term exercise therapy.

Effects of Cardiac Rehabilitation With Lumbar-Type Hybrid Assistive Limb on Muscle Strength in Patients With Chronic Heart Failure　- A Randomized Controlled Trial.

BACKGROUND: Aiming to establish an effective tool in new cardiac rehabilitation programs, we investigated the use of a lumbar-type hybrid assistive limb (HAL) in patients with heart failure (HF) who had difficulty in walking at the usual speed of healthy subjects (≈80 m/min).Methods and Results:We randomly assigned 28 HF patients (age, 73.1±13.8 years) to perform a sit-to-stand exercise with or without HAL. The sit-to-stand exercise was repeated as many times as possible as cardiac rehabilitation therapy over a period of 6-10 days. We measured 5 parameters before and after the completion of cardiac rehabilitation: B-type natriuretic peptide, Short Physical Performance Battery (SPPB), 6-min walking distance (6MWD), 30-s chair-stand test (CS-30), and isometric knee extensor muscle strength. The SPPB and 6MWD were significantly improved, and the CS-30 score was somewhat improved, after the exercise therapy in both the HAL and non-HAL groups. The knee extensor muscle strength improved significantly in the HAL group (0.29±0.11 to 0.35±0.11 kgf/kg, P<0.01), but showed no change in the non-HAL group (0.35±0.11 to 0.35±0.13 kgf/kg, P=0.40). CONCLUSIONS: The improved knee extensor muscle strength in the HAL group suggests that the lumbar-type HAL may be an effective tool for cardiac rehabilitation in HF patients with frailty, which is a predictor of poor prognosis in HF.

Efficacy of Cardiac Rehabilitation with Assistance from Hybrid Assistive Limb in Patients with Chronic Heart Failure: Protocol for a Randomized Controlled Study.

The hybrid assistive limb (HAL) provides motion assistance based on bioelectrical signals detected on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in moving on their own legs. We aim to compare the efficacy of exercise therapy performed with assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure. This investigation will be a randomized, nonblinded, controlled study. Sixty patients who satisfy the criteria to receive cardiac rehabilitation therapy under the Japanese national insurance system will be enrolled at the University of Tsukuba Hospital. Participants randomly assigned to 2 groups (HAL group and conventional group) at a 1:1 allocation ratio will perform exercise therapy either with HAL or without HAL for 5-30 min once a day for 6-10 days. Outcome parameters will be measured just before and after the completion of the exercise therapy and at 1 year after hospital discharge. The primary outcomes will be the heart rate, blood pressure, subjective ratings of exercise intensity during exercise (Borg scale), number of days from the start of exercise therapy to independent walking and to discharge, and prognosis (mortality and cardiovascular events) over the 1-year period after discharge. The secondary outcomes will be the assessment of heart failure severity, brain natriuretic peptide, grip strength, thigh muscle thickness, isometric knee extensor strength, standing ability, 10-meter walking speed, 6-min walking distance, short physical performance battery, and adverse events. Unpaired t tests will be used for baseline assessments and outcome measures. This is the first randomized controlled study to examine the efficacy and feasibility of lumbar-type HAL in patients with chronic heart failure. If the results confirm beneficial effects in the outcomes of patients with heart failure, this study will add more evidence in support of the use of the lumbar-type HAL as an effective tool in new cardiac rehabilitation programs.

Effects of a cyborg-type robot suit HAL on cardiopulmonary burden during exercise in normal subjects.

BACKGROUND: The hybrid assistive limb (HAL) is the world's first cyborg-type robot suit that provides motion assistance to physically challenged patients. HAL is expected to expand the possibilities of exercise therapy for severe cardiac patients who have difficulty in moving on their own legs. As a first step, we examined whether or not the motion assistance provided by HAL during exercise could effectively reduce the cardiopulmonary burden in healthy subjects. METHODS: A total of ten healthy male adults (35 ± 12 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer with or without assistance from HAL. The CPX protocol consisted of four 3-min stages performed in a continuous sequence: rest, 0 W, 40 W, and 80 W. The heart rate (HR), blood pressure, oxygen uptake (VO2), minute ventilation (VE), and gas exchange ratio (R) were monitored during the CPX. RESULTS: At 0 W, the HR, VO2, and VE were significantly higher when HAL was used. At 80 W, however, the HR (107 ± 14 vs 114 ± 14 beats/min, p < 0.01), systolic blood pressure (141 ± 15 vs 155 ± 20 mmHg, p < 0.01), VO2 (17.6 ± 2.4 vs 19.0 ± 2.5 mL/min/kg, p < 0.05), and R (0.88 ± 0.04 vs 0.95 ± 0.09, p < 0.05) were significantly lower when HAL was used. CONCLUSIONS: HAL has the potential to reduce cardiopulmonary burden during moderate-intensity exercise and can, therefore, be used as a support for exercise therapy. Further studies on cardiac patients are expected to contribute to the establishment of a new exercise therapy program using HAL.

