Reduction in left ventricular wall thickness after deconditioning in highly trained Olympic athletes

Mechanisms of myocardial reverse remodelling and its clinical significance: A scientific statement of the ESC Working Group on Myocardial Function

Cardiovascular disease (CVD) is the leading cause of morbimortality in Europe and worldwide. CVD imposes a heterogeneous spectrum of cardiac remodelling, depending on the insult nature, that is, pressure or volume overload, ischaemia, arrhythmias, infection, pathogenic gene variant, or cardiotoxicity. Moreover, the progression of CVD-induced remodelling is influenced by sex, age, genetic background and comorbidities, impacting patients' outcomes and prognosis. Cardiac reverse remodelling (RR) is defined as any normative improvement in cardiac geometry and function, driven by therapeutic interventions and rarely occurring spontaneously. While RR is the outcome desired for most CVD treatments, they often only slow/halt its progression or modify risk factors, calling for novel and more timely RR approaches. Interventions triggering RR depend on the myocardial insult and include drugs (renin-angiotensin-aldosterone system inhibitors, beta-blockers, diuretics and sodium-glucose cotransporter 2 inhibitors), devices (cardiac resynchronization therapy, ventricular assist devices), surgeries (valve replacement, coronary artery bypass graft), or physiological responses (deconditioning, postpartum). Subsequently, cardiac RR is inferred from the degree of normalization of left ventricular mass, ejection fraction and end-diastolic/end-systolic volumes, whose extent often correlates with patients' prognosis. However, strategies aimed at achieving sustained cardiac improvement, predictive models assessing the extent of RR, or even clinical endpoints that allow for distinguishing complete from incomplete RR or adverse remodelling objectively, remain limited and controversial. This scientific statement aims to define RR, clarify its underlying (patho)physiologic mechanisms and address (non)pharmacological options and promising strategies to promote RR, focusing on the left heart. We highlight the predictors of the extent of RR and review the prognostic significance/impact of incomplete RR/adverse remodelling. Lastly, we present an overview of RR animal models and potential future strategies under pre-clinical evaluation.

Detraining among Athletes-Is Withdrawal of Adaptive Cardiovascular Changes a Hint for the Differential Diagnosis of Physically Active People?

An athlete's training aims to achieve the highest possible sports results by improving physical dispositions which lead to cardiac adaptive changes. The annual training cycle is divided into periods. The preparatory period begins with gradually increasing training intensity and volume until the competitive period occurs, when the athlete's maximum performance is expected. Finally, the athlete enters a phase of loss of fitness, which is called detraining. Detraining is a time of resting both physically and mentally from the training regime and usually lasts about 4 weeks for endurance athletes. We collected data from much research on athletes' detraining. According to these data, the earliest change after detraining seems to be a decrease in left ventricular wall thickness and left ventricular mass, followed by decreased performance parameters, diastolic diameter of the left ventricle and size of the left atrium. A reversal of adaptive changes affects the left heart chamber first, then the right atrium and, finally, the right ventricle. Training reduction is often proposed as a method of differentiating an athlete's heart from cardiomyopathies. The aim of this study is to consider the diagnostic value of detraining in differentiating athletes' hearts from cardiomyopathies. We suggest that detraining cannot be conclusive in differentiating the disease from adaptive changes. Although a withdrawal of the characteristic morphological, functional and electrocardiographic changes occurs in healthy athletes during detraining, it can also concern individuals with cardiomyopathies due to the lower expression of abnormal features after decreased training loads. Therefore, a quick diagnosis and individual assessments using imaging and genetic tests are essential to recommend a proper type of activity.

Effects of detraining on left ventricular mass in endurance-trained individuals: a systematic review and meta-analysis

AIMS

Detraining refers to a loss of training adaptations resulting from reductions in training stimulus due to illness, injury, or active recovery breaks in a training cycle and is associated with a reduction in left ventricular mass (LVM). The purpose of this study was to conduct a systematic review and meta-analysis to determine the influence of detraining on LVM in endurance-trained, healthy individuals.

METHODS AND RESULTS

Using electronic databases (e.g. EMBASE and MEDLINE), a literature search was performed looking for prospective detraining studies in humans. Inclusion criteria were adults, endurance-trained individuals with no known chronic disease, detraining intervention >1 week, and pre- and post-detraining LVM reported. A pooled statistic for random effects was used to assess changes in LVM with detraining. Fifteen investigations (19 analyses) with a total of 196 participants (ages 18-55 years, 15% female) met inclusion criteria, with detraining ranging between 1.4 and 15 weeks. The meta-analysis revealed a significant reduction in LVM with detraining (standardized mean difference = -0.586; 95% confidence interval = -0.817, -0.355; P < 0.001). Independently, length of detraining was not correlated with the change in LVM. However, a meta-regression model revealed length of the detraining, when training status was accounted for, was associated with the reduction of LVM (Q = 15.20, df = 3, P = 0.0017). Highly trained/elite athletes had greater reductions in LVM compared with recreational and newly trained individuals (P < 0.01). Limitations included relatively few female participants and inconsistent reporting of intervention details.

CONCLUSION

In summary, LVM is reduced following detraining of one week or more. Further research may provide a greater understanding of the effects of sex, age, and type of detraining on changes in LVM in endurance-trained individuals.

The athlete's heart: insights from echocardiography

The manifestations of the athlete's heart can create diagnostic challenges during an echocardiographic assessment. The classifications of the morphological and functional changes induced by sport participation are often beyond 'normal limits' making it imperative to identify any overlap between pathology and normal physiology. The phenotype of the athlete's heart is not exclusive to one chamber or function. Therefore, in this narrative review, we consider the effects of sporting discipline and training volume on the holistic athlete's heart, as well as demographic factors including ethnicity, body size, sex, and age.

