Cardiac remodelling in adolescent athletes – sex differences progress through adolescence

Background

Cardiac remodelling beyond reference values is well-known in adult athlete's heart. Male endurance athletes are more prone to develop cardiac chambers and wall thickness above reference values. Cardiac remodelling is also described in adolescent athletes, but considered to be moderate compared to adults. However, few studies evaluate adolescent athlete's heart by paediatric echocardiographic reference values. Current paediatric reference values are sex-unspecific and do not include exercise data. The impact of sex and exercise on remodelling in adolescent athlete's heart remains unclear.

Purpose

We aimed to study the development of cardiac remodelling and potential sex differences in adolescent athletes. We hypothesized that male adolescent athletes would display greater degree of remodelling compared to female adolescent athletes.

Methods

Male (M) and female (F) adolescent cross-country skiers were recruited in a longitudinal cohort study. They were examined with echocardiography at age 12, 15 and 18. Data on exercise was collected at all examinations. We evaluated echocardiographic parameters by paediatric reference values (Z-score: number of standard deviations above estimated mean in the given body surface area). Echocardiographic measures were considered above upper reference value if Z-score was ≥2.

Results

Seventy-six athletes were examined at age 12 (48 M, 28 F), 48 at age 15 (34 M, 14 F) and 34 at age 18 (23 M, 11 F). Although Z-scores were within reference values at age 12 (Table 1), a subset of athletes displayed Z-scores ≥2 for end-diastolic intraventricular septum diameter (IVSd, M 13/48=27%, F 5/28=18%) and left ventricular posterior wall thickness (LVPWd, M 6/48=13%, F 2/28=14%). The male group demonstrated enlarged left ventricular mass (LVM) from age 15 (Figure 1). Males had greater left ventricular end-diastolic volume (LV EDV) from age 12. Additional sex differences were evident from age 15 for IVSd, LVPWd and LVM (Table 1). There was no sex difference in exercise hours. Both groups had normal myocardial function through the study period.

Conclusion

Cardiac remodelling beyond reference values was observed in athletes of both sexes from early adolescent age. Sex differences were evident from age 12 with further progression. Pathological values for LVM were more frequent in males. These findings suggest that sex differences in exercise-induced cardiac remodelling is more prominent in adolescents than previously reported. Sex and exercise history should be considered in questions of pathology.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The South-Eastern Norway Regional Health AuthorityCentre for Children and Youth Sport, Norwegian School of Sport Sciences

Compliance to guideline-recommended pharmacotherapy in patients with heart failure, 2014 to 2020

Background

Poor drug adherence in heart failure (HF) is associated with increased morbidity and mortality.

Aims

We aimed to investigate compliance to European guidelines for treatment of HF in Norway by measuring initiation and persistence of inhibitors of the renin-angiotensin system (RASi), β-blockers (BB) and mineralocorticoid receptor antagonists (MRA).

Methods

We included all patients ≥18 years with a first hospital contact for HF registered in the Norwegian Patient Registry (NPR) between 2014–2020. Patients >80 years of age and patients that deceased within the first 30 days were excluded. The study population was linked to the Norwegian Prescription Database for longitudinal data on drug prescriptions. Dual HF therapy was defined as taking at least two recommended HF drug classes, triple HF therapy was defined as taking all three drug classes. To estimate initiation, we counted the days from index HF to the first HF prescription, dual HF therapy and triple HF therapy within the first 365 days. We repeated the analysis for drug-naive patients, as some patients receive HF drugs for other indications or based on a tentative HF diagnosis. Patients were considered persistent if they did not experience any treatment break of more than 30 days. We allowed for stockpiling up to a maximum of 60 days, except for when the dose changed or if patients switched medication within the same drug class. Initiation and persistence were calculated by the Kaplan-Meier method, followed to death or December 2020.

Results

Out of 54,899 patients, 75%, 69% and 21% initiated BB, RASi and MRA, respectively (Figure 1). 13% of the population did not receive any of the three drug groups. Dual HF therapy was prescribed to 61% of the patients and triple HF therapy to 16%. In drug-naive patients, a lower proportion received any HF-drug within the first year (BB, 61%; RASi, 55%; and MRA, 19%), however, a higher proportion was collected within the first 30 days (BB, 48%; RASi, 46%; and MRA, 11%). Among the patients initiating therapy, 72% were persistent on BB, 71% on RASi and 48% on MRA throughout the first year with prominent declines in persistence around 3 and 6 months after initiation (Figure 2). Two years after initiation, the proportions of patients on BB, RASi and MRA decreased to 58%, 57% and 31%, respectively. The 5-year persistence was 38%, 37% and 15%, respectively.