Clinical Significance of the Presence of Oscillatory Breathing Both at Rest and During Exercise in Cardiac Patients.

Cardiac patients often experience nocturnal and daytime oscillatory breathing (OB). OB noted at rest sometimes becomes unclear or even disappears during exercise. We evaluated the physiological significance of OB by comparing the clinical characteristics of cardiac patients who manifested OB only at rest (group A), only during exercise (group B), and both at rest and during exercise (group C).Among 3,432 cardiac patients who underwent cardiopulmonary exercise testing (CPX), 114, 94, and 65 patients were identified as group A, B, and C, respectively. Left ventricular ejection function was 57 ± 17% in group A, 49 ± 20% in group B, and 41 ± 21% in group C (P < 0.05 for all comparisons among the 3 groups). The level of brain natriuretic peptide (BNP) was significantly higher in group C than in groups A and B. The peak VO2 was lower and the VE-VCO2 slope was higher in groups B and C than in group A.The present findings suggest that cardiac function is more impaired in cardiac patients who manifest OB both at rest and during exercise than in cardiac patients who manifest OB only at rest or only during exercise.

Utility of Nutritional Screening in Predicting Short-Term Prognosis of Heart Failure Patients.

Controlling nutritional status (CONUT) uses 2 biochemical parameters (serum albumin and cholesterol level), and 1 immune parameter (total lymphocyte count) to assess nutritional status. This study examined if CONUT could predict the short-term prognosis of heart failure (HF) patients.A total of 482 (57.5%) HF patients from the Ibaraki Cardiovascular Assessment Study-HF (n = 838) were enrolled (298 men, 71.7 ± 13.6 years). Blood samples were collected at admission, and nutritional status was assessed using CONUT. CONUT scores were defined as follows: 0-1, normal; 2-4, light; 5-8, moderate; and 9-12, severe degree of undernutrition. Accordingly, 352 (73%) patients had light-to-severe nutritional disturbances. The logarithmically transformed plasma brain natriuretic peptide (log BNP) concentration was significantly higher in the moderate-severe nutritional disturbance group (2.92 ± 0.42) compared to the normal group (2.72 ± 0.45, P < 0.01). CONUT scores were significantly higher in the in-hospital death patients [4 (3-8), n = 14] compared with patients who were discharged following symptom alleviation [3 (1-5), n = 446, P < 0.05]. With the exception of transferred HF patients (n = 22), logistic regression analysis that incorporated the CONUT score and the log BNP, showed that a higher CONUT score (P = 0.019) and higher log BNP (P = 0.009) were predictors of in-hospital death, and the median duration of hospital stay was 20 days.Our results demonstrate the usefulness of CONUT scores as predictors of short-term prognosis in hospitalized HF patients.

Nutritional screening based on the controlling nutritional status (CONUT) score at the time of admission is useful for long-term prognostic prediction in patients with heart failure requiring hospitalization.

