Improvement in exercise capacity of candidates awaiting heart transplantation

Hemoglobin is an independent predictor of improvement exercise tolerance in male patients with non-ischemic cardiomyopathy

Exercise intolerance is a symptom of chronic heart failure (CHF). The magnitude of exercise tolerance, as measured by peak oxygen uptake (peak VO2), is strongly associated with prognosis in patients with CHF. We aimed to evaluate the factors associated with improved exercise tolerance in patients with HF. In this prospective study, we recruited patients who were diagnosed with non-ischemic cardiomyopathy between September 2017 and September 2021. All patients underwent cardiopulmonary exercise testing at discharge and 6 months after enrollment. The patients were stratified according to whether peak VO2 was increased or not at 6 months. One hundred patients with a reduced left-ventricular ejection fraction (LVEF < 50%) were enrolled. Improvement of peak VO2 was observed in 74 patients. In male patients, hemoglobin level was higher in the increased peak VO2 group than in the non-increased group (15.0 ± 1.9 g/dL vs. 13.1 ± 2.1 g/dL; p < 0.01). Baseline hemoglobin level was positively correlated with the percentage change in peak VO2 (Spearman's r = 0.248, p = 0.040). Kaplan-Meier analysis demonstrated that adverse cardiac events were significantly less frequent in the increased peak VO2 group than in the non-increased group (log-rank test, p = 0.032). Multivariate logistic regression analysis identified hemoglobin level as an independent predictor of improved peak VO2 [odds ratio (OR) 1.60; 95% confidence interval (CI) 1.05-2.44; p = 0.027]. Baseline hemoglobin level is an independent predictor of improved peak VO2 in male patients with non-ischemic cardiomyopathy.

Association of device-measured physical activity with peak oxygen consumption measured by cardiopulmonary exercise testing in patients with cardiac implantable electronic devices

PURPOSE

Cardiac implantable electronic devices (CIEDs) offer diagnostic information such as device-measured physical activity (PA). Peak oxygen consumption (VO₂) measured by cardiopulmonary exercise testing (CPET) is the most objective variable showing exercise capacity. The purpose of this study was to investigate the relationship between these 2 variables.

METHODS

We retrospectively studied consecutive patients with CIEDs undergoing CPET between April 1, 2018, and January 31, 2021. These patients were divided into 2 groups: patients with peak VO₂ ≤ 14 ml/kg/min (low peak VO₂ group) and those showing peak VO₂ > 14 ml/kg/min (high peak VO₂ group). The peak device-measured PA was compared between the 2 groups. The relationship between the peak device-measured PA and peak VO₂ was also investigated.

RESULTS

There were 50 and 51 patients in the low and high peak VO₂ groups, respectively. The peak device-measured PA, which was expressed in units of hours/day, was significantly lower in the low peak VO₂ group than in the high peak VO₂ group (3.06, interquartile range [2.43-4.00] vs. 5.50, interquartile range [4.04-6.70] p < 0.01). The peak device-measured PA and peak VO₂ showed a significant positive correlation (Spearman's ρ = 0.53; p < 0.01). Furthermore, receiver operating characteristic curve analysis showed that a peak device-measured PA > 3.87 h/day could predict high peak VO₂ (80.4%, sensitivity; 72.0%, specificity). In multivariate linear regression analysis, peak device-measured PA was an independent predictor of peak VO₂ (regression coefficient, 0.61; 95% confidence interval, 0.33-0.89; p < 0.01).

CONCLUSIONS

Peak device-measured PA was significantly associated with peak VO₂.

Listing Criteria for Heart Transplant: Role of Cardiopulmonary Exercise Test and of Prognostic Scores

Patients with advanced heart failure (AdHF) have a reduced quality of life and poor prognosis. A heart transplant (HT) is an effective treatment for such patients. Still, because of a shortage of donor organs, the final decision to place a patient without contraindications on the HT waiting list is based on detailed risk-benefit analysis. Cardiopulmonary exercise tests (CPETs) play a pivotal role in guiding selection in patients with AdHF considered for an HT. Furthermore, several validated multivariable predicting scores obtained through various techniques, including the CPETs, are available and part of the decision-making process for HT listing.

Cardiopulmonary Exercise Test-The Revolving Door of Left Ventricular Assist Devices in Heart Failure

The prevalence of heart failure has an increasing tendency in the last years. Either heart failure with reduced ejection fraction (HFrEF) or with preserved ejection fraction, the treatment depends on the severity, cause, and symptoms. In case of HFrEF, careful evaluation of patient is essential for proper diagnosis, risk stratification and treatment, which should always be individualistic. Except from daily measurements, medical treatment and eventually implantation of implantable cardioverter defibrillator or cardiac resynchronization therapy, implantation of left ventricular assist device (LVAD) belongs also to therapeutic armamentarium. Other than invasive procedures, which are required for the evaluation of every patient with HFrEF, Cardiopulmonary exercise test emerges as one of the most effective noninvasive method for diagnosis, risk stratification, and treatment strategy for these patients. Cardiopulmonary exercise test can provide means for a critical evaluation of cardiovascular system. One of the most important variables is the maximal oxygen consumption (peak VO2). Its high predictive and prognostic power makes peak VO2 essential for the evaluation of patients as candidates, not only for LVAD-implantation, but also for explantation. Furthermore, regarding cardiac rehabilitation and exercise protocols, robust literature supports a follow-up of LVAD-patients by means of cardiopulmonary exercise testing.

Lean Mass Abnormalities in Heart Failure: The Role of Sarcopenia, Sarcopenic Obesity, and Cachexia

The role of body composition in patients with heart failure (HF) has been receiving much attention in the last few years. Particularly, reduced lean mass (LM), the best surrogate for skeletal muscle mass, is independently associated with abnormal cardiorespiratory fitness (CRF) and muscle strength, ultimately leading to reduced quality of life and worse prognosis. While in the past, reduced CRF in patients with HF was thought to result exclusively from cardiac dysfunction leading to reduced cardiac output at peak exercise, current evidence supports the concept that abnormalities in LM may also play a critical role. Abnormalities in the LM body composition compartment are associated with the development of sarcopenia, sarcopenic obesity, and cachexia. Such conditions have been implicated in the pathophysiology and progression of HF. However, identification of such conditions remains challenging, as universal definitions for sarcopenia, sarcopenic obesity, and cachexia are lacking. In this review article, we describe the most common body composition abnormalities related to the LM compartment, including skeletal and respiratory muscle mass abnormalities, and the consequences of such anomalies on CRF and muscle strength in patients with HF. Finally, we discuss the potential nonpharmacologic therapeutic strategies such as exercise training (ie, aerobic exercise and resistance exercise) and dietary interventions (ie, dietary supplementation and dietary patterns) that have been implemented to target body composition, with a focus on HF.

Prognostic impact of nutritional status and physical capacity in elderly patients with acute decompensated heart failure

Aims

Nutritional status as well as physical capacity is related to prognosis in patients with heart failure. The purpose of this study was to explore a simple prognostic indicator in patients with acute decompensated heart failure (ADHF) by including both nutritional status and physical capacity.

