Arrhythmias

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention | Organizations

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Definition

Arrhythmias are abnormal beats of the heart. Types of arrhythmias include:

• Heartbeats that are too slow (bradycardia)
• Heartbeats that are too fast (tachycardia)
• Extra beats
• Skipped beats
• Beats coming from abnormal areas of the heart

Causes

An arrhythmia can be caused by:

• The heart's natural pacemaker developing an abnormal rate or rhythm
• The normal conduction pathway being interrupted
• Another part of the heart taking over as pacemaker

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

• Excess caffeine
• Stress
• Tobacco use
• Alcohol use
• Diet pills or decongestants
• Cocaine
• Antidepressant medications
• Digitalis overdose
• Endocrine disorders, such as thyroid or adrenal gland problems
• Anemia
• High blood pressure
• Coronary artery disease
• Problems with heart valves
• Heart muscle damage after heart attack
• Rheumatic heart disease
• Cardiomyopathy
• Diabetes
• Liver disease
• Typhoid fever
• Hypothermia
• Electric shock or lightening strike
• Complication after near-drowning

Symptoms

Some arrhythmias may occur without any symptoms. Others may cause noticeable symptoms, such as:

• Fainting
• Dizziness, sensation of light-headedness
• Sensation of your heart fluttering (palpitations)
• Sensation of a missed or extra heart beat
• Weakness
• Fatigue
• Shortness of breath
• Chest pain

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. In particular, the doctor will listen to your heart with a stethoscope.

Tests may include:

Blood Tests – to look for certain markers in the blood that help the doctor determine what is happening with your heart

Urine Tests – to look for certain markers in the urine that help the doctor determine what is happening with your heart

Electrocardiogram (EKG) – records the heart's activity by measuring electrical currents through the heart muscle

Echocardiogram – uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart

24-hour Holter monitor – a portable EKG that you wear as you perform normal daily activities

Exercise Stress Test – records the heart's electrical activity during increased physical activity

Nuclear Scanning – radioactive material is injected into a vein and observed as it is absorbed by the heart muscle

Coronary Angiography – x-rays taken after a dye is injected into the arteries

Treatment

Treatment may include:

Antiarrhythmic Medications

These will help slow down or speed up your heart rate, depending on your need.

Cardioversion or Defibrillation

These treatments involve placing paddles on the chest or back. An electrical current is passed through the chest wall to the heart, in order to re-set its electrical circuits, and attempt to return the heart rhythm to normal.

Automatic Implantable Defibrillator

A tiny defibrillator can be surgically implanted in your chest to monitor your heart rhythm. If a dangerous arrhythmia is detected, the device automatically shocks the heart in an attempt to return the heart rhythm to normal.

Artificial Pacemaker

This device is surgically implanted in your chest. It takes over the job of providing the electrical impulses needed for establishing an appropriate heart rhythm.

Surgery

An area of the heart that is responsible for an abnormal rhythm may be surgically removed or altered to prevent it from generating an arrhythmia.

Prevention

To help prevent arrhythmias:

• Treat underlying conditions that might lead to arrhythmias.
• Avoid substances that might trigger or worsen an arrhythmia, including:
  • Caffeinated beverages
  • Alcohol
  • Tobacco
  • Certain medications
• Follow general advice for preventing the development of heart disease, including:
  • Maintain an appropriate weight.
  • Consult your doctor about a safe exercise program.
  • Stop smoking.
  • Eat a healthful diet, one that is low in saturated fat and rich in whole grains, fruits, and vegetables.
  • Appropriately treat your high blood pressure and/or diabetes.
  • Ask your doctor if you should take cholesterol-lowering medications.

Organizations

American Heart Association
http://www.americanheart.org/

SOURCES:

Heart Disease: A Textbook of Cardiovascular Medicine, 6th ed. W. B. Saunders Company, 2001.

National Heart, Lung, and Blood Institute

American Heart Association

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Last reviewed June 2001 by Medical Review Board