The Association Between β-Blocker Use and Cardiorespiratory Fitness: The Maastricht Study

Physical activity and physical fitness in children with heritable connective tissue disorders

Objectives

Health problems in patients with heritable connective tissue disorders (HCTD) are diverse and complex and might lead to lower physical activity (PA) and physical fitness (PF). This study aimed to investigate the PA and PF of children with heritable connective tissue disorders (HCTD).

Methods

PA was assessed using an accelerometer-based activity monitor (ActivPAL) and the mobility subscale of the Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT). PF was measured in terms of cardiovascular endurance using the Fitkids Treadmill Test (FTT); maximal hand grip strength, using hand grip dynamometry (HGD) as an indicator of muscle strength; and motor proficiency, using the Bruininks-Oseretsky Test of Motor Proficiency-2 (BOTMP-2).

Results

A total of 56 children, with a median age of 11.6 (interquartile range [IQR], 8.8-15.8) years, diagnosed with Marfan syndrome (MFS), n = 37, Loeys-Dietz syndrome (LDS), n = 6, and genetically confirmed Ehlers-Danlos (EDS) syndromes, n = 13 (including classical EDS n = 10, vascular EDS n = 1, dermatosparaxis EDS n = 1, arthrochalasia EDS n = 1), participated. Regarding PA, children with HCTD were active for 4.5 (IQR 3.5-5.2) hours/day, spent 9.2 (IQR 7.6-10.4) hours/day sedentary, slept 11.2 (IQR 9.5-11.5) hours/day, and performed 8,351.7 (IQR 6,456.9-1,0484.6) steps/day. They scored below average (mean (standard deviation [SD]) z-score -1.4 (1.6)) on the PEDI-CAT mobility subscale. Regarding PF, children with HCTD scored well below average on the FFT (mean (SD) z-score -3.3 (3.2)) and below average on the HGD (mean (SD) z-score -1.1 (1.2)) compared to normative data. Contradictory, the BOTMP-2 score was classified as average (mean (SD) z-score.02 (.98)). Moderate positive correlations were found between PA and PF (r(39) = .378, p < .001). Moderately sized negative correlations were found between pain intensity and fatigue and time spent actively (r(35) = .408, p < .001 and r(24) = .395 p < .001, respectively).

Conclusion

This study is the first to demonstrate reduced PA and PF in children with HCTD. PF was moderately positively correlated with PA and negatively correlated with pain intensity and fatigue. Reduced cardiovascular endurance, muscle strength, and deconditioning, combined with disorder-specific cardiovascular and musculoskeletal features, are hypothesized to be causal. Identifying the limitations in PA and PF provides a starting point for tailor-made interventions.

High-Intensity Interval Training is Safe, Feasible and Efficacious in Nonalcoholic Steatohepatitis: A Randomized Controlled Trial

BACKGROUND

High-Intensity Interval Training (HIIT) involves bursts of high-intensity exercise interspersed with lower-intensity exercise recovery. HIIT may benefit cardiometabolic health in people with nonalcoholic steatohepatitis (NASH).

AIMS

We aimed to examine the safety, feasibility, and efficacy of 12-weeks of supervised HIIT compared with a sham-exercise control (CON) for improving aerobic fitness and peripheral insulin sensitivity in biopsy-proven NASH.

METHODS

Participants based in the community [(n = 14, 56 ± 10 years, BMI 39.2 ± 6.7 kg/m², 64% male), NAFLD Activity Score 5 (range 3-7)] were randomized to 12-weeks of supervised HIIT (n = 8, 4 × 4 min at 85-95% maximal heart rate, interspersed with 3 min active recovery; 3 days/week) or CON (n = 6, stretching; 3 days/week). Safety (adverse events) and feasibility determined as ≥ 70% program completion and ≥ 70% global adherence (including session attendance, interval intensity adherence, and duration adherence) were assessed. Changes in cardiorespiratory fitness (V̇O₂peak), exercise capacity (time-on-test) and peripheral insulin sensitivity (euglycemic hyperinsulinemic clamp) were assessed. Data were analysed using ANCOVA with baseline value as the covariate.

