Treadmill exercise in assessment of the functional capacity of patients with cardiac disease

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

CLASSES OF RECOMMENDATION

LEVELS OF EVIDENCE

Heart valve disease in primary antiphospholipid syndrome

OBJECTIVES

APS-associated heart valve disease (HVD) is well described. Nonetheless, limited data exist on clinical parameters associated with the course of primary APS (pAPS) patients with HVD. The goal of this study was to assess clinical features and related outcomes in patients with APS-associated HVD.

METHODS

In this multicentre retrospective study, we identified 33 pAPS patients with HVD (pAPS-HVD group) and compared their clinical course with 128 pAPS patients with normal heart valves on echocardiography (pAPS-control group).

RESULTS

pAPS-HVD patients had more cerebrovascular events (56.3% vs 25%, P = 0.005) and livedo reticularis (24.2% vs 7.8%, P = 0.013) than pAPS-controls. Furthermore, catastrophic-APS (CAPS) (12.1% vs 2.4%, P = 0.034), recurrent thrombosis (33.3% vs 4.7%, P < 0.001) and need for advanced therapy (i.e. IVIG, plasmapheresis or rituximab) were more frequent in pAPS-HVD patients. Anti-β2-glycoprotein 1 IgG (84.8% vs 63.2%, P = 0.034), anti-cardiolipin IgG (90.9% vs 64.8%, P = 0.005) and triple positive aPL (75.8% vs 56.5%, P = 0.047) were commoner in pAPS-HVD patients vs pAPS-controls. Ten of the 33 patients with pAPS-HVD underwent valve surgery, which was associated with male gender, smoking, arterial limb ischaemia and livedo reticularis.

CONCLUSION

pAPS-HVD patients had a more severe APS clinical course including CAPS and thrombotic events as well as a specific serology, namely IgG isotype aPL antibodies and triple positivity. Our data suggest that pAPS-HVD represents a high-risk subgroup of APS patients.

Systematic Review of the Use of the 6-Minute Walk Test in Measuring and Improving Prognosis in Patients With Ischemic Heart Disease

Introduction

The 6-minute walk test (6MWT) has been used for over 30 years to assess exercise capacity in patients with respiratory disease, and more recently, in those with heart failure. However, despite being a simple and reproducible test of real-world exercise capacity, its use in patients with ischemic heart disease (IHD) is less well accepted. We sought to review systematically the evidence surrounding the 6MWT in IHD.

Methods

We searched the Medline, PubMed, Embase, and Scopus databases for the following key terms: "six minute walk test/6 minute walk test/6MWT" and "angina/coronary artery disease/coronary disease/IHD/ischemic heart disease." We followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines to select publications for full-text review and analyzed the collated data.

Results

A total of 1228 unique papers were found, of which 71 were chosen for full-text review and 37 for detailed analysis. Most (23) concerned the effect on 6MWT distance (6MWTd) of cardiac rehabilitation, with measurements commenced after an intervention (acute myocardial infarction, n = 4; open heart surgery (OHS), n = 5; percutaneous coronary intervention (PCI), n = 3; or other, n = 11). The effect on 6MWTd of OHS was investigated in 6 studies and of PCI in one study. The 6MWT is a useful measurement of physical capacity; data are limited on its ability to assess benefit following PCI.

Conclusions

The 6MWT has been studied inconsistently in IHD. The majority of data are on patients before and after CR. Data are limited concerning the effect on 6MWTd of OHS or PCI. The available data support the 6MWT as a measure of change in performance status following coronary intervention. More work is required to confirm this hypothesis.

Clinical Predictors of Adherence to Exercise Training Among Individuals With Heart Failure: THE HF-ACTION STUDY

PURPOSE

Suboptimal adherence is a major limitation to achieving the benefits of exercise interventions, and our ability to predict and improve adherence is limited. The purpose of this analysis was to identify baseline clinical and demographic characteristics predicting exercise training adherence in the HF-ACTION study cohort.

METHODS

Adherence to exercise training, defined by the total duration of exercise performed (min/wk), was evaluated in 1159 participants randomized to the HF-ACTION exercise intervention. More than 50 clinical, demographic, and exercise testing variables were considered in developing a model of the min/wk end point for 1-3 mo (supervised training) and 10-12 mo (home-based training).

RESULTS

In the multivariable model for 1-3 mo, younger age, lower income, more severe mitral regurgitation, shorter 6-min walk test distance, lower exercise capacity, and Black or African American race were associated with poorer exercise intervention adherence. No variable accounted for >2% of the variance and the adjusted R2 for the final model was 0.14. Prediction of adherence was similarly limited for 10-12 mo.

CONCLUSIONS

Clinical and demographic variables available at the initiation of exercise training provide very limited information for identifying patients with heart failure who are at risk for poor adherence to exercise interventions.

An experiential learning course for cardiovascular and sleep technology

Undergraduate programs related to allied health are often pursued by students to prepare for entrance into professional programs, but many students also ask about what types of employment options they may have upon completion of the bachelor's degree. This experiential learning course in cardiovascular and sleep technology was designed to provide opportunities for students to gain hands-on clinical skills that could help them to enter professional programs or to find employment in an allied health field such as cardiopulmonary rehabilitation, cardiovascular technology, or sleep technology. The prerequisites for this course were the completion of two semesters of anatomy and physiology. This course was based on experiential learning and was structured into three modules: clinical exercise physiology, autonomic physiology, and sleep physiology. As part of the course students completed a 4-page scientific report for one designated topic within each of the modules. The two exams in the course were essay based. The design of this course required students to review key topics from anatomy and physiology, to comprehend peer-reviewed manuscripts, to gain hands-on experiences with sophisticated physiological equipment, to work as individuals and in groups, and to become better oral and written communicators. The sleep physiology module included an introduction to electroencephalography (EEG) and a student-led nap study, which may be an effective way to introduce students to sleep medicine. We are hopeful that the summary of this course will be useful to physiology educators as they work to provide the most meaningful experiences to their undergraduates in the health sciences.NEW & NOTEWORTHY Experiential learning in clinical exercise, autonomic regulation, and sleep physiology is an impactful way to train undergraduate biomedical students to enter a variety of careers in healthcare, graduate programs in the health professions, or traditional research graduate programs. A hands-on course such as Cardiovascular and Sleep Technology provides a way, in addition to or independent of original research, to provide clinically relevant training.

Resting Oxygen Uptake Value of 1 Metabolic Equivalent of Task in Older Adults: A Systematic Review and Descriptive Analysis

BACKGROUND

It is important for sport scientists and health professionals to have estimative methods for energy demand during different physical activities. The metabolic equivalent of task (MET) provides a feasible approach for classifying activity intensity as a multiple of the resting metabolic rate (RMR). RMR is generally assumed to be 3.5 mL of oxygen per kilogram of body mass per minute (mL O2 kg-1 min-1), a value that has been criticized and considered to be overestimated in the older adult population. However, there has been no comprehensive effort to review available RMR estimations, equivalent to 1 MET, obtained in the older adult population.

OBJECTIVE

The aim of this review was to examine the existing evidence reporting measured RMR values in the older adult population and to provide descriptive estimates of 1 MET.

METHODS

A systematic review was conducted by searching PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus, and Cochrane Library, from database inception to July 2021. To this end, original research studies assessing RMR in adults ≥ 60 years old using indirect calorimetry and reporting results in mL O2 kg-1 min-1 were sought.

RESULTS

Twenty-three eligible studies were identified, including a total of 1091 participants (426 men). All but two studies reported RMR values lower than the conventional 3.5 mL O2 kg-1 min-1. The overall weighted average 1 MET value obtained from all included studies was 2.7 ± 0.6 mL O2 kg-1 min-1; however, when considering best practice studies, this value was 11% lower (2.4 ± 0.3 mL O2 kg-1 min-1).

