Abstract 2158: Myocardial Injury and Ventricular Dysfunction Related to Training Levels Among Non-Elite Participants in the Boston Marathon
Background-Multiple studies have individually documented cardiac dysfunction and biochemical evidence of cardiac injury after endurance sports; convincing associations between the two are lacking. We aimed to determine, among amateur participants in endurance sports, the associations between the observed cardiac dysfunction and injury and to elicit the risk factors for this injury and dysfunction.
Methods and Results- We screened 60 non-elite participants, pre and post the 2004 and 2005 Boston Marathon, with echocardiography and serum biomarkers. Echocardiography included conventional measures as well as tissue Doppler-derived strain and strain rate imaging. Biomarkers included troponin T (cTnT) and N-terminal pro-brain natriuetic peptide (NT-proBNP). All subjects completed the race. Echocardiographic abnormalities post-race included altered diastolic filling, increased pulmonary pressures, and right ventricular dimensions and decreased right ventricular systolic function. At baseline, all had unmeasurable troponin. Post-race, >60% of participants had an increased cTnT to above the 99th percentile of normal (>0.01 ng/ml), while 40% had a cTnT at or above the decision limit for acute myocardial necrosis (≥0.03 ng/ml). Post-race, NT-proBNP concentrations increased from 63 pg/ml (interquartile range [IQR]=21–81 pg/ml) to 131 pg/ml (IQR=82–193 pg/ml; P<0.001). The increase in biomarkers correlated with post-race diastolic dysfunction, increased pulmonary pressures and RV dysfunction (right ventricular mid strain, r=−0.70, P<0.001) and inversely with training mileage (r=−0.71, P<0.001). Compared to athletes training >45 miles/week, those that trained ≤35 miles/week demonstrated increased pulmonary pressures, right ventricular dysfunction (mid strain 16±5 vs. 25±4 %, P<0.001), myocyte injury (cTnT=0.09 vs. <0.01 ng/ml, P<0.001) and stress (NT-proBNP=182 vs. 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.