Methods and results

Patients hospitalized with ADHF (N = 203; mean age, 81 years) were enrolled. We evaluated the geriatric nutritional risk index (GNRI) on hospital admission and at discharge. A GNRI score < 92 was defined as malnutrition. Physical capacity was evaluated by simple walking test to determine if patients could walk 200 m, with a Borg scale score ≤ 13, without critical changes in vital signs. Primary endpoints were mortality and heart failure rehospitalization within 2 years. A total of 49% and 48% of patients showed malnutrition on admission and at discharge, respectively. Malnutrition at discharge was more strongly related to mortality [hazard ratio (HR) 3.382, 95% confidence interval (CI) 1.900–6.020, P < 0.0001)] than that on admission (HR 2.448, 95% CI 1.442–4.157, P = 0.001) by univariable analysis. Malnutrition at discharge was related to mortality (HR 2.370, 95% CI 1.166–4.814, P = 0.02), but malnutrition on admission was not related (HR 1.538, 95% CI 0.823–2.875, P = 0.18) by multivariable analysis. Almost half of patients (45%) could not walk 200 m, which was significantly related to mortality by univariable analysis (HR 3.303, 95% CI 1.905–5.727, P < 0.0001), but was not by multivariable analysis (HR 1.990, 95% CI 0.999–3.962, P = 0.05). The combined index including both GNRI and simple walking test was an independent and stronger predictor of mortality than either index alone by multivariable analysis (HR 2.249, 95% CI 1.362–3.716, P < 0.01). Neither malnutrition nor low physical capacity was related to heart failure rehospitalization by univariable analysis (HR 0.702, 95% CI 0.483–1.020, P = 0.06; HR 1.047, 95% CI 0.724–1.515, P = 0.81, respectively). Malnutrition at discharge significantly reduced heart failure rehospitalization by multivariable analysis (HR 0.431, 95% CI 0.266–0.698, P < 0.01). When patients were classified into Group G (both nutritional status and physical capacity at discharge were good), Group E (either was good), and Group B (both were bad), mortality rates were significantly different among the groups (log rank P < 0.0001).

Conclusion

A simple indicator including both nutritional status and physical capacity may predict 2 year mortality in elderly patients with ADHF.

Cardiopulmonary Exercise Test in heart failure: A Sine qua non

A robust literature, over the last years, supports the indication of cardiopulmonary exercise testing (CPET) in patients with cardiovascular diseases. Understanding exercise physiology is a crucial component of the critical evaluation of exercise intolerance. Shortness of breath and exercise limitation is often treated with an improper focus, partly because the pathophysiology is not well understood in the frame of the diagnostic spectrum of each subspecialty. A vital field and research area have been cardiopulmonary exercise test in heart failure with preserved/reduced ejection fraction, evaluation of heart failure patients as candidates for LVAD-Implantation, as well as for LVAD-Explantation and ultimately for heart transplantation. All the CPET variables provide synergistic prognostic discrimination. However, Peak VO2 serves as the most critical parameter for risk stratification and prediction of survival rate.

Comparison of Treadmill and Cycle Ergometer Exercise During Cardiac Rehabilitation: A Meta-analysis

OBJECTIVE

To compare treadmill versus cycling-based exercise in cardiac rehabilitation (CR) on functional capacity (FC) outcomes.

DATA SOURCE

Databases were searched for randomized studies using single modality continuous exercise.

STUDY SELECTION

Studies implemented a continuous cycling or treadmill protocol for patients with either coronary artery disease (CAD) or chronic heart failure (CHF). The effect of single modality exercise on FC (VO₂peak) was analyzed. Differences in the effect of CR on FC was assessed between the mode subgroup (cycling vs treadmill) and disease state subgroup (CAD vs CHF) within both the cycling and treadmill groups.

DATA EXTRACTION

Data were extracted from 23 studies including 600 patients (mean age 60y, 86% men).

DATA SYNTHESIS

There was a significant difference in effect size between studies that used cycling, Hedges' g=0.85 (95% confidence interval [95% CI], 0.52-1.17; k=13) and studies that used treadmill exercise, Hedges' g=0.46 (95% CI, 0.22-0.70; k=8). Within cycling studies (n=14), FC was higher among CAD patients, Hedges' g=1.03 (95% CI, 0.65-1.42; k=9) compared to those with CHF, Hedges' g=0.40 (95% CI, 0.09-0.71; k=4, P<.001). Conversely, among treadmill studies (n=9), FC was higher among CHF patients, Hedges' g=0.94 (95% CI, 0.23-1.65; k=2) compared to CAD, Hedges' g=0.33 (95% CI, 0.19-0.47; k=5; P<.01).

CONCLUSIONS

According to identified studies, when cycling was the primary mode of exercise in CR, there was larger change in FC compared to treadmill exercise. In addition, CAD patients experienced greater gains in FC when cycling was the primary mode of exercise in CR, while CHF patients benefited more from treadmill-based exercise programs.

Comparison of the long-term reproducibility of the walk test and of exercise peak oxygen consumption in patients with preserved exercise capacity

Short-term and long-term reproducibility of the cardiopulmonary (CPX) exercise test have been established. Though short and mid-term reproducibility of the walk test has been ascertained, this was not extensively done for the long-term reproducibility. The aim of the study was to examine the long-term reproducibility of distance walked in an allotted time and to check the stability of the relationship between walked distance and exercise peak VO₂ (pVO₂).

METHODS

Forty six subjects (33 men; 57 ± 14 years), referred for functional capacity assessment, were studied twice by CPX and walking test. On the same day, CPX was performed on a bicycle or a treadmill and walk test in a corridor as required by specific guidelines. We performed a 12-minute walk test and the distance covered in six minutes was systematically taken down. A free time interval of 1.5 hours was observed between the exercise tests. Distance walked in the allotted time and pVO₂ were analysed. Reproducibility was assessed according to Bland and Altman plots and intra-class coefficient correlation (ICC). The relationship between distance ambulated and pVO₂ was analysed by the Spearman coefficient correlation.

RESULTS

The time interval between the two evaluations was 290 ± 10 days. During this meantime, for those subjects having drug treatment, no change was recorded in their regimen. BMI remained stable for the entire studied population (28 ± 5 kg/m²). Minute walked distance was respectively 522 ± 83 and 527 ± 76 m in six minutes, 1033 ± 182 and 1041 ± 153 m in 12 minutes. pVO₂ was 21 ± 7 and 22 ± 7 ml/kg/min (all p = NS). The walk test was reproducible in the long-term, regardless of the modality (6 or 12-minute walk) as shown by the Bland-Altman plots and the high ICC of .89. Spearman's rho coefficient between distance ambulated and pVO₂ was modest and remained stable over time whatever the allotted time: Spearman's r = .54; p = .0011 (1st evaluation) and Spearman's r = .51; p = .0019 (2nd evaluation) between 6-minute distance walked and pVO₂.