CONCLUSION

Based on the results of this systematic review, we would advise against the application of the standard value of 1 MET (3.5 mL O2 kg-1 min-1) in people ≥ 60 years of age and encourage the direct assessment of RMR using indirect calorimetry while adhering to evidence-based best practice recommendations. When this is not possible, assuming an overall value of 2.7 mL O2 kg-1 min-1 might be reasonable. Systematic review registration: International Prospective Register of Systematic Reviews on 30 September 2020, with registration number CRD42020206440.

Effect of closed loop stimulation versus accelerometer on outcomes with cardiac resynchronization therapy: the CLASS trial

PURPOSE

Chronotropic incompetence (CI) in patients with heart failure is common and associated with impaired exercise intolerance and adverse outcomes. This study sought to determine the effects of closed loop stimulation (CLS) rate-adaptive pacing on functional capacity in patients with heart failure with reduced ejection fraction (HFrEF) and CI implanted with cardiac resynchronization therapy (CRT) devices.

METHODS

A randomized, blinded, cross-over designed trial enrolled patients with HFrEF and CI implanted with a Biotronik CRT-D to complete a quality of life questionnaire, 6-min walk distance (6MWD), and cardiopulmonary exercise testing after two programmed periods: 1-week period of CLS and 1-week period of standard accelerometer (DDDR).

RESULTS

Nine patients (6 males, mean age 71.4 years, 7 with New York Heart Association Class III, mean ejection fraction 39 ± 8%) were enrolled. Quality of life trended higher in CLS as compared to DDDR (550.8 ± 123.9 vs 489.3 ± 164.9, p = 0.06). There were no differences between CLS and DDDR in 6MWD (293.1 ± 90.2 m vs 315.1 ± 95.5 m, p = 0.52), peak heart rate (HR) 110.7 ± 14.7 bpm vs 109.7 bpm ± 14.1, p = 0.67), or peak VO2 (12.3 ± 4.9 ml/kg/min vs 12.9 ± 5.9, p = 0.47). As tests were submaximal as indicated by low respiratory exchange ratios (0.98 ± 0.11 vs 1.0 ± 0.8, p = 0.35), VE/VCO₂ slope also showed no difference between CLS and DDDR (35.8 ± 5.6 vs 35.4 ± 5.7, p = 0.65). Five patients (56%) preferred CLS programming (p = 1.0).

CONCLUSIONS

In patients with HFrEF and CI implanted with a CRT-D, peak HR, peak VO2, and 6MWD were equivalent, while there was a trend toward improved quality of life in CLS as compared to DDDR.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02693262.

Association between right ventricle two- and three-dimensional echocardiography and exercise capacity in patients with reduced left ventricular ejection fraction

Introduction

Echocardiography represents the most commonly performed noninvasive cardiac imaging test for patients with heart failure (HF). The aim of this study was to assess the relationship between exercise capacity parameters (peak oxygen consumption (VO₂) and the minute ventilation-carbon dioxide production relationship (VE/VCO₂)), two-dimensional speckle-tracking echocardiography (2D-STE) and three-dimensional echocardiography (3DE) imaging of right ventricular (RV) function in HF patients with reduced ejection fraction (EF).

Material and methods

This cross-sectional study included 54 patients with diagnosed ischemic LV systolic dysfunction (HF with reduced EF <40%) divided in subgroups based on the proposed values of the analyzed cardiopulmonary exercise testing (CPET) variables: VO₂ peak ≤ 15 ml/kg/min, VO₂ peak > 15 ml/kg/min, VE/VCO₂ slope < 36 and VE/VCO₂ slope ≥ 36. All patients underwent a physical examination, laboratory testing, conventional echocardiography, 2D-STE, 3DE, and CPET.

Results

RV fractional area change (FAC), 2D RV global longitudinal strain (GLS), 3D RV EF were significantly decreased, and RV basal diameter (BD), systolic pulmonary artery pressure (SPAP), tricuspid annular plane systolic excursion (TAPSE), ratio between tricuspid flow and tissue Doppler derived e’ of the lateral tricuspid annulus (TV E/e’) were significantly increased in the subgroups of subjects with a worse VO₂ peak and VE/VCO₂ slope values. There was a significant positive correlation between the peak VO₂ values and TAPSE, 2D RV GLS, 3D RV SV, and 3D RV EF as well as a significantly inverse correlation with VE/VCO₂ slope.

Conclusions

The observed significant correlation between the examined parameters suggests that 2D RV GLS and 3D RV EF, SV are associated with exercise capacity in patients with reduced HF.

Risk Assessment in Pulmonary Arterial Hypertension Patients: The Long and Short of it

Pulmonary arterial hypertension (PAH) is a chronic and rapidly progressive disease that is characterized by extensive narrowing of the pulmonary vasculature, leading to increases in pulmonary vascular resistance, subsequent right ventricular dysfunction, and eventual death. There are currently multiple approved drugs—developed as single or combination therapies in the last few years—that have improved outcome and functionality in PAH. However, despite improvement in short-term survival with these new effective therapies, PAH remains an incurable disease with a median survival of 7 years (Figure 1).1 This chronic disease state may be characterized by morbid events such as hospitalizations that herald rapid disease progression and account for a significant disease burden (Figure 2).23 Physician ability to predict PAH disease progression is critical for determining optimal care of patients. Accurate risk assessment allows clinicians to determine the patient's prognosis, identify treatment goals, and monitor disease progression and the patient's response to treatment. Risk assessment for PAH patients should include a range of clinical, hemodynamic, and exercise parameters, performed in a serial fashion over the treatment course. Patient risk stratification can also help physicians better allocate treatment resources in settings where they are scarce. If widely adopted, risk prediction can enhance the consistency of treatment approaches across PAH practitioners and improve the timeliness of referral for lung transplantation. Hence, along with advancing PAH treatment options, comprehensive risk prediction is essential to make individualized treatment decisions in the current treatment era.

Several tools are currently available for assessing risk in PAH (Figure 3). These include the 2015 European Society of Cardiology/European Respiratory Society pulmonary hypertension guidelines' risk variables,4 the French registry equation,5 the National Institutes of Health risk equation,6 or a risk score such as the one derived from the Registry to Evaluate Early And Long-term PAH Disease Management.1 These registries and evaluations of clinical trial sets have provided important insights into the importance of both modifiable (eg, 6-minute walk distance, functional class, brain natriuretic peptide, and nonmodifiable (eg, age, gender, PAH etiology) risk factors that predict survival. The following review explores commonly cited risk factors, both modifiable and nonmodifiable, and their implications for patient outcomes.

Impaired chronotropic response to physical activities in heart failure patients

Background

While exercise-based cardiac rehabilitation has a beneficial effect on heart failure hospitalization and mortality, it is limited by the presence of chronotropic incompetence (CI) in some patients. This study explored the feasibility of using wearable devices to assess impaired chronotropic response in heart failure patients.

Methods

Forty patients with heart failure (left ventricular ejection fraction, LVEF: 44.6 ± 5.8; age: 54.4 ± 11.7) received ECG Holter and accelerometer to monitor heart rate (HR) and physical activities during symptom-limited treadmill exercise testing, 6-min hall walk (6MHW), and 24-h daily living. CI was defined as maximal HR during peak exercise testing failing to reach 70% of age-predicted maximal HR (APMHR, 220 – age). The correlation between HR and physical activities in Holter-accelerometer recording was analyzed.

Results

Of 40 enrolled patients, 26 were able to perform treadmill exercise testing. Based on exercise test reports, 13 (50%) of 26 patients did not achieve at least 70% of APMHR (CI patients). CI patients achieved a lower % APMHR (62.0 ± 6.3%) than non-CI patients who achieved 72.0 ± 1.2% of APMHR (P < 0.0001). When Holter-accelerometer recording was used to assess chronotropic response, the percent APMHR achieved during 6MHW and physical activities was significantly lower in CI patients than in non-CI patients. CI patients had a significantly shorter 6MHW distance and less physical activity intensity than non-CI patients.

