There does appear to be a prolonging PR interval before some dropped beats (second degree type I AV block), however ... heart block unlikely. The rhythm on this ECG needs to be distinguished ...

sinus arrhythmia and 1° atrioventricular block. Abnormal findings are unrelated to regular training and also found in underlying pathological cardiac conditions. These include findings suggestive of ...

The ECG may simply show sinus rhythm or sinus bradycardia ... Second-degree sinoatrial exit block is categorized into type I and type II. Second-degree SA exit block type I (Wenkebach ...

This type of irregular heartbeat can be difficult ... it does so by using light to monitor your heart rhythm rather than taking an ECG), but it requires a $4.90 per month subscription.