Trajectory of cardiac troponin T following moderate-to-severe COVID-19 and the association with cardiac abnormalities.

BACKGROUND: COVID-19 has been associated with cardiac troponin T (cTnT) elevations and changes in cardiac structure and function, but the link between cardiac dysfunction and high-sensitive cardiac troponin T (hs-cTnT) in the acute and convalescent phase is unclear. OBJECTIVE: To assess whether hs-cTnT concentrations are associated with cardiac dysfunction and structural abnormalities after hospitalization for COVID-19, and to evaluate the performance of hs-cTnT to rule out cardiac pathology. METHODS: Patients hospitalized with COVID-19 had hs-cTnT measured during the index hospitalization and after 3-and 12 months, when they also underwent an echocardiographic study. A subset also underwent cardiovascular magnetic resonance imaging (CMR) after 6 months. Cardiac abnormalities were defined as left ventricular hypertrophy or dysfunction, right ventricular dysfunction, or CMR late gadolinium. RESULTS: We included 189 patients with hs-cTnT concentrations measured during hospitalization for COVID-19, and after 3-and 12 months: Geometric mean (95%CI) 13 (11-15) ng/L, 7 (6-8) ng/L and 7 (6-8) ng/L, respectively. Cardiac abnormalities after 3 months were present in 45 (30%) and 3 (8%) of patients with hs-cTnT ≥ and < 5 ng/L at 3 months, respectively (negative predictive value 92.3% [95%CI 88.5-96.1%]). The performance was similar in patients with and without dyspnea. Hs-cTnT decreased from hospitalization to 3 months (more pronounced in intensive care unit-treated patients) and remained unchanged from 3 to 12 months, regardless of the presence of cardiac abnormalities. CONCLUSION: Higher hs-cTnT concentrations in the convalescent phase of COVID-19 are associated with the presence of cardiac pathology and low concentrations (< 5 ng/L) may support in ruling out cardiac pathology following the infection.

Real-time feedback on chest compression efficacy by hands-free carotid Doppler in a porcine model.

Aim: Current guidelines for cardiopulmonary resuscitation (CPR) recommend a one-size-fits-all approach in relation to the positioning of chest compressions. We recently developed RescueDoppler, a hands-free Doppler ultrasound device for continuous monitoring of carotid blood flow velocity during CPR. The aim of the present study is to investigate whether RescueDoppler via real-time hemodynamic feedback, could identify both optimal and suboptimal compression positions. Methods: In this model of animal cardiac arrest, we induced ventricular fibrillation in five domestic pigs. Manual chest compressions were performed for ten seconds at three different positions on the sternum in random order and repeated six times. We analysed Time Average Velocity (TAV) with chest compression position as a fixed effect and animal, position, and sequential time within animals as random effects. Furthermore, we compared TAV to invasive blood pressure from the contralateral carotid artery. Results: We were able to detect changes in TAV when altering positions. The positions with the highest (range 19 to 48 cm/s) and lowest (6-25 cm/s) TAV were identified in all animals, with corresponding peak pressure 50-81 mmHg, and 46-64 mmHg, respectively. Blood flow velocity was, on average, highest at the middle position (TAV 33 cm/s), but with significant variability between animals (SD 2.8) and positions within the same animal (SD 9.3). Conclusion: RescueDoppler detected TAV changes during CPR with alternating chest compression positions, identifying the position yielding maximal TAV. Future clinical studies should investigate if RescueDoppler can be used as a real-time hemodynamical feedback device to guide compression position.

Hands-free continuous carotid Doppler ultrasound for detection of the pulse during cardiac arrest in a porcine model.