RESULTS

There were no HIIT-related adverse events and HIIT was globally feasible [program completion 75%, global adherence 100% (including adherence to session 95.4 ± 7.3%, interval intensity 95.3 ± 6.0% and duration 96.8 ± 2.4%)]. A large between-group effect was observed for exercise capacity [mean difference 134.2 s (95% CI 19.8, 248.6 s), ƞ² 0.44, p = 0.03], improving in HIIT (106.2 ± 97.5 s) but not CON (- 33.4 ± 43.3 s), and for peripheral insulin sensitivity [mean difference 3.4 mg/KgLegFFM/min (95% CI 0.9,6.8 mg/KgLegFFM/min), ƞ² 0.32, p = 0.046], improving in HIIT (1.0 ± 0.8 mg/KgLegFFM/min) but not CON (- 3.1 ± 1.2 mg/KgLegFFM/min).

CONCLUSIONS

HIIT is safe, feasible and efficacious for improving exercise capacity and peripheral insulin sensitivity in people with NASH.

CLINICAL TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trial Registry (anzctr.org.au) identifier ACTRN12616000305426 (09/03/2016).

Assessment of the Relationship Between Executive Function and Cardiorespiratory Fitness in Healthy Older Adults

Associations between cardiorespiratory fitness and brain health in healthy older adults have been reported using a variety of cardiorespiratory fitness estimates (CRFe). Using commonly used methods to determine CRF, we assessed the relationship between CRFe and executive function performance. Healthy older adults (n = 60, mean age 68 years, 77% women), underwent three CRF tests: a Maximal Graded Exercise Test performed on a cycle ergometer, the Rockport Fitness Walking Test, and a Non-Exercise Prediction Equation. Executive function was assessed by a computerized cognitive assessment using an N-Back task (updating cost) and a Stroop task (interference cost, global and local switch cost). Multiple hierarchical regression analyses were conducted to assess the relationship between different CRFe and executive function performance. Regardless of age and education, cardiorespiratory fitness estimated from the Maximal Graded Exercise Test and the Rockport Fitness Walking Test was significantly associated with the global switch cost. All CRFe were associated with the interference cost. No association was observed between CRFe and local switching costs or the updating costs. In the present study, not all subcomponents of executive function were related to CRFe. Interestingly, the executive functions that were associated with CRFe are those that are known to be the most affected by aging.

Hypertrophic Cardiomyopathy: Updates Through the Lens of Sports Cardiology

Purpose of review

This review will summarize the distinction between hypertrophic cardiomyopathy (HCM) and exercise-induced cardiac remodeling (EICR), describe treatments of particular relevance to athletes with HCM, and highlight the evolution of recommendations for exercise and competitive sport participation relevant to individuals with HCM.

Recent findings

Whereas prior guidelines have excluded individuals with HCM from more than mild-intensity exercise, recent data show that moderate-intensity exercise improves functional capacity and indices of cardiac function and continuation of competitive sports may not be associated with worse outcomes. Moreover, recent studies of athletes with implantable cardioverter defibrillators (ICDs) demonstrated a safer profile than previously understood. In this context, the updated American Heart Association/American College of Cardiology (AHA/ACC) and European Society of Cardiology (ESC) HCM guidelines have increased focus on shared decision-making and liberalized restrictions on exercise and sport participation among individuals with HCM.

Summary

New data demonstrating the safety of exercise in individuals with HCM and in athletes with ICDs, in addition to a focus on shared decision-making, have led to the most updated guidelines easing restrictions on exercise and competitive athletics in this population. Further athlete-specific studies of HCM, especially in the context of emerging therapies such as mavacamten, are important to inform accurate risk stratification and eligibility recommendations.

Mavacamten for treatment of symptomatic obstructive hypertrophic cardiomyopathy (EXPLORER-HCM): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Cardiac muscle hypercontractility is a key pathophysiological abnormality in hypertrophic cardiomyopathy, and a major determinant of dynamic left ventricular outflow tract (LVOT) obstruction. Available pharmacological options for hypertrophic cardiomyopathy are inadequate or poorly tolerated and are not disease-specific. We aimed to assess the efficacy and safety of mavacamten, a first-in-class cardiac myosin inhibitor, in symptomatic obstructive hypertrophic cardiomyopathy.

