Association of Electrocardiographic Signs of Right Ventricular Hypertrophy and Clot Localization in Chronic Thromboembolic Pulmonary Hypertension

The role of electrocardiography (ECG) in chronic thromboembolic pulmonary hypertension (CTEPH) diagnosis and prognosticating has not been yet established. We aimed to assess the relationships of the recommended ECG criteria of right ventricular hypertrophy (RVH) with clot localization in CTEPH patients. ECG patterns of RVH according to the American College of Cardiology Foundation were assessed in patients with newly diagnosed CTEPH. We enrolled 58 (45.3%) patients with proximal and 70 (54.7%) with distal CTEPH. Receiver-operating characteristics curves analysis indicated that the following ECG abnormalities predicted proximal CTEPH localization: R(V1) > 6 mm—AUC 0.75 (CI: 0.66–0.84, p < 0.00001); S(V6) > 3 mm—AUC 0.70 (CI: 0.60–0.79, p < 0.00001); S(I) > R(I) wave—AUC 0.67 (CI: 0.58–0.77, p = 0.0004); R(V1):S(V1) > 1.0—AUC 0.66 (CI: 0.56–0.76, p = 0.0009); R(V1) peak > 0.035 s (QRS < 120 ms)—AUC 0.66 (CI: 0.56–0.75, p = 0.0016); R(V1):S(V1) > R(V3(V4)):S(V3(V4)—)AUC-0.65 (CI: 0.54–0.75, p = 0.0081); R(aVR) > 4 mm—AUC 0.62 (CI: 0.52–0.71, p = 0.002) and P(II) > 2.5 mm—AUC 0.62 (CI: 0.52–0.72, p = 0.00162). Pulmonary vascular resistance significantly correlated with amplitudes of R(V1) (r = 0.34, p = 0.008), S(V6) (r = 0.53, p = 0.000027) and P(II) (r = 0.44, p = 0.00007). In patients with CTEPH, only 8 out of 23 ECG RVH criteria were useful for differentiating between proximal and distal CTEPH localization and we found that R(V1) and S(V6) may contribute as potential discriminators.