ECG has specificity of 70% and sensitivity of 55% in the diagnosis of PH [23]. The ECG signs of right ventricular dysfunction are right bundle branch block, rotation of the electrical cardiac axis to the right, right heart hypertrophy (R>S in V1), right ventricular repolarisation dysfunction (“right ventricular strain” RVS) and a “P pulmonale” indicating an enlarged right atrium (Figure 1) [24].

New algorithm with ECG and NT-proBNP

In the event of clinical and echocardiographic suspicion of PAH, the ECG is first checked for the presence of T wave inversions/ ST segment depressions in the chest leads (V2–V4) (“right ventricular strain pattern” – RVS). If RVS is found, the patient should always be referred for RHC. If RVS is not present, the serum concentration of NT-proBNP decides whether RHC should be performed. PAH can be ruled out with a probability verging on certainty in patients with no RVS and NT-proBNP levels ≤ 80 pg/ml. RHC is therefore not required. Thus, by using an electrocardiogram and serum values of n-terminal natriuretic peptide, 90% of all exclusion catheterisations can be avoided without overlooking a single case of genuine pulmonary arterial hypertension [25].