An electrocardiogram (EKG or ECG) is a test that records the electrical activity of your heart. This test can help determine the cause of symptoms you might be having or check the overall health of your heart. Reading a basic EKG is not that hard. However, you should always let your doctor or medical professional properly read your EKG and diagnose you. Part 1 Identifying the Parts of an EKG Readout Download Article Image titled Read an EKG Step 1 1 Understand the grids of an EKG paper printout. Voltage—the electrical signals of the heart—is measured along the vertical axis; time is measured along the horizontal axis in squares. There are large squares that are divided into smaller squares.[1] Small squares are 1 mm across and represent 0.04 seconds. The large squares measure 5 mm across and represent 0.2 seconds. 10 mm in height is equal to 1mV in voltage. Interpreting these values will help you determine if the heartbeat is irregular, or too fast or too slow.[2] Image titled Read an EKG Step 2 2 Find the QRS complex and label it on the handout. The Q wave is the downward or negative dip right before the large spike. The R wave is right after that, and is usually the largest spike on the readout. Following that is the S wave, which is the dip down below the baseline again.[3] Label all of these parts on the printout. Look at the peaks on the printout. You will need to look at the whole strip to check for an irregular heartbeat. This is a pattern called normal sinus rhythm, and it's the basic EKG of a healthy heart. Many people's EKG may vary slightly from this baseline, though, while still being completely healthy. 3 Assess your P-waves. Find the P-waves on your EKG. P-waves are the smaller spikes right before the larger spike (the R wave). They should be at the approximately same duration, direction, and shape through the entire EKG.[4] If they are not present, see if there any movement to the line at all, like a flutter, sawtooth lines, or a flat line. P-might just be a small rise, or bump, on the graph. They will not be as sharp or as high as the QRS complex. Part 2 Interpreting the Readout Download Article 1 Measure the time between your heartbeats. Locate the beginning of the P wave and the beginning of the QRS complex. This is called the PR interval. Normal duration is between 0.12 to 0.20 seconds, which is three to five small horizontal boxes.[5] This amount of time should be pretty consistent across the entire strip. If there is a varied amount of time (boxes) between beats, it can indicate an irregular heartbeat. This is only something to worry about if your doctor says so. It can be completely harmless. 2 Assess your heart rhythm. You may have a regular or irregular heart rhythm. If your rhythm is irregular, it may be regularly or irregularly. To determine the rhythm, check if the intervals are the same length. Mark a few of your R-R intervals on a separate sheet of paper. Use that sheet of paper to move along the rhythm strip