Background/Purpose: Pulse palpation is an unreliable method for diagnosing cardiac arrest. To address this limitation, continuous hemodynamic monitoring may be a viable solution. Therefore, we developed a novel, hands-free Doppler system, RescueDoppler, to detect the pulse continuously in the carotid artery. Methods: In twelve pigs, we evaluated RescueDopplers potential to measure blood flow velocity in three situations where pulse palpation of the carotid artery was insufficient: (1) systolic blood pressure below 60 mmHg, (2) ventricular fibrillation (VF) and (3) pulseless electrical activity (PEA). (1) Low blood pressure was induced using a Fogarty balloon catheter to occlude the inferior vena cava. (2) An implantable cardioverter-defibrillator induced VF. (3) Myocardial infarction after microembolization of the left coronary artery caused True-PEA. Invasive blood pressure was measured in the contralateral carotid artery. Time-averaged blood flow velocity (TAV) in the carotid artery was related to mean arterial pressure (MAP) in a linear mixed model. Results: RescueDoppler identified pulsatile blood flow in 41/41 events with systolic blood pressure below 60 mmHg, with lowest blood pressure of 19 mmHg. In addition the absence of spontaneous circulation was identified in 21/21 VF events and true PEA in 2/2 events. The intraclass correlation coefficient within animals for TAV and MAP was 0.94 (95% CI. 0.85-0.98). Conclusions: In a porcine model, RescueDoppler reliably identified pulsative blood flow with blood pressures below 60 mmHg. During VF and PEA, circulatory arrest was rapidly and accurately demonstrated. RescueDoppler could potentially replace unreliable pulse palpation during cardiac arrest and cardiopulmonary resuscitation.

Minor Myocardial Scars in Association with Cardiopulmonary Function after COVID-19.

BACKGROUND: Myocardial scars detected by cardiovascular magnetic resonance (CMR) imaging after COVID-19 have caused concerns regarding potential long-term cardiovascular consequences. OBJECTIVE: The objective of this study was to investigate cardiopulmonary functioning in patients with versus without COVID-19-related myocardial scars. METHODS: In this prospective cohort study, CMR was performed approximately 6 months after moderate-to-severe COVID-19. Before (∼3 months post-COVID-19) and after (∼12 months post-COVID-19) the CMR, patients underwent extensive cardiopulmonary testing with cardiopulmonary exercise tests, 24-h ECG, and echocardiography. We excluded participants with overt heart failure. RESULTS: Post-COVID-19 CMR was available in 49 patients with cardiopulmonary tests at 3 and 12 months after the index hospitalization. Nine (18%) patients had small late gadolinium enhancement-detected myocardial scars. Patients with myocardial scars were older (63.2 ± 13.2 vs. 56.2 ± 13.2 years) and more frequently men (89% vs. 55%) compared to those without scars. Cardiorespiratory fitness was similar in patients with and without scars, i.e., peak oxygen uptake: 82.1 ± 11.5% versus 76.3 ± 22.5% of predicted, respectively (p = 0.46). The prevalence of ventricular premature contractions and arrhythmias was low and not different by the presence of myocardial scar. Cardiac structure and function assessed by echocardiography were similar between the groups, except for a tendency of greater left ventricular mass in those with scars (75 ± 20 vs. 62 ± 14, p = 0.02 and p = 0.08 after adjusting for age and sex). There were no significant associations between myocardial scar and longitudinal changes in cardiopulmonary function from 3 to 12 months. CONCLUSION: Our findings imply that the presence of minor myocardial scars has limited clinical significance with respect to cardiopulmonary function after COVID-19.

Changes in cardiopulmonary exercise capacity and limitations 3-12 months after COVID-19.

RATIONALE: To describe cardiopulmonary function during exercise 12 months after hospital discharge for coronavirus disease 2019 (COVID-19), assess the change from 3 to 12 months, and compare the results with matched controls without COVID-19. METHODS: In this prospective, longitudinal, multicentre cohort study, hospitalised COVID-19 patients were examined using a cardiopulmonary exercise test (CPET) 3 and 12 months after discharge. At 3 months, 180 performed a successful CPET, and 177 did so at 12 months (mean age 59.3 years, 85 females). The COVID-19 patients were compared with controls without COVID-19 matched for age, sex, body mass index and comorbidity. Main outcome was peak oxygen uptake (V'O2  peak). RESULTS: Exercise intolerance (V'O2  peak <80% predicted) was observed in 23% of patients at 12 months, related to circulatory (28%), ventilatory (17%) and other limitations including deconditioning and dysfunctional breathing (55%). Estimated mean difference between 3 and 12 months showed significant increases in V'O2  peak % pred (5.0 percentage points (pp), 95% CI 3.1-6.9 pp; p<0.001), V'O2  peak·kg-1 % pred (3.4 pp, 95% CI 1.6-5.1 pp; p<0.001) and oxygen pulse % pred (4.6 pp, 95% CI 2.5-6.8 pp; p<0.001). V'O2  peak was 2440 mL·min-1 in COVID-19 patients compared to 2972 mL·min-1 in matched controls. CONCLUSIONS: 1 year after hospital discharge for COVID-19, the majority (77%), had normal exercise capacity. Only every fourth had exercise intolerance and in these circulatory limiting factors were more common than ventilator factors. Deconditioning was common. V'O2  peak and oxygen pulse improved significantly from 3 months.

