Cardiovascular screening in young athletes: a comparisonbetween different exercise tests for arrhythmia and structural heart defects detection

ABSTRACT: Background: In 1982 a pre-participation screening of athletes was launched in Italy. For younger athletes (\35y.o.). The protocol included a resting 12-lead ECG together with two more ECG recorded during the recovery phase of a submaximal test (Harvard step test, HST). More recently (2006), Veneto Region established the ECG monitoring throughout the Harvard step test. In our Sports Medicine Unit since 1998 we independently decided to use a maximal treadmill test with ECG monitoring for the same screening purposes. Purpose: Aim of this study was to compare the ability of three different exercise test modalities to detect arrhythmias, and whether they were associated with structural heart abnormalities. Methods: 1500 athletes, mean age 14.7 ± 0.6 (range 8-15yo) were evaluated (500 each) in three Sports Medicine Centers differentiating one from each other by three different test modalities: HST without ECG monitoring (HST), HST with ECG monitoring (HSTM), and maximal treadmill test with ECG monitoring (MTT). Before the exercise test, each athlete underwent a history and clinical evaluation, and a resting ECG. Athletes underwent additional echocardiography and 24-hour ECG monitoring when required. Results: the maximal heart rate achieved was 74,7% (HST), 85,6% (HSTM) and 92,1% (MTT) of the maximal predicted. Arrhythmias (VEB and/or SVEB) were observed in 1%, 2,6%, and 8.6% of the subjects for HST, HSTM, and MTT, respectively. Considering only the monitored exercise phase, arrhythmias were recorded in 0,6% of HSTM subjects (23,1% of total arrhythmias) and in 2,4% of MTT subjects (27,9%). The positive predictive value of generic arrhythmias recorded during the MTT for any echocardiographic structural heart abnormality was 0,35, while was 0,6 when both VEB and SVEB were present. Conclusions: Exercise monitoring increased the sensitivity in detecting arrhythmias and structural heart defects respect to the non monitored exercise test. The MTT induced a greater number of arrhythmias, which were associated with cardiac abnormalities (mainly mitral valve prolapse, PFO, aortic and mitral regurgitation) in 35-60% of subjects, depending on the type of arrhythmias. In athletes screening, ECG monitoring during exercise should be considered to improve the sensitivity of the exercise test.