CONCLUSIONS

The walking distance in an allotted time seems highly reproducible in the long-term. Its relationship with pVO₂ remains stable over time. It could be of value for repeated assessment of patients' exercise capacity in a first step. Further evaluation in a larger population is needed to confirm our result and its usefulness in clinical practice.

Decline in peak oxygen consumption over time predicts death or transplantation in adults with a Fontan circulation

Peak oxygen consumption (pVO₂) measured by cardiopulmonary exercise test (CPET) predicts mortality in adults with a Fontan circulation. The purpose of this study was to assess the additive prognostic value of change in pVO₂ over time.

METHODS

We analyzed a cohort of adults (≥18 years old) with a Fontan circulation who underwent at least 2 maximal CPETs separated by 6-30 months at Boston Children's Hospital between 2000 and 2015. Survival analysis was performed to determine whether changes in CPET variables, including pVO₂ between consecutive tests, were associated with subsequent clinical events. The primary outcome was transplant-free survival.

RESULTS

The study included 130 patients with 287 CPET test pairs. Average age was 26.6±9.5 years. Baseline pVO₂ averaged 22.0±5.7 mL/kg/min or 60.9%±13.7% predicted. In the cohort overall, there was no change in mean pVO₂ between sequential CPETs. Eleven patients died and 2 underwent transplant. On average, pVO₂ declined for patients who subsequently died or underwent transplant but remained stable among those who did not (-9.8%±14.6% vs 0.0±13.0%, P<.01). Those with a decline in pVO₂ between CPETs were at greater risk of death or transplantation (per 10% decrease in pVO₂: HR=2.0, 95% CI 1.2-3.1, P=.004). Change in pVO₂ remained a significant predictor of death or transplant after adjusting for pVO₂ at first CPET (per 10% decline in pVO₂: HR=2.5, 95% CI 1.5-4.2, P<.001).

CONCLUSIONS

A decline in pVO₂ between consecutive CPETs predicts increased risk for death or transplant in adults with a Fontan circulation independent of baseline pVO₂. These results support the additive clinical value of serial CPET in this population.

Prognostic value of time-related changes of cardiopulmonary exercise testing indices in stable chronic heart failure: a pragmatic and operative scheme

BACKGROUND

Although peak oxygen consumption (VO2) is an objective measurement of functional capacity linked to survival, most clinicians use clinical history to monitor changes over time of functional disability. The aim was to verify the prognostic value of time-related changes (Delta) of symptom-limited cardiopulmonary exercise testing (CPX) indices in stable chronic heart failure (CHF).

DESIGN AND METHODS

We studied 231 stable CHF patients (200 men) with left ventricular ejection fraction (LVEF) of 24 +/- 8% and peak VO2 of 14.3 +/- 8 ml/kg per min, who performed two symptom-limited CPX over time.

RESULTS

The two incremental CPX were separated by a mean interval of 258 +/- 42 days; 59 (26%) suffered cardiovascular death or underwent urgent heart transplantation during the follow-up (1167 +/- 562 days). Peak VO2, LVEF (measured at second evaluation), Deltapeak VO2 and DeltaNYHA (New York Heart Association classification) were selected as independent predictors in the total population, and LVEF, Deltapeak VO2, and NYHA in patients with peak VO2 of 14 ml/kg per min or less (106 patients); no Delta parameter was selected in patients with preserved exercise tolerance. Survival analysis was performed taking into consideration the inter-test variability of peak VO2 (6%): true fall: more than 6% decrease, decline within the measurement variability; less than 6% decrease, improvement within the measurement variability; less than 6% increase and true rise; more than 6% increase: total mortality rate was 51, 23, 19 and 14% (P < 0.0001), respectively.

CONCLUSIONS

Deltapeak VO2 is a useful outcome index; a combination of static (single) and time-related functional variables can enhance the prognostication process in stable CHF patients.

Anesthesia for Heart Transplantation

Although several new surgical therapies hold promise for changing the surgical approach to heart failure, the most effective therapy currently for patients with end- stage congestive heart failure is heart transplantation. The challenges posed to the anesthesiologist caring for these patients are great, and are increasing as a result of a shift toward transplanting medically unstable pa tients. The anesthetic management of patients undergo ing heart transplantation requires a knowledge of the pathophysiology of heart failure, the altered pharmacody namics of anesthetics in the patient with heart failure, treatment of right heart failure, as well as the impact of new surgical therapies on cardiovascular function.

Cardiopulmonary Exercise Testing in Heart Failure

Exercise intolerance, indicated by dyspnea and fatigue during exertion, is a cardinal manifestation of heart failure (HF). Cardiopulmonary exercise testing (CPET) precisely defines maximum exercise capacity through measurement of peak oxygen uptake (VO2). Peak VO2 values have a critical role in informing patient selection for advanced HF interventions such as heart transplantation and ventricular assist devices. Oxygen uptake and ventilatory patterns obtained during the submaximal portion of CPET are also valuable to recognize because of their ease of ascertainment during low-level exercise, relevance to ability to perform activities of daily living, independence from volitional effort, and strong relationship to prognosis in HF. The ability of peak VO2 and other CPET variables to be measured reproducibly and to accurately reflect HF severity is increasingly recognized and endorsed by scientific statements. Integration of CPET with invasive hemodynamic monitoring and cardiac imaging during exercise provides comprehensive characterization of multisystem reserve capacity that can inform prognosis and the need for cardiac interventions. Here, we review both practical aspects of conducting CPETs in patients with HF for clinical and research purposes as well as interpretation of gas exchange patterns across the spectrum of preclinical HF to advanced HF.

Wearable cardioverter-defibrillator as a bridge to cardiac transplantation: A national database analysis

BACKGROUND

Life-threatening ventricular arrhythmias (VAs) and sudden cardiac death (SCD) are common in patients awaiting heart transplantation (HT), and the implantable cardioverter-defibrillator (ICD) is often used for primary prevention in this setting. Use of ICDs in these patients is not without risks and is sometimes contraindicated. The wearable cardioverter-defibrillator (WCD) may be a reasonable alternative to bridge the period of risk leading up to HT.

METHODS

We obtained a convenience sample of patients prescribed an WCD as a bridge therapy to HT. The available data consisted of demographics, cardiac transplantation status, associated comorbidities, device use, device-stored electrocardiogram (ECG) and reason for discontinuing the WCD. Statistical analyses were performed using SPSS version 17 and GraphPad PRISM 5.

RESULTS

The registry included 121 patients consisting of 83 (69%) men and 38 (31%) women. The mean age was 44 ± 18 years. Mean ejection fraction was 25 ± 15%. Non-ischemic cardiomyopathy (CMP) was the underlying diagnosis in 67 (55%) patients, whereas 21 (17%) patients had ischemic CMP and 33 (27%) had a mixed or uncharacterized CMP. New York Heart Association Class III heart failure was present in 32% and 34% were in Class IV. Eighty-eight patients (73%) were being evaluated for HT or were on an HT waiting list, and 33 patients (27%) had had a prior HT, experienced rejection, and were awaiting re-transplantation. The patients wore the WCD for an average of 127 ± 392 days (median 39 days) with average daily use of 17 ± 7 hours (median 20 hours). Seven patients (6%) received appropriate WCD shocks. Fifty-one patients (42%) ended use after ICD implantation and 13 patients (11%) after HT. There were 11 deaths (9%).