Conclusion

This study found poor treatment compliance to HF medications in a real-world population of HF patients with only 61% of patients initiating dual pharmacotherapy and only 16% received all three dug classes. Nearly half of the patients discontinued RASi and BB within 2 years. The results suggest that systematic efforts should be done to increase the proportion of patients on guideline recommended therapies. These efforts should be focused on early initiation of multiple drug therapies as well as to maintain patients on treatment over time.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Novartis Norway AS and The Norwegian Research Council

Sex differences in athlete"s heart are evident from early adolescence

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): South-Eastern Norway Regional Health Authority

OnBehalf

ProCardio Center for Innovation

Introduction

Athlete’s Heart (AH) is characterized by cardiac remodelling as a response to exercise, but data on sex differences in adolescent athletes is limited.

Purpose

To study the impact of sex on development of AH in adolescent athletes. We hypothesize that male adolescent athletes develop greater morphological changes than females, also when adjusted for body surface area (BSA).

Methods

We recruited 12-year-old cross-country skiers of both sexes in a longitudinal cohort study. We examined them with echocardiography at age 12, 15 and 18.

Results

We recruited 76 athletes (48 males and 28 females). We could follow 48 participants at age 15 (34 males and 14 females), and 34 participants at age 18 (23 males and 11 females). There were no sex differences in exercise hours at any time point. Adolescent males had greater indexed LV end-diastolic volume (LV EDVi) at all time points (Figure 1). Both sexes displayed LV enlargement already at age 12, and athletes of both sexes displayed LV EDVi close to or above upper reference values for the adult population. Only males increased their indexed LV mass (LVMI) from 12 to 18 years (LVM/BSA, Δg/m²; 33 ± 27 vs 4 ± 19, P = 0.006). Male adolescent athletes increased their LVMI by 7.4 grams more and LV EDVi by 4.0 ml more than female athletes did for every 1000 hours of exercise training. Cardiac function was within normal range in both sexes throughout the study period.

Conclusion

 Sex-related differences in cardiac adaptation to exercise are evident from early adolescence. Both sexes demonstrate cardiac remodelling, but adolescent male athletes display greater morphological changes compared to female athletes. Abstract Figure 1

A nationwide registry study on heart failure in Norway from 2008–2018: variations in lookback period affect incidence estimates

Background/Introduction

Incidence estimations of heart failure from registry-based studies may vary because they depend on a retrospective search in the database to exclude previous events (prevalent cases), termed the lookback period.

Purpose

The aim of this study was to assess to what extent different lookback periods affect temporal trends in heart failure incidence utilizing national registry data.

Methods

We identified all heart failure hospital contacts (ICD-10 codes I11.0, I13.0, I13.2, I42.x and I50.x) in adult Norwegian individuals in the Norwegian Patient Registry (NPR) during 2008–2018. To calculate the influence of varying lookback period on incident cases, we defined 2018 with 10 years of lookback as a reference and calculated the relative difference by using one through nine years of lookback. Temporal trends in age-adjusted incidence rates were estimated with sensitivity analyses using fixed and varying lookback periods (including all available data).

Results

Using a lookback period of 10 years, we identified 14 862 incident patients in 2018 (6 842 women, 8 020 men) with a diagnosis of heart failure. Compared to a 10-year lookback period, application of four, six, and eight years resulted in an overestimation of incident cases by 13.5%, 6.2% and 2.3%, respectively. This corresponds to incidence rates of 5.40, 5.04 and 4.85 per 1000 person-years, respectively. Figure 1 shows that the overestimation of incident cases declined with increasing number of years included in the lookback period. The overestimation was largest in the beginning of the observational period. When assessing temporal trends in incidence rate using a fixed lookback period, the incidence rates were lower with additional years in the lookback period. However, incidence rates increased regardless of whether four, six or eight years were applied. In contrast, incidence rates were lower and declined during the period when including all available data and thereby increasing the lookback period with time. Fig. 2 shows that a relatively shorter lookback period provided higher incidence rate estimates and that the direction of the curves were similar when using a fixed lookback period. Moreover, it shows that including all available data instead of using a fixed lookback period resulted in the misleading conclusion of declining incidence rates.