Echocardiographic Evaluation of the Athlete's Heart: Focused Review and Update

PURPOSE OF REVIEW

The athlete's heart exhibits unique structural and functional adaptations in the setting of strenuous and repetitive athletic training which may be similarly found in pathologic states. The purpose of this review is to highlight the morphologic and functional changes associated with the athlete's heart, with a focus upon the insights that echocardiography provides into exercise-induced cardiac remodeling.

RECENT FINDINGS

Recent studies are aiming to investigate the long-term effects and clinical consequences of an athlete's heart. The "gray-zone" continues to pose a clinical challenge and may indicate scenarios where additional imaging modalities, or longitudinal follow-up, provide a definitive answer. Echocardiography is likely to remain the first-line imaging modality for the cardiac evaluation of elite athletes. Multimodality imaging combined with outcome and long-term follow-up studies both during training and after retirement in both men and women may help further clarify the remaining mysteries in the coming years.

Updated Blood Pressure Guidelines: Implications for Athletes

PURPOSE OF REVIEW

To review the prevalence, short- and long-term impact of exercise on blood pressure, and the evaluation and treatment of hypertension in competitive athletes.

RECENT FINDINGS

Due, in part, to inconsistencies in measurement and the definitions used, the true prevalence of hypertension is unknown as reports range from 0 to 83%. With recent changes in the blood pressure guidelines, the proportion of athletes that meet criteria for elevated blood pressure or stage 1 hypertension has increased dramatically with over one-third of collegiate and professional athletes meeting criteria for hypertension. Data consistently show that American-style football players, particularly linemen, display the highest rates of hypertension. These athletes typically have a larger body mass index, higher body fat percentage, and weight gain in serial follow-up. Many athletes with hypertension have traditional risk factors, and, to date, there is no evidence of a causal relationship between long-term sport participation and increased risk of developing hypertension. Many more athletes now meet criteria for hypertension, given the updated blood pressure guidelines. This should be taken as an opportunity for early intervention, as athletes are not immune to the development of cardiovascular risk factors and disease.

Differentiating Physiology from Pathology: The Gray Zones of the Athlete's Heart

Routine vigorous exercise can lead to electrical, structural, and functional adaptations that can enhance exercise performance. There are several factors that determine the type and magnitude of exercise-induced cardiac remodeling (EICR) in trained athletes. In some athletes with pronounced cardiac remodeling, there can be an overlap in morphologic features with mild forms of cardiomyopathy creating gray zone scenarios whereby distinguishing health from disease can be difficult. An integrated clinical approach that factors athlete-specific characteristics (sex, size, sport, ethnicity, and training history) and findings from multimodality imaging are essential to help make this distinction.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

Regulation of collagen deposition in the trout heart during thermal acclimation

The passive mechanical properties of the vertebrate heart are controlled in part by the composition of the extracellular matrix (ECM). Changes in the ECM, caused by increased blood pressure, injury or disease can affect the capacity of the heart to fill with blood during diastole. In mammalian species, cardiac fibrosis caused by an increase in collagen in the ECM, leads to a loss of heart function and these changes in composition are considered to be permanent. Recent work has demonstrated that the cardiac ventricle of some fish species have the capacity to both increase and decrease collagen content in response to thermal acclimation. It is thought that these changes in collagen content help maintain ventricle function over seasonal changes in environmental temperatures. This current work reviews the cellular mechanisms responsible for regulating collagen deposition in the mammalian heart and proposes a cellular pathway by which a change in temperature can affect the collagen content of the fish ventricle through mechanotransduction. This work specifically focuses on the role of transforming growth factor β1, MAPK signaling pathways, and biomechanical stretch in regulating collagen content in the fish ventricle. It is hoped that this work increases the appreciation of the use of comparative models to gain insight into phenomenon with biomedical relevance.

Frequent Constriction-Like Echocardiographic Findings in Elite Athletes Following Mild COVID-19: A Propensity Score-Matched Analysis

Background: The cardiovascular effects of SARS-CoV-2 in elite athletes are still a matter of debate. Accordingly, we sought to perform a comprehensive echocardiographic characterization of post-COVID athletes by comparing them to a non-COVID athlete cohort. Methods: 107 elite athletes with COVID-19 were prospectively enrolled (P-CA; 23 ± 6 years, 23% female) 107 healthy athletes were selected as a control group using propensity score matching (N-CA). All athletes underwent 2D and 3D echocardiography. Left (LV) and right ventricular (RV) end-diastolic volumes (EDVi) and ejection fractions (EF) were quantified. To characterize LV longitudinal deformation, 2D global longitudinal strain (GLS) and the ratio of free wall vs. septal longitudinal strain (FWLS/SLS) were also measured. To describe septal flattening (SF-frequently seen in P-CA), LV eccentricity index (EI) was calculated. Results: P-CA and N-CA athletes had comparable LV and RVEDVi (P-CA vs. N-CA; 77 ± 12 vs. 78 ± 13mL/m2; 79 ± 16 vs. 80 ± 14mL/m2). P-CA had significantly higher LVEF (58 ± 4 vs. 56 ± 4%, p < 0.001), while LVGLS values did not differ between P-CA and N-CA (-19.0 ± 1.9 vs. -18.8 ± 2.2%). EI was significantly higher in P-CA (1.13 ± 0.16 vs. 1.01 ± 0.05, p < 0.001), which was attributable to a distinct subgroup of P-CA with a prominent SF (n = 35, 33%), further provoked by inspiration. In this subgroup, the EI was markedly higher compared to the rest of the P-CA (1.29 ± 0.15 vs. 1.04 ± 0.08, p < 0.001), LVEDVi was also significantly higher (80 ± 14 vs. 75 ± 11 mL/m2, p < 0.001), while RVEDVi did not differ (82 ± 16 vs. 78 ± 15mL/m2). Moreover, the FWLS/SLS ratio was significantly lower in the SF subgroup (91.7 ± 8.6 vs. 97.3 ± 8.2, p < 0.01). P-CA with SF experienced symptoms less frequently (1.4 ± 1.3 vs. 2.1 ± 1.5 symptom during the infection, p = 0.01). Conclusions: Elite athletes following COVID-19 showed distinct morphological and functional cardiac changes compared to a propensity score-matched control athlete group. These results are mainly driven by a subgroup, which presented with some echocardiographic features characteristic of constrictive pericarditis.

