abnormal heart beats → αρρυθμία

[spiros]

abnormal heart beats → αρρυθμία;

If you take too much Χ you may feel sleepy, feel dizzy and experience abnormal heart beats.

[Frederique]

It seems to be written in layman's terms. This could refer to either abnormality in the cycle itself, e.g.: The Cardiac Cycle and the Physiological Basis of Left Ventricular Contraction, Ejection, Relaxation, and Filling, or in the frequency of cycles (abnormal heart rhythm, arrhythmia → αρρυθμία). I would tend to agree. :)