The Emerging WCT Paradigm Shift

You are in the middle of your clinical shift when someone walks up to you and hands you a rhythm strip. You briefly look at it and realize it is a wide-complex tachycardia (WCT). What do you do next? You have two possibilities. The first is that the strip is a ventricular tachycardia (VTach); the second is that it is a WCT with aberrancy. So, which is it?

We are constantly saying that “common things occur commonly.” This concept should be a no-brainer and simple common sense. However, in medicine, we have a tendency to avoid simple common sense since we do not receive praise for diagnosing the common disorders; we are praised for picking out the zebras. Well, if you live in New York City and you hear hoofbeats outside your window, it’s usually not a pack of wild zebras. So, how does this help us in our evaluation of a WCT?

As we discussed in the previous chapter and elsewhere, statistics show that approximately 80% of WCTs are VTachs!1-5 According to the “common things occur commonly” principle, that means that the WCT strip you are holding in your hands is probably a VTach. Top that off with the fact that the most common lethal arrhythmia is VTach and your decision seems pretty simple.

 

CLINICAL PEARL

We need to change our expectations from one in which we always identify the rhythm involved with 100% certainty, to one in which we can humbly accept the possibility that we are dealing with a WCT of unknown origin and that the severity of any WCT should be based solely on the overall end-organ perfusion.

 

Additional Information

Distracting Injuries

The most common lethal arrhythmia is VTach.

That logic is the main backbone of any discussion related to the WCTs. It is also the foundation of our personal approach to the evaluation and management of the WCTs. Why? Because at the heart of it all, the one thing we don’t want is to miss this killer. Yet, we get it wrong quite often. Here’s why . . .

In the management of trauma patients, there is a concept known as the “distracting injury.” A distracting injury is one that causes you to divert your attention from the real killer to one that just looks like a killer. Take, for example, a facial laceration. A 1-cm cut on certain parts of the face will bleed like there is no tomorrow; the patient’s face is literally a bloody mess. Professionals responding to such a scene may immediately turn their attention to the 1-cm facial laceration. Frequently, they even blame the tiny cut as the source of the patient’s hemodynamic compromise. In the meantime, the ruptured liver with massive abdominal bleeding goes unchecked. If you think this scenario is an exaggeration, think again; it happens all the time. In such cases, the cause of death is clinical ignorance.

Contrary to reason, there is a natural tendency for clinicians to focus on examples of WCTs caused by SVTs-A rather than focusing on what has a greater chance of killing their patient, VTach. That tendency to concentrate on the SVT-A exists because, deep down inside, clinicians feel that diagnosing a VTach is child’s play but correctly identifying the SVT-A makes them look like diagnostic marvels. However, recognizing VTach is not a “given.”

We must accept the humbling fact that, even in the most competent hands and despite all of our sophisticated criteria and technology, we cannot distinguish between the wide-complex SVTs-A and VTach with 100% certainty on the basis of patient history, physical exam, ECG findings, or hemodynamic status. For that reason, we need to change our expectations from one in which we always identify the rhythm involved with 100% certainty to one in which we can accept the possibility that we are dealing with a WCT of unknown origin and that the severity of any WCT should be based solely on the overall end-organ perfusion.

To sum it all up, train yourself to recognize the distracting injury, then forget it and focus your attention where it belongs, on the killer! Treat the distracting injury only when your patient is stable because a Band-Aid shouldn’t take long to put on. Always remember that your main concern should always be to diagnose the presence of VTach and to treat for that possibility until proven otherwise.