A set of guidelines regarding the use of multimodality cardiovascular (CV) imaging in young adult competitive athletes, focusing on the distinction between exercise-induced cardiac remodeling (EICR) and cardiac pathology, was formulated by an expert writing group and published in the Journal of the American Society of Echocardiography.
This report was endorsed by the American Society of Echocardiography, in conjunction with the Society of CV Computed Tomography (CT) and the Society for CV Magnetic Resonance (CMR).
Young competitive athletes with unrecognized CV disease (CVD) who undergo strenuous exercise may be at increased risk for serious adverse events, including sudden cardiac death. Expertise in and appropriate utilization of multimodality CV imaging techniques — including transthoracic echocardiography (TTE), CT angiography (CTA) and CMR — are essential in order to ensure proper diagnosis, risk stratification and ruling out of CVD in this population, as well as for the clinical management of detected pathologies. This requires selection of the appropriate imaging modality, high-quality performance of the imaging technique, as well as accurate interpretation, which demands an in-depth comprehension of EICR which may be modified in young athletes by physiological adaption, and should not be misinterpreted (ie, as resulting from pathophysiology). Cardiac specialists with training in these areas are in an ideal position to provide competitive athletes with comprehensive care.
In most cases in which CVD is suspected or confirmed, initial imaging studies should involve TTE — 2-dimensional or Doppler — with CTA or CMR follow-up as needed. The advantages of TTE include low cost and high availability, and the fact that this technique can readily be used to characterize myocardial structure, valve and proximal coronary anatomy and physiology, as well as systolic and diastolic function. The use of CMR is especially helpful when investigating potential myocardial pathology, particularly right ventricular (RV) and aortic morphology and function, but its use is limited by high cost and limited accessibility, as well as contraindications in individuals with metal implants. In certain clinical situations, CTA may be ideal, such as when the anatomy of the great vessels or the proximal coronary structures must be precisely defined. However, exposure to ionizing radiation remains a concern.
The imaging specialists who conduct and/or interpret the results of competitive athletes should understand the fundamentals of exercise physiology and EICR. Regarding left ventricular (LV) adaptations in this population, a multifactorial and complex influence of sex, ethnicity, duration of prior exercise, and type of sport determines both the geometry (eccentric vs concentric) and magnitude (chamber volumes/dimensions and absolute wall thickness) of EICR changes. When RV dilation, which is common in endurance athletes, occurs secondary to EICR, there should be concomitant biatrial dilation and eccentric LV hypertrophy/remodeling. It is not uncommon for athletes to have mild aortic dilation. In cases in which absolute aorta measurements exceed 34 mm and 40 mm in women and men, respectively, an initial TTE should be followed by CMR or gated CTA.
The distinction between EICR and pathology demands careful measurement of parasternal long-axis view of LV wall thickness to avoid inclusion of RV chordal tissue and septal trabeculations. There is generally mild LV wall thickening with EICR that varies slightly based on race, and measurements above cutoffs may indicate pathology. Pathologic LV remodeling should be suspected in any patient with LV wall thickening accompanied by indicators of reduced diastolic function and/or longitudinal systolic strain. Incomplete TTE LV visualization or uncertain etiology of thickening should be followed up with CMR.
When LV dilation is suspected on TTE, confirmatory CMR should be performed to better characterize chamber structure and function, with distinction between EICR and pathology requiring integration of the patient’s history and additional testing results rather than simple assessment of LV or left atrial dilation magnitude. Mild reductions in LV ejection fraction (by 45-55%) that occur alongside RV and biatrial dilation without diastolic dysfunction should be considered as a result of physiologic adaptation.
When RV dilation is detected on TTE without clear etiology, CMR should be performed. Endurance athletes often have RV dilation that is accompanied by LV dilation, and in the absence of structural or functional abnormalities, this adaptation should be considered physiologic. However, isolated clinical cutoffs normally used to indicate RV dilation cannot differentiate EICR from pathology in competitive athletes.
