Nephrotic syndrome does increase the risk of atrial fibrillation (AFib) through several overlapping mechanisms, including chronic inflammation, low albumin levels, hormonal activation, and electrolyte imbalances caused by treatment. While nephrotic syndrome alone isn’t typically listed as a direct cause of AFib the way high blood pressure or heart valve disease might be, the metabolic disruption it creates sets the stage for irregular heart rhythms. People with chronic kidney disease, which often accompanies or results from nephrotic syndrome, develop AFib at roughly four times the rate of people with normal kidney function.
How Kidney Disease Raises AFib Risk
The connection between kidney problems and AFib is well established. AFib is the most common heart rhythm disorder in people with chronic kidney disease, with a reported prevalence of 15% to 20%. By comparison, people with normal kidney function have an AFib prevalence of only about 3% to 4%. A large study of nearly 20 million people found that new AFib diagnoses occurred in 2.2% of those with non-dialysis kidney disease and 4.3% to 4.5% of those on dialysis, compared to just 0.6% of those without kidney disease.
Nephrotic syndrome specifically contributes to this risk because the heavy protein loss in urine triggers a cascade of problems that affect the heart. The more protein lost, the greater the danger. Research in patients with diabetes found that increasing levels of protein in the urine correlated with progressively higher rates of new AFib in a dose-dependent pattern, meaning each jump in protein loss brought a measurable jump in AFib risk.
Why Protein Loss Disrupts Heart Rhythm
The hallmark of nephrotic syndrome is losing large amounts of albumin through the kidneys. Albumin is the most abundant protein in your blood, and it does far more than maintain fluid balance. It acts as a powerful anti-inflammatory agent, and when levels drop, inflammation throughout the body rises. Levels of inflammatory markers like C-reactive protein and tumor necrosis factor-alpha climb, and this chronic inflammatory state directly damages heart tissue.
Inflammation is one of the key drivers of AFib because it promotes structural changes in the heart’s upper chambers (the atria). Research on nephrotic syndrome has shown that sustained protein loss triggers elevated levels of inflammatory molecules in heart tissue itself, while simultaneously reducing the function of calcium-handling proteins that control how heart muscle contracts and relaxes. These changes, collectively called cardiac remodeling, alter the electrical environment of the heart in ways that make erratic signaling more likely.
The Hormonal Cascade That Stiffens the Heart
Nephrotic syndrome activates a hormonal system called the renin-angiotensin-aldosterone system (RAAS), which normally regulates blood pressure, sodium balance, and fluid volume. In nephrotic syndrome, this system goes into overdrive because the kidneys retain too much sodium and fluid balance is disrupted.
When RAAS stays chronically activated, it promotes fibrosis, the buildup of stiff scar-like tissue in the heart and blood vessels. This stiffening happens through a specific growth factor signaling pathway that lays down excess collagen. Over time, the heart becomes less flexible, diastolic relaxation suffers, and the structural changes in the atria create fertile ground for AFib circuits to form. Clinical trials using medications that block this hormonal system (ACE inhibitors and related drugs) have shown improvement in cardiac stiffness, which is one reason these medications are commonly prescribed in kidney disease.
Diuretics Can Add Fuel to the Fire
One of the more underappreciated connections between nephrotic syndrome and AFib involves the treatment itself. Diuretics are a cornerstone of managing the severe swelling that comes with nephrotic syndrome, but both loop diuretics and thiazide diuretics deplete potassium and magnesium. Low levels of either mineral can trigger or worsen cardiac arrhythmias, including AFib.
When loop and thiazide diuretics are used together for resistant edema, the losses of these minerals compound. Clinical guidelines emphasize that edema in nephrotic syndrome should be reduced gradually, because aggressive diuresis can cause electrolyte disturbances, kidney injury, and even blood clots from the blood becoming too concentrated. If you’re taking diuretics for nephrotic syndrome and notice heart palpitations, skipped beats, or a racing pulse, your electrolyte levels are worth checking promptly. Oral supplements or potassium-sparing diuretics are commonly used to offset these losses.
Why the Combination Raises Stroke Risk
Having both nephrotic syndrome and AFib is a particularly concerning combination because each condition independently raises the risk of blood clots. Nephrotic syndrome creates a hypercoagulable state: low albumin shifts the balance of clotting proteins in the blood, making clots form more easily. AFib allows blood to pool in the heart’s upper chambers, which also promotes clot formation. Together, these effects compound each other. Data from a Danish national registry found that renal failure increased stroke risk in AFib patients by up to 83%.
Managing this dual risk with blood thinners is complicated. Kidney disease changes how the body processes anticoagulant medications, and the bleeding risk rises as kidney function declines. For people on dialysis, evidence remains limited. Only one newer blood thinner has been approved for use in dialysis patients. In some cases, forgoing anticoagulation entirely may be a reasonable strategy, particularly in advanced kidney disease, because the bleeding risks can outweigh the benefits. The decision is highly individual and depends on the severity of both conditions.
Recognizing AFib With Nephrotic Syndrome
AFib can feel like a fluttering or racing heartbeat, a sensation that the heart is skipping beats, lightheadedness, or unusual fatigue. In some people it causes no noticeable symptoms at all and is found incidentally. If you have nephrotic syndrome, these symptoms deserve attention because the underlying protein loss, inflammation, and hormonal changes mean your heart is under more stress than it would be otherwise. AFib that goes undetected and untreated raises stroke risk significantly, and that risk is amplified when kidney disease is already in the picture.
The degree of protein loss matters. Heavier proteinuria correlates with higher AFib risk in a graded fashion, so worsening kidney disease should prompt closer cardiac monitoring. Controlling the underlying nephrotic syndrome, whether through immunosuppressive therapy, dietary changes, or medications that reduce protein loss, addresses some of the root causes that make AFib more likely.