The word “points” refers to the additional points from multiple leads and full 12-lead ECGs. Throughout this text, you have seen many examples of arrhythmias that would have been missed if multiple leads had not been obtained. We also talked about how the differential diagnosis was narrowed down to a couple of possibilities and the final diagnosis was made by taking a look at other leads. Remember, leads are like cameras. They shoot the same information from various angles. It is only fair to use these different vantage points to increase your odds of spotting pathology.
Should you get an ECG for every PVC you see? No, that would be overkill. But, you should get one whenever there is a question about an event, a rhythm, or a finding. It is also helpful to get one when the rhythms change, because something made that rhythm change. Getting a full 12-lead ECG may clarify what changed.
Old ECGs and strips are very helpful in arrhythmia recognition. The most important reason is that they allow us to see if the morphologic features of the strip are consistent with the patient’s baseline state or if they are a result of a new problem. New problems can be dangerous. It is always worthwhile to figure out why they are occurring.
Do not try to make decisions about hypertrophy, infarct, or any other pathologic electrocardiographic process on a rhythm strip. Rhythm strips are notoriously bad for looking at morphology because the gain and other variables are too easily adjusted on the monitor. The result is that the complexes you see on a monitor are not a true representation of the morphology of the complexes, but an electronically manipulated facsimile of the true morphology. The ECG machine does not need to be “adjusted.” When something is changed on the ECG, the machine shows the changes made on the calibration bar at the end of the strip. ECG machines are standardized and, therefore, can be used to evaluate morphology; monitors are not.
The bottom line is that if you see anything suspicious about the morphology on the rhythm strip, you should obtain a full 12-lead ECG. ST depression in lead II can be due to inferior ischemia or artifact on the monitor. It can also be due to a reciprocal change from a full-blown lateral infarct. The 12-lead ECG will help you tell the difference. Use all the tools available to you; the ECG machine is one of those tools.
One final word of wisdom: If you are serious about arrhythmia recognition, learn to use and interpret ECGs. This does not mean that you have to be an expert, but you at least have to be proficient with them. Twelve-lead ECGs and arrhythmias are all part of electrocardiography. The principles involved are the same and cross over from one to the other. Likewise, it is not realistic to think that you can study one without studying the other. You will see a major improvement in your arrhythmia recognition skills after you have studied an introductory text on 12-leads. In this text, we have tried to cross the barrier by explaining the interactions in greater depth than most other texts. We hope that you have seen the connection and that you will continue to see the results of your labor over the coming years.