Interpreting an electrocardiogram, or EKG, requires analysis of the heart rate, heart rhythm, P wave, PR interval and QRS complex, according to Practical Clinical Skills. The EKG is a visual representation of the number of cycles, or beats, performed by the heart. This measurement is taken in terms of rate, which refers to the time interval for each cycle, and voltage, or the amplitude of each wave.
There are five steps to interpreting an EKG, according to the U.S. Army School of Aviation Medicine's course on EKG interpretation. The first is analysis of the heart rate, which is calculated by counting the number of R to R cycles in 6 seconds, and multiplying by 10. Next, the ventricular rhythm is determined by measuring the time interval between the R to R waves. Once determined, the rhythm is classified as regular, regularly irregular, or irregularly irregular, depending on the pattern present within the cycles.
The third element in the analysis, the P-wave, must be examined to ensure it is present in each cycle, explains the U.S. Army Medical Department and School. It should also be smooth, regular and upright in appearance. The PR interval is analyzed next; ideally, it is constant across the strip, and lasts between 0.12 and 0.20 seconds. Similarly, the QRS complex should be regular and similar in all cycles.