The prognostic value of functional capacity in patients with mild to moderate heart failure

Measurement of Functional Capacity to Discriminate Clinical from Subclinical Heart Failure in Patients ≥65 Years of Age

In order to show that reduced functional capacity in subclinical heart failure portends a higher risk of clinically overt (stage C) heart failure, we obtained the Duke activity status index (DASI) and 6-minute walk distance (6MWD) in 814 patients (age 70 [interquartile range 67 to 74] years, 51% female) with nonischemic subclinical heart failure. Reduced functional capacity was defined as: (1) DASI-derived metabolic equivalents <7, (2) 6MWD <2 standard deviations below the age-based normative mean (excluding those with mobility impairment) and (3) reduced 6MWD with reclassification where DASI was discordant. Based on reduced functional capacity and left ventricular dysfunction (LVD), subjects were classified into; (1) Stage A heart failure (436 with neither LVD nor reduced functional capacity), (2) Stage A with reduced functional capacity (n = 80), (3) Stage B heart failure (182 with LVD but preserved functional capacity) and (4) early stage C heart failure (52 with LVD and reduced functional capacity). Outcome was assessed by Kaplan-Meier survival estimates and Cox proportional hazard ratios. After a median follow-up of 13 months [interquartile range 11 to 19]), 76 (9%) developed heart failure - 6% of Stage A, 10% of Stage A-reduced functional capacity, 9% of Stage B and 37% of early Stage C (p < 0.001). After adjustment (for heart failure risk score, atrial fibrillation, pulmonary disease and therapy), the hazard ratio for development of overt heart failure in early Stage C was 5.92 (95% confidence intervals 2.92 to 11.54, p < 0.001) compared with Stage A and 3.08 (95% confidence intervals 1.47 to 6.47, p = 0.003) compared with Stage B.

Psychological and Social Factors That Correlate With Dyspnea in Heart Failure

Dyspnea is a common symptom of heart failure frequently relied upon to assess clinical functioning. The purpose of this study is to explore a broad range of medical, psychological, and social factors that correlate with dyspnea in heart failure patients. Seventy-six participants ranged from well-compensated, ambulatory subjects to those with recent hospitalization for acutely decompensated heart failure. The sample was predominantly male, mean age of 63.5 years, with mild depressive symptoms in 25%. Correlation analysis revealed that dyspnea significantly correlated with depression, fatigue, and overall health perception. Standard regression analyses indicated that depression, fatigue, and overall health perception uniquely contributed to dyspnea, explaining 38.0% of the total variance. The present study confirms that dyspnea is multifactorial, with links to psychological distress and overall health perception.

Resistance training for chronic heart failure patients on beta blocker medications

BACKGROUND

Resistance training increases the skeletal muscle strength and functional ability of chronic heart failure patients. However, there is limited data regarding the effect of resistance training on the hemodynamic responses and peak oxygen consumption (peak VO(2)) of chronic heart failure patients treated with beta-blocker. This study examined the effect of resistance training on hemodynamics, peak aerobic capacity, muscle strength and quality of life of chronic heart failure patients on beta-blockers medication.

METHODS

Fifteen men diagnosed with chronic heart failure were matched to either a resistance training program or non-training control group. At baseline and after 8 weeks of resistance training patients performed both Balke incremental and maximal strength tests and completed quality of life questionnaires.

RESULTS

The resistance training group demonstrated a significant increase of walking time and peak VO(2) by 11.7% (p=0.002) and approximately 19% (p<0.05), respectively. Peak VO(2) was significantly correlated with both walking time (r=0.54, p=0.038) and change in total weight lifted (r=0.55, p=0.034). Quality of life significantly increased by 87% (p=0.030). The improvement in quality of life was correlated with post training peak VO(2) (r=0.58, p=0.025) and total weight lifted during the post maximal strength test (r=-0.52, p=0.047).

CONCLUSIONS

The benefits from resistance training for chronic heart failure patients on beta-blocker medication included an increased aerobic and exercise capacity, skeletal muscle strength and most importantly, an improvement in the quality of life, which is the main goal of cardiac rehabilitation programs. Furthermore, with appropriate supervision, it is recommended that resistance exercise be added to the exercise rehabilitation program of these patients when possible.

Chronic heart failure in the very elderly: clinical status, survival, and prognostic factors in 188 patients more than 70 years old

BACKGROUND

Chronic heart failure (CHF) is a frequent disease with a dismal prognosis, but little is known about survival in the very elderly. There are no data on the prognostic value of cardiopulmonary exercise testing in this population. We aimed to assess exercise capacity, survival, and prognostic parameters in elderly patients with CHF.

