What is Heart Arrhythmia? Understanding Irregular Heartbeats

A heart arrhythmia, also known as cardiac arrhythmia, is an irregular heartbeat. This occurs when the electrical signals that coordinate the heart’s beats don’t function correctly. As a result, the heart may beat too fast (tachycardia), too slow (bradycardia), or with an inconsistent rhythm.

Some heart arrhythmias are harmless, while others can lead to life-threatening complications. It’s crucial to understand the different types of arrhythmias, their symptoms, causes, and potential treatments.

Typical Heartbeat

In a normal heart rhythm, the sinus node, a cluster of cells, sends an electrical signal that travels through the atria to the atrioventricular (AV) node, then into the ventricles, causing them to contract and pump blood efficiently.

Types of Heart Arrhythmias

Heart arrhythmias are often categorized by the speed of the heart rate:

Tachycardia: A fast heartbeat, typically defined as a heart rate greater than 100 beats per minute.
Bradycardia: A slow heartbeat, generally considered a heart rate less than 60 beats per minute.

Tachycardia (Fast Heartbeat)

Tachycardia encompasses various types of rapid heart rhythms, including:

Atrial Fibrillation (A-Fib): A chaotic and irregular heart rhythm originating in the atria.
Atrial Flutter: A more organized, but still rapid, rhythm in the atria.
Supraventricular Tachycardia (SVT): A rapid heart rate originating above the ventricles.
Ventricular Tachycardia (V-Tach): A fast heart rate originating in the ventricles, which can be life-threatening.

Bradycardia (Slow Heartbeat)

A heart rate below 60 beats per minute is considered bradycardia. However, a low resting heart rate is normal for physically fit individuals. Bradycardia becomes a concern when the heart can’t pump enough blood to meet the body’s needs. Types of bradycardia include:

Sick Sinus Syndrome: The sinus node malfunctions, causing the heart rate to alternate between slow and fast rhythms. Scarring near the sinus node can disrupt or block heartbeat signals.
Conduction Block: Electrical signals are slowed down or blocked as they travel through the heart’s pathways. Some blocks are asymptomatic, while others cause skipped or slowed heartbeats.

Premature Heartbeats

Premature heartbeats are extra beats that occur individually or in patterns. These can be:

Premature Atrial Contractions (PACs): Extra beats originating in the atria.
Premature Ventricular Contractions (PVCs): Extra beats originating in the ventricles.

An electrocardiogram (ECG) showing a Premature Ventricular Contraction (PVC). PVCs are early heartbeats originating in the ventricles.

These premature beats often feel like a skipped heartbeat. While generally harmless, frequent PVCs, especially in those with heart disease, can trigger longer-lasting arrhythmias or weaken the heart over time. Stress, exercise, and stimulants like caffeine and nicotine can trigger them.

Heart Arrhythmia Symptoms

Many people with heart arrhythmias experience no symptoms. An irregular heartbeat might only be detected during a routine checkup. However, when symptoms do occur, they may include:

Fluttering, pounding, or racing sensation in the chest
Fast or slow heartbeat
Chest pain
Shortness of breath
Anxiety
Fatigue
Lightheadedness or dizziness
Sweating
Fainting or near-fainting

When to Seek Medical Attention

Consult a doctor if you experience a persistently fast, slow, or skipped heartbeat. Seek immediate emergency medical care if you experience:

Chest pain
Shortness of breath
Fainting

Call 911 immediately if you suspect you are having a heart attack.

Ventricular fibrillation is a life-threatening arrhythmia causing a rapid drop in blood pressure, collapse, and loss of pulse and breathing. Immediate CPR and defibrillation (using an AED) are crucial.

Call 911.
Perform hands-only CPR: Push hard and fast (100-120 compressions per minute) on the center of the chest.
Use an AED: If available, follow the device’s instructions to deliver an electrical shock to restart the heart.

Causes of Heart Arrhythmias

Understanding how the heart works is important to understanding the causes of heart arrhythmias.

How the Heart Works

The heart has four chambers: two upper chambers (atria) and two lower chambers (ventricles). The sinus node initiates electrical signals that travel through the atria and AV node, causing the heart to contract and pump blood.

A labeled diagram of the human heart anatomy, illustrating the atria, ventricles, and major blood vessels. Understanding heart structure is crucial for comprehending arrhythmias.

