Overview

Atrial fibrillation (AF) is a kind of arrhythmia or irregular heartbeat that causes the upper chambers of the heart to contract erratically and occasionally at a rapid pace. This may also hinder blood circulation and the overall efficiency of the heart.¹

Cardiomegaly refers to the enlargement of the heart, meaning it is an increase in the heart's size. It isn't precisely a disease; it indicates that another health issue impacts your heart. In certain conditions, such as pregnancy, the need for the heart rises in some states. Additional factors may also cause the heart muscle walls to thicken or distort the heart chambers, resulting in an enlarged heart.²

Connection between atrial fibrillation and heart expansion

AF, a form of arrhythmia, may result in heart enlargement or cardiomegaly. This happens because the erratic and rapid contractions of the heart in AF can lead to the heart muscle becoming fatigued and stressed over time. This may lead to the heart chamber walls becoming thick and enlarged.

Additionally, AF can cause ineffective blood pumping in the heart, resulting in blood accumulation in the atria. This idle blood may encourage the development of blood clots, potentially resulting in severe issues like stroke.³

Reasons for atrial fibrillation

Numerous factors contribute to AF, and there is a strong connection with other cardiovascular diseases.¹ The commonly encountered causes include:

• Advanced age
• Congenital heart disease
• Valvular disease
• Coronary artery disease
• Structural heart disease
• Atrial ischemia
• Increased alcohol consumption
• Hypertension - systemic or pulmonary
• Endocrine disorders - diabetes, pheochromocytoma, and hyperthyroidism
• Genetic factors
• Neurologic disorders - subarachnoid hemorrhage or stroke
• Mitral or tricuspid valve disease
• Left ventricular dysfunction
• Pulmonary embolism
• Obstructive sleep apnea
• Inflammation - myocarditis and pericarditis

Chronic and acute conditions that bring inflammation, stress, damage or ischemia to the anatomic right atrium can cause the development of atrial fibrillation. Occasionally, it has an iatrogenic onset

Stress such as from surgery or an illness, and other surgery including heart surgery can lead to establishing an AF. AF occurs in some people with no history of heart disease or heart damage to their hearts.

Lifestyle habits that cause an AF episode may include:

• Drinking too much alcohol or caffeine
• Illegal drug use
• Smoking or using tobacco
• Consuming products with stimulant-like cold, and allergy medicine with a prescription and without one

Symptoms of Atrial Fibrillation

General symptoms

• Heart palpitations: individuals might experience a feeling of their heart racing or fluttering, frequently referred to as "skipping a beat
• Breathlessness: trouble breathing may happen during exercise or even while at rest, especially when in a flat position
• Fatigue: numerous people encounter atypical exhaustion or a deficiency of energy that impacts their everyday tasks
• Dizziness or giddiness: some individuals might experience faintness or weakness, particularly during times of increased heart rate
• Chest Pain or discomfort: although not everyone feels chest pain, it can happen and might suggest more serious underlying problems¹

Indications associated with heart enlargement

• Edema: swelling in the ankles, legs, or abdomen caused by fluid retention may indicate heart failure linked to cardiomegaly
• Waking up out of breath: this sign could suggest fluid buildup in the lungs (pulmonary congestion) resulting from heart failure
• Irregular heart rhythm: an enlarged heart can worsen AF symptoms by interfering with regular electrical signals among the chambers⁴

The interaction between AF and heart enlargement

How AF can cause heart enlargement

When AF happens, the poor contraction of the atria results in a gradual increase in pressure within these compartments.⁵ This ongoing pressure leads to:

• Dilation (enlargement): the atria can expand and grow larger because of extended pressure strain
• Hypertrophy (thickening): the muscle fibers may thicken as a compensatory response, potentially leading to further interference with normal electrical conduction

How enlarged heart can worsen AF

On the other hand, a swollen heart frequently possesses modified electrical routes that heighten the risk of AF:

• Structural modifications: the expansion changes the form and dimensions of the atria, interfering with normal conduction routes and increasing the likelihood of arrhythmias arising
• Heightened risk of recurrence: individuals with cardiomegaly have a greater chance of facing repeated occurrences of AF because of these structural alterations⁵

Complications associated with AF and heart enlargement

• Elevated stroke risk: the irregular rhythm linked to AF may cause blood to pool in the atria, heightening the likelihood of clot development and resulting stroke
• Risk of heart failure: extended periods of AF along with an enlarged heart may result in deteriorating heart function and subsequent heart failure⁵

Treatment

The treatment of AF and heart enlargement (cardiomegaly) encompasses a comprehensive strategy that features medications, treatments, and changes in lifestyle. The approach to treatment is customised for each person, depending on the intensity of symptoms, root causes, and general health.

Medications

Drugs play a crucial role in managing AF and dealing with heart enlargement. The general aims are to control the heartbeat rate, return to normal working rhythm, and prevent consequences such as a stroke. These are beta blockers, calcium channel blockers, digoxin, antiarrhythmic, and anticoagulant drugs.⁶

Cardioversion

It restores normality to an irregular heartbeat. There are two ways it can be carried out:

• Electrical cardioversion: in order to restore the normal heart rhythm a controlled electric shock is then passed through the heart. Often it is performed under local anesthetic or general anesthetic agents on an inpatient basis
• Pharmacologic cardioversion: this involves giving the body medication through the mouth or a vein to correct electrical dysrhythmia that causes AF. Those patients who can’t undergo electrical cardioversion are usually treated under this procedure⁴

Surgeries

When medications are not effective or are poorly tolerated,⁷ various procedural alternatives might be explored:

• Catheter ablation: it is also a minor invasive procedure for which a catheter is guided through the blood vessels to the heart for the removal of tissues generating uncontrolled electrical impulses. The research applied is most effective for patients who are living with this condition after the incident
• AV node ablation: for those patients with chronic AF who didn’t respond to other therapies, this technique simply ablates the AV node and effectively regulates the heart rate needed. A pacemaker is then required in order to synchronise the contractions
• Hybrid procedures: the integration of the surgical approach with a catheter ablation may be effective in treating long-standing persistent AF

Lifestyle modifications 

Lifestyle changes can significantly aid in the mitigation of AF and improvement in cardiovascular health in general:⁷

• Changes in diet: reducing the intake of cholesterol, saturated fatty acids and sodium as embraced in heart-healthy eating systems may assist in controlling high blood pressure and also enhance cardiovascular health
• Regular physical activity: physical activity might be a suitable way to enhance the status of the cardiovascular system and easily maintain body weight
• Weight management: since 40 % of the heart's workload is weight and the other excess pounds add more pressure to the heart, the heart’s workload is influenced
• Minimising stimulants: avoiding alcohol, and beverages containing caffeine and nicotine may have an impact in preventing an AFib episode
• Yoga or any other stress-reducing exercises may be useful in keeping stress levels that can provoke AF episodes in check

Summary

Atrial fibrillation (AF) is an irregular heart rhythm that can lead to heart enlargement. AF causes the heart's upper chambers to contract randomly and quickly, straining the heart muscle over time. Effective management is vital to reduce the risk of complications such as stroke and heart failure. Causes can range from age to lifestyle factors. Some of the signs are palpitation, dyspnoea, and chest pain. The complications are risk factors such as stroke and heart failure. Treatment involves medication, cardioversion, and surgical options. Lifestyle changes are also important for managing AF and heart enlargement effectively.