METHODS

We evaluated 188 patients with CHF >70 years old (mean 77 +/- 4 years, range 70-94 years) seen at our heart failure clinic between March 1992 and June 1998. A cardiopulmonary exercise test was performed in 102 patients (peak VO2 15.3 +/- 4.7, VE/VCO2 slope 39.6 +/- 15.01). All patients were followed up for at least 12 months. The prognostic end point of the study was all-cause mortality.

RESULTS

At the end of follow-up (16 +/- 10 mo, range 12-41 mo), 67 patients (35.6%) had died (1-year mortality rate 26% [95% confidence interval 20-32]). In univariate analysis New York Heart Association class (NYHA) (relative risk [RR] = 2.56, P <.0001), VE/VCO2 (RR = 1.041, P <.0001), peak VO2 (RR = 0.87, P =.0007), and fractional shortening (RR = 0.95, P <.0001) predicted mortality. Peak VO2 predicted mortality independently of age, NYHA class, and left ventricular ejection fraction. A subgroup of 12 patients with dynamic left ventricular outflow tract obstruction during stress had an excellent outcome, with a 100% survival at the end of follow-up (mean 16 +/- 7 mo, range 12-39 mo).

CONCLUSIONS

The prognosis in elderly patients with CHF is poor. Valid exercise testing results can be obtained in more than 50% of elderly patients with CHF. NYHA class and peak VO2 are the strongest prognostic factors in this population.

Relative lymphocyte count: a prognostic indicator of mortality in elderly patients with congestive heart failure

BACKGROUND

A reduction in the relative lymphocyte count is a marker of the stress response; however, its prognostic value remains undetermined. The objective of this study was to investigate the predictive value of the relative lymphocyte count for survival in elderly patients with congestive heart failure (CHF).

METHODS AND RESULTS

One thousand two hundred seventy-four consecutive patients above the age of 65 years hospitalized with heart disease were enrolled in the CHF Italian Study and followed up for 3 years. Of these, 413 patients were excluded because of factors that could affect the lymphocyte count. Of the remaining 861 patients, 423 (49%) met the criteria for the diagnosis of CHF (mean age 76 +/- 7 years, 51% men), of whom 162 patients (38%) had a relative lymphocyte count < or = 20%. The 3-year all-cause mortality in patients with CHF and a relative lymphocyte count < or = 20% was 64% compared with 40% in patients with a relative lymphocyte count > 20% (P < .0001). The age- and sex-adjusted hazard ratio for death in patients with CHF and low relative lymphocyte count was 1.76 (95% confidence interval 1.34-2.32, P = .0001). After adjustment for baseline differences and variables associated with or known to affect lymphocyte count, the hazard ratio remained significantly different from 1.0 (hazard ratio 1.73, 95% confidence interval 1.21-2.48, P = .0026).

CONCLUSION

A low relative lymphocyte count is an independent marker of poor prognosis in elderly patients with CHF. The relative lymphocyte count is a simple, accurate, widely available, and inexpensive marker that can help to identify elderly patients with CHF who are at increased risk for mortality. The pathophysiologic mechanism of this observation remains to be determined.

Myocardial high-energy phosphate metabolism in patients with stable chronic dilated cardiomyopathy under a dobutamine-induced prolonged mild workload

BACKGROUND

The myocardial phosphocreatine (PCr) to beta-adenosine triphosphate ratio measured by phosphorus 31 nuclear magnetic resonance spectroscopy, which is analogous to energy reserve, is one of the important clinical predictors in patients with dilated cardiomyopathy (DCM). However, it may vary with the cardiac workload.

METHOD

The myocardial PCr to beta-adenosine triphosphate ratio was measured before and during a 5 and 10 microgram/kg/min infusion of dobutamine in 7 patients with DCM and in 8 normal patients. Dobutamine infusion was kept constant for 50 minutes in each stage. Myocardial contractility and ventricular size were determined by echocardiography with the same protocol.

RESULTS

This ratio was unchanged from 1.5 +/- 0.4 to 1.8 +/- 0.6 in the low-dose stage and stable (1.7 +/- 0.3) in the high-dose stage in patients with DCM. The heart rate and the mean rate of circumferential fiber shortening increased dose dependently both in patients with DCM and in patients without.

CONCLUSION

These results demonstrate that constant loading of dobutamine for hours is tolerated without deterioration of myocardial metabolic function by patients with nonischemic DCM. We concluded that the high-energy phosphate metabolism of stable patients with cardiomyopathy is stable if the workload is temporary and weak. This implies the possibility that mild exercise can be tolerated in patients with heart failure.

