Irregular heartbeats are common and usually harmless. You're describing a preventricular contraction -- the skipped beat followed by the strong beat. This is probably the most common
cardiac arrhythmia. There are a LOT of
PVC triggers (anxiety, lack of sleep, too much caffeine) and most of them are easily remedied. Only a few are related to
heart disease. You needn't see your doctor about it unless you begin to experience shortness of breath, difficulty breathing,
dizziness and so forth.