Conclusion

The study found impaired chronotropic response in 50% of heart failure patients who took treadmill exercise testing. The wearable Holter-accelerometer recording could help to identify impaired chronotropic response to physical activities in heart failure patients.

Trial registration

ClinicalTrials.gov ID NCT02358603. Registered 16 May 2014.

Safety profile and utility of treadmill exercise in patients with high-gradient hypertrophic cardiomyopathy

BACKGROUND

Exercise echocardiography in the evaluation of hypertrophic cardiomyopathy (HCM) provides valuable information for risk stratification, selection of optimal treatment, and prognostication. However, HCM patients with left ventricular outflow tract gradients ≥30mm Hg are often excluded from exercise testing because of safety considerations. We examined the safety and utility of exercise testing in patients with high-gradient HCM.

METHODS

We evaluated clinical characteristics, hemodynamics, and imaging variables in 499 consecutive patients with HCM who performed 959 exercise tests. Patients were divided based on peak left ventricular outflow tract gradients using a 30-mm Hg threshold into the following: obstructive (n=152), labile-obstructive (n=178), and nonobstructive (n=169) groups.

RESULTS

There were no deaths during exercise testing. We noted 20 complications (2.1% of tests) including 3 serious ventricular arrhythmias (0.3% of tests). There was no difference in complication rate between groups. Patients with obstructive HCM had a higher frequency of abnormal blood pressure response (obstructive: 53% vs labile: obstructive: 41% and nonobstructive: 37%; P=.008). Obstructive patients also displayed a lower work capacity (obstructive: 8.4±3.4 vs labile obstructive: 10.9±4.2 and nonobstructive: 10.2±4.0, metabolic equivalent; P<.001). Exercise testing provided incremental information regarding sudden cardiac death risk in 19% of patients with high-gradient HCM, and we found a poor correlation between patient-reported functional class and work capacity.

CONCLUSION

Our results suggest that exercise testing in HCM is safe, and serious adverse events are rare. Although numbers are limited, exercise testing in high-gradient HCM appears to confer no significant additional safety hazard in our selected cohort and could potentially provide valuable information.

Clinical feasibility of a new method to identify chronotropic incompetence in heart failure patients

Heart failure patients have a high incidence of chronotropic incompetence (CI) that receives less clinical attention. This study assessed a method using wearable devices to identify CI in heart failure patients. Twenty-six heart failure patients (LVEF: 43.9  ±  5.7% with LVEF  ⩾40% in 19 patients; age: 52.8  ±  12.4 years, female patients  =  6) were enrolled. Each patient underwent symptom-limited treadmill maximal exercise testing during which the simultaneous recording of ECG Holter and physical activity using Actigraph was conducted. The APMHR ratio, the maximal heart rate during peak exercise over the age-predicted maximal heart rate (APMHR, 220-age), was determined. CI was diagnosed in patients who failed to reach at least 0.70 APMHR ratio. Holter-Actigraph recording was also applied during a 6 min hall walk (6MHW) and for 24 h to validate the method to assess impaired chronotropic response. Based on the reports of exercise testing in 26 patients, 13 patients (50%) failed to reach at least 0.70 APMHR ratio while the remaining 13 patients achieved  ⩾0.70 APMHR ratio. The APMHR ratio measured by Holter-Actigraph recording was significantly correlated with the APMHR ratio based on exercise test reports (R  =  0.99, P  <  0.001). The cut-off values of APMHR ratio (0.65) measured during 6MHW, APMHR ratio (0.69) measured during daily activities, and maximum Δ heart rate (37.8 bpm) measured during daily activities significantly predicted the results of exercise test reports with an area under the ROC curve of 0.7337, 0.7544 and 0.7870, respectively (all P values  <  0.05). This pilot study found that the wearable device can potentially help in the identification of chronotropic incompetence in heart failure patients.

Phase I safety study of ranolazine in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) causes right ventricular ischemia, dysfunction, and failure. PAH patients may benefit from antianginal agents based on a shared pathophysiology with left ventricular ischemia. A single-center, randomized, placebo-controlled trial (1∶1) to assess the acute vasoreactivity and safety of ranolazine in PAH was conducted. Plasma samples for pharmacokinetic (PK) studies were drawn during hemodynamic measurements at 0, 60, 90, 120, 240, and 360 minutes from a Swan-Ganz catheter. All patients received 500-mg doses, uptitrated to 1,000 mg at week 4, monthly evaluations, and a complete objective assessment after 12 weeks, followed by an open-label extension. Thirteen patients were randomized and 12 enrolled (6 ranolazine, 6 placebo). All patients completed the acute phase; 10 completed the 12-week study. There were no acute changes in invasive hemodynamics. At 12 weeks ranolazine was well tolerated. Only 1 of the 5 patients on ranolazine had a serum concentration considered to be in the therapeutic range. Two serious adverse events required early withdrawal (both in the ranolazine group); gastrointestinal complaints were the most common adverse event. Efficacy measures did not demonstrate any differences between treatment groups. During the open-label trial, 2 additional patients reached a therapeutic concentration. Ranolazine in PAH appears safe, without acute hemodynamic effects after a 500-mg dose. Ranolazine administrated to PAH patients receiving background PAH therapies did not consistently reach therapeutic levels. Future studies should first perform PK analysis in PAH patients receiving PAH therapies and explore the safety and tolerability of the higher doses perhaps necessary to achieve therapeutic levels in PAH patients. (

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT01757808.).

Objectively-measured sedentary time and its association with markers of cardiometabolic health and fitness among cardiac rehabilitation graduates

BACKGROUND

Sedentary time is an independent risk factor for cardiometabolic disease and mortality. It is unknown how much time individuals with coronary artery disease spend being sedentary or how their sedentary time relates to markers of health. The objectives of this study were to: (a) quantify sedentary time in a post-cardiac rehabilitation (CR) population, and (b) assess association with cardiometabolic risk, independent of moderate-to-vigorous physical activity.

DESIGN

Cross-sectional.

METHODS

As part of a larger trial, 263 recent CR graduates (∼10 days post-CR, mean age 63.6 ± 9.3 years, 75% male) wore an ActiGraph GT3X accelerometer during waking hours (≥4 days, ≥10 hours/day) to quantify sedentary time (≤150 counts per minute). Spearman correlations were computed to assess relationships between sedentary time (adjusted for wear time) with markers of cardiometabolic health and fitness. Significant markers were examined using multiple linear regressions.

RESULTS

Participants spent an average of 8 hours/day sedentary (∼14 bouts/day). Sedentary time was negatively correlated with high-density lipoprotein and [Formula: see text]O2peak and positively correlated with triglycerides, body mass index and waist circumference. After adjusting for age, sex, medications and moderate-to-vigorous physical activity, hours/day of sedentary time remained significantly associated with log[Formula: see text]O2peak (β = -0.02, p = 0.001) and body mass index (β = 0.49, p = 0.02).

CONCLUSIONS

Findings suggest that even among a group of post-CR individuals who are already probably more active than patients who have not undergone CR, sedentary time remains high and is associated with poorer cardiorespiratory fitness, suggesting a possible new area of focus among CR programs.

A Comparison of Accelerometer Cut-Points among Individuals with Coronary Artery Disease

Background

Accurate assessment of physical activity among coronary artery disease patients is important for assessing adherence to interventions. The study compared moderate-to-vigorous physical intensity activity and relationships with cardiometabolic health/fitness indicators using accelerometer cut-points developed for coronary artery disease patients versus those developed in younger and middle-aged adults.

