Now, let us discuss the proper technique for arrhythmia analysis and let's begin with three basic questions. First, what are the atria doing? Carefully analyze the rate, regularity and especially the morphology of the P wave. Next, what are the ventricles doing? Analyze rate, regularity and morphology of the QRS complexes. Finally, what if anything are the atria and the ventricles doing to each other? Determine the P-QRS relationship, for example, is there a P wave before every QRS? Once these questions are answered, we may already have a final diagnosis or we may need further steps to decide on the diagnosis.
Advanced questions for diagnosis
If after the three basic steps the diagnosis is not immediately clear, there are several advanced questions to answer for a more difinitive diagnosis. First, is the arrhythmia supraventricular or ventricular? For example, a wide, bizarre QRS with no direct relation of the P wave to the QRS strongly suggests a ventricular origin. Second, what is the regularity of the rhythm? For example, an irregularly irregular rhythm is typical of atrial fibrillation. Third, what is the character of the onset and termination? For example, ventricular tachycardia, VT, typically begins with a premature ventricular complex, PVC, and supraventricular tachycardia, SVT, with a premature atrial complex, PAC. Lastly, is the disorder due to altered impulse formation, automaticity, [animation], or altered conduction, reentry or block, [animation]. For example, this can help with further diagnosis of supraventricular tachycardia.
What's next?
Now that we understand the mechanisms and techniques of essential arrhythmia analysis, let us use our basic steps and advanced questions to examine specific arrhythmias. Cardiac rhythms can be divided into three general groups based on rate: normal, tachycardias and bradycardias. Examples and full descriptions of the arrhythmias will be presented first in the learning section, these will be followed by practice and then test arrhythmias.