Hallmarks of exercised heart

The benefits of exercise in humans on the heart have been well recognized for many years. Long-term endurance exercise training can induce physiologic cardiac hypertrophy with normal or enhanced heart function, and provide protective benefits in preventing heart failure. The heart-specific responses that occur during exercise are complex and highly variable. This review mainly focuses on the current understanding of the structural and functional cardiac adaptations to exercise as well as molecular pathways and signaling proteins responsible for these changes. Here, we summarize eight tentative hallmarks that represent common denominators of the exercised heart. These hallmarks are: cardiomyocyte growth, cardiomyocyte fate reprogramming, angiogenesis and lymphangiogenesis, mitochondrial remodeling, epigenetic alteration, enhanced endothelial function, quiescent cardiac fibroblast, and improved cardiac metabolism. A major challenge is to explore the underlying molecular mechanisms for cardio-protective effects of exercise, and to identify therapeutic targets for heart diseases.

Cardiac effects of detraining in athletes: A narrative review

BACKGROUND

Routine physical activity stimulates numerous morphologic and functional adaptations of the cardiac system, which are commonly referred to as exercise-induced cardiac remodeling (EICR). EICR has been well documented in elite and recreational athletes, but comparatively little is known about the "reverse" cardiac adaptations during detraining in an athletic population.

OBJECTIVE

To assess the morphologic and functional cardiac effects of detraining in athletes.

METHODS

Eligible studies were identified in PubMed from inception to May 2020. Studies were included if they assessed the cardiac effects of detraining periods in athletes.

RESULTS

A total of 16 studies from the literature search were identified and included in this review. These studies included athletes from multiple different sporting disciplines and detraining periods ranged from 3 weeks to 13 years. Detraining periods led to significantly decreased right ventricular and left (LV) ventricular dimensions, LV mass, and LV wall thickness, but only limited changes in systolic and diastolic functional parameters were observed.

CONCLUSIONS

From the limited data available in this population, cardiac atrophy has been observed with short periods of detraining (1-8 weeks) but often spares systolic and diastolic heart function. Supplemental exercise training during times of rehabilitation to combat cardiac regression has not been vigorously studied in athletes, so the ideal frequency, intensity, and modality of exercise needed to maintain EICR remains unclear.

Exercise Effects On Cardiovascular Disease: From Basic Aspects To Clinical Evidence

Cardiovascular (CV) disease (CVD) remains the leading cause of major morbidity and CVD- and all-cause mortality in most of the world. It is now clear that regular physical activity (PA) and exercise training (ET) induces a wide range of direct and indirect physiologic adaptations and pleiotropic benefits for human general and CV health. Generally, higher levels of PA, ET, and cardiorespiratory fitness (CRF) are correlated with reduced risk of CVD, including myocardial infarction, CVD-related death, and all-cause mortality. Although exact details regarding the ideal doses of ET, including resistance and, especially, aerobic ET, as well as the potential adverse effects of extreme levels of ET, continue to be investigated, there is no question that most of the world's population have insufficient levels of PA/ET, and many also have lower than ideal levels of CRF. Therefore, assessment and promotion of PA, ET, and efforts to improve levels of CRF should be integrated into all health professionals' practices worldwide. In this state-of-the-art review, we discuss the exercise effects on many areas related to CVD, from basic aspects to clinical practice.

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.

Cardiovascular Magnetic Resonance for the Differentiation of Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Left ventricular hypertrophy (LVH) is a common presentation encountered in clinical practice with a diverse range of potential aetiologies. Differentiation of pathological from physiological hypertrophy can be challenging but is crucial for further management and prognostication. Cardiovascular magnetic resonance (CMR) with advanced myocardial tissue characterisation is a powerful tool that may help to differentiate these aetiologies in the assessment of LVH.

RECENT FINDINGS

The use of CMR for detailed morphological assessment of LVH is well described. More recently, advanced CMR techniques (late gadolinium enhancement, parametric mapping, diffusion tensor imaging, and myocardial strain) have been used. These techniques are highly promising in helping to differentiate key aetiologies of LVH and provide valuable prognostic information. Recent advancements in CMR tissue characterisation, such as parametric mapping, in combination with detailed morphological assessment and late gadolinium enhancement, provide a powerful resource that may help assess and differentiate important causes of LVH.

Differentiating Athlete's Heart from Left Ventricle Cardiomyopathies

Imaging techniques have allowed knowing the structural adaptative changes observed in the hearts of highly trained athletes. Athletes can develop very marked structural changes and the need may rise for a differential diagnosis with real cardiomyopathy. In this chapter, authors review the physiologic and morphologic features associated with athletic training and the keys to differentiate normal adaptive athlete's heart from mild or initial expression forms of left-heart side cardiomyopathies such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and left ventricle non-compaction (LVNC).

