Premature Atrial Contraction (PAC)

A premature atrial contraction (PAC) or atrial premature contraction is "a premature beat arising from an ectopic focus within the atria."^[2] Premature contractions are classified by their origin: atrial (PACs), junctional (PJCs), or ventricular (PVCs).

• PACs are a normal electrophysiological phenomenon and do not usually require any treatment. Patients with PACs complain of palpitations and "a sense of the heart 'skipping a beat.' "
• PACs mostly occur in healthy individuals without heart disease. Stress or stimulants such as caffeine, tobacco, and alcohol can increase the frequency of PACs. Although seldom, PACs can also be a sign of underlying heart condition in the atrium.
• Although most PACs are benign, they may change into atrial flutter, atrial fibrillation, or supraventricular tachycardia.

Diagnosis of PACs on the ECG

1. Premature Atrial Complex [Online image]. (2013). Retrieved July 19, 2016, from http://www.practicalclinicalskills.com/ekg-reference-guide-details?lessonID=12
2. Premature Atrial Complex (PAC). (n.d.). Retrieved July 27, 2016, from http://lifeinthefastlane.com/ecg-library/premature-atrial-complex-pac/
3. Premature Atrial Complex. (n.d.). Retrieved July 27, 2016, from http://www.practicalclinicalskills.com/ekg-reference-guide-details?lessonID=12
4. Premature Atrial Contractions (PACs). (n.d.). Retrieved July 29, 2016, from http://www.cardiachealth.org/premature-atrial-contractions-pacs
5. MIT-BIH Arrhythmia Database. (1980). Retrieved June, 2016, from https://physionet.org/physiobank/database/mitdb/
6. Goldberger AL, Amaral LAN, Glass L, Hausdorff JM, Ivanov PCh, Mark RG, Mietus JE, Moody GB, Peng C-K, Stanley HE. PhysioBank, PhysioToolkit, and PhysioNet: Components of a New Research Resource for Complex Physiologic Signals. Circulation101(23):e215-e220 [Circulation Electronic Pages;http://circ.ahajournals.org/cgi/content/full/101/23/e215]; 2000 (June 13).