What is the Difference Between Fibrillation and Fasciculation

The key difference between fibrillation and fasciculation is that fibrillation is the abnormal rhythm of atria that takes place in cardiac muscles, while fasciculation is the contraction and relaxation of skeletal muscles.

Each muscle tissue in the body possesses a unique structure and function. Cardiac muscles facilitate contractions in the heart to pump blood, while skeletal muscles facilitate the movements of bones and other structures. Both muscles usually show rhythmic contractions and are involuntary. Fibrillation and fasciculation are two types of abnormal episodes that take place in the cardiac muscles and skeletal muscles, respectively.

CONTENTS

1. Overview and Key Difference
2. What is Fibrillation
3. What is Fasciculation
4. Similarities – Fibrillation and Fasciculation
5. Fibrillation vs Fasciculation in Tabular Form
6. Summary – Fibrillation vs Fasciculation

What is Fibrillation?

Fibrillation is an abnormal rhythm in the atria of the heart. It is described as an irregular and out-of-synch beating of the heart. Such episodes sometimes appear asymptomatic. Fibrillation may lead to complications such as valvular heart disease, coronary artery disease, heart failure, congenital heart disease, rheumatic fever, and cardiomyopathy. Common signs and symptoms of fibrillation include rapid and irregular beat of the heart, palpitations, fainting, swelling, short breath, anginal chest pain, and light-headedness.

Fibrillation is caused by several forms of cardiovascular diseases such as high blood pressure, heart failure, coronary heart disease, mitral valve stenosis, mitral regurgitation, hypertrophic cardiomyopathy, atrial enlargement, congenital heart disease, pericarditis, or previous heart surgeries. Lung diseases such as pneumonia, lung cancer, sarcoidosis, and pulmonary embolism may also lead to fibrillation. Other factors that influence fibrillation are sepsis, obesity, diabetes, stroke, dementia, and hyperthyroidism. The risk of fibrillation can be prevented by a nutritious diet, regular exercise, avoiding smoking and alcohol, and managing stress.

Episodes of fibrillation are diagnosed through electrocardiogram (ECG), electromyography (EMG), and special monitoring systems to check the heart rhythm, such as Holter monitor, portable event monitor, and trans-telephonic monitor. Fibrillation is treated using medicine to control the rhythm of the heart, blood thinners to prevent coagulation of blood, and surgeries.

What is Fasciculation?

Fasciculation is the spontaneous and involuntary muscle contraction and relaxation of muscle fibers. It is also known as a muscle twitch. Skeletal muscles contain motor units which are collectively a group of muscles and nerve fibers that work together for muscle contraction. Fasciculation takes place when one or more motor units activate suddenly. Such episodes occur without the control of the brain and therefore are involuntary. A muscle twitch is strong enough to feel. But it will not cause any sudden jerk or contraction in the muscle, which can be harmful.   Fasciculations are benign, but if they are caused due to a motor neuron disease, they can be harmful. Fasciculations usually take place in the eye, tongue, arms, fingers, feet, thighs, and calves.

Risk factors of benign fasciculation include stress, age, fatigue, strenuous exercise, consumption of alcohol and caffeine, and smoking. But fasciculation is also caused by anxiety, thyroid diseases, magnesium deficiency, and consumption of anticholinergic drugs over a long period and due to motor neuron disease. Symptoms of fasciculations are inability to exercise, shakiness in muscles, sudden jerks, muscle spasms, stiffness, fatigue, and anxiety.

Fasciculation can be prevented by reducing stress and anxiety by practicing meditation and yoga, consuming a balanced diet, and eating probiotics. Specific treatment is not given for fasciculation; however, in serious conditions, medicines that decrease the excitability of nerves, antidepressants, and immunosuppressive medications are given. Fasciculation is diagnosed by electromyography (EMG), neurological tests, and blood tests. Complications of fasciculation, if left untreated, cause pinched spinal nerve (radiculopathy), amyotrophic lateral sclerosis, Isaac’s syndrome, lupus, and multiple sclerosis.

What are the Similarities Between Fibrillation and Fasciculation?

• Fibrillation and fasciculations are associated with muscles fibers.
• Both are diagnosed under electromyography.
• These conditions can be prevented by a nutritious diet, regular exercise, avoiding smoking and alcohol, and managing stress.
• Moreover, both are involuntary.

What is the Difference Between Fibrillation and Fasciculation?

Fibrillation is the irregular and rapid beating of the atrial chambers of the heart, while fasciculation is the flickering contractions of muscle fibers within the motor unit. Thus, this is the key difference between fibrillation and fasciculation. The fibrillation potential is an action potential of individual muscle fibers, while a fasciculation is a collection of action potentials of many muscle fibers in a motor unit. Moreover, fibrillation shows very small electrical impulses, whereas fasciculations show large impulses.

The below infographic presents the differences between fibrillation and fasciculation in tabular form for side by side comparison.

Summary – Fibrillation vs Fasciculation

Fibrillation is an abnormal rhythm of the heart. It takes place in the atria and is often described as irregular and beating out of sync with the ventricles of the heart. Fasciculation, also known as muscle twitch, is the spontaneous and involuntary muscle contraction and relaxation of muscle fibers. Fibrillation shows very small electrical impulses, whereas fasciculations show large impulses. So, this is the summary of the difference between fibrillation and fasciculation.

Reference:

1. “Atrial Fibrillation.” Mayo Clinic, Mayo Foundation for Medical Education and Research.
2. McDowell, Sandy. “Benign Fasciculation Syndrome: Symptoms and Treatment.” Healthline, Healthline Media.

Image Courtesy:

1. “ECG Atrial Fibrillation” By Ewingdo – Own work (CC BY-SA 4.0) via Commons Wikimedia

2. “Follower-pioneer axons fasciculation in zebrafish” By Joaquimlfs – Own work (CC BY-SA 3.0) via Commons Wikimedia