Atrial Fibrillation (AF): The Commonest Serious Palpitation

Atrial fibrillation (AF) is the most common irregularity of the heartbeat, affecting at least 35 million people worldwide according to the latest figures. The first known report of an irregular pulse was made by Jean-Baptiste de Senac in 1749, and it was first documented by ECG in 1909 by Thomas Lewis, shortly after Willem Einthoven recorded the first ECG.

The disorder originates in the upper chambers of the heart, known as the atria, hence the name “atrial” fibrillation. The rapid, irregular, and uncontrolled contractions of these chambers are referred to as “fibrillation.” When this arrhythmia persists for extended periods, it can cause enlargement of the atria, and the poor contractions lead to blood stagnation. This, in turn, may result in clot formation, especially in the left atrial appendage—a finger-like projection.

In some patients, AF occurs in episodes, with long periods of normal heart rhythms between them. This is termed paroxysmal AF. When the arrhythmia persists, it is known as permanent AF.

The prevalence of AF increases with age. Around 0.1% of people under 50 years old are affected, while 4% of individuals between 60 and 70 years, and 14% of those over 80 years, experience it. AF is thus a common issue in the elderly population. Various underlying diseases are often associated with AF, including high blood pressure, valvular heart diseases, heart attacks, diabetes, chronic lung diseases, and congenital heart defects. However, in about half of AF patients, no underlying condition is found.

Clinical Presentation:

The most common symptom of AF is palpitation, often described as very rapid and irregular, which may prompt immediate medical attention. In patients with underlying heart disease, AF can lead to clinical deterioration, with symptoms like chest discomfort, shortness of breath, and palpitations. It can result in decompensated heart failure, requiring hospitalization.

In some cases, the first sign of AF is a stroke, leading to paralysis or hemiplegia, often accompanied by speech loss. This occurs when a clot in the atrium dislodges and travels to the brain. AF-related strokes are preventable, especially in the elderly, by managing the risk of clot formation.

Diagnosis and Evaluation:

All patients suspected of having AF need a thorough clinical evaluation, including a detailed history. An ECG is essential for diagnosing AF. For transient episodes of AF, long-term monitoring is required. One method is 24 or 48 hours of Holter monitoring. More advanced monitoring, such as Extended Loop Monitoring (ELR) using a chip attached to the chest wall, offers 7 to 10 days of continuous ECG recording, helping in cases of intermittent arrhythmia.

Management of AF:

The management of AF primarily involves controlling symptoms, specifically palpitations, using one of two approaches:

Rate control: In this approach, AF continues, but the heart rate is kept below 90 beats per minute, using various medications.

Rhythm control: Attempts to restore normal rhythm can be made using drugs, though many have long-term safety concerns. One such drug is amiodarone, but it carries risks such as thyroid, liver, and lung toxicity. Recently, non-surgical methods like ablation and pulmonary vein isolation have proven more effective and safer.

Anticoagulation Therapy:

Stroke prevention is a critical part of managing AF. Not all AF patients require anticoagulation, but many need it long-term based on their risk of stroke. The risk of stroke is assessed using several scoring systems, with one of the most common being CHA2DS2-VASc. This score incorporates factors such as heart failure, hypertension, age, diabetes, and previous strokes to determine the need for anticoagulation.

Choice of Anticoagulants:

The traditional anticoagulant for managing AF is warfarin, which is effective but requires regular blood monitoring and has numerous drug and food interactions. Newer anticoagulants such as Dabigatran, Apixaban, Rivaroxaban, and Edoxaban have largely replaced warfarin for non-valvular AF due to their fixed dosing and fewer interactions. These newer agents also have antidotes available for reversing their effects in case of bleeding or emergency surgery.

Take-Home Message:

AF is a prevalent arrhythmia, particularly in older adults, and is a significant cause of strokes and heart failure. Awareness of AF is crucial as effective management is available to prevent complications such as strokes. Early recognition and consultation with a healthcare provider are key to managing AF and preventing its serious consequences.

Prof Upendra Kaul, Cardiologist, Recipient of Padmashri and DR B C Roy Award