To interpret an ECG you need to understand the different parts of a normal sinus rhythm and what they look like. The first thing to look for is something called a P wave; this is a small elevation before the QRS complex. Next, look at the PR interval; this is measured by counting the squares from the beginning of the P wave and ending with the R wave. The PR interval represents the atrial depolarization phase. The average PR interval should be between 0.12-0.20 seconds or 3-5 squares. After the PR interval it is important to observe the QRS complex; in other words, ventricular depolarization. There should be a QRS following each P wave and it should be no longer than 0.12 seconds or 2 1/2 squares. Additionally, the S wave should return to baseline and not be elevated or depressed. After the QRS complex, a T wave should be present as a small elevation above the baseline. The S wave and T wave together are referred to as the ST interval and represent ventricular repolarization; normally it should be 0.20 seconds or less. All of these add up to a complete cycle of depolarization and repolarization of the atria and ventricles of the heart to produce cardiac output. The next thing to consider is the RR interval; it's simply a matter of looking at the distance between each QRS complex and seeing if they are uniformly spatial and regular. There should not be much variation in the distance between each R wave. Now that I have described what a normal sinus rhythm looks like, I will now provide the different descriptions of the various abnormal ECG patterns that exist. All abnormal rhythms indicate different issues or issues regarding the heart; therefore, I will also discuss what the various treatments are for each abnormal rhythm. With...... middle of the paper ...... affected by every other beat, while trigeminal is when every third beat is a PVC. Some possible causes are electrolyte imbalances, hypoxia, stress, and caffeine. Lidocaine can be used as a temporary solution, although if they are severe enough, ablation may be considered. Ablation is a minimally invasive procedure in which radiofrequency waves are used to destroy the tissue where the early heartbeat originates. Works Cited • Bradycardia (slow heart rate). WebMD. March 13, 2014 http://www.webmd.com/heart-disease/tc/bradycardia-slow-heart-rate-overview• Sinus arrhythmia. Pediatric Cardiologist, Diagnosis and Treatment of Disorders. March 13, 2014 http://pediatriheartspecialists.com/articles/detail/sinus_arrhythmia• Wolff-Parkinson-White syndrome. MedlinePlus, reliable health information for you. March 13, 2014 http://www.nlm.nih.gov/medlineplus/ency/article/000151.htm