Impact of Pirfenidone on Arrhythmic and Clinical Outcomes in Patients With Idiopathic Pulmonary Fibrosis

BACKGROUND: Atrial fibrosis is an important substrate for atrial fibrillation (AF), especially in structural heart disease. A previous study reported that pirfenidone, an antifibrotic agent, reduced atrial and left ventricular fibrosis in an animal model. OBJECTIVE: The present research aims to evaluate the effects of pirfenidone on arrhythmic and clinical outcomes in patients with idiopathic pulmonary fibrosis (IPF). METHODS: Our database of patients diagnosed with IPF between 2008 and 2023 was used to obtain echocardiography, electrocardiography (ECG), and 24-h Holter monitoring data. The study included all patients with IPF treated with or without pirfenidone. We compared arrhythmic events, including AF, atrial premature complexes, atrial tachycardia, and ventricular arrhythmias, as well as clinical outcomes based on pirfenidone use. RESULTS: Among 248 patients with IPF (74.0 ± 8.9 years), 106 (41.2%) received pirfenidone. No differences in the baseline characteristics were observed. During a median 36-month follow-up period, a lower incidence of arrhythmic events (p = 0.001) and diastolic dysfunction (p = 0.025) were observed in the pirfenidone group. Univariate analysis showed associations between arrhythmic events and hypertension, coronary artery disease, higher body weight, longer PR interval, QRS duration, and absence of pirfenidone use. In a multivariable analysis, higher body weight and absence of pirfenidone use were independent risk factors for arrhythmic events. CONCLUSIONS: Pirfenidone use to treat IPF was associated with fewer arrhythmic events and less diastolic dysfunction compared to patients who did not use pirfenidone during long-term follow-up. Additionally, obesity is associated with a higher incidence of arrhythmic events in patients with IPF.