Deidre Toia

Moderate-intensity resistance exercise training in patients with chronic heart failure improves strength, endurance, heart rate variability, and forearm blood flow

BACKGROUND Resistance exercise training was applied to patients with chronic heart failure (CHF) on the basis that it may partly reverse deficiencies in skeletal muscle strength and endurance, aerobic power (VO(2peak)), heart rate variability (HRV), and forearm blood flow (FBF) that are all putative factors in the syndrome. METHODS AND RESULTS Thirty-nine CHF patients (New York Heart Association Functional Class=2.3+/-0.5; left ventricular ejection fraction 28%+/-7%; age 65+/-11 years; 33:6 male:female) underwent 2 identical series of tests, 1 week apart, for strength and endurance of the knee and elbow extensors and flexors, VO(2peak), HRV, FBF at rest, and FBF activated by forearm exercise or limb ischemia. Patients were then randomized to 3 months of resistance training (EX, n=19), consisting of mainly isokinetic (hydraulic) ergometry, interspersed with rest intervals, or continuance with usual care (CON, n=20), after which they underwent repeat endpoint testing. Combining all 4 movement patterns, strength increased for EX by 21+/-30% (mean+/-SD, P<.01) after training, whereas endurance improved 21+/-21% (P<.01). Corresponding data for CON remained almost unchanged (strength P<.005, endurance P<.003 EX versus CON). VO(2peak) improved in EX by 11+/-15% (P<.01), whereas it decreased by 10+/-18% (P<.05) in CON (P<.001 EX versus CON). The ratio of low-frequency to high-frequency spectral power fell after resistance training in EX by 44+/-53% (P<.01), but was unchanged in CON (P<.05 EX versus CON). FBF increased at rest by 20+/-32% (P<.01), and when stimulated by submaximal exercise (24+/-32%, P<.01) or limb ischemia (26+/-45%, P<.01) in EX, but not in CON (P<.01 EX versus CON). CONCLUSIONS Moderate-intensity resistance exercise training in CHF patients produced favorable changes to skeletal muscle strength and endurance, VO(2peak), FBF, and HRV.

Reliability of isokinetic strength and aerobic power testing for patients with chronic heart failure

PURPOSE The objective of this study was to assess the reliability of testing skeletal muscle strength and peak aerobic power in a clinical population of patients with chronic heart failure (CHF). METHODS Thirty-three patients with CHF (New York Heart Association (NYHA) Functional Class 2.3 +/- 0.5; left ventricular ejection fraction 27% +/- 7%; age 65 +/- 9 years; 28:5 male-female ratio) underwent two identical series of tests (T1 and T2), 1 week apart, for strength and endurance of the muscle groups responsible for knee extension/flexion and elbow extension/flexion. The patients also underwent two graded exercise tests on a bicycle ergometer to measure peak oxygen consumption (VO(2peak)). Three months later, 18 of the patients underwent a third test (T3) for each of the measures. Means were compared using MANOVA with repeated measures for strength and endurance, and ANOVA with repeated measures for VO(2peak). RESULTS Combining data for all four movement patterns, the expression of strength increased from T1 to T2 by 12% +/- 25% (P <.001; intraclass correlation coefficient [ICC] = 0.89). Correspondingly, endurance increased by 13% +/- 23% (P =.004; ICC = 0.87). Peak oxygen consumption was not significantly different (16.2 +/- 0.8 and 16.1 +/- 0.8 mL.kg(-1).min(-1) for T1 and T2, respectively; P =.686; ICC = 0.91). There were no significant differences between T2 and T3 for strength (2% +/- 17%; P =.736; ICC = 0.92) or muscle endurance (-1% +/- 15%; P =.812; ICC = 0.96), but VO(2peak) decreased from 16.7 +/- 1.2 to 14.9 +/- 0.9 mL.kg(-1).min(-1) (-10% +/- 18%; P =.021; ICC = 0.89). CONCLUSIONS These data suggest that in a population of patients with CHF, a familiarization trial for skeletal muscle strength testing is necessary. Although familiarization is not required for assessing oxygen consumption as a single measurement, VO(2peak) declined markedly in the 3-month period for which these patients were followed. Internal consistency within patients was high for the second and third strength trials and the first and second tests of VO(2peak).

Differential response to resistance training in CHF according to ACE genotype.

