ECG PDF

ELECTROCARDIOGRAPH Lab-3 Miss Zaynab Yaseen Ahmed What is Electrocardiograph? An Electrocardiogram (ECG) records the electrical signals in the heart. It's a common and painless test used to quickly detect heart problems and monitor the heart's health. Why it's done? An electrocardiograph is a painle...

ELECTROCARDIOGRAPH Lab-3 Miss Zaynab Yaseen Ahmed What is Electrocardiograph? An Electrocardiogram (ECG) records the electrical signals in the heart. It's a common and painless test used to quickly detect heart problems and monitor the heart's health. Why it's done? An electrocardiograph is a painless, noninvasive way to help diagnose many common heart problems. A health care provider might use an electrocardiogram to determine or detect: 1. Irregular heart rhythms (arrhythmias). 2. If blocked or narrowed arteries in the heart (Coronary artery Disease) are causing chest pain or a heart attack. 3. Whether you have had a previous heart attack. 4. How well certain heart disease treatments, such as a pacemaker, are working. You may need an ECG if you have any of the following signs and symptoms: 1. Chest pain. 2. Dizziness, lightheadedness or confusion. 3. Heart palpitations. 4. Rapid pulse. 5. Shortness of breath. 6. Weakness, fatigue or a decline in ability to exercise. The origin of electricity of the heart is the sinoatrial node which is located in the right atrium which then sends the electrical activity to the atrioventricular node and to the purkinjee fibers of the heart. Electrically the most important chamber of the heart is the right atrium Mechanically the most important chamber of the heart is the left ventricle. ECG was developed by a German Scientist called Einthoven. We have three leads in Einthoven’s triangle 1. Lead I: direction of electricity from the right arm to the left arm. 2. Lead II: direction of electricity from the right arm to the left leg. 3. Lead III: direction of electricity from the left arm to the left leg. Measuring the electricity of lead II is very important because it directs the electrical pulse from the right atrium to the left ventricle (from the most important electrical chamber to the most important mechanical chamber) In hospitals they use 12 electrodes to measure ECG: 1. Right arm 2. Left arm 3. Right leg 4. Left leg 5. And the rest are placed between the fourth and fifth ribs on the left and right side of the sternum. A single electrode is positioned between this pair of electrodes on the fourth intercostal space. The result will be a series of waves shown as follows; 1. P is a wave that indicates the depolarization of the atrium. 2. QRS complex series of waves that indicate depolarization of the ventricle. 3. T wave represents repolarization of the ventricle. What is Important to know? Because the repolarization of the atrium is small it will disappear in QRS complex which is large. When doing ECG sometimes we use Gel that contains ions to increase conductivity. Sodium is an important electrolyte for the heart movement. So checking the patient’s electrolyte (specially sodium) is important. What do the results tell us? ECG results can give a health care provider details about the following: 1. Heart rate: an ECG can help identify an unusually fast heart rate (tachycardia) or an unusually slow heart rate (bradycardia). 2. Heart rhythm: an ECG can detect irregular heartbeats (arrhythmias). An arrhythmia may occur when any part of the heart's electrical system doesn't work properly. 3. Heart attack: an ECG can show evidence of a previous heart attack or one that's currently happening. 4. Blood and oxygen supply to the heart 5. Heart structure changes: an ECG can provide clues about an enlarged heart, heart defects and other heart problems.