We have decided to embark on the second monograph consisting of case studies in electrophysiology and clinical electrophysiology. This was done because of the unexpected and heartening response to the first monograph. The initial effort 3 years ago grew out of a conviction that cardiac rhythm specialists enjoy the challenge of evaluating tracings and matching wits with the authors. This need was felt to be especially important as more and more cardiac journals have chosen to either omit or strictly limit acceptance of case reports. This issue contains entirely fresh cases gleaned from colleagues from all over the country, and we are grateful for the effort and time expended to provide these case gems. In addition, we have changed the format in that we added an article related to the diagnoses and localization of acute myocardial infarction using a vectorial approach. We are indebted to our master teacher, Dr Riera, for providing both the excellent case material and the conceptual framework for using this exciting approach to diagnoses of myocardial infarction. Similarly, we thank Dr Nelson for his