CONCLUSIONS

A significant proportion of patients on the HT waiting list will have VA. WCD use in our study showed high compliance and efficacy and a low complication rate, suggesting that the WCD is a reasonable bridge therapy for preventing SCD in patients awaiting HT.

A randomized pilot trial of remote ischemic preconditioning in heart failure with reduced ejection fraction

Background

Remote ischemic preconditioning (RIPC) induced by transient limb ischemia confers multi-organ protection and improves exercise performance in the setting of tissue hypoxia. We aimed to evaluate the effect of RIPC on exercise capacity in heart failure patients.

Methods

We performed a randomized crossover trial of RIPC (4×5-minutes limb ischemia) compared to sham control in heart failure patients undergoing exercise testing. Patients were randomly allocated to either RIPC or sham prior to exercise, then crossed over and completed the alternate intervention with repeat testing. The primary outcome was peak VO2, RIPC versus sham. A mechanistic substudy was performed using dialysate from study patient blood samples obtained after sham and RIPC. This dialysate was used to test for a protective effect of RIPC in a mouse heart Langendorff model of infarction. Mouse heart infarct size with RIPC or sham dialysate exposure was also compared with historical control data.

Results

Twenty patients completed the study. RIPC was not associated with improvements in peak VO2 (15.6+/−4.2 vs 15.3+/−4.6 mL/kg/min; p = 0.53, sham and RIPC, respectively). In our Langendorff sub-study, infarct size was similar between RIPC and sham dialysate groups from our study patients, but was smaller than expected compared to healthy controls (29.0%, 27.9% [sham, RIPC] vs 51.2% [controls]. We observed less preconditioning among the subgroup of patients with increased exercise performance following RIPC (p<0.04).

Conclusion

In this pilot study of RIPC in heart failure patients, RIPC was not associated with improvements in exercise capacity overall. However, the degree of effect of RIPC may be inversely related to the degree of baseline preconditioning. These data provide the basis for a larger randomized trial to test the potential benefits of RIPC in patients with heart failure.

Trial Registration

ClinicalTrials.gov +++++NCT01128790

Functional and hemodynamic cardiac determinants of exercise capacity in patients with systolic heart failure

Decreased exercise capacity is the main symptom in patients with heart failure (HF). We assessed the association among noninvasively determined maximal cardiac output at exercise, systolic and diastolic cardiac functions at rest, and peak oxygen uptake (pVo(2)) exercise capacity in patients with congestive HF. We studied 102 patients 62 ± 11 years of age with New York Heart Association class II to IV stable HF and left ventricular (LV) ejection fraction <45%. All patients underwent echocardiography and a treadmill cardiopulmonary exercise test for evaluation of pVo(2) corrected for fat-free mass. During the cardiopulmonary exercise test, cardiac output was estimated noninvasively and continuously using Nexfin HD. Fat-free mass-corrected pVo(2) was associated in an univariate linear regression analysis with peak exercise cardiac index (CI) (beta 0.511, p <0.001), LV end-diastolic pressure estimates (peak early diastolic filling velocity/early diastolic tissue velocity [E/e'], beta -0.363, p = 0.001), and right ventricular function (tricuspid annular plane systolic excursion, beta 0.393, p <0.001). In multivariate analysis peak exercise CI (beta 0.380, p = 0.001), but not cardiac output or LV ejection fraction at rest, was an independent predictor of pVo(2). Other independent predictors of pVo(2) were E/e' (beta -0.276, p = 0.009) and tricuspid annular plane systolic excursion (beta 0.392, p <0.001), also when adjusted for age and gender. In conclusion, peak CI is an independent predictor of fat-free mass-corrected pVo(2) in patients with systolic HF. Of all echocardiographic parameters at rest, right ventricular function and E/e' were independently and significantly associated with pVo(2), whereas LV ejection fraction at rest was not.

Modest increase in peak VO2 is related to better clinical outcomes in chronic heart failure patients: results from heart failure and a controlled trial to investigate outcomes of exercise training

BACKGROUND

The prognostic ability of a single measurement of peak oxygen uptake (VO(2)) is well established in patients with chronic heart failure. The relation between a change in peak VO(2) and clinical outcomes is not well defined.

METHODS AND RESULTS

This investigation determined whether an increase in peak VO(2) was associated with a lower risk of the primary end point of time to all-cause mortality or all-cause hospitalization and 3 secondary end points. In Heart Failure and a Controlled Trial to Investigate Outcomes of Exercise Training, an exercise training trial for patients with systolic heart failure, cardiopulmonary exercise tests were performed at baseline and ≈3 months later in 1620 participants. Median peak VO(2) in the combined sample increased from 15.0 (11.9-18.0 Q1-Q3) to 15.4 (12.3-18.7 Q1-Q3) mL·kg(-1)·min(-1). Every 6% increase in peak VO(2,) adjusted for other significant predictors, was associated with a 5% lower risk of the primary end point (hazard ratio=0.95; CI=0.93-0.98; P<0.001); a 4% lower risk of the secondary end point of time to cardiovascular mortality or cardiovascular hospitalization (hazard ratio=0.96; CI=0.94-0.99; P<0.001); an 8% lower risk of cardiovascular mortality or heart failure hospitalization (hazard ratio=0.92; CI=0.88-0.96; P<0.001); and a 7% lower all-cause mortality (hazard ratio=0.93; CI=0.90-0.97; P<0.001).

CONCLUSIONS

Among patients with chronic systolic heart failure, a modest increase in peak VO(2) over 3 months was associated with a more favorable outcome. Monitoring the change in peak VO(2) for such patients may have benefit in assessing prognosis.

A simple new visualization of exercise data discloses pathophysiology and severity of heart failure

Background

The complexity of cardiopulmonary exercise testing data and their displays tends to make assessment of patients, including those with heart failure, time consuming.

Methods and Results

We postulated that a new single display that uses concurrent values of oxygen uptake / ventilation versus carbon dioxide output / ventilation ratios (–versus–), plotted on equal X–Y axes, would better quantify normality and heart failure severity and would clarify pathophysiology. Consecutive –versus– values from rest to recovery were displayed on X–Y axes for patients with Class II and IV heart failure and for healthy subjects without heart failure. The displays revealed distinctive patterns for each group, reflecting sequential changes in cardiac output, arterial and mixed venous O₂ and CO₂ content differences, and ventilation (). On the basis of exercise tests of 417 healthy subjects, reference formulas for highest and , which normally occur during moderate exercise, are presented. Absolute and percent predicted values of highest and were recorded for 10 individuals from each group: Those of healthy subjects were significantly higher than those of patients with Class II heart failure, and those of patients with Class II heart failure were higher than those of patients with Class IV heart failure. These values differentiated heart failure severity better than peak , anaerobic threshold, peak oxygen pulse, and slopes. Resting –versus– values were strikingly low for patients with Class IV heart failure, and with exercise, increased minimally or even decreased. With regard to the pathophysiology of heart failure, high values during milder exercise, previously attributed to ventilatory inefficiency, seem to be caused primarily by reduced cardiac output rather than increased .

