Table 5– Prospective validation of the Classification and Regression Tree algorithm

Pre-capillary PH diagnosed by RHC	RVS	No RVS and NT-proBNP >80 pg·mL⁻¹	No RVS and NT-proBNP ≤80 pg·mL⁻¹	Total
Yes	41	23	0	64
No	11	35	11	57
Total	52	58	11	121

Data are presented as n and results reflect the true predictive power of the decision tree because the prospectively recruited patients did not contribute to decision tree construction. A total of 121 patients were studied. Right ventricular strain (RVS) pattern was present in 52 patients, 41 of whom were diagnosed with pre-capillary pulmonary hypertension (PH) by right heart catheter (RHC). Patients without RVS pattern on ECG (n = 69) were further dichotomised according to serum N-terminal brain natriuretic peptide (NT-proBNP) levels. 58 patients displayed serum NT-proBNP levels >80 pg·mL⁻¹; of these 23 were diagnosed with pre-capillary PH. In contrast, none of the 11 patients with serum NT-proBNP ≤80 pg·mL⁻¹ were diagnosed with pre-capillary PH.