Conclusions

The length of the lookback period affects incidence estimates when calculating incidence rates from longitudinal health registry data. Our results suggest that one to five years of lookback is too short since incident cases are overestimated by 64% - 9%. A fixed lookback period of six year or more seems beneficial with less overestimation (≤6%).

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This work was supported by the Research Council of Norway and Novartis Norway AS. KMO is a PhD-student at the University of Oslo and an employee of Novartis Norway AS. Overestimation of incident cases in 2018Incidence rates

Impact of cardiac remodelling on physical fitness measured by VO2 max in preadolescent and adolescent endurance athletes

Background

Endurance training is associated with both physiological cardiac remodelling and increased maximal oxygen uptake. The relationship between VO2 max and cardiac dimension has not been described in young athletes or in longitudinal studies.

Aims

This study aims to explore the impact of cardiac remodelling on VO2 max in a cohort of young athletes assessed at age 12, 15 and 18.

Methods

Seventy-six promising young cross country skiers were examined at age 12 with echocardiography, including 3D and cardiopulmonary exercise test (CPX). Forty-six (61%) participated in the first follow-up at age 15 and 36 (47%) athletes completed the second follow-up at age 18. The impact of left ventricular (LV) mass and LV end-diastolic volume (EDV) on VO2 max at each time point was assessed using mixed model analysis. Correlation coefficients were calculated at each time point.

Results

There were moderate to very strong correlations between the cardiac parameters and VO2 max at all time points (Figure). In the full model, each improvement in VO2 max of 1000 mL/min at age 15 was associated with an increase in LV mass of 18 g (p<0.001) and an increase in LV EDV of 36 mL (p<0.001), while each improvement in VO2 max of 1000 mL/min at age 18 was associated with an increase in LV mass of 19 g (p<0.001) and LV EDV of 31 mL (p<0.001).

Conclusion

Physical fitness measured by VO2 max is strongly correlated to LV mass and volume in adolescent athletes, suggesting a strong link between cardiac adaption and VO2 max in young athletes.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): South-Eastern Norway Health Authority

431 Impact of endurance training versus non-endurance training on cardiac morphology and physical fitness in highly trained young athletes

Funding Acknowledgements

South-Eastern Norway Regional Health Authority

OnBehalf

Center for Cardiological Innovation

Background

Endurance exercise is closely correlated with physical fitness and the development of the athlete’s heart. The impact of changes in exercise-patterns in young athletes is poorly described.

Aims

This study aims to explore the impact of endurance training versus non-endurance training on cardiac morphology and physical fitness in young endurance athletes.

Methods

Forty-eight cross-country skiers were examined at age 12 (12.1 ± 0.2 years) and then again at age 15 (15.3 ± 0.3 years). Echocardiography, including 3D echocardiography, and cardiopulmonary exercise testing was performed in all participants. Self-reported data on weekly hours of endurance and weekly hours of non-endurance training was collected.

Results

At follow-up, thirty-one (65%) of the endurance athletes were still active and 17 (35%) were not. There was a moderate, positive correlation between weekly hours of endurance-only training and changes in VO2 max from baseline to follow-up (R = 0.55, p < 0.001), but no correlation was found for weekly hours of all types of training (Figure). Weekly hours of endurance-only training also showed moderate, positive correlations with changes in chamber dimensions, including indexed 3D left ventricular (LV) end-diastolic volume (R = 0.45, p < 0.01), 3D LV end-systolic volume (R = 0.35, p < 0.05), right ventricular (RV) end-diastolic area (R = 0.39, p < 0.01) and RV end-systolic area (R = 0.44, p < 0.01). No correlation was found for weekly hours of all types of training.

Conclusion

Only endurance training is sufficient to induce cardiac remodeling, including dilatation of both ventricles, in highly trained adolescent athletes.

Abstract 431 Figure.