Conclusion

–versus– measurements and displays, extractable from future or existing exercise data, separate the 3 groups (healthy subjects, patients with Class II heart failure, and patients with Class IV heart failure) well and confirm the dominant role of low cardiac output rather than excessive in heart failure pathophysiology. (J Am Heart Assoc. 2012;1:e001883 doi: 10.1161/JAHA.112.001883.)

Health-related quality of life and exercise tolerance in recipients of heart transplants and left ventricular assist devices: a prospective, comparative study

BACKGROUND

The aim of this study was to evaluate and compare health-related quality of life (HRQoL) and physical exercise tolerance in patients after heart transplantation (HTx) or implantation of a left ventricular assist device (LVAD).

METHODS

A prospective, comparative design was used to characterize changes over time in HRQoL (SF-36) and exercise tolerance in patients after HTx (n = 54) and during LVAD support (n = 36). Nine LVAD patients were lost for follow-up. The majority of patients in both groups were male (97%); the LVAD cohort tended to be younger (p = 0.06).

RESULTS

HRQoL improved significantly in HTx patients in the SF-36 physical (p = 0.02), but not in the psychosocial (p = 0.27) component score during follow-up. In the LVAD group, HRQoL showed improvements for both the SF-36 physical and psychosocial component scores (both p = 0.04). Between-group comparisons revealed better HRQoL for the HTx cohort than the LVAD cohort for 2 of 8 SF-36 subscales. Age-, gender- and body mass index (BMI)-adjusted exercise tolerance (workload; VO(2max)) showed significant improvements for both HTx (p = 0.01) and LVAD (p = 0.01) patients. Adjusted maximum oxygen consumption was higher for HTx patients (p = 0.05) relative to LVAD patients at 8 ± 1 months after implant.

CONCLUSION

HRQoL and exercise capacity increased in both groups over the time-course of the study. After adjusting for relevant variables, HTx patients showed a higher exercise tolerance compared with the LVAD group during follow-up. Thus, future large-scale intervention studies should emphasize the specific needs of these patient cohorts.

Candesartan improves maximal exercise capacity in hypertensives: results of a randomized placebo-controlled crossover trial

Cardiac hypertrophy and remodelling in hypertension has been associated with impaired exercise capacity. The authors tested whether an angiotensin receptor blocker, candesartan, improved exercise peak oxygen volume (VO2) in this population. A total of 154 untreated hypertensive patients, aged 40 to 66 years, with World Health Organization stage I or II hypertension and left ventricular hypertrophy, were randomized to receive placebo, candesartan (32 mg), each of these plus aspirin (300 mg/d), or the same preparations in a reverse order, for 3 weeks, with a 3-week washout period between treatments. The authors measured maximal workload and oxygen reserve with an exercise test, 24 hour-ambulatory blood pressure, and echocardiography at the end of each treatment. Hypertensive patients did not achieve the maximal workload (116 [99-133] W vs 132 (AMA style = no period on vs) [116-149] W; P=.01). This impaired exercise capacity was in a multiple regression analysis related to lower oxygen reserve (r=0.49, P<.001), and the lower oxygen reserve to higher left ventricular hypertrophy by echocardiography (beta=-0.34), respectively. The use of candesartan alone or with aspirin resulted in an improvement of peak VO2 and exercise tolerance, when compared with controls. Patients with hypertension and cardiac hypertrophy cannot achieve a predicted maximal workload. The use of an angiotensin receptor blocker in therapy may represent a useful treatment in these patients for its effect on exercise peak VO2 and exercise tolerance. The use of aspirin did not affect outcome.

Absence of Exercise Capacity Improvement After Exercise Training Program

Background— Exercise training is established as adjuvant therapy for chronic heart failure, but the prognostic value of improvement in exercise capacity after exercise training has never been evaluated.

Methods and Results— In this prospective bicentric study, all chronic heart failure patients with left ventricular ejection fraction <45% who underwent an exercise training program in a cardiac rehabilitation center between January 2004 and September 2006 were consecutively included. Improvement in exercise capacity was assessed by change in peak oxygen consumption (δPV o 2 ) and in PV o 2 expressed as a percentage of predicted PV o 2 (δ%PPV o 2 ) measured before and after the training program. We included 155 patients (54�12 years old, male 81%, left ventricular ejection fraction=29.5�7.1%). Patients underwent 20 (10–30) training sessions. PV o 2 and %PPV o 2 were significantly increased after the training program (14% and 13%, respectively, P <0.001 for both). After 16�6 months follow-up, 27 patients had a cardiac event (death [n=12], cardiac transplantation [n=5], hospitalization for acute heart failure [n=10]). Univariate analysis revealed that among 17 significant predictors of cardiac events, the 2 more powerful ones were level of B-type natriuretic peptide at baseline ( P <0.0001) and improvement in exercise capacity as assessed by δPV o 2 and δ%PPV o 2 ( P <0.0001). Multivariate analysis revealed B-type natriuretic peptide level and δ%PPV o 2 as only independent predictive factors of outcome ( P =0.01). The risk ratio of cardiac events for nonresponse versus response to the training program (defined as median δ%PPV o 2 <6%) was 8.2 ( P =0.0006).

Conclusions— Among patients with chronic heart failure, the lack of improvement in exercise capacity after an exercise training program has strong prognostic value for adverse cardiac events independent of classical predictive factors such as left ventricular ejection fraction, New York Heart Association class, and B-type natriuretic peptide level.

Acute hemodynamic and functional effects of surgical ventricular restoration and heart transplantation in patients with ischemic dilated cardiomyopathy

OBJECTIVES

Peak oxygen uptake (VO(2)) and ventilatory efficiency have prognostic implications in the population with congestive heart failure. This study evaluated quality-of-life functional capacity after the 2 treatment strategies of surgical ventricular restoration and transplantation for severe left ventricular dysfunction of ischemic cause.

METHODS

The 75-patient study population (between 2004 and 2006) with severe heart failure included 35 patients undergoing surgical ventricular restoration (mean age, 62.6 +/- 8.7 years), sometimes together with coronary artery bypass grafting or mitral surgery, and 40 cardiac transplant recipients (mean age, 55.6 +/- 7.7 years). Preoperative and 6-month postoperative function (peak VO(2), the anaerobic threshold, and the slope of minute ventilation/carbon dioxide uptake), cardiac catheterization parameters (left and right), and hospital and early outcomes were evaluated.

RESULTS

The 2 groups had comparable baseline functional impairment and experienced similar hospital stay and early outcomes. They also showed similar improvements in left ventricular volume indexes and hemodynamic parameters and sustained significant improvements of median VO(2), anaerobic threshold, and minute ventilation/carbon dioxide uptake values.