Hypertrophic cardiomyopathy: an updated review on diagnosis, prognosis, and treatment

Hypertrophic cardiomyopathy (HCM) represents a phenotype of left ventricular hypertrophy unexplained by abnormal loading conditions. The definition is based on clinical criteria; however, there are numerous underlying etiologic factors. The MOGE(S) classification provides a standardized approach for multimodal characterization of HCM. HCM is associated with increased morbidity and mortality, and especially the assessment of the risk of sudden cardiac death is of paramount importance. In this review, we summarize essential knowledge and recently published data on clinical presentation, diagnosis, genetic analyses, differential diagnosis, prognosis, and treatment options that are necessary for understanding and management of HCM.

Cardiac Imaging in the Athlete: Shrinking the "Gray Zone"

PURPOSE OF THE REVIEW

This review will explore frequently encountered diagnostic challenges and summarize the role cardiac imaging plays in defining the boundaries of what constitutes the athlete's heart syndrome versus pathology.

RECENT FINDINGS

Investigations have predominantly focused on differentiating the athlete's heart from potentially lethal pathological conditions that may produce a similar cardiac morphology. Guidelines have identified criteria for identifying definitive pathology, but difficulty arises when individuals fall in the gray zone of expected athletic remodeling and pathology. Transthoracic echo has traditionally been the imaging modality of choice utilizing parameters such as wall thickness, wall:volume ratio, and certain diastolic parameters. Newer echocardiogram techniques such as strain imaging and speckle tracking have potential additive utility but still need further investigation. Cardiac magnetic resonance (CMR) imaging has emerged as an additive technique to help differentiate the phenotypic overlap between these groups. Utilizing gadolinium enhancement and T1 mapping along with its excellent spatial resolution can help distinguish pathology from physiology. Both established and novel cardiac imaging modalities have been used for uncovering the at risk athletes with cardiomyopathies. The issue is of practical importance because athletes are frequently referred to the cardiologist with symptoms of fatigue, palpitations, presyncope, and/or syncope concerned about the safety of their future participation. Imaging is a key component of risk stratification and identifying normal findings of the developed athlete and those "at-risk" athletes.

Evidence of altered cardiac autonomic regulation in myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and meta-analysis

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition with no reliable diagnostic biomarkers. Studies have shown evidence of autonomic dysfunction in patients with ME/CFS, but results have been equivocal. Heart rate (HR) parameters can reflect changes in autonomic function in healthy individuals; however, this has not been thoroughly evaluated in ME/CFS.

METHODS

A systematic database search for case-control literature was performed. Meta-analysis was performed to determine differences in HR parameters between ME/CFS patients and controls.

RESULTS

Sixty-four articles were included in the systematic review. HR parameters assessed in ME/CFS patients and controls were grouped into ten categories: resting HR (RHR), maximal HR (HRmax), HR during submaximal exercise, HR response to head-up tilt testing (HRtilt), resting HR variability (HRVrest), HR variability during head-up tilt testing (HRVtilt), orthostatic HR response (HROR), HR during mental task(s) (HRmentaltask), daily average HR (HRdailyaverage), and HR recovery (HRR) Meta-analysis revealed RHR (MD ± 95% CI = 4.14 ± 1.38, P < .001), HRtilt (SMD ± 95% CI = 0.92 ± 0.24, P < .001), HROR (0.50 ± 0.27, P < .001), and the ratio of low frequency power to high frequency power of HRVrest (0.39 ± 0.22, P < .001) were higher in ME/CFS patients compared to controls, while HRmax (MD ± 95% CI = -13.81 ± 4.15, P < .001), HR at anaerobic threshold (SMD ± 95% CI = -0.44 ± 0.30, P = 0.005) and the high frequency portion of HRVrest (-0.34 ± 0.22, P = .002) were lower in ME/CFS patients.

CONCLUSIONS

The differences in HR parameters identified by the meta-analysis indicate that ME/CFS patients have altered autonomic cardiac regulation when compared to healthy controls. These alterations in HR parameters may be symptomatic of the condition.

Regression of Left Ventricular Mass in Athletes Undergoing Complete Detraining Is Mediated by Decrease in Intracellular but Not Extracellular Compartments

BACKGROUND

Athletic cardiac remodeling can occasionally be difficult to differentiate from pathological hypertrophy. Detraining is a commonly used diagnostic test to identify physiological hypertrophy, which can be diagnosed if hypertrophy regresses. We aimed to establish whether athletic cardiac remodeling assessed by cardiovascular magnetic resonance is mediated by changes in intracellular or extracellular compartments and whether this occurs by 1 or 3 months of detraining.

METHODS

Twenty-eight athletes about to embark on a period of forced detraining due to incidental limb bone fracture underwent clinical assessment, ECG, and contrast-enhanced cardiovascular magnetic resonance within a week of their injury and then 1 month and 3 months later.

RESULTS

After 1 month of detraining, there was reduction in left ventricular (LV) mass (130±28 to 121±25 g; P<0.0001), increase in native T1 (1225±30 to 1239±30 ms; P=0.02), and extracellular volume fraction (24.5±2.3% to 26.0±2.6%; P=0.0007) with no further changes by 3 months. The decrease in LV mass was mediated by a decrease in intracellular compartment volume (94±22 to 85±19 mL; P<0.0001) with no significant change in the extracellular compartment volume. High LV mass index, low native T1, and low extracellular volume fraction at baseline were all predictive of regression in LV mass in the first month.

