Question: where is the av nodal delay represented in the ecg
[{'answer': 'PR segment', 'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 26, 'start_character': 259, 'end_paragraph_id': 26, 'end_character': 269, 'bleu_score': 1.0, 'section': 'Section::::ECG.:AV node and bundles: PR interval.\n'}]}, {'provenance': [{'wikipedia_id': '650897', 'title': 'Electrical conduction system of the heart', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 352, 'bleu_score': 0.948486611721371, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3748429189967747683}, 'section': 'Section::::ECG.:AV node and bundles: PR interval.\n'}]}]