Go find a paramedic. Or ask a nearby hospital EMS department staff what they use. Usually you'll find they teach from photocopies, hand-typed "pearls", and lots and lots of practice strips. I found this FAR better than any EKG book. Barring the time availabilities for practice strips, you can certainly get a crash course and a flow-chart type analysis for EKGs in less than 4 hours that will enable you to recognize most "bad" rhythms -- anything else you can say "gee, i dunno, but it's not normal and looks bad.....". Word: learn what's normal first. Then everything else is abnormal (not kidding here.)
Anyone else with better quick learning advice?