Role of the electrocardiogram in the risk stratification of pulmonary hypertension

Introduction: The prognosis of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) remains dismal. Better risk prediction is needed. This study investigated the prognostic value of ECG characteristics.

Methods: In this single-centre prospective study, consecutive treatment-naïve patients with PAH or CTEPH were included at time of diagnosis. From the 12-lead ECG, obtained at baseline, the following parameters were collected: heart rate (HR), rhythm, QRS axis, conduction times, P-top amplitudes in II, R-top and S-wave amplitudes in V1 and V5 and repolarisation disorders. Associations between the ECG and transplant-free survival was assessed by Kaplan-Meier curves and Cox-proportional hazard regressions.

Results: In total, 140 patients were included (median age: 60.7 years, 63.6% female). The ECG was abnormal in 86.2%: sinus rhythm was not present in 9.3%, right QRS axis was observed in 47.8%, mean QRS duration was 101±17 ms. Only 42.5% of the patients had normal repolarisation, 34.5% had right ventricular strain and 14.4% non-specific repolarisation disorders. Over a median follow-up time of 3.49 (IQR: 1.37-6.42) years, 45 patients (32.5%) died or underwent lung transplantation. Transplant-free survival was worse in patients presenting with an abnormal ECG (64.0% vs 86.0%; p=0.037). The following ECG characteristics were associated with all-cause mortality or lung transplantation: heart rate (HR 1.02, 95% CI: 1.00 to 1.05), QRS duration >120 ms (HR 2.61, 95% CI: 1.01 to 6.71) and S-wave amplitude in V5 (HR 1.10, 95% CI: 1.04 to 1.17).

Conclusion: Only 13.8% of patients with PAH and CTEPH presented with a normal ECG, which is associated with favourable outcome. The ECG provides additional prognostic value to current clinical parameters and should be considered in risk prediction.