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OBJECTIVE: Systemic sclerosis-related pulmonary hypertension (SSc-PH) is a common complication of SSc associated with accelerated mortality. We hypothesized that cardiac axis deviation may indicate abnormalities in cardiac function allowing for prognostication of disease severity and mortality. METHODS: This was a retrospective study where electrocardiograms (ECGs) were reviewed for cardiac axis deviation and their association with echocardiography and cardiopulmonary hemodynamics on right heart catheterization. The primary outcome observed was all-cause mortality from the time of PH diagnosis. RESULTS: ECGs were reviewed from 169 patients with SSc-PH. Right axis deviation (RAD) and left axis deviation (LAD) occurred in 28.4% and 30.8% of patients with SSc-PH, respectively. Compared to those without, patients with RAD exhibited predominantly right-sided cardiac disease on echocardiography and increased PH severity by cardiopulmonary hemodynamics including a greater mean pulmonary artery pressure (42.0 ± 12.5 mm Hg vs. 29.8 ± 7.0 mm Hg) and pulmonary vascular resistance (645.6 ± 443.2 dyns/cm(5) vs. 286.3 ± 167.7 dyn·s/cm(5)). LAD was associated with predominantly left-sided cardiac disease on echocardiography but was not associated with PH severity on cardiopulmonary hemodynamics. Both RAD (HR: 10.36; 95% CI: 4.90 - 21.93; p < 0.001) and LAD (HR: 2.94; 95% CI: 1.53 – 5.68; p = 0.001) were associated with an increased hazard for all-cause mortality. CONCLUSION: RAD and LAD reflect structural cardiac abnormalities and are associated with poor prognosis in patients with SSc-PH. These findings support the importance of electrocardiography, an inexpensive, widely available non-invasive test, in risk stratification.