Diltiazem reduces levels of NT-proBNP and improves symptoms compared with metoprolol in patients with permanent atrial fibrillation.

Aims: Short-term treatment with calcium channel blockers lowers levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) and reduces rhythm-related symptoms compared to treatment with beta-blockers. The aim of this study was to compare the longer-term effects of metoprolol and diltiazem for rate control in patients with permanent atrial fibrillation after six months.

Methods and results: Men and women with permanent atrial fibrillation and preserved left ventricular systolic function were randomised to receive either diltiazem 360 mg or metoprolol 100 mg once daily. The primary endpoint was the level of NT-proBNP after a six-month treatment period. Secondary endpoints included heart rate, rhythm-related symptoms and exercise capacity. A total of 93 patients (mean age 71 ±7 years, 28 women) were randomised. After six months' treatment, mean levels of NT-proBNP decreased in the diltiazem group and increased in the metoprolol group, with a significant between-group difference (409.8 pg/mL, 95% CI: 230.6 - 589.1, P<0.001). Treatment with diltiazem significantly reduced rhythm-related symptoms compared to baseline, but no change was observed in the metoprolol group. Diltiazem and metoprolol had similar effects on heart rate and exercise capacity.

Conclusion: Diltiazem reduced NT-proBNP levels and improved rhythm-related symptoms. Metoprolol increased peptide levels but had no impact on symptoms despite similar heart rate reduction. Non-dihydropyridine calcium channel blockers should be considered more often for rate control in permanent atrial fibrillation.