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Calcium Channel Blockers for AFib: What to Know

Medically Reviewed by James Beckerman, MD, FACC on July 11, 2022

When you have atrial fibrillation, the two upper chambers of your heart (atria) don't beat in sync with the two lower chambers (ventricles). This makes your heart beat out of rhythm and sometimes very fast. It can cause symptoms like shortness of breath, dizziness, and chest pain.

Medicines to help control your heart rate – the number of times your heart beats – and rhythm are an important part of treatment for atrial fibrillation (AFib). Calcium channel blockers are one type. They treat AFib by slowing your heart rate and relaxing the heart muscle so it doesn't have to work as hard.

AFib also raises your risk for heart failure. That’s when your heart can't pump out enough blood to meet your body's needs. If your heart can't beat strongly enough, blood can pool in your heart and form clots. A clot could travel to your brain and cause a stroke. This can happen even if your AFib doesn’t lead to heart failure.

How Do Calcium Channel Blockers Help With AFib?

Calcium channel blockers help control your heart rate and lower your blood pressure if it's high. They also ease AFib symptoms and make it easier to exercise. Staying active is important to protect your heart.

These medications won't stop AFib from getting worse, though. If you have persistent AFib, which lasts more than 7 days, it could still turn into the permanent type, which lasts longer than a year.

How Do Calcium Channel Blockers Work?

Calcium is a mineral that helps your heart and blood vessels squeeze (contract) to push blood throughout the body. Calcium channel blockers don't let as much calcium get into the cells of your heart muscle and blood vessels. This relaxes the heart and allows blood vessels to widen. Your heart doesn't have to work as hard to pump blood.

Two calcium channel blockers treat AFib:

How Do You Take Calcium Channel Blockers?

The calcium channel blocker you take comes as a capsule or tablet. Your doctor might start you on a low dose, then raise it if your symptoms still aren't under control. Your heart rate and blood pressure play a role in which dose you get.

If you have severe AFib symptoms, you'll get these medicines through an IV in a hospital.

You might take calcium channel blockers on their own or with other rate control medicines to help them work better. Regular checkups are important when taking this medication.

Possible side effects of calcium channel blockers include:

Tell your doctor if you have any of these. There may be things you can do to ease them.

Call 911 or go to the hospital right away if you have:

  • Severe chest pain
  • A severe headache
  • Shortness of breath you haven’t had before
  • Swelling of your mouth, tongue, or lips

Avoid grapefruit and grapefruit juice when taking calcium channel blockers. They can interact with these medicines and increase side effects such as dizziness and headache.

Some calcium channel blockers can affect kidney function. So you may need tests to check how well your kidneys are working.

Who Shouldn't Take Calcium Channel Blockers?

Calcium channel blockers may not be safe if you’ve had a heart attack or have:

You shouldn't take calcium channel blockers if you have a type of heart failure called left ventricular failure. That’s when your left ventricle is so damaged that it can't pump enough blood to your body. Another name for this is heart failure with reduced ejection fraction. Calcium channel blockers make it worse because they slow your heartbeat and lower the amount of blood your heart pumps even more.

You also shouldn't take them if you have a severe heart block (AV block). That’s when problems with your heart's electrical system keep it from pumping enough blood. Calcium channel blockers also aren't recommended if you have sick sinus syndrome – damage to your right atrium that affects your heart rhythm.

What Other Medicines Treat AFib?

Calcium channel blockers work very well at controlling the heart rate, but they don't help everyone. If you don't get better on calcium channel blockers or you have bothersome side effects, you can try a different type of rate control medicine.

Digoxin (Lanoxin) treats AFib. So do these beta-blockers:

Beta-blockers are about as safe and effective as calcium channel blockers. Digoxin is also good for controlling the heart rate, but it can lead to serious side effects.

Rhythm control medicines are another way to treat an abnormal heart rhythm from AFib. Your heart rhythm is the pattern of your heartbeat. In AFib, it may be too fast or irregular.

Rhythm control medicines might work if you can't take rate control medicines or they don't help. Some people take these medicines after a calcium channel blocker to get back to a normal heart rhythm after their heart rate is already under control.

Examples of rhythm control medicines are:

These medicines don't help everyone who takes them, and they can cause serious side effects. Your doctor may need to monitor you closely while you take a rhythm control drug.

If you have a problem with any medication, don't stop taking it on your own. Stopping could be risky. Untreated AFib increases your risk for stroke and heart failure. Talk to your doctor. You may be able to switch to another rate control medicine that works better for you.

Can Surgery Treat AFib?

A medical procedure is another option if none of the medications help. Catheter ablation uses radio waves, intense cold, or a laser to create scar tissue in your heart. The scar tissue stops the abnormal signals that make your heart flutter.

The MAZE procedure is a type of open surgery to create scar tissue in the heart. There is also a less invasive version called the mini MAZE that is done through a smaller opening in your chest.

Show Sources

SOURCES:

Academic Emergency Medicine: "Safety and efficiency of calcium channel blockers versus beta-blockers for rate control in patients with atrial fibrillation and no acute underlying illness."

American Heart Association: "Atrial Fibrillation Medications."

Circulation: "Rate-Control Treatment and Mortality in Atrial Fibrillation."

Cleveland Clinic: "Calcium Channel Blockers," "Heart Block."

European Heart Journal: "Calcium channel blockers improve exercise capacity and reduce N-terminal Pro-B-type natriuretic peptide levels compared with beta-blockers in patients with permanent atrial fibrillation."

Evidence-Based Practice: "Are beta-blockers more effective for rate control than calcium channel blockers in patients with atrial fibrillation?"

Heart Foundation: "Calcium channel blockers."

Heart & Stroke: "Atrial Fibrillation."

Johns Hopkins Medicine: "Sick Sinus Syndrome," "What is Afib?"

Mayo Clinic: "Atrial Fibrillation," "Calcium channel blockers."

Medscape: "Atrial Fibrillation Medication," "Diltiazem."

National Health Service (U.K.): "Atrial fibrillation medications."

Seconds Count: "Understand Atrial Fibrillation."

StatPearls: "Calcium Channel Blockers."

Stop Afib: "Catheter Ablation for Atrial Fibrillation," "Rate Control Medication for Atrial Fibrillation," "Rhythm Control Medication for Atrial Fibrillation," "Surgery Procedures for Atrial Fibrillation."

Vascular Health and Risk Management: "Avoiding permanent atrial fibrillation: treatment approaches to prevent disease progression."

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