The relationship between cardiac function and neuropsychological status among heart transplant candidates

BACKGROUND

Cognitive deficits among heart transplant candidates have been well documented. This study was designed to examine the hypothesis that impaired cognitive test performance among heart transplant candidates may be attributed, in part, to decreased cerebral perfusion secondary to poor cardiac function.

METHODS AND RESULTS

Sixty-two patients participated in the study who underwent heart catheterization within 1 day of completing a battery of cognitive tests. Multiple demographic and patient characteristics were examined for their potential moderating role in the relationship between measures of cardiac function and cognitive performance including age, education, race, gender, psychiatric history, medication usage, cardiac surgical history, and self-reported symptoms of depression and anxiety. Only age and education were significantly related to cognitive performance (P < .01). Thus, partial correlation analyses controlling for age and education were used to examine the relationship between cardiac function and cognitive performance. In general, increasing hemodynamic pressure variables (ie, pulmonary artery pressure and right atrial pressure), and to a lesser extent cardiac output and cardiac index, were related (r = - .32 to - .43; P < .01) to decreased performance on cognitive tasks that assessed simple attention, speed of mental processing, and mental flexibility (Digit Span-Forward, Trail Making Test-Part B, Symbol Digits Modalities Test, and Stroop Neuropsychological Screening Test). Left ventricular ejection fraction, systemic and pulmonary vascular resistance, and mean arterial pressure were largely unrelated to cognitive performance in this sample of patients with end stage cardiac disease.

CONCLUSIONS

Hemodynamic pressure variables seem to be most consistently related (ie, inversely) to cognitive functioning among heart transplant candidates.

Serial exercise testing and prognosis in selected patients considered for cardiac transplantation

OBJECTIVES

This study sought to examine the predictive value of variables obtained from serial maximal exercise testing, echocardiography, and ejection fraction in patients referred as potential heart transplant candidates.

BACKGROUND

Variables such as peak VO2, left ventricular dimensions, ejection fraction, and hemodynamic measurements are known to predict prognosis in heart failure, but there are few data on the impact of serial measurements of these variables on subsequent mortality.

METHODS AND RESULTS

Two hundred sixty-three ambulatory patients with severe heart failure referred as potential candidates for heart transplantation who underwent two exercise tests (mean 7.8 months apart) after optimal medical treatment were identified. At the same two time points, echocardiography was performed in 106 (37%) and ejection fraction was measured in 84 (30%). During a mean follow-up period of 3.9+/-0.1 years, 70 (25%) died and 45 (19%) underwent heart transplantation. Exercise capacity, peak exercise heart rate, and peak exercise systolic blood pressure achieved were all significantly higher among survivors compared with nonsurvivors. Among the survivors a slight increase in peak VO2 and ejection fraction were observed, but there were no significant differences in the changes of any of the measured variables between survivors and nonsurvivors. There were no significant differences in survival between patients with increased versus those with decreased peak VO2, left ventricular dimensions, or ejection fraction.

CONCLUSION

Although peak VO2, left ventricular dimensions, and ejection fraction predict survival, changes in these parameters do not add any prognostic information in patients with severe heart failure who have been stabilized with optimal medical treatment. Routine use of these procedures therefore does not seem to be warranted and should be performed only in the context of a specific clinical situation. Serial measurements of these parameters do not appear to be useful in the risk stratification of patients referred for heart transplantation.

Usefulness of peak oxygen consumption in predicting outcome of heart failure in women versus men

This investigation finds that percent of predicted maximum oxygen consumption, an age- and gender-adjusted measurement of exercise, capacity, describes the degree of functional impairment in women more accurately than peak oxygen consumption. This evidence must be considered when cardiopulmonary metabolic parameters are used for prognostic stratification of women with heart failure.

Using a 6-minute walk test to predict outcomes in patients with left ventricular dysfunction

Maximal oxygen consumption (VO2MAX) is an independent variable that predicts outcomes in patients suffering from left ventricular dysfunction (LVD). Determining VO2MAX in a rehabilitation setting is not only costly and time-consuming but it would also be beyond many patients' physical abilities. This study's goal was to show that a simpler and less costly 6-minute walk test can predict mortality in patients with LVD. Sixty-six Phase 1 cardiac rehabilitation patients with LVD performed the 6-minute walk test upon admission and at discharge from a rehabilitation hospital. Upon discharge, the group that was able to walk significantly longer distances upon discharge had a higher survival rate 3 months after discharge. The 6-minute walk test can predict longer survival in patients with LVD and can provide valuable information for determining treatment plans, future prognosis, and home disposition of deconditioned LVD patients in a rehabilitation setting.

