Multimedia Gallery
Electrocardiogram
If your heart has been beating too fast, or you've been having chest pain, both you and your doctor will want to find out what's causing the problem so you can get it treated. One way to diagnose heart problems is with a test of the heart's electrical activity, called an electrocardiogram or ECG, or EKG for short.
Your heart is controlled by an electrical system, much like the electricity that powers the lights and appliances in your home. Electrical signals make your heart contract so that it can pump blood out to your body. Heart disease, abnormal heart rhythms, and other heart problems can affect those signals. Using an ECG, your doctor can identify problems in your heart's electrical system and diagnose heart disease.
So, how is an ECG done?
First you'll lie down on a table. You'll have to lie very still while the test is done. Small patches, called electrodes, will be attached to several places on your arms, legs, and chest. The patches won't hurt, but some of the hair in those areas may be shaved so the patches will stick to your skin. The patches are then attached to a machine. You'll notice that when the machine is turned on, it produces wavy lines on a piece of paper. Those lines represent the electrical signals coming from your heart. If the test is normal, it should show that your heart is beating at an even rate of 60 to 100 beats per minute.
Many different heart conditions can show up on an ECG, including a fast, slow, or abnormal heart rhythm, a heart defect, coronary artery disease, heart valve disease, or an enlarged heart. An abnormal ECG may also be a sign that you've had a heart attack in the past, or that you're at risk for one in the near future.
If you're healthy and you don't have any family or personal history of heart disease, you don't need to have an ECG on a regular basis. But if you are having heart problems, your doctor may recommend getting this test. An ECG is pretty accurate at diagnosing many types of heart disease, although it doesn't always pick up every heart problem. You may have a perfectly normal ECG, yet still have a heart condition. If your test is normal but your doctor suspects that you have a heart problem, he may recommend that you have another ECG, or a different type of test to find out for sure.
Electrocardiogram
Review Date: 5/8/2022
Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Animations
- Abdominal aortic aneurysm
- Abdominal pain
- Aneurysm description
- Arrhythmias
- Atherosclerosis
- Atrial fibrillation
- Balloon angioplasty - short...
- Blood clotting
- Blood flow
- Blood pressure
- Brain components
- Cardiac and vascular disord...
- Cardiac arrhythmia - conduc...
- Cardiac arrhythmia symptoms
- Cardiac arrhythmia tests: E...
- Cardiac arrhythmia: Additio...
- Cardiac arrhythmia: Heart p...
- Cardiac arrhythmia: Physica...
- Cardiac arrhythmia: Taking ...
- Cardiac catheterization
- Cardiac catheterization - a...
- Cardiac conduction system
- Cardiac CT scan overview
- Cardiomyopathy
- Cardiovascular system
- Causes and side effects of ...
- Cerebral aneurysm
- Chest pain
- Childhood obesity
- Cholesterol and triglycerid...
- Coronary artery bypass graf...
- Coronary artery disease
- Coronary artery disease (CA...
- Directional coronary athere...
- Electrocardiogram
- Epinephrine and exercise
- Erection problems
- Essential hypertension
- Exercise
- Hardening of arteries
- Healthy Guide to Fast Food
- Heart attack
- Heart bypass surgery
- Heart failure
- Heart formation
- Heartbeat
- How to use a pill cutter
- Hypertension
- Hypertension - overview
- Muscle types
- NICU consultants and suppor...
- Nuclear stress test
- Obstructive sleep apnea
- Percutaneous transluminal c...
- Preeclampsia
- Smoking
- Smoking tips to quit
- Snoring
- Stent
- Stroke
- Stroke
- Stroke - secondary to cardi...
- Tachycardia
- Tobacco use - effects on ar...
- Tracking your blood pressur...
- Type 2 diabetes
- Understanding cholesterol r...
- Vacation health care
- Valvular heart disease (VHD...
- Varicose veins
- Varicose veins overview
- Venous insufficiency
- What makes your heart beat?
Illustrations
- 15/15 rule
- Absent pulmonary valve
- Acute MI
- Adjustable gastric banding
- Aerobic exercise
- Alcoholic cardiomyopathy
- Alpha-glucosidase inhibitors
- Angina
- Anomalous left coronary artery
- Anterior heart arteries
- Aortic aneurysm
- Aortic dissection
- Aortic rupture - chest x-ray
- Aortic stenosis
- Aortopulmonary window
- Arterial embolism
- Arterial plaque build-up
- Arterial tear in internal c...
- Arteries of the brain
- Artery cut section
- Atherosclerosis
- Atherosclerosis of internal...
- Atherosclerosis of the extr...
- Atrial septal defect
- Atrioventricular block - EC...
- Atrioventricular canal (end...
- Auscultation
- Bacterial pericarditis
- Balance receptors
- Bicuspid aortic valve
- Biguanides
- Biliopancreatic diversion (BPD)
- Biliopancreatic diversion w...
- Biopsy catheter
- Blood pressure
- Blood pressure check
- Blood test
- Bradycardia
- Brain
- Brainstem function
- Breathing
- Bronchial cancer - CT scan
- Calcium benefit
- Calcium source
- Calories and fat per serving
- Cardiac arteriogram
- Cardiac catheterization
- Cardiac catheterization
- Carotid dissection
- Carotid duplex
- Carotid stenosis - X-ray of...
- Carotid stenosis - X-ray of...
- Cataract
- Cataract - close-up of the eye
- Central nervous system and ...