The objective of the study was to clarify whether controlling nutritional status (CONUT) is useful for predicting the long-term prognosis of patients hospitalized with heart failure (HF). A total of 482 (57.5%) HF patients from the Ibaraki Cardiovascular Assessment Study-HF (N = 838) were enrolled (298 men, 71.7 ± 13.6 years). At admission, blood samples were collected and nutritional status assessed using CONUT. CONUT scores were defined as follows: 0-1, normal; 2-4, light; 5-8, moderate; and 9-12, severe undernutrition. Accordingly, 352 (73%) patients had light-to-severe nutritional disturbances. In the follow-up period [median 541.5 (range 354-786) days], 109 deaths were observed. A Kaplan-Meier analysis revealed that all-cause deaths occurred more frequently in HF patients with nutritional disturbances [n = 93 (26.4%)] than in those with normal nutrition [n = 16 (12.3%); log-rank p < 0.001]. The Cox proportional hazard analyses revealed that a per point increase in the CONUT score was associated with an increased risk of all-cause death (hazard ratio 1.142; 95% confidence interval, 1.044-1.249) after controlling simultaneously for age, sex, previous history of HF hospitalization, log brain natriuretic peptide, and use of therapeutic agents at admission (tolvaptan and aldosterone antagonists). This study suggests that nutritional screening using CONUT scores is helpful in predicting the long-term prognosis of patients hospitalized with HF in a multicenter registry setting.

Impact of aging on the clinical outcomes of Japanese patients with coronary artery disease after percutaneous coronary intervention.

Japan has become an aging society, resulting in an increased prevalence of coronary artery disease. However, clinical outcomes of elderly Japanese patients after percutaneous coronary intervention (PCI) remain unclear. Of the 15,227 patients in the Shinken Database, a single-hospital-based cohort of new patients, 1,214 patients who underwent PCI, was evaluated to determine the differences in clinical outcomes between the elderly (≥75 years) (n = 260) and the non-elderly (<75 years) (n = 954) patients. A major adverse cardiac event (MACE) was defined as a composite end point, including all-cause death, myocardial infarction (MI), and target lesion revascularization. Male gender and obesity were less common, and the estimated glomerular filtration rate (eGFR) was significantly lower in the elderly than in the non-elderly. Left ventricular ejection fraction (LVEF) was comparable between these groups. Left main trunk disease and multivessel disease were more common in the elderly than in the non-elderly group. Occurrence of MACE was frequent, and the incidences of all-cause death, cardiac death, and the admission rate for heart failure were significantly higher in the elderly patients. Multivariate analysis showed that prior MI, low eGFR, and poor LVEF were independent predictors for all-cause death in the elderly patients. Elderly patients had worse clinical outcomes than the non-elderly patients. Low eGFR and LVEF were independent predictors of all-cause death after PCI, suggesting that left ventricular dysfunction and renal dysfunction might synergistically contribute to the adverse clinical outcomes of the elderly patients undergoing PCI.

Prevalence and the long-term prognosis of functional mitral regurgitation in Japanese patients with symptomatic heart failure.

Functional mitral regurgitation (FMR) is a common and critical condition in patients with heart failure (HF); however, the prevalence and clinical outcome of FMR in Japanese real-world clinical practice remain unclear. Within a single hospital-based cohort in the Shinken Database 2004-2011, which comprised all new patients (n = 17,517) who visited the Cardiovascular Institute, we followed symptomatic HF patients. A total of 1,701 patients were included: 104 FMR patients (who had moderate to severe FMR) and 1,597 non-FMR patients (who had none or mild FMR). FMR patients had lower rates of hypertension and dyslipidemia, but higher rates of dilated cardiomyopathy, atrial fibrillation, and New York Heart Association functional class III/IV. FMR patients had higher levels of brain natriuretic peptide and lower left ventricular function. Use of cardiovascular drugs was more common among FMR patients. Kaplan-Meier curves revealed that the incidences of all-cause death, cardiovascular death, and admission for HF were significantly higher in FMR patients. The adjusted Cox regression analysis showed that significant FMR was associated with higher incidences of all-cause death [hazard ratio (HR) 2.179, 95 % confidence interval (CI) 1.266-3.751; P = 0.005], cardiovascular death (HR 2.371, 95 % CI 1.157-4.858; P = 0.018), and admission for HF (HR 1.819, 95 % CI 1.133-2.920; P = 0.013). FMR was common in Japanese symptomatic HF patients and was associated with adverse long-term outcomes. Establishing optimal therapeutic strategies for FMR is warranted.

Long-term incidence and prognostic factors of the progression of new coronary lesions in Japanese coronary artery disease patients after percutaneous coronary intervention.

