The present disclosure describes methods, devices, and systems for generating, adjusting, and using cardiac waveform morphology templates. The morphology templates include target regions associated with features of cardiac waveforms. The target regions may be adjusted based on relationships between the target regions and features of detected cardiac waveforms associated with the target regions. The templates may be used to analyze cardiac waveforms to classify or monitor various waveform morphologies. Templates may be created or eliminated, for instance, based on a frequency of use. According to one approach, template creation involves providing target regions defined by one or more characteristics. The target regions are adjusted based on detected cardiac waveform features having similar characteristics. A template may be created using the target regions adjusted by this process.