CONCLUSIONS

Regression of athletic LV hypertrophy can be detected after just 1 month of complete detraining and is mediated by a decrease in the intracellular myocardial compartment with no change in the extracellular compartment. Further studies are needed in athletes with overt and pathological hypertrophy to establish whether native T1 and extracellular volume fraction may complement electrocardiography, echocardiography, cardiopulmonary exercise testing, and genetic testing in predicting the outcome of detraining.

No impact of sports practice before or after atrial fibrillation ablation on procedure efficacy in athletes: a case–control study

Aims

Limited data exist on the efficacy of catheter ablation (CA) for sport-related atrial fibrillation (AF). Impact of sports practice resumption post-CA remains unknown. We aimed to determine AF CA efficacy in athletes vs. non-athletes, and to assess the impact of sport practice resumption.

Methods and results

From 1153 first-time AF CA performed between 2009 and 2017, 73 athletes were matched with 73 sedentary patients based on age, sex, and closest CA procedure date. Athletes were defined as performing ≥6 h/week of vigorous sports to achieve ≥2000 h accumulated lifetime sports activity. They were mostly males (93.2%) with a mean age of 55 ± 9.8 years. Before CA, athletes practiced 10.2 ± 3.9 h/week of vigorous exercise vs. 4.6 ± 3.4 after CA. Within first year after CA, physical activity was stopped in 12 (16.4%) athletes, lowered in 45 (61.9%), and resumed at same intensity in 16 (21.9%). Athletes and non-athletes suffered from same AF recurrence rates during 5-year follow-up after CA: 38 (52.0%) vs. 35 (47.9%), respectively [adjusted hazard ratio (HR) on age, body mass index (BMI), obstructive sleep apnoea (OSA), and reduced left ventricular ejection fraction (LVEF), 1.17 (0.70–1.97, P = 0.54)]. No significant impact of physical activity resumption status was found regarding AF recurrence rates at 1-year and beyond (P = 0.60). Procedure effectiveness was significantly lower in athletes with non-paroxysmal AF [adjusted on age, BMI, reduced LVEF, and OSA HR 2.36 (confidence interval 1.19–4.70), P = 0.01].

Conclusion

Sports practice before and after CA has no significant impact on AF recurrence rates in athletes within 5-year after AF CA.

Cardiac hypertrophy is stimulated by altered training intensity and correlates with autophagy modulation in male Wistar rats

Background

The mechanism for cardiac hypertrophy process that would be a benefit for improvement of cardiovascular endurance needed to be investigated throughly. Specific intensity of training may play a role for homeostasis process in cardiac during training. In the present study, we examine the effect of different intensity of treadmill training on cardiac hypertrophy process and autophagy related gene expression in male wistar rats.

Methods

Three different intensities of treadmill training were conducted on 15 male wistar rats (Low Intensity: 10 m/minute, Moderate Intensity: 20 m/minute, and High Intensity: 30 m/minute) compared to 5 sedentary rats as control. Training duration was 30 min per day, frequency was 5 days per week, during 8 weeks period. Heart weight and heart weight/body weight ratio were measured after the experiments. Left ventricle myocardium was taken for microscopic analysis with HE staining. mRNA was extracted from left ventricle myocardium for examining αMHC and autophagy related gene expression (PIK3CA, mTOR, LC3, p62) using semi quantitative PCR.

Results

We observed that altered training intensity might stimulate cardiac hypertrophy process. MI and HI training increased heart weight and heart weight/body weight ratio. This finding is supported by microscopic result in which cardiac hypertrophy was found in MI and HI, with focal fibrosis in HI, and increased αMHC gene expression in MI (p < 0.05) and HI (p = 0.076). We also observed decreased PIK3CA (LI 0.8 fold, MI 0.9 fold), mTOR (LI 0.9 fold, MI 0.9 fold), LC3 (LI 0.9 fold, MI 0.8 fold, HI 0.8 fold), and p62 (LI 0.8 fold, MI 0.9 fold) compared to control. Interestingly, we found increased mTOR (HI 1.1 fold) and p62 (HI 1.1 fold) compared to control.

Conclusion

Training with different intensity creates different cardiac hypertrophy process based on heart weight and heart weight/body weight ratio, microscopic examination and autophagy related gene expression.

Characterization of the dynamic changes in left ventricular morphology and function induced by exercise training and detraining

BACKGROUND

Although exercise-induced cardiac hypertrophy has been intensively investigated, its development and regression dynamics have not been comprehensively described. In the current study, we aimed to characterize the effects of regular exercise training and detraining on left ventricular (LV) morphology and function.

METHODS

Rats were divided into exercised (n = 12) and control (n = 12) groups. Exercised rats swam 200 min/day for 12 weeks. After completion of the training protocol, rats remained sedentary for 8 weeks (detraining period). Echocardiographic follow-up was performed regularly to obtain LV long- and short-axis recordings for speckle-tracking echocardiography analysis. Global longitudinal and circumferential strain and systolic strain rate were measured. LV pressure-volume analysis was performed using additional groups of rats to obtain haemodynamic data.

RESULTS

Echocardiographic examinations showed the development of LV hypertrophy in the exercised group. These differences disappeared during the detraining period. Strain and strain rate values were all increased after the training period, whereas supernormal values rapidly reversed to the control level after training cessation. Load-independent haemodynamic indices, e.g., preload recruitable stroke work, confirmed the exercise-induced systolic improvement and complete regression after detraining.

CONCLUSIONS AND TRANSLATIONAL ASPECT

Our results provide the first comprehensive data to describe the development and regression dynamics of morphological and functional aspects of physiological hypertrophy in detail. Speckle-tracking echocardiography has been proven to be feasible to follow-up changes induced by exercise training and detraining and might provide an early possibility to differentiate between physiological and pathological conditions.

