Question: what is backflow of blood in the heart called
[{'answer': 'Regurgitation', 'provenance': [{'wikipedia_id': '6171862', 'title': 'Regurgitation (circulation)', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 13, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6171862', 'title': 'Regurgitation (circulation)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 269, 'bleu_score': 0.9529077664391161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10928508467657335086}, 'section': 'Section::::Abstract.'}]}]