Eplerenone might affect atrial fibrosis in patients with hypertension

BACKGROUND: Eplerenone is reported to reduce the development of atrial fibrillation (AF). The aim of this study was to clarify the mechanism of eplerenone for AF prevention from the viewpoint of P wave morphology, which is reported to correlate with atrial fibrosis. METHODS: Thirty-five patients with hypertension, who were randomized to receive eplerenone (n = 16) or amlodipine (n = 19) for 1 year, were evaluated. P wave signal-averaged electrocardiography was recorded at baseline and 1 year after entry, and P wave duration (Ad) and P wave dispersion (P-disp) were obtained. Serum levels of intact procollagen type I N-terminal propeptide (PINP) and N-terminal procollagen-III peptide (PIIIP) were also measured. RESULTS: There were no significant differences in baseline clinical characteristics including Ad, P-disp, and the decrease in blood pressure at 1-year follow-up between the two groups. Ad and P-disp (mean ± standard deviation) significantly increased in patients on amlodipine after 1 year (140 ± 21 ms to 139 ± 19 ms vs 132 ± 10 ms to 136 ± 12 ms, P < 0.01 and 14 ± 7 ms to 9 ± 4 ms vs 12 ± 5 to 16 ± 8, P < 0.01, respectively). PINP was significantly more decreased in patients with eplerenone than amlodipine (56.6 ± 30.4 μg/mL to 46.6 ± 19.4 μg/mL vs 41.5 ± 16.2 μg/L to 48.7 ± 21.3 μg/L, P < 0.01). Percent changes of Ad, P-disp, PINP, and PIIIP were significantly smaller in patients with eplerenone than amlodipine (0.0 ± 4.7% vs 3.2 ± 4.4%, P < 0.05, - 28.6 ± 31.0% vs 46.3 ± 73.0%, P < 0.01, - 5.6 ± 38.1% vs 22.7 ± 42.7%, P < 0.05, and - 9.2 ± 25.1% vs 7.4 ± 19.0%, P < 0.05, respectively). CONCLUSIONS: Eplerenone reduced the increase of Ad and P-disp with a decrease of PINP and PIIIP, which might translate into reduction of atrial fibrosis. This study showed that eplerenone may be useful as upstream therapy for AF in patients with hypertension.