title: Myocardial injury and ventricular dysfunction related to training levels among nonelite participants in the Boston marathon.
abstract: BACKGROUND
  Multiple studies have individually documented cardiac dysfunction and biochemical evidence of cardiac injury after endurance sports; however, convincing associations between the two are lacking. We aimed to determine the associations between the observed transient cardiac dysfunction and biochemical evidence of cardiac injury in amateur participants in endurance sports and to elicit the risk factors for the observed injury and dysfunction.
  
  
  RESULTS
  We screened 60 nonelite participants, before and after the 2004 and 2005 Boston Marathons, with echocardiography and serum biomarkers. Echocardiography included conventional measures as well as tissue Doppler-derived strain and strain rate imaging. Biomarkers included cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP). All subjects completed the race. Echocardiographic abnormalities after the race included altered diastolic filling, increased pulmonary pressures and right ventricular dimensions, and decreased right ventricular systolic function. At baseline, all had unmeasurable troponin. After the race, > 60% of participants had increased cTnT > 99th percentile of normal (> 0.01 ng/mL), whereas 40% had a cTnT level at or above the decision limit for acute myocardial necrosis (> or = 0.03 ng/mL). After the race, NT-proBNP concentrations increased from 63 (interquartile range [IQR] 21 to 81) pg/mL to 131 (IQR 82 to 193) pg/mL (P<0.001). The increase in biomarkers correlated with post-race diastolic dysfunction, increased pulmonary pressures, and right ventricular dysfunction (right ventricular mid strain, r=-0.70, P<0.001) and inversely with training mileage (r=-0.71, P<0.001). Compared with athletes training > 45 miles/wk, athletes who trained < or = 35 miles/wk demonstrated increased pulmonary pressures, right ventricular dysfunction (mid strain 16+/-5% versus 25+/-4%, P<0.001), myocyte injury (cTnT 0.09 versus < 0.01 ng/mL, P<0.001), and stress (NT-proBNP 182 versus 106 pg/mL, P<0.001).
  
  
  CONCLUSIONS
  Completion of a marathon is associated with correlative biochemical and echocardiographic evidence of cardiac dysfunction and injury, and this risk is increased in those participants with less training.
authors.affiliation: Cardiac Ultrasound Laboratory, Division of Cardiology, Massachusetts General Hospital, 55 Fruit St, Boston, MA 02115-2696, USA.
authors.forename: Tomas G
authors.initials: TG
authors.lastname: Neilan
authors.forename: James L
authors.initials: JL
authors.lastname: Januzzi
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lee-Lewandrowski
authors.forename: Thanh-Thao
authors.initials: TT
authors.lastname: Ton-Nu
authors.forename: Danita M
authors.initials: DM
authors.lastname: Yoerger
authors.forename: Davinder S
authors.initials: DS
authors.lastname: Jassal
authors.forename: Kent B
authors.initials: KB
authors.lastname: Lewandrowski
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Siegel
authors.forename: Jane E
authors.initials: JE
authors.lastname: Marshall
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Douglas
authors.forename: David
authors.initials: D
authors.lastname: Lawlor
authors.forename: Michael H
authors.initials: MH
authors.lastname: Picard
authors.forename: Malissa J
authors.initials: MJ
authors.lastname: Wood
mesh_terms: D001265:Athletic Injuries / Q000453:epidemiology / Q000209:etiology*; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D001900:Boston; D003971:Diastole; D006801:Humans; D009206:Myocardium; D010809:Physical Fitness; D012420:Running; D020107:Troponin T / Q000097:blood; D018497:Ventricular Dysfunction, Right / Q000453:epidemiology* / Q000209:etiology
chemical_list: D015415:Biomarkers; D020107:Troponin T