Can an electrocardiogram prevent sudden cardiac arrest in young teenagers/adults who die during marathons?

Maybe: valuation to prevent said nothing athletes can be done by an exam by my making position and or cardiologist and echocardiogram and EKG along with a family history can help identify some of the risk factors . I doing these things this can decrease some of the risk of sudden death by knowing some of the high-risk patients

Prevent sudden death: There are 2 main reasons young athletes suffer sudden death: arrytmias, which risk may show on an ECG and anatomical abnormalities such as IHSS (Idiopathic hypertrophic subaortic stenosis) or aberrant coronary arteries, which may show on an Echocardiogram. Some phycisians think both tests should be done to extreme athletes, prior to participation.

No: Deaths in triathlons are mostly from drowning. Deaths in distance runners are mostly from electrolyte troubles. Sudden death warnings on EKG include long QT and Brugada which seldom kill during exercise. I would trust history and auscultation (for HCMP, etc) for warnings and think EKG offers less yield.

Screen test: ECG is used because it is relatively inexpensive. We have no good cost effective screening test. Cardiac arrest is rare when compared to the numbers of exercising population. Tests become more effective when a specific question within the effectiveness of the test are the reason for the test.

Sudden death : In some it can detect a sign but not in all

Maybe: An EKG can't prevent it but it may help find suggestive findings that put one at high risk and some communities are implementing these screening tools to look for Brugada, Long QT, LVH, etc, which are the more common threats.