A major clinical trial found that treating atrial fibrillation with early rhythm control significantly reduces the risk of cardiovascular death, stroke, heart failure hospitalization, and heart attacks in patients with mild to moderate chronic kidney disease (CKD). The findings suggest a new treatment approach for a common complication affecting kidney patients, though researchers emphasize the need for more study in those with advanced kidney disease.

What Is the Connection Between Atrial Fibrillation and Kidney Disease?

Atrial fibrillation, or AFib, is an irregular heartbeat that affects millions of people. For those with CKD, the combination can be particularly dangerous. A separate study using Japanese health records found that new-onset AFib accelerates kidney function decline in working-age adults. Among nearly 24,000 people with newly diagnosed AFib, kidney function declined at a rate of 1.23 mL/min/1.73 m2 per year, compared to 0.94 mL/min/1.73 m2 in healthy controls. This difference suggests that managing AFib effectively may help preserve kidney function.

The EAST-AFNET 4 trial, an international study involving 2,789 patients, directly compared two treatment strategies for AFib in people with kidney disease. About 23% of trial participants had CKD, with most having mild to moderate kidney function loss. Researchers randomly assigned patients to receive either early rhythm control (attempting to restore normal heart rhythm) or usual care with rate-control drugs (allowing an irregular rhythm but controlling how fast the heart beats).

How Does Early Rhythm Control Compare to Standard Treatment?

The results favored early rhythm control across both groups. Among kidney disease patients, the composite outcome of cardiovascular death, stroke, heart failure hospitalization, or acute coronary syndrome occurred in 5.8% of those receiving early rhythm control per 100 person-years, compared to 8.5% in the usual care group. For patients without kidney disease, the rates were 3.4% versus 4.1%, respectively.

Early rhythm control proved especially effective at preventing AFib recurrence in kidney disease patients. Those receiving rhythm control had a 35% lower risk of AFib returning compared to those on rate-control drugs. Importantly, kidney function remained stable in all groups over the two-year study period, with no significant decline in glomerular filtration rate (GFR), a key measure of kidney function.

What Are the Key Findings for Kidney Disease Patients?

• Cardiovascular Protection: Early rhythm control reduced the combined risk of death, stroke, heart failure hospitalization, and heart attacks in kidney disease patients by approximately 32% compared to standard rate-control treatment.
• AFib Prevention: Kidney disease patients receiving early rhythm control had significantly better protection against AFib recurrence, with a hazard ratio of 0.65 compared to 0.82 in non-kidney disease patients.
• Kidney Function Stability: Neither treatment strategy caused measurable decline in kidney function over two years, suggesting both approaches are safe for the kidneys themselves.

However, the study revealed an important caveat. Patients with kidney disease receiving early rhythm control experienced a higher rate of safety events (27.2%) compared to those without kidney disease (13.8%). This suggests that while the treatment is effective, kidney disease patients may need closer monitoring during therapy.

"Early rhythm control effectively and safely reduced a composite outcome of death, stroke, hospitalization for heart failure, and acute coronary syndrome with and without CKD," noted Paulus Kirchhof, MD, of the University Heart and Vascular Center Hamburg. "These findings support the use of early rhythm control in patients with AFib and CKD, while highlighting the need for further dedicated studies in this field."

Paulus Kirchhof, MD, University Heart and Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf

What Do Experts Say About Advanced Kidney Disease?

One important limitation emerged from the trial: very few participants had advanced CKD, and none were on dialysis. In the small subset of patients with the most severe kidney disease, early rhythm control was not significantly more effective than usual care and actually led to higher safety event rates. This gap in evidence prompted editorialists to call for more rigorous research in advanced kidney disease populations.

"This treatment paradigm continues to evolve as we can now advocate for a rhythm-control strategy for AFib in patients with mild-to-moderate CKD," wrote Poojita Shivamurthy, MD, and Rajat Deo, MD, MTR, of Penn Medicine. "However, to understand the role of rhythm control in advanced CKD, we need rigorous analytic methods that account for the competing risk of noncardiovascular events and a net clinical benefit assessment in future studies."

Poojita Shivamurthy, MD, and Rajat Deo, MD, MTR, Penn Medicine, University of Pennsylvania

The findings represent a meaningful advance for the estimated 37 million Americans with CKD who may also develop AFib. For those with mild to moderate kidney disease, early rhythm control offers a new option that may reduce serious cardiovascular complications. Yet the research also underscores that kidney disease is not a single condition; treatment strategies that work well for some patients may need adjustment for others with more advanced disease. Nephrologists and cardiologists will likely use these results to refine how they manage AFib in their kidney disease patients, while researchers continue investigating the best approach for those with severe kidney dysfunction.