Rapid Weight Loss and Arrhythmia

Heart arrhythmia is an irregular heartbeat that can develop when the electrical signals that coordinate your heartbeats are not working correctly. Several things can contribute to this condition, including rapid changes in body weight.

“We know that excess weight has negative impacts on health. So, we often recommend weight loss for people who want to improve their overall health. However, extreme and rapid weight loss can have side effects, including heart arrhythmia,” says Lindsay Harris, MBA, APRN, NE-BC, a Mass General Brigham advanced practice registered nurse. Harris is senior nursing director for Advanced Practice Nursing at Brigham and Women’s Hospital, where she cares for cardiac patients.

Harris shares what patients need to know about arrhythmias from rapid weight loss, and how they’re treated.

How weight loss can lead to arrhythmia

Rapid weight loss can cause an arrhythmia due to rapid changes in:

• Body composition

• Electrolyte and nutrient balance

• Hydration

“These changes can all impact heart function and rhythm,” says Harris. “Electrolyte changes during weight loss are often the cause of arrhythmia.”

Electrolytes are minerals such as sodium and potassium. They help carry the electrical signals that maintain a normal heartbeat. Large weight changes over a short period of time can shift electrolyte levels.

Lack of nutrients and water can also play a role in arrhythmias brought on by rapid weight loss. Not getting enough water can upset electrolyte balance. Not getting enough nutrients from a very restrictive diet can cause low levels of essential nutrients and electrolytes.

Atrial fibrillation and weight loss

“We like to focus on gradual weight loss through lifestyle changes when we talk about weight loss and management,” says Harris. However, surgery and weight loss drugs can create excellent long-term results in the types of patients they’re intended for.

Any method of rapid weight loss may affect heart function and cause arrhythmia such as atrial fibrillation, or Afib. The extent of weight loss that may cause arrhythmia depends on the individual. “It’s personal and depends on starting weight, how quickly the weight was lost, and other factors,” says Harris.

In general, the more rapid the weight loss, the higher the risk. Your care team can help you minimize your risk.

Harris discusses different methods of rapid weight loss and how they may lead to arrhythmia:

Calorie restriction and heart arrhythmia

Research from the European Society of Cardiology shows that cutting calories too much can cause changes in heart function. Calories are a measure of how much energy a food provides for your body to use.

“Restricting to 600 to 800 calories per day over time can negatively impact heart function,” says Harris. “This calorie restriction can cause changes that interfere with the heart’s electrical system.”

Anything that affects the heart’s electrical signals can cause abnormal heart rhythm. Another study in the Journal of the American Heart Association showed that low-carb diets, which some people use to lose weight, increased the risk of Afib.

Weight loss surgery and heart arrhythmia

The more severe and rapid the weight loss is, the more it can affect your body and increase the risk of developing arrhythmia. Extreme, sudden nutrition intake changes, which are common after weight loss surgery, can also contribute to arrhythmia.

“The nutrition changes following bariatric surgery, for example, can upset the body’s normal functioning,” says Harris. “Again, it comes back to changes in nutrition and electrolytes that can impact heart function.”

Over-exercising and heart arrhythmia

Excessive exercise can cause dehydration, which can shift electrolyte balance. Over-exercising can also cause inflammation and changes in the heart's structure, raising the risk of arrhythmia.

Weight loss medications and heart arrhythmia

“We’ve had an influx of weight loss medications into the market, and we don’t have much data yet about their longer-term impacts on heart health,” says Harris. “Right now, there’s some conflicting information about how these drugs may affect arrhythmias.” However, any method of extreme and rapid weight loss, including medications, carries the risk of an arrhythmia.

Is an arrhythmia from rapid weight loss reversible?

Yes, weight-loss-induced arrhythmia is often reversible, but you may need treatment. “Some types of arrhythmias are more reversible or treatable than others. Different types require different treatments,” says Harris.

Depending on the type and severity of the arrhythmia, you may need treatment such as medication or surgery.

“If you develop an arrhythmia due to rapid weight loss, part of the treatment is also balanced nutrition, calorie intake, hydration, and activity in addition to medication or surgery,” says Harris.

Your primary care provider, cardiologist, or electrophysiologist can help you implement these lifestyle changes. Harris confirms that working closely with your care team before, during, and after weight loss is the best way to protect your heart health and prevent arrhythmias.