###HUMAN: count the number of patients whose diagnoses short title is atrial fibrillation and drug route is tp?, ###ASSISTANT: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE diagnoses.short_title = "Atrial fibrillation" AND prescriptions.route = "TP"