Revascularization of an initially non-target site due to its progression as a new culprit lesion has emerged as a new therapeutic target of coronary artery disease (CAD) in the era of drug-eluting stents. Using the Shinken database, a single-hospital-based cohort, we aimed to clarify the incidence and prognostic factors for progression of previously non-significant coronary portions after prior percutaneous coronary intervention (PCI) in Japanese CAD patients. We selected from the Shinken database a single-hospital-based cohort of Japanese patients (n = 15227) who visited the Cardiovascular Institute between 2004 and 2010 to undergo PCI. This study included 1,214 patients (median follow-up period, 1,032 ± 704 days). Additional clinically driven PCI to treat previously non-significant lesions was performed in 152 patients. The cumulative rate of new-lesion PCI was 9.5 % at 1 year, 14.4 % at 3 years, and 17.6 % at 5 years. There was no difference in background clinical characteristics between patients with and without additional PCI. Prevalence of multi-vessel disease (MVD) (82 vs. 57 %, p < 0.001) and obesity (47 vs. 38 %, p = 0.028) were significantly higher and high-density lipoprotein cholesterol (HDL) level (51 ± 15 vs. 47 ± 12 mg/dl, p < 0.001) was significantly lower in patients with additional PCI than those without. Patients using insulin (6 vs. 3 %, p = 0.035) were more common in patients with additional PCI. Multivariate analysis showed that MVD, lower HDL, and insulin use were independent determinants of progression of new culprit coronary lesions. In conclusion, progression of new coronary lesions was common and new-lesion PCI continued to occur beyond 1 year after PCI without attenuation of their annual incidences up to 5 years. Greater coronary artery disease burden, low HDL, and insulin-dependent DM were independent predictors of progression of new culprit coronary lesions.

Effects of statin treatment in patients with coronary artery disease and chronic kidney disease.

Statins reduce cardiovascular morbidity and mortality from coronary artery disease (CAD). However, the effects of statin therapy in patients with CAD and chronic kidney disease (CKD) remain unclear. Within a single hospital-based cohort in the Shinken Database 2004-2010 comprising all patients (n = 15,227) who visited the Cardiovascular Institute, we followed patients with CKD and CAD after percutaneous coronary intervention (PCI). A major adverse cardiovascular and cerebrovascular event (MACCE) was defined by composite end points, including death, myocardial infarction, cerebral infarction, cerebral hemorrhage, and target lesion revascularization. A total of 391 patients were included in this study (median follow-up time 905 ± 679 days). Of these, 209 patients used statins. Patients with statin therapy were younger than those without. Obesity and dyslipidemia were more common, and the glomerular filtration rate (GFR) was significantly higher, in patients undergoing statin treatment. MACCE and cardiac death tended to be less common, and all-cause death was significantly less common, in patients taking statins. Multivariate analysis showed that low estimated GFR, poor left ventricular ejection fraction, and the absence of statin therapy were independent predictors for all-cause death of CKD patients after PCI. Statin therapy was associated with reduced all-cause mortality in patients with CKD and CAD after PCI.

Relation between oscillatory breathing and cardiopulmonary function during exercise in cardiac patients.

BACKGROUND: Oscillatory breathing, alternating between hyperpnea and hypopnea, has been recognized in cardiac patients, especially in those with heart failure. We evaluated whether the cycle length and amplitude of oscillatory breathing correlate with impaired cardiopulmonary function during exercise. METHODS AND RESULTS: We analyzed respiratory gas data during cardiopulmonary exercise testing (CPX) in 17 cardiac patients (68 ± 12 years) who showed clear oscillatory ventilation during CPX. The cycle length (time from peak to peak) and the amplitude (difference between peak and nadir) for both oscillating ventilation (VE) and oscillating O(2) uptake (VO(2)) were calculated from several consecutive oscillations noted at rest, and compared with indices of CPX. Oscillating VO(2) preceded oscillating VE in 16 of the 17 patients. Peak VO(2) (10.3 ± 3.1 ml min(-1)kg(-1)) correlated significantly negatively with the cycle length of the VE oscillation (r=-0.60, P=0.010), and of the VO(2) oscillation (r=-0.61, P=0.008), and the difference in time between the peak of oscillating VE and the corresponding peak of VO(2) (r=-0.58, P=0.012). Similarly, the slope of the increase in VE to the increase in CO(2) output (45.6 ± 11.5) correlated significantly positively with the cycle length of the VE and VO(2) oscillations (r=0.68, P=0.002; r=0.67, P=0.003, respectively). CONCLUSIONS: The cycle length of oscillatory breathing is closely related to impaired cardiac reserve during exercise in cardiac patients.

