What are heart rhythm disorders?

The heart requires an electrical impulse or signal from the heart’s internal electrical system (or conduction system) in order to produce a heartbeat. The electrical impulse starts in the atria, or upper chambers of the heart, and travels down to the ventricles, or lower chambers of the heart, causing the heart to contract and pump blood throughout the body. One heartbeat refers to the alternating contraction and relaxation of the two atria and two ventricles. The two atria contract at the same time, then relax, followed by the two ventricles contracting, then relaxing.

A heart rhythm disorder means that your heart is beating improperly—too fast, too slow or with an irregular rhythm. Heart rhythm disorders (also called arrhythmias) are problems with your heart’s internal electrical system that result in irregular heartbeats. Types of heart rhythm disorders include atrial fibrillation, sick sinus syndrome and ventricular tachycardia.

Heart rhythm disorder can result from a variety of causes, including underlying heart disease (such as coronary artery disease, heart valve disease or heart failure), thyroid dysfunction or an electrolyte abnormality (e.g., a potassium, magnesium or calcium imbalance). Heart rhythm disorders may occur without underlying heart disease and be caused by stimulants such as caffeine, emotional stress, prescribed as well as illicit drugs, or physical activity.

Heart rhythm disorders range from harmless to life-threatening, and a wide range of treatments are available. Our experienced cardiovascular team gives you access to specialized technology for diagnosing and treating your heart rhythm disorder.

Researchers at Bluhm Cardiovascular Institute’s Clinical Trials Unit of Northwestern University are currently conducting clinical trials and recruiting volunteers to participate in clinical trials related to heart rhythm disorders. Discussions with your clinical team will determine if you are a candidate to participate in a specific clinical trial.

VOLT-AF This clinical investigation is intended to demonstrate safety and effectiveness of the Volt™ Pulsed Field Ablation (PFA) Catheter Sensor Enabled™, the Volt™ PFA Generator, Agilis™ NxT Steerable Introducer Dual-Reach™, and EnSite™ X EP System EnSite™ Pulsed Field Ablation Module for the treatment of symptomatic, recurrent, drug-refractory paroxysmal and persistent atrial fibrillation.
Principal Investigator: Bradley Knight, MD 

REACT-AF The purpose of this study is to assess whether it is safe and effective to stop oral anticoagulation medications (a blood-thinning medication) during prolonged periods of normal heart rhythm in participants with infrequent episodes of atrial fibrillation (AF). Participants are randomized to one of two groups: Standard of Care (SOC) Group or Intervention Group. Participants in the SOC group will remain on their previously prescribed oral anticoagulant. Those randomized to the Intervention group will take the oral anticoagulant for 30 days only if a prolonged episode of AF is detected on an AF-sensing Apple smartwatch. Participation will last up to 60 months and requires one visit to the site at time of enrollment, all other follow-up will be conducted virtually.
Principal Investigators:
Rod S. Passman, MD 
Bradley P. Knight, MD