Changes in cardiac structure and function from 3 to 12 months after hospitalization for COVID-19.

BACKGROUND: Cardiac function may be impaired during and early after hospitalization for COVID-19, but little is known about the progression of cardiac dysfunction and the association with postacute COVID syndrome (PACS). METHODS: In a multicenter prospective cohort study, patients who had been hospitalized with COVID-19 were enrolled and comprehensive echocardiography was performed 3 and 12 months after discharge. Twenty-four-hour electrocardiogram (ECG) was performed at 3 and 12 months in patients with arrhythmias at 3 months. RESULTS: In total, 182 participants attended the 3 and 12 months visits (age 58 ± 14 years, 59% male, body mass index 28.2 ± 4.2 kg/m2 ). Of these, 35 (20%) had severe COVID-19 (treatment in the intensive care unit) and 74 (52%) had self-reported dyspnea at 3 months. From 3 to 12 months there were no significant overall changes in any measures of left or right ventricle (LV; RV) structure and function (p > .05 for all), including RV strain (from 26.2 ± 3.9% to 26.5 ± 3.1%, p = .29) and LV global longitudinal strain (from 19.2 ± 2.3% to 19.3 ± 2.3%, p = .64). Changes in echocardiographic parameters from 3 to 12 months did not differ by COVID-19 severity or by the presence of persistent dyspnea (p > .05 for all). Among patients with arrhythmia at 3 months, there was no significant change in arrhythmia burden to 12 months. CONCLUSION: Following COVID-19, cardiac structure and function remained unchanged from 3 to 12 months after the index hospitalization, irrespective of COVID-19 severity and presence of persistent dyspnea. These results suggest that progression of cardiac dysfunction after COVID-19 is rare and unlikely to play an important role in PACS.

Cardiac Dysfunction and Arrhythmias 3 Months After Hospitalization for COVID-19.

Background The extent of cardiac dysfunction post-COVID-19 varies, and there is a lack of data on arrhythmic burden. Methods and Results This was a combined multicenter prospective cohort study and cross-sectional case-control study. Cardiac function assessed by echocardiography in patients with COVID-19 3 to 4 months after hospital discharge was compared with matched controls. The 24-hour ECGs were recorded in patients with COVID-19. A total of 204 patients with COVID-19 consented to participate (mean age, 58.5 years; 44% women), and 204 controls were included (mean age, 58.4 years; 44% women). Patients with COVID-19 had worse right ventricle free wall longitudinal strain (adjusted estimated mean difference, 1.5 percentage points; 95% CI, -2.6 to -0.5; P=0.005) and lower tricuspid annular plane systolic excursion (-0.10 cm; 95% CI, -0.14 to -0.05; P<0.001) and cardiac index (-0.26 L/min per m2; 95% CI, -0.40 to -0.12; P<0.001), but slightly better left ventricle global strain (-0.8 percentage points; 95% CI, 0.2-1.3; P=0.008) compared with controls. Reduced diastolic function was twice as common compared with controls (60 [30%] versus 29 [15%], respectively; odds ratio, 2.4; P=0.001). Having dyspnea or fatigue were not associated with cardiac function. Right ventricle free wall longitudinal strain was worse after intensive care treatment. Arrhythmias were found in 27% of the patients, mainly premature ventricular contractions and nonsustained ventricular tachycardia (18% and 5%, respectively). Conclusions At 3 months after hospital discharge with COVID-19, right ventricular function was mildly impaired, and diastolic dysfunction was twice as common compared with controls. There was little evidence for an association between cardiac function and intensive care treatment, dyspnea, or fatigue. Ventricular arrhythmias were common, but the clinical importance is unknown. Registration URL: http://clinicaltrials.gov. Unique Identifier: NCT04535154.

