ECG Readings Simplified: A Visual Guide

Let's examine the key measurements and intervals in an ECG tracing.The PR interval represents the time between atrial and ventricular activation, normally lasting between zero point twelve and zero point twenty seconds.The QRS duration shows how long ventricular depolarization takes, typically between zero point zero six and zero point ten seconds.The QT interval represents total ventricular activity, normally between zero point thirty six and zero point forty four seconds.To calculate heart rate, we count the number of large squares between consecutive R waves.In this example, there are five large squares between R waves.Using the formula of three hundred divided by the number of large squares, we can calculate the heart rate.In this case, three hundred divided by five equals sixty beats per minute.Normal sinus rhythm shows regular P waves followed by QRS complexes, occurring at a rate between sixty and one hundred beats per minute.In tachycardia, the heart beats faster than one hundred beats per minute, showing compressed intervals between complexes.Bradycardia is characterized by a slow heart rate below sixty beats per minute, with longer intervals between complexes.ST segment elevation is a critical finding that may indicate cardiac injury or ischemia. Notice how the segment after the QRS complex is raised above the baseline.Let's compare these different heart rates side by side. Notice how the spacing between complexes changes with different rates.Various cardiac conditions can cause changes in wave morphology, such as enlarged P waves, missing P waves, or wide QRS complexes.