P1507 Early and late morphological changes in the athlete"s heart: a longitudinal cohort study in young elite athletes

Funding Acknowledgements

South-Eastern Norway Regional Health Authority

OnBehalf

Center for Cardiological Innovation

Background

Recent studies have suggested an initial concentric remodelling in the early development of the athlete’s heart in endurance athletes. However, the development from the early to the fully developed endurance athlete’s heart has not been described in longitudinal studies.

Aims

This study aims to explore the morphological changes occurring in hearts of young endurance athletes transitioning through adolescence.

Methods

Forty-eight cross-country skiers were examined at age 12 (12.1 ± 0.2 years) and then again at age 15 (15.3 ± 0.3 years). Cardiopulmonary exercise test and echocardiography, including 3D acquisitions, was performed in all subjects at both baseline and follow-up.

Results

At follow-up, 31 (65%) of the endurance athletes were still active and 17 (35%) were not. No differences in cardiac morphology were identified at baseline. At 15 years of age, the active endurance athletes had greater VO2 max, 3D indexed left ventricular end-diastolic and end-systolic volumes (Table). Relative wall thickness (RWT) decreased in the active endurance athletes during follow-up (0.35 ± 0.05 to 0.31 ± 0.04, p < 0.001), but not in the former athletes. Four active endurance athletes had RWT above the upper reference values at baseline; at follow up, all had normalized.

Conclusion

After an early concentric remodeling in the 12 years old athletes, those who continued regular endurance training developed eccentric changes with chamber dilatation and a drop in RWT. In contrast, those who ceased endurance training maintained a comparable wall thickness, but did not develop chamber dilatation nor experience a drop in RWT.

Baseline Follow-up Active athletes (n = 31) Former athletes (n = 17) p-value Active athletes (n = 31) Former athletes (n = 17) p-value VO2 max, indexed 65 ± 7 63 ± 7 0.33 62 ± 8 57 ± 6 <0.05 Interventricular septum thickness, mm 7.9 ± 0.8 7.8 ± 1.0 0.54 8.1 ± 1.2 7.8 ± 0.9 0.41 LV end-diastolic diameter, mm/m2 2.1 ± 0.3 2.0 ± 0.3 0.60 3.0 ± 0.2 2.9 ± 0.2 0.34 LV poster wall thickness, mm 7.3 ± 0.9 6.8 ± 0.9 0.07 7.8 ± 1.2 8.1 ± 1.2 0.42 3D LV end-diastolic volume, mL/m2 76 ± 8 74 ± 8 0.89 84 ± 11 79 ± 10 <0.05 3D LV end-systolic volume, mL/m2 33 ± 4 33 ± 4 0.99 36 ± 6 32 ± 3 <0.05 3D LV ejection fraction, % 56 ± 3 56 ± 3 0.93 58 ± 3 59 ± 2 0.52 3D LV Mass/BSA, g/m2 69 ± 7 71 ± 4 0.57 76 ± 11 74 ± 6 0.19 Relative wall thickness 0.35 ± 0.05 0.33 ± 0.05 0.12 0.31 ± 0.04 0.33 ± 0.05 0.05 Data expressed as mean ± SD. P-values calculated using the Student"s paired t-test. Volumes are indexed to body surface area.

Effect of rhEPO administration on serum levels of sTfR and cycling performance

PURPOSE

We assessed the possibility of using soluble transferrin receptor (sTfR) as an indicator of doping with recombinant erythropoietin (rhEPO).

METHODS

A double-blind, placebo-controlled study was conducted with the administration of 5,000 U of rhEPO (N = 10) or placebo (N = 10) three times weekly (181-232 U x kg(-1) x wk-1) for 4 wk to male athletes. We measured hematocrit and the concentration of hemoglobin, sTfR, ferritin, EPO, and quantified the effects on performance by measuring time to exhaustion and maximal oxygen uptake (VO2max) on a cycle ergometer.