Metabolic Mechanisms of Exercise-Induced Cardiac Remodeling

Exercise has a myriad of physiological benefits that derive in part from its ability to improve cardiometabolic health. The periodic metabolic stress imposed by regular exercise appears fundamental in driving cardiovascular tissue adaptation. However, different types, intensities, or durations of exercise elicit different levels of metabolic stress and may promote distinct types of tissue remodeling. In this review, we discuss how exercise affects cardiac structure and function and how exercise-induced changes in metabolism regulate cardiac adaptation. Current evidence suggests that exercise typically elicits an adaptive, beneficial form of cardiac remodeling that involves cardiomyocyte growth and proliferation; however, chronic levels of extreme exercise may increase the risk for pathological cardiac remodeling or sudden cardiac death. An emerging theme underpinning acute as well as chronic cardiac adaptations to exercise is metabolic periodicity, which appears important for regulating mitochondrial quality and function, for stimulating metabolism-mediated exercise gene programs and hypertrophic kinase activity, and for coordinating biosynthetic pathway activity. In addition, circulating metabolites liberated during exercise trigger physiological cardiac growth. Further understanding of how exercise-mediated changes in metabolism orchestrate cell signaling and gene expression could facilitate therapeutic strategies to maximize the benefits of exercise and improve cardiac health.

Cardiovascular response to prescribed detraining among recreational athletes

Exercise-induced cardiac remodeling (EICR) and the attendant myocardial adaptations characteristic of the athlete’s heart may regress during periods of exercise reduction or abstinence. The time course and mechanisms underlying this reverse remodeling, specifically the impact of concomitant plasma volume (PV) contraction on cardiac chamber size, remain incompletely understood. We therefore studied recreational runners ( n = 21, age 34 ± 7 yr; 48% male) who completed an 18-wk training program (~7 h/wk) culminating in the 2016 Boston Marathon after which total exercise exposure was confined to <2 h/wk (no single session >1 h) for 8 wk. Cardiac structure and function, exercise capacity, and PV were assessed at peak fitness (10–14 days before) and at 4 wk and 8 wk postmarathon. Mixed linear modeling adjusting for age, sex, V̇o2peak, and marathon finish time was used to compare data across time points. Physiological detraining was evidenced by serial reductions in treadmill performance. Two distinct phases of myocardial remodeling and hematological adaptation were observed. After 4 wk of detraining, there were significant reductions in PV (Δ −6.0%, P < 0.01), left ventricular (LV) wall thickness (Δ −8.1%, <0.05), LV mass (Δ −10.3%, P < 0.001), and right atrial area (Δ −8.2%, P < 0.001). After 8 wk of detraining, there was a significant reduction in right ventricle chamber size (end-diastolic area Δ = −8.0%, P < 0.05) without further concomitant reductions in PV or LV wall thickness. Abrupt reductions in exercise training stimulus result in a structure-specific time course of reverse cardiac remodeling that occurs largely independently of PV contraction.

NEW & NOTEWORTHY Significant reverse cardiac remodeling, previously documented among competitive athletes, extends to recreational runners and occurs with a distinct time course. Initial reductions in plasma volume and left ventricular (LV) mass, driven by reductions in wall thickness, are followed by contraction of the right ventricle. Consistent with data from competitive athletes, LV chamber volumes appear less responsive to detraining and may be a more permanent adaptation to sport.

Advanced Non-invasive Imaging Techniques in Chronic Heart Failure and Cardiomyopathies : Focus on Cardiac Magnetic Resonance Imaging and Computed Tomographic

Cardiomyopathies (Cs) are a heterogeneous group of myocardial diseases with structural and/or functional abnormalities.The aetiology is due to genetic-family substrate in most cases, however, the correct and detailed analysis of morphofunctional abnormalities (severity and distribution of hypertrophy, ventricular dilatation, ventricular dysfunction) and tissue characteristics (myocardial fibrosis, myocardial infiltration) are a crucial element for a definite diagnosis.Among the different diagnostic imaging modalities applied in clinical practice (echocardiography, nuclear medicine), cardiac magnetic resonance (CMR) has emerged as a non-invasive diagnostic tool having high ability to quantify systolic function and tissue abnormalities that represent the substrates of many Cs.The main added value of CMR is the ability to identify cardiomyopathies with respect to ischemic heart disease and, above all, to discriminate the major types of cardiomyopathies based on morpho-functional presentation patterns and the presence and location of myocardial fibrosis.Many CMR elements allow increasing diagnostic accuracy but CMR data should be integrated with an appropriate clinical and instrumental context.Computed Tomographic (CT) scan technology has showed a complementary role in patients having Cs and HF.In this chapter, the diagnostic, pathophysiologic and prognostic value of CMR and CT in heart failure due to the most common cardiomyopathies will be discussed.