Impact of age and gender on peak oxygen uptake in chronic heart failure

Anthropometric and demographic characteristics are important determinants of exercise performance in healthy subjects, but their influence has not yet been studied in severe chronic heart failure, although peak oxygen uptake is frequently assessed in such patients for prognostic purposes. The aim of the present analysis was to examine the association between peak oxygen uptake and age, gender, and measures of body size in patients with severe chronic heart failure. We selected 122 (99 male) adult heart transplant candidates who were able to perform a bicycle ergometer test with respiratory gas analysis until voluntary fatigue. Peak oxygen uptake was higher in male than in female patients, both before and after adjustment for weight. In single regression analysis on the total study population, peak oxygen uptake was positively related to weight and to height, but inversely to age (r = 0.59 (P < 0.001), 0.42 (P < 0.001), and -0.33 (P < 0.001), respectively). Multiple stepwise regression analysis identified weight (P < 0.001), age (P < 0.001), and gender (P < 0.01) as independent determinants of peak oxygen uptake (cumulative R2 = 0.45). Similar to the findings in healthy subjects, peak oxygen uptake of patients with severe chronic heart failure is influenced by anthropometric and demographic characteristics.

Determinants of perceived health in patients with left ventricular dysfunction: a structural modeling analysis

OBJECTIVE

Few studies have evaluated the determinants of perceived health in patients with chronic illness. The present study was designed to evaluate the role of biomedical, demographic, and psychosocial influences on global subjective health by means of a structural equation modeling approach.

METHOD

A conceptual model of perceived health was tested in a subsample of patients (N = 146) from the multicenter Studies of Left Ventricular Dysfunction (SOLVD) trial. Domain-specific quality of life constructs (emotional status, social support, and physical functioning), were assessed by means of multiple indicators. These latent (mediating) variables, along with six single-indicator biomedical and background variables, were modeled as predictors of a composite index of perceived health.

RESULTS

A satisfactory fit was obtained for the proposed model, with practical fit indices ranging from .89 to .95. High levels of perceived health were associated with low levels of emotional distress and high levels of physical functioning. Social support was positively correlated with physical functioning and negatively associated with emotional distress. Among the background variables, no direct associations were observed between any of the single-indicator variables and perceived health. Several background variables (eg, age, income, walk-test scores) had indirect effects via associations with the latent variables of physical functioning and emotional distress.

CONCLUSIONS

These findings support the use of a structural modeling approach in assessing determinants of perceived health in patients with congestive heart failure. Further research is needed to evaluate the utility of the model in other patient populations.

Cardiac performance in conscious healthy dogs during dobutamine infusion

The aim of this study was to determine the cardiac performance of conscious healthy dogs during stimulation with dobutamine. Eight healthy unsedated beagle dogs were used. Cardiac output was measured by the thermodilution technique and blood pressures by extravascular pressure transducers. Dobutamine challenge at a dosage ranging from 27.5 to 50 micrograms kg-1 min-1 induced a significant rise in cardiac power index (CPI), cardiac index (CI), stroke index (SI) and heart rate (HR) and a significant decrease in pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR). The highest CPI was 2.05 times greater than its basal resting value. The CI was primarily responsible for this increase in CPI. The SI and HR contributed approximately 55 per cent and 45 per cent respectively of the maximal increase in CI.

Congestive heart failure in the elderly

Several aspects of congestive heart failure are discussed in the light of international literature and of recent findings of our group. The annual incidence of heart failure in elderly subjects, aged >or=75y, is 13 to 50/1000, while it is 1.6/1000 in people aged 45-54 y. The prevalence of heart failure is about 3% in subjects aged 45-64% in subjects aged more than 65 y and 10% in subjects aged more than 75 y. These data are confirmed by our population based study in elderly subjects. The etiology of congestive heart failure is similar in elderly and middle-aged patients. However, several anatomo-functional, hormonal and autonomic nervous system changes, typical of congestive heart failure, occur during physiologic ageing processes also. These findings may explain the dramatic evolution of congestive heart failure in elderly patients. Moreover, some features of the elderly - e.g. comorbidity, atypical clinical presentations, loss of autonomy, increased iatrogen risk should be considered. No specific drugs exist for the pharmacologic treatment of heart failure in the elderly, so that the geriatric specificity in the treatment of heart failure can be recognized in the art of drug choice and dosage, to obtain the best results with the least side effects. The multiple etiology of congestive heart failure, the comorbidity, the loss of autonomy and the deterioration of cognitive functions suggest the need for multidimensional approach and continuative intervention in elderly patients with heart disease, and in particular with congestive heart failure. Further studies on disease- and age-related changes are necessary to develop new and more potent strategies to secure 'successful ageing'.

The six-minute walk test predicts peak oxygen uptake and survival in patients with advanced heart failure

BACKGROUND

The 6-min walk test (6'WT) is a simple measure of functional capacity and predicts survival in patients with moderate heart failure (HF).

