Right Atrium Enlargement Predicts Supraventricular Arrhythmia Risk in PAH

Enlargement of the right atrium (RA) is associated with an increased risk for supraventricular arrhythmias (SVAs) in patients with pulmonary arterial hypertension (PAH), according to study findings published in Heart & Lung.

Investigators recruited 97 consecutive adult patients with PAH from 2010 to 2014 and followed the patients until January 2017. Treatment-naïve patients and patients with a history of treatment for PAH were included in this study. The investigators also examined specific predictors of newly diagnosed clinically significant SVA (csSVA) in patients with no history of SVA at enrollment.

Almost half of the patient population (46.4%) had any SVA, including paroxysmal atrial fibrillation (AF) (n=10), permanent AF (n=8), paroxysmal atrial flutter (n=2), permanent atrial flutter (n=1), or other types of supraventricular tachycardia (n=24). Patients with SVA were older (57.2±13.1 vs 39.2±15.4; P <.0001), walked a shorter distance in the 6-minute walking test (332.6±109.5 m vs 376.7±111.1 m; P =.047), and were more likely to be treated with beta-blockers (55.6% vs 15.4%; P <.0001) compared with patients without SVA.

These patients also had higher NT-proBNP levels (3206.1±4400.7 vs 1259.1±1730.0; P =.004), higher RA area index (19.0±4.9 cm²/m² vs 14.6±3.7 cm²/m²; P <.0001), higher left atrial area index (13.1±4.9 cm²/m² vs 11.2±3.8 cm²/m²; P =.048), and greater mean RA pressure (7.7±3.9 mm Hg vs 6.0±4.9 mm Hg; P =.01).

In patients with no history of csSVA who were in sinus rhythm at enrollment (n=85), csSVA occurred in 15.3% during an observation period of 37.0±19.9 months. Age, right ventricular ejection fraction, right ventricular end diastolic index, RA area index, and mean RA pressure were the best predictors of csSVA occurrence in this cohort. In a multivariate analysis, however, only RA area index demonstrated significant predictive value for csSVA in patients with PAH (hazard ratio, 1.23; 95% CI, 1.11-1.36; P =.0001). An RA enlargement of 21.7 cm²/m² was deemed the optimal threshold for determining csSVA.

Although the findings from this study may provide important clinical implications for patients with PAH, further research with more participants may be needed to verify the study results.

The investigators suggested that “patients with a large RA, especially larger than >21.7 cm²/m², should undergo a comprehensive risk assessment and treatment escalation to prevent disease progression.”

Reference

Waligóra M, Tyrka A, Miszalski-Jamka T, et al. Right atrium enlargement predicts clinically significant supraventricular arrhythmia in patients with pulmonary arterial hypertension [published online February 14, 2018]. Heart Lung. doi:10.1016/j.hrtlng.2018.01.004