Cardiac bradyarrhythmia results from disturbance of the generation or conduction of cardiac electrical activity and can be corrected by implantation of artificial pacemakers(PM). Cardiac PMs are used effectively to replace or control the heart's intrinsic electrical activity. Compared with early PM models, which paced at a fixed rate and could not be inhibited or synchronized with the underlying heart rhythm, modern PM systems have become more sophisticated in terms of programmable modes and rate responsiveness, and they are better able to mimic the physiological pattern of cardiac activation. Permanent pacing systems consist of an implantable pulse generator containing a battery and electronic circuitry, together with one (single chamber PM) or two (dual chamber PM) leads. The leads both conduct intrinsic atrial or ventricular signals to the sensing circuitry and deliver the pulse generator charge to the myocardium. This book provides a comparison between physiological and clinical parameters among patients with single chamber and dual chamber PM through symptomatic, clinical, programmable, and echo-cardiographical characters of the PMs.