METHODS

To assess the role of the 6'WT in the evaluation of patients with advanced HF, 45 patients (age 49 +/- 8 years, mean +/- SD; New York Heart Association class 3.3 +/- 0.6; left ventricular ejection fraction 0.20 +/- 0.06; right ventricular ejection fraction 0.31 +/- 0.11) underwent symptom-limited cardiopulmonary exercise testing and the 6'WT during cardiac transplant evaluation.

RESULTS

Mean 6'WT distance ambulated was 310 +/- 100 m and peak oxygen uptake (peak Vo2) was 12.2 +/- 4.5 mL/kg/min. There was a significant correlation between 6'WT distance ambulated and peak Vo2 (r = 0.64, p < 0.001). Multivariate analysis of patient characteristics, resting hemodynamics, and 6'WT results identified the distance ambulated during the 6'WT as the strongest predictor of peak Vo2 (p < 0.001). 6'WT distance ambulated less than 300 m predicted an increased likelihood of death or pretransplant hospital admission for continuous inotropic or mechanical support within 6 months (p = 0.04), but did not predict long-term overall or event-free survival with a mean follow-up of 62 weeks. Peak Vo2 was the best predictor of long-term overall and event-free survival.

CONCLUSIONS

In patients with advanced HF evaluated for cardiac transplantation, distance ambulated during the 6'WT predicts (1) peak Vo2 and (2) short-term event-free survival.

Prognostic significance of peak oxygen uptake in hypertension

The aim of this study was to investigate the prognostic value of cardiopulmonary fitness in hypertension. From 1972 to 1982 oxygen uptake and heart rate were recorded during an exercise test to exhaustion in 216 patients (143 men). Their outcome was ascertained in 1994. During 3,411 patient years of follow-up, 53 patients suffered at least one fatal or nonfatal cardiovascular event and 25 patients died. After adjustment for age, gender, and weight, the relative hazard rates (RHR; Cox regression) of peak oxygen uptake (l.min-1) amounted to 0.44 (P = 0.01) for the first occurring cardiovascular events and 0.35 (P = 0.05) for all-cause mortality. These RHR remained significant after additional adjustment for traditional cardiovascular risk factors (RHR = 0.45 and 0.28, respectively; P < 0.05). Heart rate at 50 W did not predict outcome after adjustment for age and gender (P = 0.94 and 0.14, respectively), nor after additional adjustment for heart rate at rest (P = 0.86 and 0.61, respectively). In conclusion, a lower peak oxygen uptake, but not a higher submaximal heart rate, is significantly and independently associated with a higher incidence of cardiovascular events and a higher total mortality in hypertensive patients.

Oxygen Deficit During Exercise Testing in Heart Failure

Measurements of oxygen deficit during submaximal exercise were correlated with the anaerobic threshold (as measured by gas exchange analysis), peak work rate on a ramp protocol, and the ability to perform constant work rate exercise in 10 male patients with New York Heart Association class 2 congestive heart failure and 12 age- and gender-matched normal controls. All subjects performed a maximal ramp exercise test for measurement of the anaerobic threshold. In addition, several 15-min constant work rate exercise sessions were conducted to evaluate oxygen deficit, measured as the area between the "ideal" square curve of oxygen consumption at the onset of constant work rate exercise and the actual exponentially shaped curve. Since the oxygen deficit significantly correlated with the plateau oxygen consumption during the 25-W constant work rate exercise (r = 0.61, p = 0.002), the oxygen deficit was normalized by the rectangular area of 15-min oxygen consumption above baseline. This normalized value significantly correlated with the inverse of the anaerobic threshold (r = 0.81, p < 0.0001). The logarithm of the normalized oxygen deficit significantly correlated with the maximum ramp work rate (r = -0.86, p < 0.0001) and the highest constant work rate sustained for 15 min (r = -0.82, p < 0.0001). In addition, the time to reach plateau oxygen consumption for the 25-W exercise significantly correlated with the inverse of the anaerobic threshold (r = -0.78, p < 0.0001), the maximum ramp work rate (r = -0.76, p < 0.0001), and the highest constant work rate sustained for 15 min (r = -0.74, p < 0.0001). Thus, the oxygen deficit seen in patients with heart failure during constant work rate exercise results from abnormally slow oxygen uptake kinetics and correlates with exercise capacity as measured by anaerobic threshold (via gas exchange analysis) and maximal and submaximal exercise tolerance. Oxygen deficit warrants further evaluation as a submaximal index of functional capacity in patients with heart failure.