Methods

A total of 231 adults with coronary artery disease wore an Actigraph GT3X accelerometer for ≥4 days (≥10 hours/day). Moderate-to-vigorous intensity physical activity between cut-points was compared using Bland-Altman analyses. Partial spearman correlations assessed relationships between moderate-to-vigorous intensity physical activity from each cut-point with markers of cardiometabolic health and fitness while controlling for age and sex.

Results

Average time spent in bouts of moderate-to-vigorous intensity physical activity using coronary artery disease cut-points was significantly higher than the young (mean difference: 13.0±12.8 minutes/day) or middle-aged (17.0±15.2 minutes/day) cut-points. Young and middle-aged cut-points were more strongly correlated with body mass index, waist circumference and systolic blood pressure, while coronary artery disease cut-points had stronger relationships with triglycerides, high-density and low-density lipoproteins. All were similarly correlated with measures of fitness.

Conclusion

Researchers need to exert caution when deciding on which cut-points to apply to their population. Further work is needed to validate which cut-points provide a true reflection of moderate-to-vigorous intensity physical activity and to examine relationships among patients with varying fitness.

Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction

To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population.

Benefits of intensive treadmill exercise training on cardiorespiratory function and quality of life in patients with pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) restricts the ability to engage in physical activity and decreases longevity. We examined the impact of aerobic exercise training on function and quality of life in patients with World Health Organization group 1 PH.

METHODS

Patients were randomized to a 10-week education only (EDU) or education/exercise combined (EXE) group. The exercise program consisted of 24-30 sessions of treadmill walking for 30-45 min per session at 70% to 80% of heart rate reserve. Outcome variables included changes in 6-min walk test (6MWT) distance, time to exercise intolerance, peak work rate (WR) from a cardiopulmonary treadmill test, and quality-of-life measures, including the Short Form Health Survey, version 2 (SF-36v2) and Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR).

RESULTS

Data are presented as mean SD. Twenty-three women (age, 54 11 years; BMI, 31 7 kg/m 2 ) were randomized to the EDU (n 5 13) or EXE (n 5 10) groups. Following 10 weeks of intervention, patients in the EXE group demonstrated an improvement in 6MWT distance (56 45 m; P 5 .002), increased time to exercise intolerance (1.9 1.3 min; P 5 .001), and peak WR (26 23 W; P 5 .004). Additionally, the EXE group scored significantly ( P , .050) better on six of the eight scales on SF-36v2, and fi ve of the six scales on CAMPHOR. In contrast, no significant improvement was observed for any of the outcome measures following EDU. No adverse events were noted in either group.

CONCLUSION

Ten weeks of brisk treadmill walking improved 6MWT distance, cardiorespiratory function, and patient-reported quality of life in female patients with group 1 PH.

6-min walk test provides prognostic utility comparable to cardiopulmonary exercise testing in ambulatory outpatients with systolic heart failure

OBJECTIVES

The goal of this study was to compare the prognostic efficacy of the 6-min walk (6MW) and cardiopulmonary exercise (CPX) tests in stable outpatients with chronic heart failure (HF).

BACKGROUND

CPX and 6MW tests are commonly applied as prognostic gauges for systolic HF patients, but few direct comparisons have been conducted.

METHODS

Stable New York Heart Association (NYHA) functional class II and III systolic HF patients (ejection fraction ≤ 35%) from the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial were studied. 6MW distance (6MWD) and CPX indices (peak oxygen consumption [VO(2)] and ventilatory equivalents for exhaled carbon dioxide [VE/VCO(2)] slope) were compared as predictors of all-cause mortality/hospitalization and all-cause mortality over 2.5 years of mean follow-up.

RESULTS

A total of 2,054 HF-ACTION participants underwent both CPX and 6MW tests at baseline (median age 59 years; 71% male; 64% NYHA functional class II and 36% NYHA functional class III/IV). In unadjusted models and in models that included key clinical and demographic covariates, C-indices of 6MWD were 0.58 and 0.65 (unadjusted) and 0.62 and 0.72 (adjusted) in predicting all-cause mortality/hospitalization and all-cause mortality, respectively. C-indices for peak VO(2) were 0.61 and 0.68 (unadjusted) and 0.63 and 0.73 (adjusted). C-indices for VE/VCO(2) slope were 0.56 and 0.65 (unadjusted) and 0.61 and 0.71 (adjusted); combining peak VO(2) and VE/VCO(2) slope did not improve the C-indices. Overlapping 95% confidence intervals and modest integrated discrimination improvement values confirmed similar prognostic discrimination by 6MWD and CPX indices within adjusted models.

CONCLUSIONS

In systolic HF outpatients, 6MWD and CPX indices demonstrated similar utility as univariate predictors for all-cause hospitalization/mortality and all-cause mortality. However, 6MWD or CPX indices added only modest prognostic discrimination to models that included important demographic and clinical covariates.

Late gadolinium enhancement cardiovascular magnetic resonance predicts clinical worsening in patients with pulmonary hypertension

BACKGROUND

Late gadolinium enhancement (LGE) occurs at the right ventricular (RV) insertion point (RVIP) in patients with pulmonary hypertension (PH) and has been shown to correlate with cardiovascular magnetic resonance (CMR) derived RV indices. However, the prognostic role of RVIP-LGE and other CMR-derived parameters of RV function are not well established. Our aim was to evaluate the predictive value of contrast-enhanced CMR in patients with PH.

METHODS

RV size, ejection fraction (RVEF), and the presence of RVIP-LGE were determined in 58 patients with PH referred for CMR. All patients underwent right heart catheterization, exercise testing, and N-terminal pro-brain natriuretic peptide (NT-proBNP) evaluation; results of which were included in the final analysis if performed within 4 months of the CMR study. Patients were followed for the primary endpoint of time to clinical worsening (death, decompensated right ventricular heart failure, initiation of prostacyclin, or lung transplantation).

RESULTS

Overall, 40/58 (69%) of patients had RVIP-LGE. Patients with RVIP- LGE had larger right ventricular volume index, lower RVEF, and higher mean pulmonary artery pressure (mPAP), all p < 0.05. During the follow-up period of 10.2 ± 6.3 months, 19 patients reached the primary endpoint. In a univariate analysis, RVIP-LGE was a predictor for adverse outcomes (p = 0.026). In a multivariate analysis, CMR-derived RVEF was an independent predictor of clinical worsening (p = 0.036) along with well-established prognostic parameters such as exercise capacity (p = 0.010) and mPAP (p = 0.001).

CONCLUSIONS

The presence of RVIP-LGE in patients with PH is a marker for more advanced disease and poor prognosis. In addition, this study reveals for the first time that CMR-derived RVEF is an independent non-invasive imaging predictor of adverse outcomes in this patient population.

Treadmill testing improves survival prediction models in pulmonary arterial hypertension

BACKGROUND

Six-minute walk distance (6MWD) is used in the REVEAL equation to predict 1-year survival for patients with pulmonary arterial hypertension. We sought to determine whether exercise treadmill testing (ETT) could be used in its place.

METHODS

This was a single-center study in which 449 patients were enrolled. The variables predictive of survival in the REVEAL equation were evaluated and compared with survival predicted by the REVEAL equation without an exercise measure and a revised equation using ETT.

RESULTS

The addition of ETT to the equation improved the predictive ability of the REVEAL equation in the high- and low-risk patient groups.

CONCLUSION

The study findings suggest that the addition of ETT parameters to the REVEAL prognostic equation improves the predictive value of the equation when 6-minute walk distance is unavailable.

Electrogram-based optimal atrioventricular and interventricular delays of cardiac resynchronization change individually during exercise

BACKGROUND

Limited data suggest that optimal atrioventricular (AV) and interventricular (VV) delays are different at rest than during exercise in patients with heart failure. We assessed the feasibility and reproducibility of an electrogram-based method of optimization called QuickOpt at rest and during exercise.