Cardiac pathology 6 months after hospitalization for COVID-19 and association with the acute disease severity.

BACKGROUND: Coronavirus disease 2019 (COVID-19) may cause myocardial injury and myocarditis, and reports of persistent cardiac pathology after COVID-19 have raised concerns of long-term cardiac consequences. We aimed to assess the presence of abnormal cardiovascular resonance imaging (CMR) findings in patients recovered from moderate-to-severe COVID-19, and its association with markers of disease severity in the acute phase. METHODS: Fifty-eight (49%) survivors from the prospective COVID MECH study, underwent CMR median 175 [IQR 105-217] days after COVID-19 hospitalization. Abnormal CMR was defined as left ventricular ejection fraction (LVEF) <50% or myocardial scar by late gadolinium enhancement. CMR indices were compared to healthy controls (n = 32), and to circulating biomarkers measured during the index hospitalization. RESULTS: Abnormal CMR was present in 12 (21%) patients, of whom 3 were classified with major pathology (scar and LVEF <50% or LVEF <40%). There was no difference in the need of mechanical ventilation, length of hospital stay, and vital signs between patients with vs without abnormal CMR after 6 months. Severe acute respiratory syndrome coronavirus 2 viremia and concentrations of inflammatory biomarkers during the index hospitalization were not associated with persistent CMR pathology. Cardiac troponin T and N-terminal pro-B-type natriuretic peptide concentrations on admission, were higher in patients with CMR pathology, but these associations were not significant after adjusting for demographics and established cardiovascular disease. CONCLUSIONS: CMR pathology 6 months after moderate-to-severe COVID-19 was present in 21% of patients and did not correlate with severity of the disease. Cardiovascular biomarkers during COVID-19 were higher in patients with CMR pathology, but with no significant association after adjusting for confounders. TRIAL REGISTRATION: COVID MECH Study ClinicalTrials.gov Identifier: NCT04314232.

Cardiopulmonary exercise capacity and limitations 3†months after COVID-19 hospitalisation.

BACKGROUND: This study aimed to describe cardiopulmonary function during exercise 3 months after hospital discharge for COVID-19 and compare groups according to dyspnoea and intensive care unit (ICU) stay. METHODS: Participants with COVID-19 discharged from five large Norwegian hospitals were consecutively invited to a multicentre, prospective cohort study. In total, 156 participants (mean age 56.2 years, 60 females) were examined with a cardiopulmonary exercise test (CPET) 3 months after discharge and compared with a reference population. Dyspnoea was assessed using the modified Medical Research Council (mMRC) dyspnoea scale. RESULTS: Peak oxygen uptake (V'O2  peak) <80% predicted was observed in 31% (n=49). Ventilatory efficiency was reduced in 15% (n=24), while breathing reserve <15% was observed in 16% (n=25). Oxygen pulse <80% predicted was found in 18% (n=28). Dyspnoea (mMRC ≥1) was reported by 47% (n=59). These participants had similar V'O2  peak (p=0.10) but lower mean±sd V'O2  peak·kg-1 % predicted compared with participants without dyspnoea (mMRC 0) (76±16% versus 89±18%; p=0.009) due to higher body mass index (p=0.03). For ICU- versus non-ICU-treated participants, mean±sd V'O2  peak % predicted was 82±15% and 90±17% (p=0.004), respectively. Ventilation, breathing reserve and ventilatory efficiency were similar between the ICU and non-ICU groups. CONCLUSIONS: One-third of participants experienced V'O2  peak <80% predicted 3 months after hospital discharge for COVID-19. Dyspnoeic participants were characterised by lower exercise capacity due to obesity and lower ventilatory efficiency. Ventilation and ventilatory efficiency were similar between ICU- and non-ICU-treated participants.

