You are beginning your rounds early in the morning when you get called to see one of your patients. He is a 92 year old male with mild dementia, HTN, BPH, CAD, CHF and is currently admitted for treatment of pneumonia. The call is for respiratory distress. When you get to the bedside, you notice the patient is in moderate distress, tachypnic, abdominal breathing and needs to be intubated. His vitals are significant for tachycardia at 135, respiratory rate at 30, 92% saturation on 100% face mask. On exam pertinent positives are rales bilaterally, and an irregular pulse. The decision is made to intubate. Lasix are given and while you are waiting for anesthesia to intubate the patient, you get an EKG to examine why he has an apparent irregular tachycardia and if it needs to be treated. Here is the EKG, what is the rhythm?

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The interpretation of the EKG makes a difference in the decision tree with management of this patient. This is only a rhythm strip so we will not go through the entire process, but we can make a diagnosis of what the rhythm is based on this tracing.

Starting from the beginning it is a irregular tachycardia at a rate of about 140's, and it is narrow suggesting a supra-ventricular origin. Based on these two findings, the differential now consists of Atrial Fibrillation, Atrial Flutter and Multi-Focal Atrial Tachycardia (MAT). The next step is to see if there is any organized atrial activity or p waves and in the bottom lead, lead III, there is distinct p waves present. This allows us to eliminate atrial fibrillation from the picture. The next step is to determine of this is atrial flutter vs MAT. If you quickly glance at this, it may seem to the eye that these p waves march out, but in actuality if you take calipers, they do not. There fore atrial flutter is also eliminated. So this must be MAT.

However, real life is not a multiple choice test, so why is it MAT. Looking at lead three again, there are definitely 3 different distinct p waves, and also different P-R intervals with the different p waves morphology which would be consistent with MAT. The reason for the different P-R's is due to the fact that the different p waves are coming from different atrial foci, hence the name "Multi-focal" and there for different distances to the AV node, making different P-R intervals depending on where the next p wave comes from. It is also MAT because the rate is greater than 100, because if it was slower than 100 we call it wondering atrial pacemaker.

Now this is important in this case because the diagnosis of MAT means that this is not A-Fib/ Flutter and hence does not need to be anticoagulated to prevent the risk of stroke. If it was just assumed it was flutter or fib with out closer review, he would have been anticoagulated needlessly and been vulnerable to all the risks that come with it. The treatment for MAT is treat the underlying cause. IN his case, he did not have a smoking history, no history of COPD which is one of the most common reasons to develop MAT. However, included in the differential for causes of MAT is hypoxia, and given he went into acute respiratory distress and hypoxic by O2 saturations, it was hypothesized that the acute hypoxia caused him to go into this rhythm.