METHODS

In this phase 3, randomised, double-blind, placebo-controlled trial (EXPLORER-HCM) in 68 clinical cardiovascular centres in 13 countries, patients with hypertrophic cardiomyopathy with an LVOT gradient of 50 mm Hg or greater and New York Heart Association (NYHA) class II-III symptoms were assigned (1:1) to receive mavacamten (starting at 5 mg) or placebo for 30 weeks. Visits for assessment of patient status occurred every 2-4 weeks. Serial evaluations included echocardiogram, electrocardiogram, and blood collection for laboratory tests and mavacamten plasma concentration. The primary endpoint was a 1·5 mL/kg per min or greater increase in peak oxygen consumption (pVO₂) and at least one NYHA class reduction or a 3·0 mL/kg per min or greater pVO₂ increase without NYHA class worsening. Secondary endpoints assessed changes in post-exercise LVOT gradient, pVO₂, NYHA class, Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score (KCCQ-CSS), and Hypertrophic Cardiomyopathy Symptom Questionnaire Shortness-of-Breath subscore (HCMSQ-SoB). This study is registered with ClinicalTrials.gov, NCT03470545.

FINDINGS

Between May 30, 2018, and July 12, 2019, 429 adults were assessed for eligibility, of whom 251 (59%) were enrolled and randomly assigned to mavacamten (n=123 [49%]) or placebo (n=128 [51%]). 45 (37%) of 123 patients on mavacamten versus 22 (17%) of 128 on placebo met the primary endpoint (difference +19·4%, 95% CI 8·7 to 30·1; p=0·0005). Patients on mavacamten had greater reductions than those on placebo in post-exercise LVOT gradient (-36 mm Hg, 95% CI -43·2 to -28·1; p<0·0001), greater increase in pVO₂ (+1·4 mL/kg per min, 0·6 to 2·1; p=0·0006), and improved symptom scores (KCCQ-CSS +9·1, 5·5 to 12·7; HCMSQ-SoB -1·8, -2·4 to -1·2; p<0·0001). 34% more patients in the mavacamten group improved by at least one NYHA class (80 of 123 patients in the mavacamten group vs 40 of 128 patients in the placebo group; 95% CI 22·2 to 45·4; p<0·0001). Safety and tolerability were similar to placebo. Treatment-emergent adverse events were generally mild. One patient died by sudden death in the placebo group.

INTERPRETATION

Treatment with mavacamten improved exercise capacity, LVOT obstruction, NYHA functional class, and health status in patients with obstructive hypertrophic cardiomyopathy. The results of this pivotal trial highlight the benefits of disease-specific treatment for this condition.

FUNDING

MyoKardia.

Spiroergometric assessment of cardiorespiratory fitness in subjects with severe obesity: A challenge of reference

BACKGROUND AND AIMS

Severe obesity is associated with poor physical performance but objective data are scarce.

METHODS AND RESULTS

Bicycle spiroergometry data with focus on peak oxygen uptake (V˙O_2,peak) and workload (W_peak) from 476 subjects with severe obesity (BMI ≥ 35.0 kg/m²; 70% women) were analysed. In a first step, V˙O_2,peak values were compared with reference values calculated upon different formulas (Wassermann; Riddle). Thereafter, multivariate regression analyses were performed to identify determinants of cardiorespiratory fitness. Cardiorespiratory fitness reference classes for V˙O_2,peak and W_peak were established by stratifying the sample upon identified determinants. Absolute V˙O_2,peak (1.87 ± 0.47 vs. 2.40 ± 0.59 l/min) and W_peak (131 ± 26 vs. 168 ± 44 W) were lower in women than men (both p<0.001). Same pattern was found for relative V˙O_2,peak and W_peak, respectively (both p < 0.05). In women, measured V˙O_2,peak was lower than predicted by Wasserman (p < 0.001) but not by Riddle (p = 0.961). In men, V˙O_2,peak was lower than calculated by both Wasserman and Riddle formulas (both p ≤ 0.003). Multivariate analyses revealed height and age to be the main determinants of cardiorespiratory fitness in both sexes. Subsequent statistical analyses of calculated reference fitness classes revealed that V˙O_2,peak and W_peak differed between the age- and height-defined groups in both sexes (all p < 0.001).

CONCLUSION

Data indicate that the evaluation of cardiorespiratory fitness in subjects with severe obesity is largely biased by selected references values for comparison. Our newly established reference fitness classes upon height and age might be helpful in the clinical context when dealing with obese patients.