Exercise intolerance in heart failure with preserved ejection fraction: A reappraisal of central mechanisms?

Effects of 12-Week Home-based Resistance Training on Peripheral Muscle Oxygenation in Children With Congenital Heart Disease: A CHAMPS Study

Background

A hallmark feature of children with congenital heart disease (CHD) is exercise intolerance. Whether a home-based resistance training intervention improves muscle oxygenation (as measured by tissue oxygenation index, TOI) and exercise tolerance (V ˙ O2 reserve) during aerobic exercise in children with CHD compared with healthy children is unknown.

Methods

We report findings for 10 children with CHD (female/male: 4/6; mean ± standard deviation age: 13 ± 1 years) and 9 healthy controls (female/male: 5/4; age: 12 ± 3 years). Children with CHD completed a 12-week home-based exercise programme in addition to 6 in-person sessions. Exercise tolerance was assessed with a peak exercise test. Vastus lateralis TOI was continuously sampled during the peak V ˙ O2 test via near-infrared spectroscopy.

Results

There was a medium effect (Cohen's d = 0.67) of exercise training on lowering TOI at peak exercise (pre: 30 ± 16 %total labile signal vs post: 20 ± 13 % total labile signal; P = 0.099). Exercise training had a small effect (Cohen's d = 0.23) on increasing V ˙ O2 reserve by 1.6 mL/kg/min (pre: 27.2 ± 5.7 mL/kg/min vs post: 29.4 ± 8.8 mL/kg/min; P = 0.382). There was also a small effect (Cohen's d = 0.27) of exercise on peak heart rate (pre: 175 ± 23 beats/min vs post: 169 ± 21 beats/min; P = 0.18). TOI, V ˙ O2 reserve, and heart rate were generally lower than healthy control participants.

Conclusions

Our findings indicate that home-based resistance training may enhance skeletal muscle oxygen extraction (lower TOI) and subsequently V ˙ O2 reserve in children with CHD.

Hypocalcaemia predicts 12-month re-hospitalization in heart failure

BACKGROUND

Potential pathophysiology of heart failure with preserved ejection fraction (HFpEF) has not been fully explored. The aim of the study was to reveal the association of serum calcium concentration at baseline with 12-month clinical outcome in the disease.

MATERIALS AND METHODS

A total of 350 patients with newly diagnosed HFpEF were included in this prospective observational study. There were no malignant tumour, kidney disease, thyroid disease, calcium and vitamin D supplements in the patients. All of them received 12-month follow-up, and endpoints were cardiac re-hospitalization and death. Baseline serum calcium concentration was measured using AIA2000ST enzyme immunoassay analyser. Cardiopulmonary exercise, six-minute walk distance test, EQ5D questionnaire and cardiac ultrasound were performed to evaluate exercise capacity, quality of life and left ventricle function.

RESULTS

Multivariate COX regression analysis revealed that baseline hypocalcaemia was associated with the increased risk of cardiac re-hospitalization and death during the follow-up period (HR: 2.10, 95% CI: 1.69-2.61; HR: 8.26, 95% CI: 2.88-23.70). Furthermore, baseline hypocalcaemia was related to the deterioration of 6-minute walk distance, quality of life score (EQ-5D), right quadriceps strength, left atrium volume index and left ventricular ejection fraction during the follow-up period (HR: 1.65, 95% CI: 1.21-2.26; HR: 1.55, 95% CI: 1.12-2.11; HR: 2.56, 95% CI: 1.68-3.89; HR: 1.44, 95% CI: 1.03-1.98; HR: 1.36, 95% CI: 1.02-1.80).

CONCLUSION

Baseline hypocalcaemia predicted 12-month cardiac re-hospitalization and death in HFpEF patients without calcium and vitamin D supplements partly through left ventricle and skeletal muscle function pathways.