Sinus premature contraction is an early contraction in the normal rhythm of the heart. Normally, the heart has a special conduction system that is responsible for the formation and conduction of the heart impulses that cause the heart to beat rhythmically, and the location where the impulses are initiated is called the pacing point. The normal pacing point is the sinoatrial node. When the ectopic pacing point is prematurely excited, the heart will contract prematurely, also known as preterm contraction or premature and extrasystole, which is a common arrhythmia and can be seen in patients with heart disease as well as in healthy adults. This condition is usually treated aggressively for the primary cause and most patients have a good prognosis. Patients will have a range of clinical symptoms such as cardiac arrest, chest tightness, shortness of breath, and weakness. If patients are not treated aggressively it can lead to malignant arrhythmias and, in severe cases, sudden cardiac death.