- Cerebellum - function
- Cerebral aneurysm
- Cholesterol
- Cholesterol producers
- Circle of Willis
- Circulation of blood throug...
- Circulatory system
- Clubbing
- Coarctation of the aorta
- Conduction system of the heart
- Constrictive pericarditis
- Coronary angiography
- Coronary artery blockage
- Coronary artery disease
- Coronary artery disease
- Coronary artery fistula
- Coronary artery spasm
- Coronary artery stent
- Crossed eyes
- CT scan
- Culture-negative endocarditis
- Cyanosis of the nail bed
- Cyanotic heart disease
- DASH diet
- Deep veins
- Deep veins
- Deep venous thrombosis - il...
- Developmental process of at...
- Dextrocardia
- Diabetes and exercise
- Diabetic emergency supplies
- Digestive system
- Dilated cardiomyopathy
- Double aortic arch
- Double inlet left ventricle
- Double outlet right ventricle
- Drug induced hypertension
- Duplex/doppler ultrasound test
- Ear anatomy
- Ebstein's anomaly
- ECG
- ECMO
- Effects of age on blood pressure
- Eisenmenger syndrome (or co...
- Electrocardiogram (ECG)
- Emphysema
- Endarterectomy
- Endocrine glands
- Enlarged view of atherosclerosis
- Exercise - a powerful tool
- Exercise 30 minutes a day
- Exercise can lower blood pr...
- Exercise with friends
- Eye
- Facial drooping
- Fast food
- Fish in diet
- Food and insulin release
- Food label guide for candy
- Food label guide for whole ...
- Foot swelling
- Fruits and vegetables
- Glucose in blood
- Glucose test
- Healthy diet
- Healthy diet
- Heart - front view
- Heart - section through the...
- Heart attack symptoms
- Heart beat
- Heart chambers
- Heart valves
- Heart valves - anterior view
- Heart valves - superior view
- High blood pressure tests
- Holter heart monitor
- Hypertension
- Hypertensive kidney
- Hypertrophic cardiomyopathy
- Infective endocarditis
- Insulin pump
- Insulin pump
- Intracerebellar hemorrhage ...
- Intracerebral hemorrhage
- Janeway lesion on the finger
- Jaw pain and heart attacks
- Left atrial myxoma
- Left cerebral hemisphere - ...
- Left heart catheterization
- Leg pain (Osgood-Schlatter)
- Lifestyle changes
- Lobes of the brain
- Low blood sugar symptoms
- Low nasal bridge
- Lower leg edema
- Lower leg muscles
- Lung mass, right lung - CT scan
- Lung mass, right upper lobe...
- Lung nodule, right lower lu...
- Lung with squamous cell can...
- Lungs
- Lymph tissue in the head an...
- Male reproductive anatomy
- Mitral stenosis
- Mitral valve prolapse
- Monitoring blood pressure
- MRI scans
- MUGA test
- Muscular atrophy
- myPlate
- Neck pain
- Neck pulse
- Normal anatomy of the heart
- Normal heart anatomy (cut s...
- Normal heart rhythm
- Normal lung anatomy
- Omega-3 fatty acids
- Otoscope examination
- Pacemaker
- Pericarditis
- Pericardium
- Pericardium
- Peripartum cardiomyopathy
- Pharmacy options
- Pitting edema on the leg
- Plaque buildup in arteries
- Post myocardial infarction ...
- Posterior heart arteries
- Post-MI pericarditis
- Prevention of heart disease
- Progressive build-up of pla...
- Ptosis - drooping of the eyelid
- Pulmonary nodule, solitary ...
- Quitting smoking
- Radial pulse
- Read food labels
- Respiratory cilia
- Respiratory system
- Retrocalcaneal bursitis
- Right atrial myxoma
- Right cerebral hemisphere -...
- Roux-en-Y stomach surgery f...
- Saturated fats
- Secondhand smoke and lung cancer
- Shin splints
- Slit-lamp exam
- Smoking hazards
- Smoking hazards
- Sodium content
- Sources of fiber
- Stable angina
- Starchy foods
- Striae in the popliteal fossa
- Stroke
- Sulfonylureas drug
- Superficial thrombophlebitis
- Superficial thrombophlebitis
- Swan Ganz catheterization
- Taking your carotid pulse
- Thiazolidinediones
- Thoracic organs
- Thromboangiitis obliterans
- Thrombus
- Thyroid cancer - CT scan
- Tobacco and cancer
- Tobacco and chemicals
- Tobacco and vascular disease
- Tobacco health risks
- Totally anomalous pulmonary...
- Totally anomalous pulmonary...
- Totally anomalous pulmonary...
- Trans fatty acids
- Transient Ischemic attack (TIA)
- Tricuspid Regurgitation
- Tricuspid Regurgitation
- Type I diabetes
- Ultrasound, normal fetus - ...
- Ultrasound, ventricular sep...
- Untreated hypertension
- Varicose veins
- Vascular ring
- Venous blood clot
- Ventricular septal defect
- Ventricular tachycardia
- Vertebra, thoracic (mid back)
- Vertical banded gastroplasty
- Vertigo
- Visual acuity test
- Visual field test
- Vitamin B1 benefit
- Vitamin B1 source
- Vitamin C benefit
- Vitamin C deficit
- Vitamin C source
- Vitamin E and heart disease
- Warming up and cooling down
- Wine and health