Q&A Topic: Detection of Complex Arrhythmias of the Heart
Sei Iwai, MD, FACC, FHRS
Q: What is an arrhythmia? What causes it, and what are the associated symptoms?
A: “Arrhythmia” is a very broad term. Basically, it refers to any irregular heartbeat that can arise from an abnormal area of the heart, and is too fast, too slow or irregular. Some types of arrhythmias are benign while others can be quite dangerous. Certain arrhythmias can cause no symptoms; others can potentially cause a variety of symptoms, including palpitations, shortness of breath, dizziness, fainting, chest discomfort, and in some instances, cardiac arrest.
The cause of an arrhythmia depends on the specific type. For example, some can be due to "extra pathways" within the heart or a degeneration of the conduction system. Some occur due to scar damage from a prior heart attack or from inherited abnormalities in the heart.
Q: What would make arrhythmias difficult to detect?
A: Arrhythmias may be difficult to detect if they cause either no symptoms or nonspecific or intermittent symptoms. Traditional cardiac monitors such as a Holter monitor — typically worn for 24-48 hours — or even an external-event monitor (which can be worn for weeks) can still miss arrhythmias that are infrequent. Documenting the specific arrhythmia is important because the therapy can be quite different depending on what is causing the issues. Currently, there are small implantable monitors that have a battery life of a few years. These may be utilized if it is important to monitor for recurrent but infrequent arrhythmias. In addition, consumer products such as the FitBit, Apple Watch and Kardia allow patients to be proactive in documenting their heart rate and/or a one-lead electrocardiogram (depending on the product).
Q: What are the treatment options for complex arrhythmia?
A: The treatment options depend on the specific arrhythmia. Certain arrhythmias require no therapy, while others may be treated with medications. Medications can include beta-blockers or calcium channel blockers for some, and stronger antiarrhythmic medications for others.
When medical therapy is ineffective or not tolerated, catheter ablation can be performed for many arrhythmias, including supraventricular tachycardia, atrial fibrillation and ventricular tachycardia. Patients with very slow heart rhythms may be candidates for a pacemaker implantation to keep the heart rate above a target range. In addition, certain patients with a history of, or who are at high risk of, sudden cardiac death also may have an implantable cardiac defibrillator implanted.
Q: Can patients do anything to reduce their risk of developing arrhythmia?
A: Most arrhythmias cannot be "avoided." However, taking care of one's heart and treating existing medical conditions may decrease the likelihood of developing arrhythmias such as atrial fibrillation (AF). For example, it has been shown that strict treatment of high blood pressure, diabetes mellitus and other conditions like sleep apnea will reduce the risk of developing AF, as well as the complications associated with it. Also importantly, weight control/loss and aerobic exercise can also decrease the risk.
Sei Iwai, MD, FACC, FHRS
Westchester Medical Center, flagship of the Westchester Medical Center Health Network
Director, Cardiac Electrophysiology Service
19 Bradhurst Ave, Suite 3850S
Hawthorne, NY 10532