CONCLUSIONS

Both surgical strategies resulted in a significant and comparable improvement of functional capacity at the 6-month evaluation. These early studies must be repeated to determine the long-term benefits of surgical ventricular restoration because maximal VO(2) and ventilatory efficiency lose their prognostic survival role after transplantation.

Psychosocial and behavioural factors in heart transplant candidates – an overview

Mortality among heart transplant (HTX) candidates remains high. This review of the literature shows that psychosocial characteristics like depression, social isolation and coping strategies contribute to morbidity and mortality in heart failure (HF) patients, and may also be relevant to the prognosis of HTX candidates. Based on the research to date, physical activity favourably affects subjective and objective parameters not only in HF patients, but also in HTX candidates. Depression is prevalent among HTX candidates, especially in ischaemic patients, and seems to be related to earlier transplantation. Findings on the effects of depression on pretransplant mortality are conflicting. Not much is known concerning social isolation, coping, nutrition, or weight loss in this patient group. Identification of modifiable psychosocial and behavioural variables related to clinical status in this patient group is clearly needed and will aid the development of behavioural interventions to supplement medical therapies.

Prognostic impact of peakVO2-changes in stable CHF on chronic beta-blocker treatment

BACKGROUND

Peak oxygen uptake (pVO2) is used for risk stratification in chronic heart failure (CHF), but little is known about the prognostic impact of pVO2-changes in patients on chronic beta-blocker (BBL) therapy. We therefore prospectively evaluated individual pVO2-changes at a 6-month interval in patients all receiving BBL.

METHODS

194 patients with stable CHF on stable medication were included (V1) and underwent clinical evaluation and exercise testing. Testing was repeated (V2) at 5.7+/-1.5 months after V1 and patients were followed >12 months after V2. Death or hospitalisation due to cardiac reasons was the predefined EP (EPP, end-point positive; n=62; EPN, end-point negative; n=113).

RESULTS

Initial characteristics did not differ between EPP and EPN. Multivariate cox regression analysis revealed that change of pVO2 (EPP: -0.6+/-2.6 ml/kg min; EPN: +2.5+/-3.3 ml/kg min; p<0.001) was independent to pVO2, LVEF, NTproBNP and NYHA at V2 for prediction of the combined end-point during follow-up. An increase of pVO2 by 10% was identified as an adequate cut-off value for risk stratification and ROC-analysis showed the significant incremental prognostic value of the determination of pVO2 changes in combination with pVO2.

CONCLUSIONS

Serial measurements of pVO2 yield additional information for risk stratification in clinically homogenous CHF patients receiving BBL. This is the first study demonstrating this fact within a narrow predefined interval with all patients on BBL.

A prospective, randomized, double-blind, placebo controlled trial of beta-blockade in patients who have undergone surgical correction of tetralogy of Fallot

AIMS

Our purpose was to evaluate the effect of a treatment over six months with bisoprolol on the surrogate parameters of N-Terminal-pro brain natriuretic peptide, subsequently to be described as brain natriuretic peptide, peak uptake of oxygen, and ventricular function assessed by magnetic resonance imaging in grown ups and adults who had undergone surgical correction of tetralogy of Fallot.

METHODS AND RESULTS

We designed a prospective, randomized, double-blind, placebo controlled trial. We enrolled 33 patients, aged 30.9 plus or minus 9.5 years in either class 1 or 2 of the grading of the New York Heart Association class with both levels of brain natriuretic peptide greater than 100 pg/ml and a reduced peak uptake of oxygen less than 25 ml/kg/min. During treatment with Bisoprolol, the levels of brain natriuretic peptide increased significantly from 206 plus or minus 95 to 341 plus or minus 250 pg/ml (p< 0.05), and those of atrial natriuretic peptide from 4117 plus or minus 1837 to 5340 plus or minus 2102 fmol/ml (p = 0.0005). These measures remained unchanged in the group of patients receiving the placebo. Peak uptake of oxygen did not differ significantly in either group, nor did treatment have any significant effect on right and left ventricular volumes and ejection fractions as determined by magnetic resonance imaging. The clinical state as judged within the grading system of the New York Heart Association was also unchanged by beta-blockade.

CONCLUSION

Beta blockade with Bisoprolol seems to have no beneficial effect on asymptomatic or mildly symptomatic patients with right ventricular dysfunction secondary to repaired tetralogy of Fallot with residual pulmonary regurgitation and/or stenosis.

Ease of noninvasive measurement of cardiac output coupled with peak VO2 determination at rest and during exercise in patients with heart failure

Peak oxygen consumption (VO2) is a powerful prognostic predictor of survival in patients with heart failure (HF) because it provides an indirect assessment of a patient's ability to increase cardiac output (CO). However, many peripheral factors affect VO2. Inert gas rebreathing using low-concentration soluble and insoluble inert gases can derive CO by the Fick principle. The Innocor rebreathing system uses an oxygen-enriched mixture of an inert soluble gas (0.5% nitrous oxide) and an inert insoluble gas (0.1% sulfur hexafluoride) measured by photoacoustic analyzers over a 5-breath interval. The practicality of this device in measuring CO and VO2 during exercise was assessed in patients with HF. Ninety-two consecutive exercise tests were prospectively performed in 88 patients with HF using the Innocor system. Incremental bicycle exercise was performed with CO measurements at rest, at 50 W, and at peak exercise. The mean age of the 68 men and 20 women was 54 +/- 13 years; 33% had coronary artery disease, and 67% had dilated cardiomyopathy. The mean left ventricular ejection fraction was 24 +/- 9%. Patients were able to rapidly learn the rebreathing technique and easily integrate it into the exercise protocol. Eighty-six percent of the tests had successful measurement of metabolic and cardiac output data. Mean CO at rest was 3.5 +/- 1.1 L/min and increased to 7.2 +/- 2.7 L/min. Mean peak VO2 was 12.6 +/- 4.7 ml/kg/min. A significant linear correlation was observed between peak VO2 and peak CO (r = 0.64, p <0.0001). In conclusion, combined metabolic stress testing with inert gas rebreathing can be easily performed in patients with HF.

Psychosoziale Aspekte und Gesundheitsverhalten bei Herzinsuffizienz

Zusammenfassung. Für die steigende Zahl von Patienten mit Herzinsuffizienz stehen verschiedene medizinische Behandlungsansätze zur Verfügung, darunter als letzte Option die Herztransplantation (HTX). Ergänzende psychosoziale und behaviorale Interventionen erscheinen aus verschiedenen Gründen auch für Patienten auf der HTX-Warteliste sinnvoll. Unser Literaturüberblick zeigt, dass bekannte psychosoziale koronare Risikofaktoren wie Depressivität und soziale Isolation auch bei Herzinsuffizienz Morbidität und Mortalität erhöhen. Körperliche Aktivität wirkt sich dagegen günstig auf subjektive und objektive Parameter aus. Diese Faktoren stellen erste Ansatzpunkte für verhaltensorientierte Interventionen dar. Welche Rolle andere koronare Risikofaktoren (z.B. Feindseligkeit, Ärger, Ernährung und Gewichtsreduktion) spielen, ist bislang ungeklärt. Ausblickend werden einige viel versprechende Forschungsansätze skizziert.

