ICD 9 Codes 401 for Essential ypertension ICD 9 codes for Essential hypertension 401.0, 401.1, 401.9. ICD 9 Codes 402 for Hypertensive Heart Disease ICD 9 codes for Hypertensive heart disease 402.00, 402.01, 402.10, 402.11, 402.90, 402.91.