Factors that can disrupt these electrical signals and cause arrhythmias include:

Heart attack or scarring from a previous heart attack
Coronary artery disease (blocked arteries)
Changes in heart structure (cardiomyopathy)
Diabetes
High blood pressure
COVID-19 infection
Thyroid disorders (overactive or underactive)
Sleep apnea
Certain medications (cold and allergy remedies)
Excessive alcohol or caffeine consumption
Drug abuse
Genetics
Smoking
Stress or anxiety

Risk Factors for Heart Arrhythmias

Several factors increase the risk of developing heart arrhythmias:

Coronary artery disease, heart problems, and heart surgery: These conditions damage the heart and disrupt electrical signaling.
High blood pressure: Increases the risk of coronary artery disease and stiffening of the heart walls.
Congenital heart defects: Heart problems present at birth.
Thyroid disease: Overactive or underactive thyroid glands can trigger irregular heartbeats.
Obstructive sleep apnea: Causes pauses in breathing during sleep, leading to slow and irregular heartbeats.
Electrolyte imbalance: Disrupts electrical signaling in the heart.
Certain medicines and supplements: Some medications can cause arrhythmias.
Excessive alcohol use: Affects electrical signaling.
Caffeine, nicotine, or illegal drug use: Stimulants increase heart rate and can lead to arrhythmias.

Complications of Heart Arrhythmias

Potential complications of heart arrhythmias include:

Blood clots, leading to stroke
Heart failure
Sudden cardiac death

Blood-thinning medications can reduce the risk of stroke associated with atrial fibrillation and other arrhythmias. Treatment to control heart rate may improve heart function in cases of arrhythmia-induced heart failure.

Preventing Heart Arrhythmias

Lifestyle changes to manage heart disease can help prevent heart arrhythmias:

Don’t smoke.
Eat a low-salt, low-saturated fat diet.
Exercise regularly (at least 30 minutes most days).
Maintain a healthy weight.
Reduce and manage stress.
Control high blood pressure, high cholesterol, and diabetes.
Get adequate sleep (7-9 hours).
Limit or avoid caffeine and alcohol.

By understanding the causes, symptoms, and prevention methods related to “What Is Heart Arrhythmia,” individuals can take proactive steps to protect their heart health and overall well-being.

References

Kusumoto FM, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Journal of the American College of Cardiology. 2018; doi:10.1016/j.jacc.2018.10.044.
Arrhythmia. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/arrhythmia. Accessed June 13, 2023.
How the heart works. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/how-heart-works. Accessed June 13, 2023.
Panchal AR, et al. 2018 American Heart Association focused update on advanced cardiovascular life support use of antiarrhythmic drugs during and immediately after cardiac arrest. Circulation. 2018; doi:10.1161/CIR.0000000000000613.
January CT, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in Collaboration With the Society of Thoracic Surgeons. Circulation. 2019; doi:10.1161/CIR.0000000000000665.
Jalife J, et al., eds. Assessment of the patient with a cardiac arrhythmia. In: Zipes and Jalife’s Cardiac Electrophysiology: From Cell to Bedside. 8th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed June 13, 2023.
Libby P, et al., eds. Approach to the patient with cardiac arrhythmias. In: Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed June 13, 2023.
Cronin EM, et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm. 2020; doi:10.1016/j.hrthm.2019.03.002.
Ferri FF. Atrial fibrillation. In: Ferri’s Clinical Advisor 2023. Elsevier; 2023. https://www.clinicalkey.com. Accessed June 13, 2023.
Lévy S, et al. Arrhythmia management for the primary care clinician. https://www.uptodate.com/contents/search. Accessed June 13, 2023.
Tisdale JE, et al. Drug-induced arrhythmias: A scientific statement from the American Heart Association. Circulation. 2020; doi:10.1161/CIR.0000000000000905.
Long B, et al. Cardiovascular complications in COVID-19. American Journal of Emergency Medicine 2020; doi:10.1016/j.ajem.2020.04.048.
Ami TR. Allscripts EPSi. Mayo Clinic. May 13, 2023.
Asirvatham SJ (expert opinion). Mayo Clinic. July 27, 2019.
Noseworthy PA (expert opinion). Mayo Clinic; Sept. 17, 2021.
Lee R. Atrial fibrillation: Surgical ablation. https://www.uptodate.com/contents/search. Accessed June 13, 2023.
What is arrhythmia? American Heart Association. https://www.heart.org/en/health-topics/arrhythmia. Accessed June 13, 2023.
What is atrial fibrillation? American Heart Association. https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af. Accessed Aug. 8, 2023.