Arrhythmias Research

• Safety and effectiveness of treatment: The NHLBI began the landmark Cardiac Arrhythmia Suppression Trial in 1986. The study tested whether a particular class of drugs to treat arrhythmias could prevent sudden cardiac arrest in people who had asymptomatic or mild ventricular arrhythmias and had recently had a heart attack. The study showed that the drugs actually increased the likelihood of death due to arrhythmias. Because it showed that some of the medicines were not safe, the study ended early and changed the way arrhythmias are treated today.
• Surgery versus medicine: The NHLBI-supported Catheter Ablation versus Antiarrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial compared catheter ablation, which is a common procedure to treat atrial fibrillation, a type of arrhythmia, with medicine. More than 2,200 patients participated in the study around the world. The researchers found that catheter ablation was no better than medicines at treating atrial fibrillation. However, patients who got catheter ablation experienced fewer symptoms and had a better quality of life than those who got the medicine alone. Read more about the results of this study: Surgery no better than medication at preventing serious complications of atrial fibrillation.
• Impact of genetic factors: In 2002, NHLBI-supported researchers identified a gene variant that is associated with arrhythmia in African Americans. The study found that when the variant is combined with other risk factors such as taking certain medicines or having low blood potassium or heart disease, the risk of life-threatening arrhythmias is increased.
• Risk factors for arrhythmias: The NHLBI supports several long-term studies to better understand the risk factors for heart disease. The Atherosclerosis Risk in Communities (ARIC) study found that having an arrhythmia, specifically premature beats in the heart’s ventricles, may increase a person’s risk of stroke. ARIC also helped define factors that increase the risk of arrhythmias. Another ARIC study looked at racial differences in atrial fibrillation. The study found that African Americans are less likely than whites to have atrial fibrillation but more likely to have poor outcomes, including stroke, heart failure, and death. Data from ARIC and the Framingham Heart Study have also been used to develop models for predicting a patient’s risk of atrial fibrillation.

These studies and others that the NHLBI funds continue to explore how lifestyle habits, other heart and blood vessel diseases, stress, and genes are linked to arrhythmias and how these risk factors affect different populations. Data from these studies are available through the Biologic Specimen and Data Repository Information Coordinating Center (BioLINCC) and the Trans-Omics for Precision Medicine (TOPMed) Program.

Our Division of Cardiovascular Sciences and its Adult and Pediatric Cardiac Research Program and Heart Failure and Arrhythmias Branch oversee much of the research that NHLBI supports on arrhythmias.

Current research on developing new methods to diagnose and monitor arrhythmias

Technology advances: Through a Small Business Innovation Research grant, the NHLBI supported the development of the RHYTHMIA HDx™ Mapping System. This innovative technology accurately measures the heart’s electrical activity and provides 3-dimensional maps detailing how well the heart is working. This can help doctors more accurately diagnose arrhythmias to select the right treatment option for each patient. 

Find more NHLBI-funded studies on diagnosing and monitoring arrhythmias at NIH RePORTER.

Current research on causes of arrhythmias 

NHLBI-supported research has helped reveal how lifestyle habits, certain medicines, our genes, and stress can lead to arrhythmias. We continue to fund studies to further explore the causes and risk factors of arrhythmias. 

• Computer-based screening: Several medicines can raise the risk of arrhythmias. We fund research to develop computer programs to screen new medicines to identify those that are likely to cause or worsen arrhythmias. 
• Obesity's impact on the heart: We fund research into how obesity and fat deposits around the heart can raise the risk of atrial fibrillation. 
• Genetic studies: We support large-scale genomic studies to find genes that are linked to arrhythmia, including studies conducted through an international atrial fibrillation consortium, AFGen. Other studies are exploring whether certain genes raise the risk of arrhythmias after heart surgery and identifying which changes to the genes that control our heart rhythm are harmless and which changes cause specific types of arrhythmias. 

Find more NHLBI-funded studies on the causes of arrhythmias at NIH RePORTER. 

Current research on diagnosing and monitoring arrhythmias 

The NHLBI supports research to improve imaging technology to diagnose and monitor arrhythmias. 

• Magnetic-resonance imaging (MRI) technology: We fund research to develop and test new MRI technology to monitor scar tissue formation in specific areas of the heart after treatment for arrhythmias. 
• Better MRI cardiac images: We support research to improve the quality of cardiac MRI images in people who use an implantable electronic device such as a pacemaker to prevent or treat arrhythmia. 

Learn more about how the NHLBI is supporting the development of new technologies to improve heart health: Highlights in Heart Health. 

Find more NHLBI-funded studies on diagnosing arrhythmias at NIH RePORTER. 

Research on treatments for arrhythmia 

The NHLBI supports research to develop innovative treatments for arrhythmias to help limit complications and improve quality of life. In a study of ventricular tachycardia (a fast rhythm), researchers developed a noninvasive catheter-free method for mapping and treating the area of the heart where the abnormal rhythm originates. The procedure combines cardiac imaging and electrocardiography (EKG) with stereotactic body radiation therapy — originally developed to deliver precise, high-dose radiation to tumors.

Current research includes:

• New medicines: We fund basic science and pharmacology studies to develop and test the safety of new types of medicines to treat arrhythmias. 
• Genetic therapies: We support studies to develop genetic therapies to correct gene mutations that cause arrhythmias. 
• Effectiveness and safety of current treatments: A type of arrhythmia called atrial fibrillation is a common complication of long-term kidney disease. We support research to explore whether the medicines and procedures commonly used to treat atrial fibrillation are safe and effective in people who have kidney disease. 
• Sudden cardiac arrest: Many people who have arrhythmias have no symptoms and may not know that they have this condition until they have cardiac arrest. The NHLBI funds research to improve methods to restart the heart during cardiac arrest and to prevent repeated events of cardiac arrest. 

Find more NHLBI-funded studies on treatments for arrhythmias at NIH RePORTER.

Our Division of Intramural Research (DIR) and its Cardiovascular Branch conduct research on diseases that affect the heart and blood vessels. Specific projects aim to answer clinically relevant questions in diagnostics, therapeutics, and interventions. For example, NHLBI researchers developed an improved, more precise method of catheter ablation to treat problems causing arrhythmia. The technique, called interventional cardiovascular MR (iCMR), uses magnetic resonance imaging (MRI) to guide the placement of the catheter in the heart.

Other DIR groups, such as the Systems Biology Center, perform research on heart and vascular diseases.

Supporting heart health in women

The NHLBI created The Heart Truth® in 2002 to raise awareness about heart disease as the leading cause of death in women. The Heart Truth is focused on making sure that women know about their risk for heart disease and know that healthy lifestyle changes can lower this risk. The program provides free science-based educational materials and information about heart-healthy living and coordinates activities for American Heart Month.

Studying innovations to improve heart and vascular disease outcomes

The Cardiothoracic Surgical Trials Network (CTSN) is an international network that studies heart valve disease, arrhythmias, heart failure, coronary heart disease, and the complications of surgery. CTSN researchers have worked to improve outcomes for people who have atrial fibrillation and need heart valve surgery. Researchers have also compared treatments that helped control heart rate and treatments that helped control heart rhythm as a first treatment option after surgery.