RESULTS

Hematocrit increased from 42.7 +/- 1.6% to 50.8 +/- 2.0% in the EPO group, and peaked 1 d after treatment was stopped. In the EPO group, there was an increase in sTfR (from 3.1 +/- 0.9 to 6.3 +/- 2.3 mg x L(-1) , P < 0.001) and in the ratio between sTfR and ferritin (sTfR-ferritin(-1)) (from 3.2 +/- 1.6 to 11.8 +/- 5.1, P < 0.001). The sTfR increase was significant after 1 wk of treatment and remained so for 1 wk posttreatment. Individual values for sTfR throughout the study period showed that 8 of 10 subjects receiving rhEPO, but none receiving placebo, had sTfR levels that exceeded the 95% confidence interval for all subjects at baseline (= 4.6 mg x L(-1)). VO2max increased from 63.6 +/- 4.5 mL x kg(-1) x min(-1) before to 68.1 +/- 5.4 mL x kg(-1) x min(-1) 2 d post rhEPO administration (7% increase, P = 0.001) in the EPO group. Hematocrit, sTfR, sTfR-ferritin(-1), and VO2max did not change in the placebo group.

CONCLUSION

Serum levels of sTfR may be used as an indirect marker of supranormal erythropoiesis up to 1 wk after the administration of rhEPO, but the effects on endurance performance outlast the increase in sTfR.

The effect of acute vs chronic treatment with beta-adrenoceptor blockade on exercise performance, haemodynamic and metabolic parameters in healthy men and women

1. Variable results have been reported on the effect of beta-adrenoceptor blockers on maximal oxygen uptake (VO2 max) and exercise endurance. This may in part be due to different subject populations, but it could also be due to an adaption of metabolic and haemodynamic responses to exercise during chronic treatment with beta-adrenoceptor blockers. The present study was therefore carried out to examine the effect of acute and chronic administration of the non-selective beta-adrenoceptor blocker propranolol on both peak VO2 and exercise performance in the same subjects. Since the effect of beta-adrenoceptor blockade has not been properly investigated in women, eight healthy women were compared with seven men. Progressive bicycle exercise to exhaustion was performed after propranolol 0.15 mg kg-1 i.v. (acute) or 80 mg three times daily for 2 weeks (chronic) or placebo given according to a double-blind crossover design. 2. Mean (s.e. mean) peak VO2, was significantly reduced from 42.3 (1.6) ml min-1 kg-1 during placebo to 40.3 (1.2, P < 0.05) ml min-1 kg-1 after acute and 39.1 (1.2, P < 0.001) ml min-1 kg-1 after chronic propranolol treatment. No significant difference in peak VO2 between the two propranolol treatment regimens was observed (mean difference 1.2, 95% CI -0.1 to 2.4 ml min-1 kg-1). There was no treatment interaction with gender. 3. Cumulative work, 163 (9.3) kJ, was significantly reduced by acute, 148 (7.7, P < 0.001) kJ, and chronic, 147 (7.6, P < 0.001) kJ, administration of propranolol since the time to exhaustion was reduced by 5.3% and 5.3%, respectively. There was no significant difference between the two regimens of propranolol (mean difference 0.2, 95% CI -6.7 to 7.0 kJ) or between the sexes. Maximal knee extensor and handgrip strengths were not affected by propranolol. 4. Whereas sex did not influence ventilatory, haemodynamic or metabolic parameters, some differences were observed between acute and chronic propranolol treatment. During submaximal exercise oxygen uptake was reduced by approximately 2% and RER values increased by 0.04-0.05 after chronic treatment in contrast to no effect of acute propranolol treatment. Heart rate and systolic blood pressure were reduced significantly more after chronic compared with acute propranolol treatment; peak heart rate being 186 (2.2), 147 (2.3) and 134 (2.3) beats min-1, and peak systolic blood pressure being 189 (7), 171 (4) and 161 (4) mmHg after placebo, acute and chronic propranolol administration, respectively. Also the exercise induced rise in potassium and lactate levels were modified differentially; the rise in potassium concentration was less after chronic compared with acute propranolol treatment and lactate levels were reduced only after chronic administration of propranolol. In contrast, ventilation, which was unchanged after propranolol during submaximal exercise, was reduced to similar extent at exhaustion from 108 (6.4) to 97 (7.2) and 96 (5.9) l min-1 after acute and chronic propranolol administration, respectively. Diastolic blood pressure and subjective perception of fatigue were similar across the treatment regimens. 5. The study has demonstrated that acute and chronic administration of propranolol result in different haemodynamic and metabolic response to exercise, although endurance and peak oxygen consumption were reduced to the same extent. The response to propranolol was not significantly different between men and women.