Valor pronóstico de las medidas seriadas de la functión ventricular izquierda y del rendimiento en el ejercicio en la insuficiencia cardiaca crónica

INTRODUCTION AND OBJECTIVES

The prognostic value of a single measurement of ejection fraction and peak oxygen uptake in chronic heart failure has been extensively investigated. The aim of our study was to evaluate the prognostic significance of serial changes in ejection fraction and exercise performance in moderate to severe chronic heart failure.

METHODS

182 patients (156 men, 53 [47-58] years) underwent echocardiography and cardiopulmonary exercise testing at baseline and after 10 [8-12] months. Most patients had idiopathic dilated cardiomyopathy (69%) and all patients presented left ventricular ejection fraction <45%. Median follow-up was 21 [14-34] months; cardiac death and heart transplantation were the end-points. Hazard ratio (HR, per unit) is presented with its 95% confidence interval (CI).

RESULTS

During follow-up 18 patients (9.9%) died and 14 (7.7%) underwent heart transplantation. Baseline ejection fraction (HR, 0.94, 95% CI, 0.89-0.98 P=.006) and mitral regurgitation (HR, 4.22, 95% CI, 1.63-10.92, P=.003), and delta (second examination-baseline) ejection fraction (HR, 0.93, 95% CI, 0.88-0.98, P=.01) were the only significant variables at univariate analysis. Both ejection fraction and delta ejection fraction remained independently associated with events at multivariate analysis. The prognostic power significantly increased between a model including ejection fraction alone and another one including ejection fraction plus delta ejection fraction.

CONCLUSIONS

In clinically stable patients with chronic heart failure, ejection fraction and its changes were independently associated with outcome; on the contrary, serial cardiopulmonary exercise testing did not provide significant prognostic value. Baseline plus changes in ejection fraction showed better prognostic performance than baseline ejection fraction alone.

Work-rate affects cardiopulmonary exercise test results in heart failure

AIMS

Cardiopulmonary exercise test (CPET) is used to evaluate patients with chronic heart failure (HF) usually by means of a personalized ramp exercise protocol. Our aim was to evaluate if exercise duration or ramp rate influences the results.

METHODS AND RESULTS

Ninety HF patients were studied (peak V (O(2)): >20 ml/min/kg, n=28, 15-20 ml/min/kg, n=39 and <15 ml/min/kg, n=23). Each patient did four CPET studies. The initial study was used to separate the subjects into three groups, according to their exercise capacity. In the remaining studies, work-rate was increased at three different rates designed to have the subjects reach peak exercise in 5, 10 and 15 min from the start of the ramp increase in work-rate, respectively. The order was randomized. The work-rate applied for the total population averaged 22.7+/-8.0, 11.6+/-3.7, 7.5+/-2.9 W/min with effective loaded exercise duration of 5 min and 16 s+/-29 s, 9 min and 43 s+/-49 s and 14 min and 32 s+/-1 min and 12 s for the 5-, 10- and 15-min tests, respectively. Peak V (O(2)) averaged 16.9+/-4.3*, 18.0+/-4.4 and 18.0+/-5.4 ml/min/kg for the 5-, 10- and 15-min tests, (*=p<0.001 vs. 10 min). The shortest test had the lowest peak heart rate and ventilation and highest peak work-rate. Peak V (O(2)) and heart rate were lowest in 5-min tests regardless of HF severity. The DeltaV (O(2))/Deltawork-rate was lowest in 5-min tests and highest in 15-min tests. At all ramp rates, DeltaV (O(2))/Deltawork-rate was lower for the subjects with the lower peak V (O(2)). The V (e)/V (CO(2)) slope and V (O(2)) at anaerobic threshold were not affected by the protocol for any grade of HF.

CONCLUSIONS

In chronic HF, exercise protocol has a small effect on peak V (O(2)) and DeltaV (O(2))/Deltawork but does not affect V (O(2)) at anaerobic threshold and V (e)/V (CO(2)) slope.

Validation of peak exercise oxygen consumption and the Heart Failure Survival Score for serial risk stratification in advanced heart failure

The Heart Failure Survival Score (HFSS) and peak exercise oxygen consumption (VO2) accurately assess mortality in ambulatory patients who have advanced heart failure and are referred for initial cardiac transplant evaluation. We investigated the prognostic value of the HFSS and peak VO2 when applied serially to these patients. This study included 227 adults (mean age +/- SD 52 +/- 10 years old) who presented for reevaluation >60 days after initial evaluation (352 +/- 238 days). The HFSS was determined from mean arterial blood pressure, heart rate, left ventricular ejection fraction, serum sodium, peak VO2, heart failure etiology, and width of QRS complex. Survival without reevaluation, United Network of Organ Sharing 1 transplant, or left ventricular assist device was determined by the Kaplan-Meier method with censoring at United Network of Organ Sharing 2 transplant. Survival differed by HFSS stratum (p <0.001) and by peak VO2 stratum (p <0.001). Patients whose HFSS or peak VO2 deteriorated from low risk to medium or high risk had lower survival rates than did patients whose values remained at low risk (p <0.01 and p <0.001, respectively). Patients who started at medium or high risk and improved to low risk tended to have higher survival rates than those who remained medium or high risk (p = 0.06 and p <0.16, respectively). Patients who improved to low risk had a 1-year survival rate of 72% for HFSS and peak VO2. However, patients who improved to low risk and were treated with beta blockers had a 1-year survival rate (89% for HFSS and 83% for peak VO2) comparable to that after transplant (84%). Peak VO2 and the HFSS can be successfully used for serial evaluation of mortality risk in ambulatory patients who have advanced heart failure.

Resistance Exercise Training in Patients with Heart Failure

The utility, safety and physiological adaptations of resistance exercise training in patients with chronic heart failure (CHF) are reviewed and recommendations based on current research are presented. Patients with CHF have a poor clinical status and impaired exercise capacity due to both cardiac limitations and peripheral maladaptations of the skeletal musculature. Because muscle atrophy has been demonstrated to be a hallmark of CHF, the main principle of exercise programmes in such patients is to train the peripheral muscles effectively without producing great cardiovascular stress. For this reason, new modes of training as well as new training methods have been applied. Dynamic resistance training, based on the principles of interval training, has recently been established as a safe and effective mode of exercise in patients with CHF. Patients perform dynamic strength exercises slowly, on specific machines at an intensity usually in the range of 50-60% of one repetition maximum; work phases are of short duration (< or =60 seconds) and should be followed by an adequate recovery period (work/recovery ratio >1 : 2). Patients with a low cardiac reserve can use small free weights (0.5, 1 or 3 kg), elastic bands with 8-10 repetitions, or they can perform resistance exercises in a segmental fashion. Based on recent scientific evidence, the application of specific resistance exercise programmes is safe and induces significant histochemical, metabolic and functional adaptations in skeletal muscles, contributing to the treatment of muscle weakness and specific myopathy occurring in the majority of CHF patients. Increased exercise tolerance and peak oxygen consumption (V-dotO(2peak)), changes in muscle composition, increases in muscle mass, alterations in skeletal muscle metabolism, improvement in muscular strength and endurance have also been reported in the literature after resistance exercise alone or in combination with aerobic exercise. According to new scientific evidence, appropriate dynamic resistance exercise should be recommended as a safe and effective alternative training mode (supplementary to conventional aerobic exercise) in order to counteract peripheral maladaptation and improve muscle strength, which is necessary for recreational and daily living activities, and thus quality of life, of patients with stable, CHF.