High day-to-day and diurnal variability of oxidative stress and inflammation biomarkers in people with type 2 diabetes mellitus and healthy individuals.

Objective: Assess the variability and differences in oxidative stress, antioxidant, and inflammatory biomarkers in people with type 2 diabetes mellitus (T2D) and healthy controls. Methods:: Ten men and women diagnosed with T2D and ten healthy matched controls (CON) were recruited. Participants had venous blood taken at six different time points on different days, three in the morning (after overnight fast) and three in the afternoon. Inflammation (IL-6, 8, 10 and TNF-α), oxidative stress/antioxidant biomarkers (F2-isoprostanes, protein carbonyls, total antioxidant capacity (TAC), glutathione peroxidase activity, IL-6, 8 & 10 and TNF-α) were assessed. Results:: Biomarker concentrations were similar between groups. There was large variability in nearly all biomarkers for both groups. For inflammatory measures, intra-individual coefficients of variation (CV) ranged from 64.0-92.1% and 100.9-259.0% for inter-individual differences. CVs for oxidative stress markers were lower (7.4-31.2% for intra-individual and 8.6-43.0% for inter-individual). TAC had the lowest intra-individual CV - 7% for T2D and 8% for CON. Protein carbonyls were more variable in the afternoon (34% CV) compared to morning (24% CV) in CON. IL-6 intra-individual CV was different between groups for afternoon measurements (93% T2D, 60% CON). Conclusion:: Oxidative stress and inflammatory biomarkers show considerable variation in both T2D and healthy populations. Trial registration: ClinicalTrials.gov identifier: NCT01206725.

Accuracy of Longitudinal Assessment of Visceral Adipose Tissue by Dual-Energy X-Ray Absorptiometry in Children with Obesity.

Background: Increased visceral adipose tissue (VAT) is strongly associated with cardiometabolic risk factors. Accurate quantification of VAT is available through magnetic resonance imaging (MRI), which incurs a significant financial and time burden. We aimed to assess the accuracy of dual-energy X-ray absorptiometry- (DXA-) derived VAT (DXA-VAT) against a gold standard MRI protocol (MRI-VAT) in children with normal weight and obesity cross-sectionally, and over the course of a lifestyle intervention. Methodology: MRI-VAT and DXA-VAT were quantified in 61 children (30 normal weight and 31 with obesity) at baseline. Children with obesity entered a three-month exercise and/or nutrition intervention after which VAT was reassessed. MRI- and DXA-VAT cross-sectional area, volume, and mass were quantified, and associations were calculated at baseline (n = 61) and pre-post intervention (n = 28, 3 participants dropped out). Method agreement was assessed through Bland-Altman analysis, linear regression, and Passing-Bablok regression. Results: At baseline, all DXA- and MRI-VAT outcomes were strongly associated (r = 0.90, P < 0.001). However, there were no significant associations between absolute or relative change in DXA- and MRI-VAT outcomes (r = 0.25-0.36, P > 0.05). DXA significantly overestimated VAT CSA (cross-sectional area), volume, and mass when compared with MRI (P < 0.001) at baseline. Significant proportional bias was observed for all DXA-VAT outcomes at baseline and for relative longitudinal changes in DXA-VAT. Conclusions: Although DXA-VAT outcomes were strongly associated with MRI-VAT outcomes at baseline, estimates were subject to proportional bias in children with obesity and normal weight. DXA lacks validity for detecting changes in VAT among children with obesity. This trial is registered with NCT01991106.

Cardiac function in newborns of obese women and the effect of exercise during pregnancy. A randomized controlled trial.

