Figure 1.

P wave morphology Type 1 and 2. The two principal orthogonal P wave morphology types earlier observed have been denoted Type 1 and 2. Type 1 is characterized by a positive Lead X, positive Lead Y, and negative Lead Z. Type 2 is characterized by a positive Lead X, a positive Lead Y, and a biphasic Lead Z with a transition from negative to positive. P wave onset and end are marked by vertical bars.