METHODS

Patients with a St Jude Medical cardiac resynchronization therapy implantable cardioverter-defibrillator were subjected to a graded treadmill test, and QuickOpt was repeatedly measured prior to, during, and after the exercise.

RESULTS

Twenty-four patients (16 males, aged 67.4 ± 7.7 years) participated. At rest, delays (in ms) were 110.4 ± 20.1 for sensed AV delay and -70 (LV pacing first) to +20 (RV pacing first) for VV delay. The changes in QuickOpt-derived delays at rest were not significant despite change in body position. During exercise, QuickOpt-derived AV delays did not change in 11 patients, were shorter during peak exercise in 8 patients, and were longer in 3 patients (average value during peak exercise was 126.5 ± 15.8 ms, P = 0.04 compared to baseline). The QuickOpt-derived VV delay gradually shifted toward earlier right ventricular pacing during exercise in 19 patients, while no changes were seen in 3 patients, and a shift occurred toward earlier left ventricular pacing in 2 patients (average value during peak exercise was -30.7 ± 22.2; P = 0.001 compared to baseline). There was no correlation between changes in the QuickOpt-derived AV and VV delays and heart rate.

CONCLUSIONS

The application of electrogram-based algorithm is feasible both at rest and during exercise. The results are reproducible. QuickOpt-derived AV and VV delays individually change during exercise.

Comparison across races of peak oxygen consumption and heart failure survival score for selection for cardiac transplantation

The aim of the present study was to determine whether peak oxygen consumption (VO(2)) and the Heart Failure Survival Score (HFSS) predict prognosis in European-American, African-American, and Hispanic-American patients with chronic heart failure referred for heart transplantation. The peak VO(2) and the HFSS have previously been shown to effectively risk stratify patients with chronic heart failure and are criteria for the listing for heart transplantation. However, the effect of race on the predictive value of these variables has not been studied. A total of 715 patients with congestive heart failure (433 European American, 126 African American, 123 Hispanic American, and 33 other), who had been referred for heart transplantation, underwent cardiopulmonary exercise testing with measurement of the peak VO(2) and calculation of the HFSS. A total of 354 patients had died or undergone urgent heart transplantation or implantation of a left ventricular assist device during the 962 +/- 912 days of follow-up. On univariate and multivariate Cox hazard analysis, both peak VO(2) and the HFSS were powerful prognostic markers in the overall cohort and in the separate races. In the receiver operating characteristic curve analysis, the areas under the curve at 1 and 2 years of follow-up were greater for the HFSS than for peak VO(2). In conclusion, HFSS and peak VO(2) can be used for transplant selection; however, in the era of modern therapy and across races and genders, the HFSS might perform better than the peak VO(2).

A dosing/cross-development study of the multikinase inhibitor sorafenib in patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) and cancer share elements of pathophysiology. This provides an opportunity for the cross-development of anticancer agents that can be used in improving PAH care. The adaptation of new drugs across these disease populations warrants a structured approach. This study was a 16-week, phase Ib, single-center, open-label trial of the multikinase/angiogenesis inhibitor sorafenib. In order to assess the safety of sorafenib in PAH, patients with advanced but stable disease on parenteral prostanoids (with or without oral sildenafil) were initiated on treatment at the lowest active dosage administered to cancer patients: 200 mg daily. Patients underwent weekly clinical evaluations and monthly functional testing and dose escalations to a final dosage of 400 mg twice daily. Among 12 patients (10 of them women), sorafenib was well tolerated at 200 mg twice daily. The most common adverse events were moderate skin reactions on the hands and feet and alopecia. Our conclusion was therefore that this is a tolerable dosing regimen for testing the therapeutic activity of sorafenib in PAH patients.

Value of exercise treadmill testing in the risk stratification of patients with pulmonary hypertension

BACKGROUND

The ability of the Naughton-Balke exercise treadmill test, an objective indicator of exercise capacity, to predict abnormal hemodynamics and mortality in pulmonary hypertension is unknown.

METHODS AND RESULTS

We performed a cohort study of 603 patients with pulmonary hypertension from 1982 to 2006, and studied the utility of exercise treadmill test as a predictor of abnormal hemodynamics and death. We used multivariable linear regression to determine whether exercise capacity, measured in metabolic equivalents, was associated with abnormal hemodynamics, and we used a Cox proportional hazards model to determine whether decreased exercise capacity predicted death. Mean age was 50+/-15 years, 76% were women, 63% had World Health Organization category I pulmonary arterial hypertension, and 23% were World Health Organization functional classes I and II. Mean exercise capacity was 3.7+/-2.2 metabolic equivalents. Decreased exercise capacity was independently associated with elevated right atrial and mean pulmonary artery pressure, decreased cardiac index, and increased pulmonary vascular resistance. During median follow-up of 4.6 years, 36% of the patients died. Decreased exercise capacity was associated with mortality (multivariable hazard ratio, 1.18; 95% CI, 1.01 to 1.37 for each 1-metabolic equivalent decrease in exercise capacity; P=0.031; P=0.052 after adjusting for invasive hemodynamic variables). Decreased exercise capacity also predicted mortality in functional classes I-II patients, 24% of whom died (hazard ratio, 1.53; 95% CI, 1.04 to 2.26 for each 1-metabolic equivalent decrease in exercise capacity; P=0.032), although this association did not persist after adjusting for invasive hemodynamic variables (P=0.63).

CONCLUSIONS

Reduced exercise capacity on exercise treadmill test is associated with worse hemodynamics and is a predictor of mortality in patients with pulmonary hypertension.

Short-term effects of aerobic exercise on functional capacity, fatigue, and quality of life in patients with post-polio syndrome

OBJECTIVE

To investigate and compare the impact of hospital and home exercise programmes on aerobic capacity, fatigue, and quality of life in patients with post-polio syndrome.

DESIGN

A prospective, randomized controlled trial.

SETTING

Department of Physical Medicine and Rehabilitation, University Hospital.

SUBJECTS

Thirty-two patients were divided into two groups for either hospital- or home-based aerobic exercise programme.

MAIN OUTCOME MEASURES

Patients were assessed before and after the rehabilitation programme, with respect to functional capacity (pVo2), fatigue (Fatigue Severity Scale, Fatigue Impact Scale) and quality of life (Nottingham Heath Profile).

RESULTS

After the exercise programme, improvement was observed in the hospital exercise group compared to a pre-exercise period in all Nottingham Heath Profile scores (except sleep scores), pVo2, Fatigue Severity Scale and Fatigue Impact Scale (cognitive, physical, psychosocial, total) (P<0.05). In contrast, in the home exercise group a decrease was observed in pVo2 scores after the rehabilitation programme, compared to a pre-rehabilitation period (P<0.05). In addition, a significant improvement was observed in the home exercise group after the rehabilitation programme in all parameters excluding Fatigue Impact Scale-physical, Fatigue Impact Scale-psychosocial, and Nottingham Heath Profile-sleep (P<0.05). When the two exercise groups were compared, improvement was observed in the hospital exercise group compared to the home exercise group in pVo2 and Fatigue Severity Scale-total, Fatigue Impact Scale-physical, Fatigue Impact Scale-psychosocial, Fatigue Impact Scale-total, and Nottingham Heath Profile-energy scores (P<0.05).

CONCLUSION

Fatigue and quality of life were both improved in the home and hospital exercise groups. An increase was also found in the functional capacity in the hospital exercise group. A regular exercise programme is beneficial to patients with post-polio syndrome.

Selective serotonin reuptake inhibitors and the incidence and outcome of pulmonary hypertension

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) prevent the development of and reverse pulmonary hypertension (PH) in animal models. We sought to determine whether SSRIs are associated with a decreased incidence of PH in at-risk patients and whether SSRIs are associated with decreased mortality in patients with established PH.