BACKGROUND: The prevalence of maternal obesity is rising. Pre-pregnancy obesity is associated with later cardiovascular disease in the child and the underlying pathogenesis begins in early life. Therefore, pregnancy and infancy are key periods for potential intervention. The aim of this study was to study the cardiac function in newborns of obese women compared to newborns of normal-weight women, and to determine if exercise intervention during pregnancy could have an effect on cardiac function of newborns to obese women. MATERIAL AND METHODS: Fifty-five pregnant women, 51 obese (BMI ≥ 30 kg/m2) and four overweight (BMI 28-30 kg/m2), were randomized to an exercise training group (n = 27) or a control group (standard maternity care, n = 28). From gestational week 14 until delivery participants in the intervention group were offered supervised training sessions three times weekly. In addition, they were told to exercise at home once weekly. All newborns had an echocardiogram performed 1-3 days and 6-8 weeks after delivery. The results were compared with newborns of normal weight women (n = 20, standard maternity care). RESULTS: Newborns of obese women had an impaired systolic and diastolic cardiac function with reduced global strain, strain rate, tissue Doppler velocities and a thicker intraventricular septum at birth and after 6-8 weeks after delivery compared to newborns of normal weight women. Exercise had no statistically significant effect on either of the cardiac function parameters. The mean (± standard deviation) adherence to the exercise protocol was 1.3 ± 0.8 sessions per week for supervised training and 0.8 ± 0.7 sessions per week for home-based exercise training. CONCLUSIONS: Newborns of obese women had reduced cardiac function and thicker intraventricular septum compared to newborns of normal weight women. Exercise training during pregnancy had no significant effect, potentially due to a low number of subjects and low adherence to the exercise protocol. TRIAL REGISTRATION: ClinicalTrials.gov NCT01243554.

Effect of High Intensity Interval Training on Cardiac Function in Children with Obesity: A Randomised Controlled Trial.

BACKGROUND: High intensity interval training (HIIT) confers superior cardiovascular health benefits to moderate intensity continuous training (MICT) in adults and may be efficacious for improving diminished cardiac function in obese children. The aim of this study was to compare the effects of HIIT, MICT and nutrition advice interventions on resting left ventricular (LV) peak systolic tissue velocity (S') in obese children. METHODS: Ninety-nine obese children were randomised into one of three 12-week interventions, 1) HIIT [n = 33, 4 × 4 min bouts at 85-95% maximum heart rate (HRmax), 3 times/week] and nutrition advice, 2) MICT [n = 32, 44 min at 60-70% HRmax, 3 times/week] and nutrition advice, and 3) nutrition advice only (nutrition) [n = 34]. RESULTS: Twelve weeks of HIIT and MICT were equally efficacious, but superior to nutrition, for normalising resting LV S' in children with obesity (estimated mean difference 1.0 cm/s, 95% confidence interval 0.5 to 1.6 cm/s, P < 0.001; estimated mean difference 0.7 cm/s, 95% confidence interval 0.2 to 1.3 cm/s, P = 0.010, respectively). CONCLUSIONS: Twelve weeks of HIIT and MICT were superior to nutrition advice only for improving resting LV systolic function in obese children.

Effect of High-Intensity Interval Training on Fitness, Fat Mass and Cardiometabolic Biomarkers in Children with Obesity: A Randomised Controlled Trial.

BACKGROUND: Paediatric obesity significantly increases the risk of developing cardiometabolic diseases across the lifespan. Increasing cardiorespiratory fitness (CRF) could mitigate this risk. High-intensity interval training (HIIT) improves CRF in clinical adult populations but the evidence in paediatric obesity is inconsistent. OBJECTIVES: The objectives of this study were to determine the efficacy of a 12-week, HIIT intervention for increasing CRF and reducing adiposity in children with obesity. METHODS: Children with obesity (n = 99, 7-16 years old) were randomised into a 12-week intervention as follows: (1) HIIT [n = 33, 4 × 4-min bouts at 85-95% maximum heart rate (HRmax), interspersed with 3 min of active recovery at 50-70% HRmax, 3 times/week] and nutrition advice; (2) moderate-intensity continuous training (MICT) [n = 32, 44 min at 60-70% HRmax, 3 times/week] and nutrition advice; and (3) nutrition advice only (nutrition) [n = 34]. CRF was quantified through a maximal exercise test ([Formula: see text]) while adiposity was assessed using magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry (DXA) and air-displacement plethysmography. RESULTS: HIIT stimulated significant increases in relative [Formula: see text] compared with MICT (+3.6 mL/kg/min, 95% CI 1.1-6.0, P = 0.004) and the nutrition intervention (+5.4 mL/kg/min, 95% CI 2.9-7.9, P = 0.001). However, the intervention had no significant effect on visceral and subcutaneous adipose tissue, whole body composition or cardiometabolic biomarkers (P > 0.05). CONCLUSION: A 12-week, HIIT intervention was highly effective in increasing cardiorespiratory fitness when compared with MICT and nutrition interventions. While there were no concomitant reductions in adiposity or blood biomarkers, the cardiometabolic health benefit conferred through increased CRF should be noted. CLINICAL TRIALS REGISTRATION NUMBER: Clinicaltrials.gov; NCT01991106.

