Certified Rhythm Analysis Technician (CRAT) Practice Exam 2025 – All-in-One Study Guide for Exam Success!

The correct answer is calculating using the 1500 method. This method is applicable when the morphology of the R waves is consistent because it relies on accurately measuring the number of small boxes between R waves on an electrocardiogram (ECG). The 1500 method involves counting the number of small boxes between successive R waves and then dividing 1500 by that count to derive the heart rate in beats per minute (bpm). A consistent R wave morphology ensures that measurements taken between R waves are reliable and that the intervals accurately reflect the heart's rhythm.

When R waves display consistent morphology, it indicates a stable and regular rhythm, which is ideal for applying this method, as irregularities could lead to inaccuracies in heart rate calculation. The consistency in morphology confirms that the R-R intervals are regular, enhancing the precision of the results obtained through the 1500 method.

Other methods mentioned, such as counting R waves over a specific time interval or using the small box method, can also be used, but they are often less precise when the rhythm is irregular. Using a stopwatch during observation is typically not a standardized method for calculating heart rate from ECG readings and may not provide the direct precision that the 1500 method offers when R wave morphology is consistent