Although physiologic hypertrabeculation of the LV apex is common among competitive athletes, particularly in black and/or endurance competitors, this feature needs tobe distinguished from noncompaction cardiomyopathy. When hypertrabeculation is seen in the context of abnormal LV wall thickness or systolic/diastolic dysfunction and cardiomyopathy is suspected, incomplete TTE visualization of the area should be followed by CMR imaging.
Young adult competitive athletes should undergo a CV screening prior to engaging in sports. This screening should include a focused history and physical exam and may incorporate a 12-lead electrocardiogram. Although TTE, CTA and CMR are not recommended as part of this initial screening, those responsible for such programs must be closely connected to medical centers staffed with sports cardiologists and imaging experts, in order to further evaluate any abnormal findings detected during the process.
In athletes who present with chest pain, TTE should be used as a first-line strategy for investigation, followed by maximal effort-limited (not heart rate[HR]-limited) exercise testing with immediate post-exercise TTE before HR recovery can occur. Anomalous coronary vasculature should be excluded through careful examination of the origins and proximal course of the left and right coronary circulation. If this cannot be accomplished using TTE, CTA or CMR should be performed to clarify coronary anatomy.
Neurally mediated syncope that occurs following exercise or that is unrelated to strenuous effort is common among competitive athletes and does not require evaluation with noninvasive imaging studies. However, when the etiology of syncope is uncertain, and especially when it occurs during exercise, comprehensive assessment is necessary. This evaluation should involve TTE, followed by CTA or CMR, in order to rule out structural or valvular disease. In addition, maximal effort-limited exercise testing should be performed.
Athletes who report palpitations that begin or intensify during strenuous activity should undergo TTE initially to look for structural disease. This should be followed in some cases (based on presentation and TTE findings), by CMR. Maximal effort-limited exercise testing with or without imaging should also be performed in these patients. In individuals evaluated for symptomatic or asymptomatic ventricular pre-excitation, TTE can exclude complex congenital heart disease, PRKAG2 gene-mediated hypertrophic cardiomyopathy, and Ebstein’s anomaly.
When a young athlete presents with inappropriate exertional dyspnea, either as a new sign or an indicator of nonresponsiveness to therapy for a previously identified noncardiac cause, a TTE should be performed. This should be followed by maximal effort-limited exercise testing with or without imaging.
Finally, when an athlete reports a decline in performance and his or her initial evaluation suggests possible coronary, myocardial or valvular pathology (or when there is no clear explanation for this change), TTE should be performed. Clinical suspicions should help determine the addition of CTA, CMR and/or exercise testing.
Additional recommendations briefly addressed the evaluation of slightly older competitive athletes, pediatric athletes, and those with congenital heart disease.
“Differentiating EICRfrom mild forms of pathology remains challenging in clinical practice and corollary data in specific groups, including children and people with congenital heart disease, are sparse. Further acquisition of normative data, particularly data derived from CMR and CTA, may further address these important contemporary clinical challenges,” noted the authors.
Conflicts of Interest Disclosures
The following authors reported relationships with one or more commercial interests: Pamela S Douglas, MD, FASE owns stock in UpToDate/Kluwer and is DSMB for REAL TIMI 63B; Christopher M Kramer, MD received grant support from Regeneron and is a consultant for Cytokinetics; Eric Williamson, MD is an unpaid consultant for Siemens Medical and is the recipient of an investigator-initiated research grant from GE Healthcare.
Baggish AL, Battle RW, Beaver TA, et al. Recommendations on the use of multimodality cardiovascular imaging in young adult competitive athletes: a report from the American Society of Echocardiography in collaboration with the Society of Cardiovascular Computed Tomography and the Society for Card. J Am Soc Echocardiogr. 2020;33(5):523-549. doi:10.1016/j.echo.2020.02.009