TO THOSE with extensive electrocardiographic experience, especially if it includes a large proportion of young adults, the finding of the pattern of a short PR interval and a prolonged QRS complex comes as no great surprise. That it is not a rare occurrence, as might be concluded from the many papers in the literature reporting one or two cases, needs to be emphasized, because this combination is still all too frequently misinterpreted as being of clinical significance. Such misinterpretation might be considered negligible if the electrocardiographic findings occurred but rarely. On the other hand, if the pattern is as frequent . . .