Cochin Cardiac Club

Health Blog by Dr.Uday Nair



Atrial fibrillation describes an irregular and often rapid heart rhythm. The irregular rhythm, or arrhythmia, results from abnormal electrical impulses in the heart. The irregularity can be continuous, or it can come and go.
Normal heart contractions begin as an electrical impulse in the right atrium. This impulse comes from an area of the atrium called the sinoatrial (SA) or sinus node, the "natural pacemaker

  • The impulse then continues into the ventricles, causing ventricular contraction that pushes the blood out of the heart, completing a single heartbeat.
In a person with a normal heart rate and rhythm the heart beats 50-100 times per minute.

In atrial fibrillation, multiple impulses travel through the atria at the same time.
  • Instead of a coordinated contraction, the atrial contractions are irregular, disorganized, chaotic, and very rapid. The atria may contract at a rate of 400-600 per minute.
  • These irregular impulses reach the AV node in rapid succession, but not all of them make it past the AV node. Therefore, the ventricles beat slower, often at rates of 110-180 beats per minute in an irregular rhythm.
  • The resulting rapid, irregular heartbeat causes an irregular pulse and sometimes a sensation of fluttering in the chest.

Exams and Tests

The doctor may hear a fast heartbeat while listening to the heart with a stethoscope. The pulse may feel rapid, irregular, or both. The normal heart rate is 60 - 100, but in atrial fibrillation/flutter the heart rate may be 100 - 175. Blood pressure may be normal or low.

An ECG shows atrial fibrillation or atrial flutter.
 Continuous ambulatory cardiac monitoring -- Holter monitor (24 hour test) -- may be necessary because the condition often occurs at some times but not others (sporadic).

Tests to find underlying heart diseases may include:
  • Coronary angiography
  • Echocardiogram
  • Electrophysiologic study (EPS)
  • Stress test
  • Nuclear imaging tests

The Three Types of Atrial Fibrillation

  • Paroxysmal Atrial Fibrillation - the abnormal electrical signals and quickened heart rate begin suddenly and then stop on their own. Patients may experience mild or severe symptoms. Symptoms can last for just a few seconds or minutes, or persist for hours, and even days. Paroxysmal atrial fibrillation generally originates from the junction of the pulmonary veins within the left atrium (the left upper chamber of the heart).
  • Persistent Atrial Fibrillation - in this case the atrial fibrillation only stops when the patient receives treatment.
  • Longstanding Persistent Atrial Fibrillation - used to be called Permanent Atrial Fibrillation. The patient's normal heart rhythm cannot be restored with the usual treatments. Paroxysmal and Persistent Atrial Fibrillation can occur more frequently and eventually become Longstanding Persistent Atrial Fibrillation
Causes of atrial fibrillation ;
  • Alcohol use (especially binge drinking)
  • Congestive heart failure
  • Coronary artery disease (especially after a heart attack or coronary artery bypass surgery)
  • Heart surgery
  • High blood pressure (hypertension)
  • Hypertrophic cardiomyopathy
  • Medications
  • Overactive thyroid gland (hyperthyroidism)
  • Pericarditis
  • Valvular heart disease (especially mitral stenosis and mitral regurgitation


You may not be aware that your heart is not beating in a normal pattern, especially if it has been occurring for some time.
Symptoms may include:
  • Pulse that feels rapid, racing, pounding, fluttering, or too slow
  • Pulse that feels regular or irregular
  • Sensation of feeling the heart beat (palpitations)
  • Shortness of breath
  • Confusion
  • Dizziness, light-headedness
  • Fainting
  • Fatigue
Note: Symptoms may begin or stop suddenly. This is because atrial fibrillation may stop or start on its own.


In certain cases, atrial fibrillation may need emergency treatment to get the heart back into normal rhythm. This treatment may involve electrical cardioversion or intravenous (IV) drugs such as amiodarone. Drugs are typically needed to keep the pulse from being too fast.
Daily medications taken by mouth are used in two different ways:
  • To slow the irregular heartbeat. These medications may include beta-blockers, calcium channel blockers, and digitalis.
  • To keep atrial fibrillation from coming back. These medications may work well in many people, but they can have serious side effects. Many patients may go back to atrial fibrillation even while taking these medications.
Blood thinners, such as heparin and warfarin  reduce the risk of a blood clot traveling in the body (such as a stroke). Because these drugs increase the chance of bleeding, not everyone will use them. Antiplatelet drugs such as aspirin or clopidogrel may also be prescribed. Your doctor will consider your age and other medical problems to decide which drug is best.
A procedure called radiofrequency ablation can be used to destroy areas in your heart that may be causing your heart rhythm problems. Cardiac ablation procedures are done in a hospital laboratory by specially trained staff. Reasons why ablation may be done include:
  • When medicines are not controlling the symptoms, or are causing side effects
  • When the condition will become dangerous if not treated
  • As a possible cure for some patients with atrial flutter
Some patients may need the radiofrequency ablation done directly on an area of the heart called the AV junction. Ablation of the AV junction leads to complete heart block. This condition needs to be treated with a permanent pacemaker.

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