Utility of the amplitude of RV1+SV5/6 in assessment of pulmonary hypertension

Electrocardiogram (ECG) has been widely used for assessment of right ventricular (RV) hypertrophy (RVH) in patients with pulmonary hypertension (PH). However, it still remains unclear which ECG criteria of RVH are useful to predict for the severity of PH. The aim of our study was to examine the utility of ECG findings of RVH in assessment of PH. A total of 53 patients (42 women, mean age; 57.6 ± 16.4 years) with pre-capillary PH, who were diagnosed by right heart catheterization, underwent blood sampling, ECG, and cardiac magnetic resonance within a week before the right heart catheterization. We assessed the traditional ECG criteria of RVH in PH patients, and compared to age- and gender-matched control subjects without PH confirmed by 2-dimensional echocardiography (n = 42, mean age 55.3 ± 15.9 years). We also analyzed the clinical variables associated with ECG findings in patients with PH. Mean pulmonary arterial pressure (mPAP), cardiac index, and pulmonary vascular resistance (PVR) in PH patients were 35.3 ± 11.9 mmHg, 2.82 (2.09-3.45) L/min/m2, and 576 ± 376 dyne·sec·cm-5, respectively. The prevalence of right axis deviation (43.4%), R:S ratio V1 > 1 (32.1%), and RV1+SV5/6 > 10.5 mm (69.8%) in PH patients was greater than those in control subjects (p < 0.001). In univariate analysis, mPAP, PVR, RV wall thickness, RV mass index, RV volume, and RV ejection fraction (EF) (inversely) were significantly correlated with the amplitude of RV1+SV5/6. Multiple regression analysis revealed that mPAP and RVEF (inversely) were independently associated with the amplitude of RV1+SV5/6 (R2 = 0.282). Also, we performed the survival analysis among pre-capillary PH patients. During a mean follow-up of 3.7 years, patients with ≥ 16.4 mm of RV1+SV5/6 had worse prognosis than those with < 16.4 mm (Log rank p = 0.015). In conclusion, the amplitude of SV1+RV5/6 could be the most useful factor reflected for RV remodeling, hemodynamics and survival in patients with pre-capillary PH.