Maximal exercise tolerance in chronic congestive heart failure. Relationship to resting left ventricular function

The relationship between maximal exercise tolerance and resting radionuclide indexes of left ventricular systolic and diastolic function were evaluated in 20 ischemic and 44 idiopathic cardiomyopathy patients with New York Heart Association class 2-4 chronic congestive heart failure. Left ventricular ejection fraction, peak systolic ejection rate, peak diastolic filling rate, time to peak filling from end-systolic volume, and fractional filling in early diastole were measured from the radionuclide ventriculogram. All patients underwent symptom-limited exercise testing with on-line measurement of oxygen consumption. In the ischemic group, all of the radionuclide indexes correlated poorly with maximal exercise oxygen consumption (VO2max) except the peak systolic ejection rate which correlated modestly (r = 0.58, p < 0.05). Peak systolic ejection rate was significantly lower (p < 0.01) as were the peak diastolic filling rate and fractional filling in the first third of diastole (p < 0.05) in ischemic patients with marked exercise intolerance (VO2max < or = 14 mL/kg/min) compared with those with preserved exercise tolerance (VO2max > 14 mL/kg/min). In the idiopathic group, none of the radionuclide indexes correlated well with VO2max; and all indexes were similar in patients with and without marked exercise intolerance. These data suggest that (1) resting left ventricular ejection fraction poorly predicts maximal exercise capacity in both ischemic and idiopathic cardiomyopathy and (2) resting peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole may predict exercise tolerance in ischemic but not idiopathic cardiomyopathy.

Heart rate variability and its relation to ventricular arrhythmias in congestive heart failure

BACKGROUND

It has been shown that heart rate variability is decreased in patients with congestive heart failure and that depressed heart rate variability is associated with a propensity to ventricular arrhythmias. Little is known, however, about heart rate variability in patients with both congestive heart failure and ventricular arrhythmias.

METHODS

Spectral heart rate variability was analysed from 24 hour ambulatory electrocardiograms in 15 controls, 15 patients with non-sustained ventricular tachycardia associated with clinically normal hearts (NHVT group), and 40 patients with congestive heart failure (CHF group) secondary to either ischaemic heart disease (n = 15) or idiopathic dilated cardiomyopathy (n = 25). Of the 40 patients with congestive heart failure 15 had no appreciable ventricular arrhythmias (ventricular extrasystoles < 10 beats/h and no salvos) and formed the CHF-VA- group. Another 15 patients with congestive heart failure and non-sustained ventricular tachycardia formed the CHF-NSVT group.

RESULTS

Heart rate variability was significantly lower in the CHF group than in controls (mean (SD) total frequency 23 (12) v 43 (13) ms; low frequency 12 (8) v 28 (9) ms; high frequency 8 (5) v 14 (7) ms; p < 0.001). The differences in heart rate variability between controls and the NHVT group, between ischaemic heart disease and dilated cardiomyopathy, and between the CHF-VA- and CHF-NSVT groups were not significant. In the CHF group heart rate variability was significantly related to left ventricular ejection fraction but not associated with ventricular arrhythmias. The frequency of ventricular extrasystoles was significantly related to the high frequency component of heart rate variability (r = 0.54, p < 0.05) in the NHVT group. Stepwise multiple regression analysis showed that in the CHF group, heart rate variability was predominantly related to left ventricular ejection fraction (p < 0.05). There was no significant difference in heart rate variability between survivors (n = 34) and those who died suddenly (n = 6) at one year of follow up in the CHF group.

CONCLUSION

In patients with congestive heart failure, heart rate variability is significantly decreased. The depressed heart rate variability is principally related to the degree of left ventricular impairment and is independent of aetiology and the presence of ventricular arrhythmias. The data suggest that analysis of heart rate variability does not help the identification of patients with congestive heart failure at increased risk of sudden death.

Quality of life among patients post-myocardial infarction at baseline in the Survival and Ventricular Enlargement (SAVE) trial

A quality of life ancillary study was incorporated into the Survival and Ventricular Enlargement (SAVE) trial of captopril versus placebo among patients who survived an acute myocardial infarction with compromised ventricular functioning, but no overt heart failure. Assessments included patient symptoms, health perceptions, emotional, cognitive, social and sexual levels of functioning, as well as potential covariates, such as life events and social support. The purpose of this study was to evaluate the psychometric properties of the quality of life measures in the SAVE at baseline, and provide a pre-randomization profile of the SAVE patients. One hundred and eighty-four patients participated in this aspect of the trial. Reliability alpha coefficients were adequate or better for all questionnaires, except for life events and sexual activities. Consistent with prior studies, the quality of life parameters were uncorrelated with ventricular ejection fraction. Despite experiencing a recent myocardial infarction with compromised ventricular functioning, patients at baseline generally neither appeared depressed nor focused on symptoms. The baseline findings support the inclusion of the quality of life ancillary study in the overall SAVE trial because of the independent contribution likely to be achieved in terms of evaluating both disease progression and treatment efficacy.

