# Effects of diltiazem and metoprolol on levels of high-sensitivity troponin I in patients with permanent atrial fibrillation: a randomized trial

## TL;DR

This study found that both diltiazem and metoprolol reduced high-sensitivity troponin I levels in patients with permanent atrial fibrillation over six months.

## Contribution

The study is the first to compare the effects of diltiazem and metoprolol on troponin levels in AF patients without heart disease or failure.

## Key findings

- Both diltiazem and metoprolol significantly reduced heart rate at rest and during exercise.
- Both drugs significantly lowered hs-TnI levels at rest and during peak exercise after six months.
- No significant differences were observed between the two treatment groups in troponin reduction.

## Abstract

High-sensitive (hs-) cardiac troponin assays provide prognostic information in atrial fibrillation (AF) patients. Few studies have explored the impact of long-term rate control therapy on levels of troponin in AF patients without coronary heart disease and heart failure. This substudy of the RATe control in Atrial Fibrillation (RATAF) II study aimed to compare the effects of six months’ treatment with diltiazem and metoprolol on hs-troponin I (TnI) levels both at rest and during exercise testing in patients with permanent AF.

This was a parallel-group, randomized, investigator-blinded clinical trial. The cohort consisted of 93 patients (28 women, mean age 71 ± 7 years) with symptomatic, permanent AF with preserved left ventricular systolic function and no coronary heart disease. Participants were randomized in a 1:1 ratio to receive either diltiazem 360 mg (n = 49) or metoprolol 100 mg (n = 44) once daily for six months. Blood tests were drawn at rest and during peak exercise testing at baseline, one month and six months’ treatment. This research has been supported by grants from the South-Eastern Norway Regional Health Authority and Vestre Viken Hospital Trust.

Six months’ treatment with diltiazem and metoprolol significantly lowered the heart rate at rest and peak exercise. Both treatment groups exhibited a decrease in hs-TnI levels at rest (diltiazem p = 0.008, metoprolol p = 0.03) and peak exercise (diltiazem p < 0.001, metoprolol p = 0.004) at six months compared to baseline levels, with no significant differences observed between the groups.

In patients with permanent AF, six months of rate control therapy with diltiazem or metoprolol lowered levels of hs-TnI. Further research is warranted to determine whether this reduction translates into an improved prognosis.

NCT02695992. Registration date: 2015–04-28.

The online version contains supplementary material available at 10.1186/s12872-025-04574-2.