This text discusses the clinical-pharmacological approaches to rational prescribing of drugs for the treatment of syndrome arrhythmia. It explains cardiac arrhythmias as disturbances of frequency, rhythm, and sequence of contractions of the heart. The text also mentions the normal sinus rhythm provided by the sinus node automaticity, with a frequency of 60 to 80 beats per minute in most healthy adults at rest. Furthermore, it delves into four classes of antiarrhythmic agents that influence the electrical processes in the myocardium.