BACKGROUND The Angiotensin Converting Enzyme (ACE) gene may influence the risk of heart disease and the response to various forms of exercise training may be at least partly dependent on the ACE genotype. We aimed to determine the effect of ACE genotype on the response to moderate intensity circuit resistance training in chronic heart failure (CHF) patients. METHODS The relationship between ACE genotype and the response to 11weeks of resistance exercise training was determined in 37 CHF patients (New York Heart Association Functional Class=2.3±0.5; left ventricular ejection fraction 28±7%; age 64±12years; 32:5 male:female) who were randomised to either resistance exercise (n=19) or inactive control group (n=18). Outcome measures included V˙O(2peak), peak power output and muscle strength and endurance. ACE genotype was determined using standard methods. RESULTS At baseline, patients who were homozygous for the I allele had higher V˙O(2peak) (p=0.02) and peak power (p=0.003) compared to patients who were homozygous for the D allele. Patients with the D allele, who were randomised to resistance training, compared to non-exercising controls, had greater peak power increases (ID p<0.001; DD p<0.001) when compared with patients homozygous for the I allele, who did not improve. No significant genotype-dependent changes were observed in V˙O(2peak), muscle strength, muscle endurance or lactate threshold. CONCLUSION ACE genotype may have a role in exercise tolerance in CHF and could also influence the effectiveness of resistance training in this condition.

Effect of exercise training on left ventricular remodeling in diabetic patients with diastolic dysfunction: rationale and design.

Introduction This study will examine the effects of combined aerobic and resistance training on left ventricular remodeling in diabetic patients with diastolic dysfunction. This is the first randomized controlled trial to look for effects of combined strength training and aerobic exercise on myocardial function as well as other clinical, functional, or psychological parameters in diabetic patients with isolated diastolic dysfunction, and will provide important insights into the potential management strategies for heart failure with preserved ejection fraction. Methods and Analysis This is a prospective, randomized controlled investigator initiated single center trial. Diabetic patients with LV diastolic dysfunction suitable for exercise training intervention will be randomized to three months of a supervised combination of aerobic and strength training exercises, or supervised light stretching (control arm). Pre and post intervention assessment will include stress echocardiography, peak aerobic power with 12-lead ECG, dual-energy X-ray absorptiometry, muscle strength, the capacity to perform activities of daily living (ADLs), and questionnaires to assess self-perceived quality of life and symptoms of depression. The primary endpoint is to compare any change in tissue Doppler-derived LV systolic and early diastolic velocities. Ethics and Dissemination The current trial protocol has been approved by the Human Research Ethics Committee of Austin Health and the University of Melbourne, Melbourne. The study will be performed in accordance with the Declaration of Helsinki. The investigator, regardless of the outcome, will publish the results of the study. Trial Registration Australian New Zealand Clinical Trials Registry: ACTRN12610000943044.

Hopelessness and cognitive impairment are risk markers for mortality in systolic heart failure patients

OBJECTIVE Depression exacerbates the burden of heart failure and independently predicts mortality. The aim of this study was to investigate which specific symptoms of depression predict all-cause mortality in systolic heart failure patients. METHODS Consecutive outpatients with heart failure and impaired left ventricular ejection fraction (LVEF), attending an Australian metropolitan heart function clinic between 2001 and 2011, were enrolled. The Cardiac Depression Scale (CDS) was completed as a component of usual care. Baseline clinical characteristics were drawn from hospital databases. The primary end-point was all-cause mortality, obtained from the Australian National Death Index. RESULTS A total of 324 patients (68.5% male) were included (mean age at enrolment = 66.8 ± 14.36 years), with a median follow-up time of 6.7 years (95% CI 5.97-7.39) and a mortality rate of 50% by the census date. Mean LVEF = 31.0 ± 11.31%, with 25% having NYHA functional class of III or IV. Factor analysis of the CDS extracted six symptom dimensions: Hopelessness, Cognitive Impairment, Anhedonia/Mood, Irritability, Worry, and Sleep Disturbance. Cox regression analyses identified Hopelessness (HR 1.024, 95% CI 1.004-1.045, p = .018) and Cognitive Impairment (HR 1.048, 95% CI 1.005-1.093, p = .028) as independent risk markers of all-cause mortality, following adjustment of known prognostic clinical factors. CONCLUSION Hopelessness and cognitive impairment are stronger risk markers for all-cause mortality than other symptoms of depression in systolic heart failure. These data will allow more specific risk assessment and potentially new targets for more effective treatment and management of depression in this population.