Assessment of quality of life as observed from the baseline data of the Studies of Left Ventricular Dysfunction (SOLVD) trial quality-of-life substudy

The improvement of aspects of a patient's quality of life may be as important as prolonging survival in evaluating clinical trials of heart failure. The purpose of this study was to analyze the psychometric properties of the baseline measures from the quality-of-life substudy from the Studies of Left Ventricular Dysfunction (SOLVD) trial. The measures included the 6-Minute Walk Test, Dyspnea Scale, Living with Heart Failure, Physical Limitations, Psychologic Distress and Health Perceptions, as reported by both patients and staff. Cognitive functioning, such as Vocabulary, Digit Span and Trails Making, was also assessed. Patients were classified as New York Heart Association class I (n = 158) versus II or III (n = 150). The internal consistencies (i.e., reliabilities) of the self-report measures were high, except for the Health Perceptions of Class II or III patients. Reliability of the SOLVD quality-of-life battery was confirmed by significantly better life quality among New York Heart Association class I patients versus class II or III patients combined on the Walk Test, Physical Limitations, Dyspnea, Living with Heart Failure, Psychologic Distress and staff perceptions of patient health. In accordance with prior studies, the measures were uncorrelated with left ventricular ejection fraction. By demonstrating strong internal consistencies, reliability based on physician reports, and independence of ejection fraction levels, use of this quality-of-life assessment battery in this and other clinical trials of compromised ventricular functioning is supported.

Comparison between New York Heart Association classification and peak oxygen consumption in the assessment of functional status and prognosis in patients with mild to moderate chronic congestive heart failure secondary to either ischemic or idiopathic dilated cardiomyopathy

To compare the value of the New York Heart Association (NYHA) classification and measurement of peak oxygen consumption (VO2) in the assessment of functional status and prognosis in patients with mild to moderate chronic congestive heart failure (CHF), 94 patients with clinically stable NYHA class II and III CHF were prospectively studied. In all patients, left ventricular ejection fraction was less than or equal to 40% (mean 22 +/- 9); 49 patients were in NYHA class II, and 45 were in NYHA class III. Mean peak VO2 was 17 +/- 5 ml/min/kg. During a follow-up period of 23 +/- 11 months, 21 patients died. The 1-, 2- and 3-year cumulative survival rates for the 94 patients were 88, 79 and 69%, respectively. Functional status, as assessed both by peak VO2 and NYHA classification, and left ventricular ejection fraction were significantly worse in the group of nonsurvivors. The most powerful independent predictor of mortality was peak VO2. Although mean peak VO2 was significantly higher in NYHA class II than in NYHA class III (20 +/- 4 vs 13 +/- 3 ml/min/kg, p less than 0.0001), categorization into subgroups on the basis of the attained peak VO2 revealed a marked discrepancy with the NYHA classification. Nevertheless, the survival curves of patients subdivided at a peak VO2 of 16 ml/min/kg showed a strong resemblance with survival curves of both NYHA classes.(ABSTRACT TRUNCATED AT 250 WORDS)

Methods for assessing quality of life in the cardiac arrhythmia suppression trial (CAST)

The CAST was a randomized, double-blind placebo-controlled multicentre trial of antiarrhythmic medications designed to suppress ventricular arrhythmias in patients after an acute myocardial infarction (MI). A collection of 21 items derived from established scales was used to assess aspects of quality of life in CAST. The questions focused on symptoms, mental health, physical functioning, social functioning, life satisfaction, and life expectancy. Additional aspects included exposure to major stressful life events, and perceived social support and social integration. Work status was also recorded. Using the baseline values of 1465 (98%) out of 1498 patients enrolled in the CAST main study between 15 June 1987 and 19 April 1989, the reliability and validity of the scales used in CAST were computed. High internal consistency reliability (> or = 0.70) was found for Symptoms, Mental Health, and Physical Functioning. The discriminative validity, in particular for Symptoms, Mental Health, Physical and Social Functioning, showed that patients with heart failure and previous MI, as well as those suffering from angina and dyspnea, had a worse quality of life than those patients who were not experiencing these symptoms. It was concluded that the scales selected to form the CAST quality of life questionnaire were both reliable and clinically valid for this patient population and therefore could be used to detect disease progression and treatment effects.