Effects of smoking habit on the prevalence of atrial fibrillation in Japanese patients with special reference to sex differences.

BACKGROUND: Tobacco smoking is a well-known risk factor for cardiovascular disease, but controversial results have been reported regarding its relationship with atrial fibrillation (AF). Moreover, no study on the relationship between smoking and AF has yet been undertaken in a Japanese context. METHODS AND RESULTS: We used data from the Shinken Database 2004-2011 (men/women, n=10,714/6,803, respectively), which included all new patients attending the Cardiovascular Institute between June 2004 and March 2012. AF was diagnosed in 1,698 and 598 men and women, respectively. In men, smokers were more prevalent in the AF than in the non-AF group (54.5% vs. 44.7%), whereas in women the prevalence of smokers was similar between AF and non-AF groups (14.4% vs. 15.4%). This discrepancy between the sexes seems to derive from a characteristic distribution pattern of smoking habit in women. After adjustment for various cofactors, smoking was independently associated with AF (odds ratio 1.54; 95% confidence interval 1.35-1.75; P<0.001) without a significant interaction between sex categories (P=0.195). CONCLUSIONS: Smoking was independently associated with AF without a significant interaction between sex categories among Japanese patients visiting a cardiovascular hospital. Further studies using a prospective cohort design are required to confirm a causal link between smoking and AF in Japanese patients.

Recent characteristics and outcomes of Japanese stable angina pectoris after percutaneous coronary intervention. An observational cohort study using the Shinken Database.

The mortality and morbidity of patients with stable angina pectoris (SAP) after percutaneous coronary intervention (PCI) in Japan differ from those in Western countries, although Japanese data are limited. We selected from the Shinken Database a single-hospital-based cohort of Japanese patients (n = 15,227) who visited The Cardiovascular Institute between 2004 and 2010 to undergo PCI. We followed-up the patients after PCI. A major adverse cardiac event (MACE) was defined as composite endpoints including all-cause death, acute myocardial infarction (AMI), and target-lesion revascularization (TLR). This study included 747 SAP patients (median follow-up period, 1,000 ± 703 days). The all cause mortality rate in SAP was 1.3% at 1 year, 2.7% at 3 years, and 6.1% at 5 years. The AMI rate was 0.5% at 1 year, 1.1% at 3 years, and 3.0% at 5 years, and the MACE rate was 14.0% at 1 year, 17.6% at 3 years, and 25.6% at 5 years. Moreover, new lesion PCI and heart failure admission continued to occur beyond 1 year after PCI without attenuation of their annual incidences up to 5 years. Multivariate analysis showed that poor left ventricular ejection fraction, chronic kidney disease (CKD), and absence of statin treatment were independent predictors of all-cause death of SAP patients after PCI. The results of the present study revealed the characteristics and long-term outcomes of Japanese SAP patients after PCI. The results of the present study suggest cardiorenal interaction and statin treatment play important roles in the long-term outcomes of Japanese CAD patients treated by PCI.

Efficacy and safety of surgical energy devices for axillary node dissection: a systematic review and network meta-analysis.

Various surgical energy devices are used for axillary lymph-node dissection. However, those that reduce seroma during axillary lymph-node dissection are unknown. We aimed to determine the best surgical energy device for reducing seroma by performing a network meta-analysis to synthesize the current evidence on the effectiveness of surgical energy devices for axillary node dissection for breast cancer patients. We searched MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, and World Health Organization International Clinical Trials Platform Search Portal. Two reviewers independently selected randomized controlled trials (RCTs) comparing electrosurgical bipolar vessel sealing (EBVS), ultrasonic coagulation shears (UCS), and conventional techniques for axillary node dissection. Primary outcomes were seroma, drained fluid volume (mL), and drainage duration (days). We analyzed random-effects and Bayesian network meta-analyses. We evaluated the confidence of each outcome using the CINeMA tool. We registered with PROSPERO (CRD42022335434). We included 34 RCTs with 2916 participants. Compared to the conventional techniques, UCS likely reduces seroma (risk ratio [RR], 0.61; 95% credible interval [CrI], 0.49-0.73), the drained fluid volume (mean difference [MD], - 313 mL; 95% CrI - 496 to - 130), and drainage duration (MD - 1.79 days; 95% CrI - 2.91 to - 0.66). EBVS might have little effect on seroma, the drained fluid volume, and drainage duration compared to conventional techniques. UCS likely reduce seroma (RR 0.44; 95% CrI 0.28-0.69) compared to EBVS. Confidence levels were low to moderate. In conclusion, UCS are likely the best surgical energy device for seroma reduction during axillary node dissection for breast cancer patients.