Cyclin D2 is a critical mediator of exercise-induced cardiac hypertrophy

A number of signaling pathways underlying pathological cardiac hypertrophy have been identified. However, few studies have probed the functional significance of these signaling pathways in the context of exercise or physiological pathways. Exercise studies were performed on females from six different genetic mouse models that have been shown to exhibit alterations in pathological cardiac adaptation and hypertrophy. These include mice expressing constitutively active glycogen synthase kinase-3β (GSK-3βS9A), an inhibitor of CaMK II (AC3-I), both GSK-3βS9A and AC3-I (GSK-3βS9A/AC3-I), constitutively active Akt (myrAkt), mice deficient in MAPK/ERK kinase kinase-1 (MEKK1-/-), and mice deficient in cyclin D2 (cyclin D2-/-). Voluntary wheel running performance was similar to NTG littermates for five of the mouse lines. Exercise induced significant cardiac growth in all mouse models except the cyclin D2-/- mice. Cardiac function was not impacted in the cyclin D2-/- mice and studies using a phospho-antibody array identified six proteins with increased phosphorylation (greater than 150%) and nine proteins with decreased phosphorylation (greater than 33% decrease) in the hearts of exercised cyclin D2-/- mice compared to exercised NTG littermate controls. Our results demonstrate that unlike the other hypertrophic signaling molecules tested here, cyclin D2 is an important regulator of both pathologic and physiological hypertrophy. Impact statement This research is relevant as the hypertrophic signaling pathways tested here have only been characterized for their role in pathological hypertrophy, and not in the context of exercise or physiological hypertrophy. By using the same transgenic mouse lines utilized in previous studies, our findings provide a novel and important understanding for the role of these signaling pathways in physiological hypertrophy. We found that alterations in the signaling pathways tested here had no impact on exercise performance. Exercise induced cardiac growth in all of the transgenic mice except for the mice deficient in cyclin D2. In the cyclin D2 null mice, cardiac function was not impacted even though the hypertrophic response was blunted and a number of signaling pathways are differentially regulated by exercise. These data provide the field with an understanding that cyclin D2 is a key mediator of physiological hypertrophy.

Complete Reversion of Cardiac Functional Adaptation Induced by Exercise Training

PURPOSE

Long-term exercise training is associated with characteristic cardiac adaptation, termed athlete's heart. Our research group previously characterized in vivo left ventricular (LV) function of exercise-induced cardiac hypertrophy in detail in a rat model; however, the effect of detraining on LV function is still unclear. We aimed at evaluating the reversibility of functional alterations of athlete's heart after detraining.

METHODS

Rats (n = 16) were divided into detrained exercised (DEx) and detrained control (DCo) groups. Trained rats swam 200 min·d for 12 wk, and control rats were taken into water for 5 min·d. After the training period, both groups remained sedentary for 8 wk. We performed echocardiography at weeks 12 and 20 to investigate the development and regression of exercise-induced structural changes. LV pressure-volume analysis was performed to calculate cardiac functional parameters. LV samples were harvested for histological examination.

RESULTS

Echocardiography showed robust LV hypertrophy after completing the training protocol (LV mass index = 2.61 ± 0.08 DEx vs 2.04 ± 0.04 g·kg DCo, P < 0.05). This adaptation regressed after detraining (LV mass index = 2.01 ± 0.03 vs 1.97 ± 0.05 g·kg, n.s.), which was confirmed by postmortem measured heart weight and histological morphometry. After the 8-wk-long detraining period, a regression of the previously described exercise-induced cardiac functional alterations was observed (DEx vs DCo): stroke volume (SV; 144.8 ± 9.0 vs 143.9 ± 9.6 μL, P = 0.949), active relaxation (τ = 11.5 ± 0.3 vs 11.3 ± 0.4 ms, P = 0.760), contractility (preload recruitable stroke work = 69.5 ± 2.7 vs 70.9 ± 2.4 mm Hg, P = 0.709), and mechanoenergetic (mechanical efficiency = 68.7 ± 1.2 vs 69.4 ± 1.8, P = 0.742) enhancement reverted completely to control values. Myocardial stiffness remained unchanged; moreover, no fibrosis was observed after the detraining period.

CONCLUSION

Functional consequences of exercise-induced physiological LV hypertrophy completely regressed after 8 wk of deconditioning.

Risk stratification of sudden cardiac death in hypertension

In the United States, up to 450,000 people per year die suddenly; an average of 1 sudden death every 70s. Strategies for preventing sudden cardiac death are urgently needed. Systemic arterial hypertension is a major risk factor for sudden cardiac death and the increasing burden of hypertension is a worldwide problem. The lifetime risk of sudden cardiac death at 30years of age is higher by 30% in individuals with hypertension. Each 20/10mmHg increase in systolic/diastolic blood pressure, is associated with a 20% additional increase in sudden cardiac death risk. Theoretically, antihypertensive treatment should be an effective strategy for sudden cardiac death prevention. However, a recent meta-analysis of 15 randomized controlled trials showed that antihypertensive treatment does not reduce the incidence of sudden cardiac death. This manuscript reviews ECG predictors of sudden cardiac death and the importance of risk stratification for appropriate management of hypertension.

Can the Drosophila model help in paving the way for translational medicine in heart failure?

Chronic heart failure is a common consequence of various heart diseases. Mechanical force is known to play a key role in heart failure development through regulating cardiomyocyte hypertrophy. In order to understand the complex disease mechanism, this article discussed a multi-disciplinary approach that may aid the illustration of heart failure molecular process.

Discrimination of the "Athlete's Heart" from real disease by electrocardiogram and echocardiogram

Chronic physical training has been shown to produce multiple changes in the heart, resulting in the athlete's heart phenotype. Some of the changes can make it difficult to discern athlete's heart from true cardiac disease, most notably hypertrophic cardiomyopathy. Other diseases such as dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy may be difficult to rule in or out. In this article, the physiological cardiac changes of chronic athletic training are reviewed. A methodological approach using electrocardiography and echocardiography to differentiate between athlete's heart and cardiac disease is proposed.

Endurance Exercise and the Heart: Friend or Foe?