Changing strategies in the management of chronic congestive heart failure

Recent studies have more clearly defined the role of drug therapy in patients with chronic congestive heart failure (CHF). Treatment of patients with asymptomatic left ventricular dysfunction (New York Heart Association [NYHA] class I) cannot be recommended at this time. The benefit of prophylactic treatment with angiotensin-converting enzyme inhibitors (ACEIs) or vasodilators in patients at high risk for developing symptomatic CHF is currently being evaluated. Treatment of patients with symptomatic CHF (NYHA class II-IV) should be initiated with a combination of a diuretic, digoxin, and an ACEI. This combination has been shown to reduce the mortality rate in patients with NYHA class II-IV CHF. Patients who remain symptomatic despite treatment with this combination may benefit from the addition of the direct-acting, nonspecific vasodilators--hydralazine and a nitrate. The addition of the nonspecific vasodilators to an ACEI has not been tested in controlled trials. In patients who remain symptomatic despite treatment with diuretics, digoxin, ACEIs, and nonspecific vasodilators, treatment options are not clear. The use of beta-agonists, phosphodiesterase inhibitors, and intermittent fixed-dose, fixed-interval dobutamine should be avoided as these agents are associated with a high mortality rate. Heart transplantation should be considered early in the course of CHF to allow for preservation of other vital organ systems. Unfortunately, heart transplantation is available to only a very small minority of potential transplant candidates.

Validation of a computerized technique for detection of the gas exchange anaerobic threshold in cardiac disease

Respiratory gas exchange data were collected from 77 men greater than 6 months after acute myocardial infarction. Maximal exercise was performed on an ergometer cycle programmed for a ramp protocol of 15 W/min. The gas exchange anaerobic threshold (ATge) was determined by analysis of the carbon dioxide elimination (VCO2) vs oxygen consumption (VO2) curve below a respiratory exchange ratio of 1.00 using a computerized algorithm. This value was estimated at the inflection of VCO2 from a line with a slope of 1 which intersects the VCO2 vs VO2 curve. The relation of the ATge to the lactate acidosis threshold was studied in 29 patients. The reproducibility of the ATge method was studied in 77 patients. Mean (+/- standard deviation) VO2 for the ATge was 905 +/- 220 vs 866 +/- 299 ml/min for the lactate acidosis threshold (r = 0.86, p less than 0.001). Mean VO2 at the ATge for test 1 was 968 +/- 225 vs 952 +/- 217 ml/min for test 2 (r = 0.71, p less than 0.001). Mean peak VO2 was 1,392 +/- 379 vs 912 +/- 202 ml/min at the ATge (r = 0.76, p less than 0.001). Results demonstrate that this ATge method correlates well with the lactate acidosis threshold, is reproducible, and should be useful as an objective measure of submaximal exercise performance.

Assessing cardiac pumping capability by exercise testing and inotropic stimulation

In heart failure both functional capacity and prognosis are primarily determined by the degree of pump dysfunction. Although data on haemodynamic function at rest may indicate impaired cardiac function, they do not assess the capacity of the heart to respond to stress. Maximal bicycle ergometry and incremental intravenous inotropic stimulation in 31 patients with moderately severe heart failure were evaluated as methods of stressing the heart to determine cardiac pumping capability, which is defined as the cardiac power obtained during maximal stimulation. There was good agreement between the cardiac pumping capabilities assessed by these two methods. Maximal cardiac power output was better than maximal cardiac output and left ventricular stroke work index in representing cardiac pumping capability, because it was less dependent on the type of stimulation used during evaluation. Inotropic challenge is at least as effective as exercise testing in assessing cardiac pumping capability in heart failure, and may be a better method in patients who find physical exercise difficult.

Congestive heart failure

Congestive heart failure (CHF) is not a single entity but a symptom complex that may represent the consequence of mechanical abnormalities, myocardial abnormalities, and/or disturbances of cardiac rhythm. In turn, it affects virtually every organ system in the body. This review focuses on CHF due to systolic dysfunction of the left ventricle, which comprises the majority of cases of this condition. Recent data suggest that CHF may be the most frequent primary diagnosis in patients on medical services in nonmilitary hospitals in this country: it affects approximately 2% of the United States population, or some 4 million people. The mortality rate for CHF is also worse than for many forms of cancer; thus, new therapeutic alternatives are imperative. In order to devise new therapeutic strategies, a detailed understanding of the pathophysiology of this condition is required. The relative advantages and disadvantages of various pharmacologic and nonpharmacologic approaches are considered in detail. Certain medications, such as the angiotensin converting enzyme (ACE) inhibitors, have been shown to improve survival, and heart transplantation is clearly life-saving for those who are eligible for this therapy. However, the real challenge is to devise strategies to prevent the occurrence of heart failure, or interrupt its progress at a very early stage.