Diseases & Conditions

 

Arrhythmia

Diseases & Conditions

 

What is an arrhythmia?

An arrhythmia is an abnormal heart rhythm caused by disturbances in the electrical impulses that coordinate the heartbeat. It can be manifested by irregularity, abnormally fast rates, or abnormally slow rates of hearbeat. An irregular fast heartbeat is called tachycardia while an irregular slow heartbeat is called bradycardia. Arrhythmias are harmless most of the time and often do not cause symptoms. On the other hand, some arrhythmias can be serious and life-threatening requiring medical attention.1

 

What are the types of arrhythmias?

The electrical system of the heart is responsible for generating the signals that trigger the heart to beat. The process begins in the upper chambers of the heart called atria, which pump blood into the lower chambers called ventricles. The heart has a natural pacemaker known as the sinus node located at the top of the right atrium that will send out the electrical impulses. The normal electrical impulses generate the normal heart beat that ranges from 60 to 100 beats per minute. The types of arrhythmias depend on whether the tachycardia or bradycardia originate in the atria or in the ventricles.2

 

What causes an arrhythmia?

Arrhythmias may be caused by many different factors, including:3

  • Smoking
  • Heavy alcohol use
  • Use of some drugs
  • Too much caffeine
  • Strong emotions such as stress or anger
  • Hypertension
  • A heart attack
  • Coronary heart disease
  • Heart failure
  • Rheumatic heart disease
  • Problems in the thyroid gland (hyperthyroidism and hypothyroidism)
  • Congenital heart defects

Sometimes the cause of arrhythmias is unknown.

                                     

What are the signs and symptoms of an arrhythmia?

Many arrhythmias cause no signs or symptoms. When symptoms are present, they arise from both slow and fast arrhythmias, but they may be different from person to person. The classic symptoms of arrhythmias include:4

  • Palpitations
  • Dizziness
  • Fainting
  • Chest pain
  • Shortness of breath
  • Light headedness

 

How are arrhythmias diagnosed?

To find the problem, a doctor will take a medical history, ask about symptoms, give a thorough physical examination, and order specific tests which include:5

  • Electrocardiogram also called ECG or EKG is the most common test used to diagnose arrhythmias. This test detects and records the heart's electrical activity
  • Holter monitor is a recorder to be worn with electrodes attached to the chest for 24-48 hours that is able to detect irregular heart rhythms
  • Event monitor is a recorder that patients can use when they have infrequent symptoms to record one- to two-minute irregular heart rhythm
  • Stress test is performed when the patient is exercising to make his heart works hard and beats faster
  • Echocardiogram is a test that uses ultrasound to evaluate heart muscle and heart valves
  • Cardiac catheterization consists of a thin tube placed into a blood vessel and guided to the heart. Using an X-ray machine, the doctor will be able to see any damage to the heart including blockage and measure the pressure in the heart
  • Electrophysiology study consists of electrodes catheters placed into veins and passed into the heart to record electrical activity
  • Head-up tilt table test measures the heart electrical activity when the patient is changing positions from laying down to standing up

 

How are arrhythmias treated?

Treatment of arrhythmias depends on the type and seriousness of the disease and may include:6

  • Lifestyle changes including eating heart-healthy foods, exercising regularly, quitting smoking, maintaining a healthy weight, controlling cholesterol levels and blood pressure and maintaining follow-up care.
  • Medicine to prevent and control arrhythmias
  • Medicine to treat related conditions such as hypertension, coronary artery disease and heart failure
  • Anticoagulants to reduce the risk of blood clots and stroke
  • Cardiac defibrillation and implanted cardioverter defibrillators: These devices continuously monitor the heart rhythm and automatically deliver shocks if a dangerously slow heart beat is detected
  • A pacemaker to help the heart beat more regularly
  • Surgery is a recommended treatment for arrhythmias when other treatments are not effective. An example is maze surgery which is a procedure aiming at preventing the spread of disorganized electrical signals. A coronary artery bypass grafting is recommended when coronary heart disease is the cause of the arrhythmia.


 References:

  1. Kastor, John A., ed. Arrhythmias. WB Saunders Company, 2000.
  2. Heart arrhythmia (Causes) http://www.mayoclinic.org/diseases-conditions/heart-arrhythmia/basics/causes/con-20027707 (Accessed December 19, 2015)
  3. What Causes an Arrhythmia? (- NHLBI, NIH) https://www.nhlbi.nih.gov/health/health-topics/topics/arr/causes (Accessed December 19, 2015)
  4. Zaret, Barry L., Lawrence S. Cohen, and Marvin Moser. Yale university school of medicine heart book. William Morrow and Co., 1992.
  5. Heart Test (HRS) http://www.hrsonline.org/Patient-Resources/Symptoms-Diagnosis/Heart-Test (Accessed December 19, 2015)
  6. Treatment (HRS) http://www.hrsonline.org/Patient-Resources/Treatment (Accessed December 19, 2015)