METHODS

In a case-control study of patients enrolled in the Surveillance of Pulmonary Hypertension in America (SOPHIA) registry, we tested whether patients without PH (no-PH group; n = 155) were more likely to be receiving SSRIs when compared to those with confirmed PH (n = 1,180). In a separate cohort study of adults with documented PH in the referral-based Pulmonary Hypertension Connection (PHC) registry (n = 542), we classified patients into categories by SSRI use, and we examined whether SSRI use was associated with decreased mortality.

RESULTS

In SOPHIA, the confirmed PH group was less likely to be receiving SSRIs compared with the no-PH group (univariate odds ratio [OR], 0.56 [95% confidence interval (CI), 0.39 to 0.82]; p = 0.003; multivariate OR, 0.71l [95% CI, 0.48 to 1.06]; p = 0.09). In the PHC, 69 of 542 patients (13%) were receiving SSRIs at the time of referral. During a mean (+/- SD) follow-up period of 4.0 +/- 3.1 years, 12% of patients receiving SSRIs vs 23% of patients not receiving SSRIs died (hazard ratio [HR], 0.35; 95% CI, 0.14 to 0.87; p = 0.023). The association between SSRI use and decreased mortality persisted after adjusting for age, gender, etiology of PH, and obesity (HR, 0.35; 95% CI, 0.14 to 0.88; p = 0.026).

CONCLUSIONS

SSRIs appear to be associated with a decreased development of PH and a decreased mortality in PH. These findings provide a rationale for clinical trials of SSRIs in PH.

Association of Serum Creatinine With Abnormal Hemodynamics and Mortality in Pulmonary Arterial Hypertension

Background— Renal dysfunction predicts mortality in patients with cardiovascular disease. How renal dysfunction relates to hemodynamics and mortality in pulmonary arterial hypertension (PAH) remains unclear.

Methods and Results— We performed a cohort study of 500 patients with World Health Organization group I PAH from 1982 to 2006 with data on demographics, comorbidities, medications, functional class, laboratory tests, exercise testing results, and hemodynamics. Serum creatinine (SCr) was determined on entry into the study (initial PAH clinic visit). Vital status was determined from hospital records and the Social Security Death Index. We used a Cox proportional hazards analysis to determine whether SCr was an independent predictor of mortality. Mean age on entry into the study was 48±14 years, and 79% of subjects were female. Mean SCr was 1.05±0.35 mg/dL. Elevated SCr was associated with higher right atrial pressure and lower cardiac index. During a median follow-up of 3.5 years, 279 deaths (55.8% of the cohort) occurred. Compared with patients with SCr <1.0 mg/dL, those with SCr 1.0 to 1.4 mg/dL and SCr >1.4 mg/dL had an increased hazard ratio of death (unadjusted hazard ratio 1.65, 95% confidence interval 1.26 to 2.17, P <0.0001 for SCr 1.0 to 1.4 mg/dL; unadjusted hazard ratio 2.54, 95% confidence interval 1.73 to 3.71, P <0.0001 for SCr >1.4 mg/dL). On multivariable analysis, we found a significant interaction between SCr and right atrial pressures (interaction P <0.0001); increased SCr best predicted death in patients with right atrial pressure <10 mm Hg.

Conclusions— Renal dysfunction is associated with a worse hemodynamic profile and is an independent predictor of mortality in PAH. Measurement of SCr is practical and offers a simple way to noninvasively predict outcome.

Health related quality of life in patients awaiting heart transplantation

Quality of life is an important outcome measure in patients with end-stage heart failure waiting for heart transplantation. The purpose of this study was to investigate the relationship between aspects of quality of life and physiological and psychosocial variables in patients with end-stage heart failure. A total of 123 patients participated in the study. The functional status was assessed with New York Heart Association (NYHA) functional classification, a 6-minute walk test (6 MWT) and peak oxygen uptake (pVO(2)). Health related quality of life (HRQOL) was measured with Medical Outcomes Study, 36-item Short Form Survey (SF-36), and Minnesota Living with Heart Failure Questionnaire (MLHFQ). Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI) were used to assess psychological symptoms. A significant relationship was found between HRQOL (SF-36 and MLHFQ) and functional status (NYHA, 6 MWT and pVO(2)) (p < 0.05). Psychological symptoms (BDI) were associated with HRQOL (p < 0.05). In addition to clinical derangements, functional limitation and psychological distress can lead to limitations in activities of daily life through impairment of quality of life. It would be helpful to evaluate psychological symptoms and quality of life in patients with end-stage heart failure besides routine clinical evaluations.

Acute effects of a single dose of phosphodiesterase type 5 inhibitor (sildenafil) on systemic arterial blood pressure during exercise and 24-hour ambulatory blood pressure monitoring in heart transplant recipients

BACKGROUND

Arterial systemic hypertension (SH) can be associated with a decrease in endothelium-dependent nitric oxide (NO). Sildenafil increases cyclic guanosine monophosphate (cGMP), a mediator of NO. However, little is known about the effects of PDE5 inhibition on 24-hour ambulatory pressure (ABP) and exercise blood pressure, noreprinephrine (Nor), and exercise capacity, especially after orthotopic heart transplantation (OHT).

METHODS

We studied 22 OHT patients who on the 1st day underwent a cardiopulmonary (CP) self-controlled treadmill 6' walk test (6') and, then, an ECG monitored CP treadmill maximal exercise test (Ex) within 60 and 90 minutes after oral Sildenafil (Sil; 50 mg) or placebo (Pl) given at random, and ABP. We determined at basal position (b), in the last minute of the 6' and at the peak Ex, the HR (bpm), Systolic blood pressure (SBP), and diastolic blood pressure (DBP), (mm Hg), VO2 (mL/kg/min), Slope VE/VCO2, exercise time (ET, min), distance (D; miles), and Nor (pg/mL). Also, after CP tests, 24-h SBP and DBP, the measurements were repeated on the 2nd day when the cross-over was done.

RESULTS

Sil significantly reduced blood pressure in the basal position and during exercise. It also promoted a significant reduction in SBP and DBP during 24 hours, daytime and nighttime. Sil did not change exercise capacity.

CONCLUSION

The NO-cGMP pathway seems to play a role in blood pressure control in OHT. In addition to antihypertensive therapy, PDE5 inhibition may have potential beneficial effects on hypertensive OHT.

Creation of a Model Comparing 6-Minute Walk Test to Metabolic Equivalent in Evaluating Treatment Effects in Pulmonary Arterial Hypertension

BACKGROUND

The 6-minute walk test (6MWT) is the current standard to assess exercise capacity in pulmonary arterial hypertension (PAH). We compared the Naughton-Balke treadmill test reported in exercise metabolic equivalents (METs) with the 6MWT to evaluate whether MET could be a useful tool to assess exercise capacity.

METHODS

Serial 6MWTs followed by Naughton-Balke treadmill tests were performed in 47 PAH patients initiating a change in PAH therapy at baseline (i.e., Time 0) and Weeks 6, 12, 24 and 48; New York Heart Association (NYHA) functional class (FC) was also assessed. Hemodynamics data were recorded at baseline and Weeks 12 and 48. Treadmill time was converted to MET. Generalized estimating equation models, receiver-operating characteristic curves and fixed-effect linear models were utilized to create a model comparing 6MWT to MET.

RESULTS

MET correlated with 6MWT (r = 0.62). Piecewise linear function described the relationship between 6MWT and MET. 6MWT and MET were both associated with FC (p < 0.001) with similar ability to discriminate FC. Changes in hemodynamics in response to a change in PAH therapy correlated with changes in both 6MWT and MET. In less sick patients (i.e., FC II), the changes in 6MWT were less pronounced than with MET.

CONCLUSIONS

MET appears to be a reliable measure of exercise capacity in PAH, and correlates with 6MWT. MET can be used in clinical assessment and is helpful in demonstrating improvements in exercise capacity in less sick patients.