Overshoot phenomena of respiratory gas variables during exercise recovery in cardiac patients.

BACKGROUND: Transient increases (overshoot) in respiratory gas variables have been observed during exercise recovery, but their clinical significance is not clearly understood. Our group evaluated the relationship between the presence of overshoot of respiratory gas variables and the parameters obtained from cardiopulmonary exercise testing (CPX). METHODS AND RESULTS: In total, 227 patients with various cardiac diseases underwent CPX. The overshoot phenomena of O2 uptake (·VO2), ·VO2/heart rate (O2-pulse), and CO2 output (·VCO2) were analyzed by respiratory gas analysis during recovery after maximal exercise. The overshoot of ·VO2, O2-pulse, and ·VCO2 were recognized in 11 (5%), 43 (19%), and 12 (5%) patients, respectively. Compared with the patients without a ·VO2 overshoot, those with a ·VO2 overshoot had a significantly lower peak ·VO2 (12.3±3.7 vs. 17.9±6.2ml·min⁻¹·kg⁻¹, P=0.003), lower anaerobic threshold (9.4±1.7 vs. 12.4±3.3 ml·min⁻¹·kg⁻¹, P=0.001), higher ·VE-·VCO2 slope (38.0±5.2 vs. 33.2±9.6, P=0.013), and lower left ventricular ejection fraction (LVEF) (39.9±22.8 vs. 55.8±16.8%, P=0.003). Similar findings were obtained for the patients with an O2-pulse overshoot and those with a ·VCO2 overshoot. CONCLUSIONS: The overshoot phenomena of respiratory gas variables during recovery after maximal exercise are correlated with impaired cardiopulmonary function during exercise in cardiac patients.

Abnormal end-tidal PO(2) and PCO(2) at the anaerobic threshold correlate well with impaired exercise gas exchange in patients with left ventricular dysfunction.

BACKGROUND: The aim of the present study was to compare the end-tidal O(2) pressure (PETO(2)) to end-tidal CO(2) pressure (PETCO(2)) in cardiac patients during rest and during 2 states of exercise: at anaerobic threshold (AT) and at peak. The purpose was to see which metabolic state, PETO(2) or PETCO(2), best correlated with exercise limitation. METHODS AND RESULTS: Thirty-eight patients with left ventricular (LV) ejection fraction <40% underwent cardiopulmonary exercise testing (CPX). PETO(2) and PETCO(2) were measured during CPX, along with peak O(2) uptake (VO(2)), AT, slope of the increase in ventilation (VE) relative to the increase in CO(2) output (VCO(2)) (VE vs. VCO(2) slope), and the ratio of the increase in VO(2) to the increase in work rate (ΔVO(2)/ΔWR). Both PETO(2) and PETCO(2) measured at AT were best correlated with peakVO(2), AT, ΔVO(2)/ΔWR and VE vs. VCO(2) slope. PETO(2) at AT correlated with reduced peak VO(2) (r=-0.60), reduced AT (r=-0.52), reduced ΔVO(2)/ΔWR (r=-0.55) and increased VE vs. VCO(2) slope (r=0.74). PETCO(2) at AT correlated with reduced peak VO(2) (r=0.67), reduced AT (r=0.61), reduced ΔVO(2)/ΔWR (r=0.58) and increased VE vs. VCO(2) slope (r=-0.80). CONCLUSIONS: PETCO(2) and PETO(2) at AT correlated with peak VO(2), AT and ΔVO(2)/ΔWR, but best correlated with increased VE vs. VCO(2) slope. PETO(2) and PETCO(2) at AT can be used as a prime index of impaired cardiopulmonary function during exercise in patients with LV failure.