Figure 3 shows that six features are informative to predict patient origin (i.e., differ between partner sites): patient status, use of beta blockers and ACE inhibitors, systolic blood pressure, NYHA classification, and first diagnosis date of HF. For example, node 7 in Figure 3 shows that a subset of Heidelberg patients is characterized by outpatient status, absence of beta blockers, presence of ACE inhibitors, and a systolic blood pressure of ≤130 (i.e., absence of hypertension). Here, ACE is linked to hydrops fetalis.