Characteristics of cardiac and vascular structure and function in Prader-Willi syndrome

OBJECTIVE

Prader-Willi syndrome (PWS) is a genetic obesity syndrome characterized by hyperphagia, behavioural disturbance and intellectual disability. PWS appears to be associated with a high incidence of sudden death, suspected to be cardiopulmonary in origin. We therefore sought to provide an assessment of cardiac and vascular structure and function in patients with PWS.

PATIENTS

Nine patients with genetically confirmed PWS, mean age 28 years, body mass index (BMI) 42 kg/m2, were compared with nine age- and gender-matched lean controls.

MEASUREMENTS

Lipid parameters, high-sensitivity C-reactive protein (hs-CRP) and fasting glucose and insulin were measured. To assess cardiac structure and function, a resting electrocardiogram (ECG), exercise stress test, 24-h continuous ECG monitoring, and echocardiogram were obtained. Patients and control subjects also underwent comprehensive noninvasive vascular assessment, including venous-occlusion forearm plethysmography, brachial artery flow-mediated dilatation (FMD), radial artery tonometry and carotid intima-media thickness (IMT) measurements.

RESULTS

All patients with PWS had significantly elevated hs-CRP (> 3.0 mg/l) (mean 11.5 mg/l, median 11.47, interquartile range: 4.48-15.8 mg/l), compared with controls (P < 0.001). Five of nine patients with PWS had subnormal exercise capacity (< 4 mets on exercise stress testing). Twenty-four-hour ECG monitoring revealed prolonged sinus pauses in one patient, up to 4.8 s, requiring pacemaker insertion. Microvascular function as assessed by peak hyperaemic flow response was decreased in PWS (6.1 +/- 1.0 times baseline flow vs. controls 13.5 +/- 1.6 times baseline flow, P = 0.01). Other measures were similar between PWS and controls.

CONCLUSIONS

This group of PWS patients had significantly raised levels of the inflammatory marker hs-CRP and evidence of microcirculatory dysfunction, both of which are associated with coronary artery disease and early sudden death. The sinus node dysfunction may in itself be a risk factor for sudden cardiac death.

Exercise Testing in Asymptomatic Aortic Stenosis

AIMS

To determine the safety of exercise testing (ET) in patients with moderate or severe asymptomatic aortic stenosis (AAS) and its accuracy to predict the need for surgery and mortality.

METHODS

106 consecutive patients with AAS performed a maximal ET.

RESULTS

Follow-up [10.7 (4.9-19.4) months (percentile 25-75)] was completed in 102 patients (96.2%), 63.9 years (+/-15.1), 65 (61.3%) male, peak gradient 82.8 mm Hg (+/-25.4), mean gradient 50.5 mm Hg (+/-16.6), valve area 0.67 cm(2) (+/-0.16); 67 patients (65.7%) had abnormal ET. Among the 35 patients with normal ET, there were no deaths and 10 aortic valve replacements (AVR) (28.5%) were performed. Among the 67 patients with abnormal ET, 37 (55.2%) had events (35 AVR and 2 died) (p <0.0001). There were no complications with ET.

CONCLUSION

ET may be performed safely in patients with AAS. ET gives additional information to an AVR decision.

Impedance cardiography as a noninvasive technique for atrioventricular interval optimization in cardiac resynchronization therapy

INTRODUCTION

Impedance cardiography (IC) and Doppler echocardiography (DE) are two noninvasive methods to evaluate hemodynamics in patients with dual-chamber pacemakers. The aim of the present study was to compare both techniques in respect to their ability of AV-interval optimization in cardiac resynchronization therapy (CRT) based on cardiac output (CO) measurements.

METHODS AND RESULTS

Twenty-four patients (64 +/- 8 years) with congestive heart failure (EF<35%; NYHA III-IV) and LBBB (>150 ms) were evaluated at baseline and 1 month after implantation of a CRT-D. The optimal AV interval was defined by IC and subsequently by transaortic flow DE as the interval corresponding to the highest CO measured at different AV intervals, varying from 60 to 200 ms (with 20 ms increments). For standardization and comparison of both techniques, a fixed atriobiventricular pacing rate of 90 beats/min was used. Absolute values of COmax were higher by IC (5.8+/-0.9 l/min) as compared to DE (4.6 +/- 0.9 l/min, p < 0.01). The optimal AV interval as determined by IC varied interindividually from 80-180 ms (mean: 121+/-18 ms). In DE, the range was also 80-180 ms with the mean optimal AV interval of 128+/-23 ms. Thus, there was a strong correlation for AV-interval optimization in CRT between both methods (r=0.74; p<0.001).

CONCLUSION

In CRT, AV-interval optimization based on CO values determined by IC correlates closely to those measured by transaortic flow DE. Impedance cardiography as an easy and cost-effective technique for AV-interval optimization is a promising alternative for routine management of heart failure patients on a beat-to-beat analysis during CRT follow-up.

Mapping the emergence of heart disease in a black, urban population in Africa: The Heart of Soweto Study

BACKGROUND

There is increasing evidence that many populations in the developing world are in "epidemiologic transition" with the subsequent emergence of more "affluent" disease states. The "Heart of Soweto Study" will systematically investigate the emergence of heart disease (HD) in a large urban population in South Africa.

METHODS

Part of the conurbation of Johannesburg, South Africa, Soweto is a predominantly Black African community of 1 million individuals. During an initial two year period, all individuals presenting to the local Baragwanath Hospital (3500 beds) with any form of HD will be studied. Demographic and diagnostic coding data in those with pre-established HD will form an abbreviated clinical registry of >12,000 "prevalent" cases. Similarly, socio-demographic, clinical and diagnostic data (e.g. echocardiography and ECG) in newly diagnosed patients will form a more detailed clinical registry of >5000 "incident" cases. Sub-studies of the relationship between HIV status and HD and the optimal management of chronic heart failure will also be performed.

RESULTS

These data will provide a unique insight into the causes and consequences of a broad spectrum of HD-related conditions in a "developing world" community in epidemiologic transition. Initially documented population rates, in addition to detailed examinations of the underlying risk factors and causes of HD-related morbidity/mortality will provide an important platform for future stages of the study: a community-based, population screening program and culturally specific primary and secondary programs of care.

CONCLUSION

There is an urgent need to systematically track the emergence of HD in the developing world. Initially involving more than 15,000 individuals, the unique Heart of Soweto Study has the potential to provide a wealth of information in this regard.

Observer reproducibility and validity of systems for clinical classification of angina pectoris: comparison with radionuclide imaging and coronary angiography

OBJECTIVE

To assess reproducibility and validity of clinical classification of angina pectoris (AP) patients.

DESIGN

Fifty-six patients scheduled for coronary angiography because of stable AP were classified by two independent observers with regard to (i) type and (ii) severity of chest pain (Canadian Cardiovascular Society, CCS) and (iii) cardiac functional status (New York Heart Association, NYHA). Myocardial perfusion imaging (MPI) was performed in 55 including measurement of ejection fraction in 46, angiography was undertaken in 51.

RESULTS

Observers agreed 100% on the presence (n = 45) or absence (n = 11) of angina. They agreed in 52 (93%), 48 (86%), and 42 (75%) patients with regard to type of pain, CCS grade, and NYHA class, respectively. In the remaining patients, they disagreed by one class only. The positive and negative predictive values of typical/atypical angina for perfusion abnormalities and coronary disease were 55%/82% and 53%/ 82%, respectively.

CONCLUSIONS

Observer agreement was excellent for presence, type, and severity of chest pain but moderate with regard NYHA class. Clinical judgment could not predict with reasonable accuracy abnormal perfusion or coronary artery disease.

