Reddit mentions of A Practical Apporach to EKG Interpretation 4th Edition

Dubin's is probably going to be the most popular suggestion, but I'm going to offer a dissenting voice. Dubin is a great first step, but in my opinion the way it's taught focuses too heavily on rote memorization to develop pattern recognition, and not enough on what the pathology is behind certain patterns. Raj Anand's A Practical Approach to EKG Interpretation goes more into the physiology and pathology that causes EKGs. The first half of the book is all about systematically reading EKGs, the second half is several dozen EKGs, presented initially with a step-wise explanation that decreases as time goes on. Eventually all you have is the EKG and the answer (don't look before hand!). I also like Anand's book because his method of determining the QRS axis is superior and far quicker than to other methods, I have found.

If you're also looking for free materials, [ECGpedia.org] (http://en.ecgpedia.org/wiki/Main_Page) is a wiki on EKGs and has some good explanations of tracings, although they don't have the greatest sample EKGs to show pathology. ECG Maven, put out by Harvard Medical School, is a good place to cut your teeth afterwards on EKGs with varying difficulties. Just make sure you click to see high resolution images because the resolution is terrible on the initial images. Finally Life in the Fast Lane has some good example EKGs, and their approach is somewhere between Dubin and Anand's.