Left ventricular morphology and function in adolescents: Relations to fitness and fatness.

BACKGROUND: Obesity in childhood predisposes individuals to cardiovascular disease and increased risk of premature all-cause mortality. The aim of this study was to determine differences in LV morphology and function in obese and normal-weight adolescents. Furthermore, relationships between LV outcomes, cardiorespiratory fitness (CRF) and adiposity were explored. METHODS: LV morphology was assessed using magnetic resonance imaging (MRI) in 20 adolescents (11 normal-weight [BMI equivalent to 18kg/m2-25kg/m2] and 9 obese [BMI equivalent to ≥30kg/m2]); 13.3±1.1years, 45% female, Tanner puberty stage 3 [2-4]) using magnetic resonance imaging (MRI). Global longitudinal strain (GLS), strain rate (SR) and traditional echocardiographic indices were used to assess LV function. CRF (peak oxygen consumption), percent body fat (dual-energy x-ray absorptiometry), abdominal adipose tissue (MRI), and blood biochemistry markers were also evaluated. RESULTS: Adolescents with obesity showed significantly poorer LV function compared to normal-weight adolescents (P<0.05) indicated by higher GLS (+6.29%) and SR in systole (+0.17s-1), and lower SR in early diastole (-0.61s-1), and tissue Doppler velocities (S' -2.7cm/s; e' -2.3cm/s; A' -1.1cm/s). There were no group differences in LV morphology when indexed to fat free mass (P>0.05). Moderate to strong associations between myocardial contractility and relaxation, adiposity, arterial blood pressure and cardiorespiratory fitness were noted (r=0.49-0.71, P<0.05). CONCLUSION: Obesity in adolescence is associated with altered LV systolic and diastolic function. The notable relationship between LV function, CRF and adiposity highlights the potential utility of multidisciplinary lifestyle interventions to treat diminished LV function in this population. CLINICAL TRIAL REGISTRATION: NCT01991106.

Exercise intensity, redox homeostasis and inflammation in type 2 diabetes mellitus.

OBJECTIVES: To compare 12 weeks of exercise training at two intensities on oxidative stress, antioxidants and inflammatory biomarkers in patients with type 2 diabetes (T2D). DESIGN: Randomized trial. METHODS: Thirty-six participants with T2D were randomized to complete either 12 weeks of treadmill based high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT), followed by 40 weeks of home-based training at the same intensities. Plasma inflammation, oxidative stress and antioxidant biomarkers (total F2-isoprostanes, protein carbonyls, total antioxidant capacity, glutathione peroxidase activity, interleukin-10, interleukin-6, interleukin-8 and TNF-α) were measured at baseline, 12-weeks and 1-year. RESULTS: There were no significant changes (p>0.05) in oxidative stress and inflammation biomarkers from baseline to 12-weeks in either intervention. A decrease in total antioxidant capacity in the MICT group from baseline to 1-year by 0.05mmol/L (p=0.05) was observed. There was a significant difference (p<0.05) when groups were separated by sex with females in the MICT group having a 22.1% (p<0.05) decrease in protein carbonyls from baseline to 1-year. CONCLUSIONS: HIIT and MICT had no acute effect on oxidative stress and inflammatory biomarkers in patients with T2D.