Efficacy and safety of sildenafil added to treprostinil in pulmonary hypertension

Pulmonary arterial hypertension (PAH) is characterized by abnormalities in endothelial and smooth muscle cell function. Prostacyclin released by endothelial cells is a potent vasodilator by increasing cyclic adenosine monophosphate. Sildenafil, an inhibitor of phosphodiesterase-5, increases cyclic guanosine monophosphate in the lungs, producing vasodilation. To test for a therapeutic benefit of the combination of a prostacyclin analogue, subcutaneous treprostinil, and sildenafil, a proof-of-concept, open-label investigational trial was initiated. Subjects with PAH in World Health Organization (WHO) functional classes II to IV receiving subcutaneous treprostinil for > or =6 months were evaluated with an exercise treadmill test using the Naughton-Balke protocol at baseline and after 12 weeks. Sildenafil 50 mg 3 times daily was added to the treprostinil. Mean treadmill times in seconds were compared before and after 12 weeks of therapy. Nine subjects enrolled in the trial; 7 were women (mean age 35 years). At baseline, 3 subjects were in WHO functional class II and 6 subjects were in WHO functional class III. The mean treadmill time at baseline was 465 +/- 167 seconds and at 12 weeks was 656 +/- 205 seconds (42% improvement, p = 0.049). All patients had symptomatic improvement. In conclusion, this pilot study of subcutaneous treprostinil with sildenafil for PAH suggests additive beneficial effects.

Application of a Virtual Reality–Enhanced Exercise Protocol in Patients After Coronary Bypass

OBJECTIVE

To determine whether, by using training enhanced by virtual reality (VR) displays, patients who had undergone coronary artery bypass graft (CABG) surgery could more effectively attain long-term cardiopulmonary results than those not using VR technology.

DESIGN

Randomized controlled trial.

SETTING

Exercise testing laboratory in a medical center.

PARTICIPANTS

Consecutive sample of 32 patients who had undergone CABG surgery.

INTERVENTIONS

All subjects were randomly assigned to 1 of 2 submaximal endurance programs, with or without simulated training. In all other respects, the 2 programs were identical. Each section lasted for 30 minutes and was conducted twice a week for about 3 months. Graded exercise tests, conducted before and after training, evaluated cardiorespiratory changes.

MAIN OUTCOME MEASURES

The cardiorespiratory and hemodynamic parameters were evaluated at both peak and submaximal exertion.

RESULTS

At the follow-up exercise tests (performed at 5.4 mo after surgical intervention), the VR group achieved significantly higher value in peak oxygen consumption (VO2peak), peak metabolic equivalents (METS), and amount of VO2 at anaerobic threshold than the non-VR group. Significant gain was attained in VO2peak and peak MET value accrued to those who participated in simulation-based aerobic training.

CONCLUSIONS

Our study outcomes clearly support the perceived benefits of rehabilitation programs that incorporate VR to augment patients' recovery of their physical capacity.

Long term biventricular resynchronisation therapy in advanced heart failure: effect on neurohormones

OBJECTIVE

To assess prospectively the effect of cardiac resynchronisation therapy (CRT) on New York Heart Association (NYHA) functional class, cardiac function, cardiopulmonary exercise performance, and neurohormonal activation during 24 months' follow up.

DESIGN

Controlled study.

PATIENTS AND RESULTS

124 patients with severe congestive heart failure (ejection fraction < 35%, NYHA III-IV) and left bundle branch block (QRS duration > 150 ms) were enrolled (control group, n = 59; CRT group, n = 65) and followed up at 1, 3, 12, and 24 months. Compared with the control group, CRT led to significant short and long term improvements in functional NYHA functional class (mean (SEM) 2.1 (0.4) v 2.8 (0.4) at 24 months, p < 0.05), mean ejection fraction (25.7 (4)% v 21.1 (5)% at 24 months, p < 0.05), peak Vo(2) (16.8 (3.9) v 12.6 (3.5) ml/kg x min at 24 months, p < 0.01), and Vo(2) at anaerobic threshold (14.4 (3.7) v 10.8 (3.2) ml/kg x min at 24 months, p < 0.05). In addition, CRT for one and 12 months significantly decreased the plasma concentrations of noradrenaline (norepinephrine) and N-terminal fragment of pro-brain natriuretic peptide, whereas no changes were observed for other neurohormones such as antidiuretic hormone, aldosterone, and endothelin.

CONCLUSION

Long term CRT (<or= 24 months) results in significant improvement of NYHA class and cardiopulmonary exercise capacity and a short term decrease in neurohormonal activation.

Amiodarone versus sotalol for atrial fibrillation

BACKGROUND

The optimal pharmacologic means to restore and maintain sinus rhythm in patients with atrial fibrillation remains controversial.

METHODS

In this double-blind, placebo-controlled trial, we randomly assigned 665 patients who were receiving anticoagulants and had persistent atrial fibrillation to receive amiodarone (267 patients), sotalol (261 patients), or placebo (137 patients) and monitored them for 1 to 4.5 years. The primary end point was the time to recurrence of atrial fibrillation beginning on day 28, determined by means of weekly transtelephonic monitoring.

RESULTS

Spontaneous conversion occurred in 27.1 percent of the amiodarone group, 24.2 percent of the sotalol group, and 0.8 percent of the placebo group, and direct-current cardioversion failed in 27.7 percent, 26.5 percent, and 32.1 percent, respectively. The median times to a recurrence of atrial fibrillation were 487 days in the amiodarone group, 74 days in the sotalol group, and 6 days in the placebo group according to intention to treat and 809, 209, and 13 days, respectively, according to treatment received. Amiodarone was superior to sotalol (P<0.001) and to placebo (P<0.001), and sotalol was superior to placebo (P<0.001). In patients with ischemic heart disease, the median time to a recurrence of atrial fibrillation was 569 days with amiodarone therapy and 428 days with sotalol therapy (P=0.53). Restoration and maintenance of sinus rhythm significantly improved the quality of life and exercise capacity. There were no significant differences in major adverse events among the three groups.

CONCLUSIONS

Amiodarone and sotalol are equally efficacious in converting atrial fibrillation to sinus rhythm. Amiodarone is superior for maintaining sinus rhythm, but both drugs have similar efficacy in patients with ischemic heart disease. Sustained sinus rhythm is associated with an improved quality of life and improved exercise performance.

Therapy of ischemic cardiomyopathy with the immunomodulating agent pentoxifylline: results of a randomized study

BACKGROUND

Inflammatory immune activation commonly occurs in heart failure and may perpetuate this syndrome. We sought to determine whether the immunomodulating agent pentoxifylline enhances left ventricular function in patients with ischemic cardiomyopathy. We also investigated the effect of therapy on levels of brain natriuretic peptide (NT-pro BNP), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), and the marker of apoptosis, Fas/Apo-1.

METHODS AND RESULTS

In a single-center, prospective, randomized, double-blind, placebo-controlled study, 38 patients with ischemic cardiomyopathy received pentoxifylline 400 mg TID or placebo in addition to standard therapy. Clinical assessment, radionuclide ventriculography, echocardiography, and blood analyses were performed at baseline and after 6 months. There were no differences in baseline characteristics between the groups. Five patients died (4 in the placebo group). Pentoxifylline treatment resulted in an improvement in functional class (P<0.005) and an increase in systolic blood pressure (P<0.05) and left ventricular radionuclide ejection fraction (P<0.05) compared with the placebo-treated group. There were reductions in plasma concentrations of CRP, NT-pro BNP, TNF-alpha, and Fas/Apo-1 in the pentoxifylline compared with the placebo-treated group.

CONCLUSIONS

In patients with heart failure due to ischemic left ventricular dysfunction, the addition of pentoxifylline to standard therapy results in improvements in clinical status and radionuclide ejection fraction, which are accompanied by reductions in plasma markers of inflammation, prognosis, and apoptosis.