In patients with systemic sclerosis-related pulmonary hypertension (SSc-PH), right axis deviation (RAD) and left axis deviation (LAD) reflect structural cardiac abnormalities are associated with worse outcomes and increased risk for mortality, according to findings published in Arthritis Care & Research. Researchers suggested the importance of the inexpensive, widely available, and noninvasive diagnostic test of electrocardiography in risk stratification.
A common complication of SSc that is associated with accelerated mortality is SSc-PH; however, it is unclear if electrical cardiac axis deviations also indicate a poorer prognosis for patients compared with those without such deviations. Study investigators hypothesized that cardiac axis deviation may indicate cardiac function abnormalities, allowing for predictions of disease severity and mortality.
They conducted a retrospective cohort study reviewing electrocardiograms (ECGs) of patients with SSc-PH for cardiac axis deviation and assessed whether it is associated with echocardiography and cardiopulmonary hemodynamics on right heart catheterization (RHC). The primary study outcome was all-cause mortality from the time of PH diagnosis.
ECGs of 169 study participants with SSc-PH were reviewed; right axis deviation (RAD) was seen in 28.4% of participants, and left axis deviation (LAD) was seen in 30.8%. Twenty-five participants (14.8%) were lost to follow-up, and 22 participants (13.0%) did not reach 5 years of follow-up. After these participants were excluded, the 5-year all-cause mortality was 41.8%. Using a univariable Cox proportional hazards regression, significant associations with all-cause mortality were found for male sex (hazard ratio [HR] 2.34; 95% CI, 1.36-4.04; P =.002), forced vital capacity (FVC) % predicted (HR 0.98; 95% CI, 0.96-0.99; P =.001), New York Heart Association (NYHA) functional class III-IV (HR 1.87; 95% CI, 1.08-3.24; P =.026), and treatment with pulmonary arterial hypertension (PAH)-specific medications (HR 4.08; 95% CI, 2.17-7.66; P <.001).
Diffuse cutaneous SSc subtype classification or age at PH diagnosis was not associated with mortality. RAD presence within 1 year after PH diagnosis was associated with an HR of 10.06 (95% CI, 5.35-18.95; P <.001) for all-cause mortality.
After adjusting for male sex, FVC % predicted, NYHA functional classification, age at PH diagnosis, receipt of PAH-specific medications, and diffuse cutaneous SSc subtype classification, the researchers used multivariable Cox proportional hazards regression to find that RAD within 1 year after PH diagnosis was associated with an HR of 3.69 (95% CI, 1.24-10.98; P =.019) for all-cause mortality. In the adjusted model, LAD was associated with an HR of 2.94 (95% CI, 1.53-5.68; P =.001) for all-cause mortality.
Despite the inherent limitations of a retrospective study, investigators concluded that “abnormalities in cardiac conduction, particularly cardiac axis deviation are common in SSc-PH. RAD was associated with increase PH severity by cardiopulmonary hemodynamics. Furthermore, both RAD and LAD were associated with increased hazard of mortality suggesting a role for ECGs, an inexpensive, widely available noninvasive test, in prognostication of patients with SSc-PH.”
Disclosure: Multiple study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Lui JK, Sangani RA, Chen CA, et al. The prognostic value of cardiac axis deviation in systemic sclerosis-related pulmonary hypertension [published online June 3, 2021]. Arthritis Care Res (Hoboken). doi: 10.1002/acr.24724