Although low- to moderate-intensity exercise has well-known cardiovascular benefits, it has been increasingly suggested that prolonged strenuous endurance exercise (SEE) could have potential deleterious cardiac effects. In effect, the term 'cardiac overuse injury' (or 'over-exercise') has been recently reported to group all the possible deleterious cardiac consequences of repeated exposure to SEE or 'over-exercise'. In this article, we provide a balanced overview of the current state of knowledge regarding the 'pros' and 'cons' of SEE from a cardiological point of view.

Recommendations for participation in competitive sport and leisure-time physical activity in individuals with cardiomyopathies, myocarditis and pericarditis

Several relatively uncommon, but important cardiovascular diseases are associated with increased risk for acute cardiac events during exercise (including sudden death), such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy (ARVC) and myo-pericarditis. Practising cardiologists are frequently asked to advise on exercise programmes and sport participation in young individuals with these cardiovascular diseases. Indeed, many asymptomatic (or mildly symptomatic) patients with cardiomyopathies aspire to a physically active lifestyle to take advantage of the many documented benefits of exercise. While recommendations dictating the participation in competitive sport for athletes with cardiomyopathies and myo-pericarditis have recently been published as a consensus document of the European Society of Cardiology, no European guidelines have addressed the possible participation of patients with cardiomyopathies in recreational and amateur sport activities. The present document is intended to offer a comprehensive overview to practising cardiologists and sport physicians of the recommendations governing safe participation in different types of competitive sport, as well as the participation in a variety of recreational physical activities and amateur sports in individuals with cardiomyopathies and myo-pericarditis. These recommendations, based largely on the experience and insights of the expert panel appointed by the European Society of Cardiology, include the most up-to-date information concerning regular exercise and sports activity in patients with cardiomyopathies and myo-pericarditis.

Differentiating the athlete's heart from hypertrophic cardiomyopathy

PURPOSE OF REVIEW

Exercise-induced cardiac remodeling (EICR), or athlete's heart, refers to the cardiac structural and functional adaptations to exercise training. Although the degree of physiological left ventricular hypertrophy (LVH) is typically mild in trained athletes, in some LVH is substantial enough to prompt concern for hypertrophic cardiomyopathy (HCM). This review summarizes the available imaging tools to help make this important clinical distinction.

RECENT FINDINGS

Advanced echocardiographic techniques (tissue and Doppler and speckle tracking) and cardiac magnetic resonance imaging are being investigated to aid in the differentiation of EICR and HCM in 'gray-zone' hypertrophy cases. Higher early diastolic (E') velocity by tissue Doppler imaging has been documented in athletes. HCM patients have been found to have lower global longitudinal strain (GLS) when compared with athletes with LVH. Analysis of twisting and untwisting of the LV with speckle tracking may also help distinguish athlete's heart from HCM. Studies of the expected degree and time course of LVH regression after exercise cessation (in the setting of prescribed detraining) are needed as this may be a useful adjunct to determine the cause of LVH in particularly challenging cases.

SUMMARY

Ongoing research with novel imaging techniques continues to improve the ability to distinguish athlete's heart from HCM in situations of 'gray-zone' hypertrophy.

The multi-modality cardiac imaging approach to the Athlete's heart: an expert consensus of the European Association of Cardiovascular Imaging

The term 'athlete's heart' refers to a clinical picture characterized by a slow heart rate and enlargement of the heart. A multi-modality imaging approach to the athlete's heart aims to differentiate physiological changes due to intensive training in the athlete's heart from serious cardiac diseases with similar morphological features. Imaging assessment of the athlete's heart should begin with a thorough echocardiographic examination.Left ventricular (LV) wall thickness by echocardiography can contribute to the distinction between athlete's LV hypertrophy and hypertrophic cardiomyopathy (HCM). LV end-diastolic diameter becomes larger (>55 mm) than the normal limits only in end-stage HCM patients when the LV ejection fraction is <50%. Patients with HCM also show early impairment of LV diastolic function, whereas athletes have normal diastolic function.When echocardiography cannot provide a clear differential diagnosis, cardiac magnetic resonance (CMR) imaging should be performed.With CMR, accurate morphological and functional assessment can be made. Tissue characterization by late gadolinium enhancement may show a distinctive, non-ischaemic pattern in HCM and a variety of other myocardial conditions such as idiopathic dilated cardiomyopathy or myocarditis. The work-up of athletes with suspected coronary artery disease should start with an exercise ECG. In athletes with inconclusive exercise ECG results, exercise stress echocardiography should be considered. Nuclear cardiology techniques, coronary cardiac tomography (CCT) and/or CMR may be performed in selected cases. Owing to radiation exposure and the young age of most athletes, the use of CCT and nuclear cardiology techniques should be restricted to athletes with unclear stress echocardiography or CMR.

Influence of Physical Activity on Hypertension and Cardiac Structure and Function

The global burden of hypertension is rising and accounts for substantial morbidity and mortality. Lifestyle factors such as diet and physical inactivity contribute to this burden, further highlighting the need for prevention efforts to curb this public health epidemic. Regular physical activity is associated with lower blood pressure, reduced cardiovascular risk, and cardiac remodeling. While exercise and hypertension can both be associated with the development of left ventricular hypertrophy (LVH), the cardiac remodeling from hypertension is pathologic with an associated increase in myocyte hypertrophy, fibrosis, and risk of heart failure and mortality, whereas LVH in athletes is generally non-pathologic and lacks the fibrosis seen in hypertension. In hypertensive patients, physical activity has been associated with paradoxical regression or prevention of LVH, suggesting a mechanism by which exercise can benefit hypertensive patients. Further studies are needed to better understand the mechanisms underlying the benefits of physical activity in the hypertensive heart.