Anemia and heart failure

Over the past few years, anemia has emerged as a powerful independent predictor of adverse outcomes in chronic heart failure (CHF). It affects up to 50% of patients with CHF, depending on the definition of anemia used and on the population studied. Even small reductions in hemoglobin are associated with worse outcome. However, the causes of anemia in CHF remain unclear, although impairment of renal function and inflammatory cytokines are proposed mechanisms. Both may act through impairment of the synthesis or action of erythropoietin. Preliminary studies have demonstrated improvement in symptoms, exercise tolerance, quality of life, and reductions in hospitalizations when patients with severe CHF were treated with erythropoietin. The benefits and the potential risks of such therapies will be further addressed in upcoming larger randomized trials. The recent interest in anemia reflects a new perspective in heart failure therapy, focusing on non-cardiovascular comorbidities.

Réadaptation physique des patients insuffisants cardiaques chroniques

A BENEFICIAL METHOD: Heart failure combines with peripheral vascular and muscular abnormalities that can be effectively improved by rehabilitation. The data in the literature appears to demonstrate the efficacy and excellent tolerance of such exercise. Regarding functional results and improved quality of life, rehabilitation is as equally efficient as the medical treatment that it completes. It can currently be proposed to the majority of patients exhibiting left ventricular systolic dysfunction and who are are only partially improved with medical treatment alone. MODALITIES: The rehabilitation of heart failure must, optimally, be set-up in ambulatory settings, notably within the context of a health care network. Its modalities remain to be specified in on-going studies and its impact on prognosis has to be determined.

Evaluation of impedance cardiography as an alternative to pulmonary artery catheterization in critically ill patients

Invasive pulmonary artery catheterization has historically been the method of choice for the evaluation of hemodynamic status. Impedance cardiography (ICG) is an accurate, noninvasive technique to obtain hemodynamic status information without the risk and cost associated with invasive methods. The purpose of this prospective, observational study was to determine whether the availability of ICG could decrease the need for placement of a pulmonary artery catheter in critically ill patients in coronary care units. After the need for hemodynamic data was determined, ICG parameters were provided to the attending physician who then decided whether pulmonary artery catheter insertion was still necessary. Of 107 subjects enrolled in the study, 14 (13%; 95% confidence interval, 7.3%-21.0%) were judged by the treating physicians to have indications for hemodynamic monitoring. In these subjects, the provision of ICG data allowed the physician to avoid placement of a pulmonary artery catheter in 10/14 patients (71%; 95% confidence interval, 41.9%-91.6%). When ICG was utilized, clinicians reported that the information was helpful in 10/10 patients (100%; 95% confidence interval, 74.1%-100.0%) and improved outcome in 6/10 patients (60%; 95% confidence interval, 26.2%-87.8%). ICG can replace the pulmonary artery catheter in coronary care unit patients, and clinicians utilizing ICG believe it aids medical decision making and improves patient outcomes.

Searching for evidence: refractory questions in advanced heart failure

BACKGROUND

Despite ample data from randomized clinical trials (RCTs), the management of advanced heart failure (HF) varies greatly. We examined the most common refractory questions arising in routine inpatient management of advanced HF.

METHODS

From the inpatient HF service at 1 hospital, we prospectively recorded clinical questions arising for which there were no clear answers available about HF management. When possible, patients received angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and spironolactone as used in RCTs. We identified the topics and frequencies of questions and categorized them as Group 1--whether to use a therapy--or Group 2--how to use a therapy.

RESULTS

During 2 separate months, 318 questions arose among 57 patients. The most common topics involved the use of diuretics, potassium, and ACE inhibitors, most often about how to titrate diuretics, what targets to use to optimize diuretic therapy, and how to select discharge doses of diuretics. Questions of whether to use a therapy occurred 73 times, and how to use a therapy, 242 times. RCT data were difficult to apply to these questions because little information exists about how to combine and titrate HF drugs and how to adjust diuretics. Questions about individual drugs arose in patients who fell outside the average RCT entry criteria for age, blood pressure, and creatinine.

CONCLUSION

Most refractory questions focused on how to integrate and adjust therapies within the overall medical regimen and how to apply data to patients not represented in RCTs. Future studies should evaluate strategies of care for the advanced HF population.

Orthotopic heart transplantation: highlights and limitations

A little more than three decades after the successful introduction of cardiac transplantation, this revolutionary concept of advanced heart failure treatment has gained tremendous momentum and is considered the gold standard therapy in selected patients. More specific modalities of immunosuppression continue to decrease the impact of acute and chronic rejection and immunosuppression-related side effects. The success of cardiac transplantation has led to a widespread initiation of transplant programs and a run on cardiac transplantation waiting lists. The increasing gap between waiting lists and donor organ supply has stimulated research to identify those patients who benefit most from cardiac transplantation, as well as research to develop alternative therapies for advanced heart failure. Furthermore, it serves as a stimulus to address paradigmatic issues that are fundamental to modern medicine and society.

Benefits of cardiac resynchronization therapy in outpatients with indicators for heart transplantation

BACKGROUND

Despite several new advances in the treatment of end-stage congestive heart failure (CHF) the number of patients moving onto the heart transplant list continues to rise. Recently, cardiac resynchronization therapy (CRT) has become a Food and Drug Administration (FDA)-approved therapy for advanced CHF. Currently, there are no available data on CRT in cardiac transplant candidates.

METHODS

To determine the effects of CRT on potential transplant candidates we retrospectively reviewed patients (n = 34) enrolled in resynchronization trials at our center who met accepted criteria for transplantation. Ventricular function, oxygen uptake and New York Heart Association (NYHA) class were compared at baseline and after 6 months of active therapy for each patient.

RESULTS

CRT reduced QRS duration from 178 +/- 29 to 143 +/- 17 msec (p < 0.0001) and NYHA class from 3.1 +/- 0.3 to 1.8 +/- 0.7 (p < 0.0001). Ejection fraction (EF) increased from 18.4 +/- 5.1 to 25.1 +/- 8.4% (p < 0.0001) and maximum VO(2) increased from 11.9 +/- 1.8 to 15.3 +/- 3 ml/kg/min (p < 0.0001). Only 2 of the initial 34 patients still met the criteria for transplantation at 6 months.

CONCLUSIONS

CRT improves ventricular function, oxygen uptake and NYHA class in ambulatory patients who have a QRS of >130 msec and might be considered candidates for cardiac transplantation. Transplantation can be prevented or deferred in the majority of patients. Outpatients with chronic CHF and a widened QRS should be evaluated for CRT before being listed for cardiac transplantation.