TY - CHAP M1 - Book, Section TI - Chapter 2. Arrhythmia Management A1 - Takayesu, James K. A2 - Cline, David M. A2 - Ma, O. John A2 - Cydulka, Rita K. A2 - Meckler, Garth D. A2 - Handel, Daniel A. A2 - Thomas, Stephen H. PY - 2012 T2 - Tintinalli's Emergency Medicine Manual, 7e AB - Some variation in the sinoatrial (SA) node discharge rate is common; however, if the variation exceeds 0.12 second between the longest and shortest intervals, sinus arrhythmia is present. The electrocardiogram (ECG) characteristics of sinus arrhythmia are (a) normal sinus P waves and PR intervals, (b) 1:1 atrioventricular (AV) conduction, and (c) variation of at least 0.12 second between the shortest and longest P–P interval (Fig. 2-1). Sinus arrhythmias are affected primarily by respiration and are most commonly found in children and young adults, disappearing with advancing age. Occasional junctional escape beats may be present during very long P–P intervals. No treatment is required. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accessemergencymedicine.mhmedical.com/content.aspx?aid=56271061 ER -