Changes in body position are known to cause changes in the ECG mainly in the electrical axis, QRS amplitude, ST segment, and T wave. These shifts have been attributed to changes in the anatomical orientation of the heart in the chest cavity, changes in lung volume, and change of electrode contact with the skin.
ECGs are standardly recorded in the supine position; however, due to time and space constraints as well as patient limitations, they are often performed in other positions (sitting, standing).
Ideally, your patient should be in a supine position. However, some patients will not tolerate this. If that's the case, you can put them in a Semi-Fowler's position, partially reclined. Whichever position your patient is in for the EKG, just remember to repeat that position for any future, repeat EKGs you may acquire.
Body position changes may cause QRS and ST-T changes and trigger false alarms. Placement of arm and leg electrodes in a coronary care unit environment is usually near the thorax instead of standard position at the wrists and ankles.
You don't need to do anything special to prepare for the test. You can eat and drink as normal beforehand. Before the electrodes are attached, you'll usually need to remove your upper clothing, and your chest may need to be shaved or cleaned.
In such cases, any device that may interfere with the ECG signal should be turned off: these include cell phones within 25 cm of the ECG sensor module, electrical beds, surgical and fluorescent lamps.
Having an ECG
An ECG is a simple test that usually doesn't need any special preparation. You can eat and drink as normal before having an ECG (unless your doctor has advised otherwise). Always let your doctor know what medicines you are taking before you have an ECG.
Inaccurate electrode placement and differences in inter-individual human anatomies can lead to misinterpretation of ECG examination.
Skin preparation is an essential part of any ECG test. Residues and oils on the skin and reduce the conduction of the electoral signal and hurt the quality of the test. Shaving the area, cleaning with alcohol, and rubbing the area with a towel are smart ways to get a better signal.
Limb leads are made up of 4 leads placed on the extremities: left and right wrist; left and right ankle. The lead connected to the right ankle is a neutral lead, like you would find in an electric plug. It is there to complete an electrical circuit and plays no role in the ECG itself.
Conclusion. The effect of different extreme breath-holding positions on the QRS complex is on average small but may be substantial in individuals. Lack of standardization of breathing instructions during recording of the ECG may result in differences in application of amplitude criteria and poorer reproducibility.
Modern ECG machines will present you with a computerized interpretation of the readout ('the CI'). This computer diagnosis is frequently wrong (up to 20% of cases)!
In the atrium, stress impacts components of the signal-averaged ECG. These changes suggest mechanisms by which everyday stressors can lead to arrhythmia.
As one may note, the Right Leg (RL) is not included in the original electrical activity of the heart model [1,2,3]. This is because the original instrument used to demonstrate the limbs' ECG by Einthoven was an extremely sensitive galvanometer (Ampere-meter) [1,4].
For a standard 12-lead ECG, the electrodes are placed on all 4 limbs and 6 positions on the chest wall. Additional leads are sometimes added for a 15-lead ECG. You will be asked to remain still, breathing normally while the machine is started and a sample (usually 3 to 4 seconds) from each electrode site is recorded.
With a resting ECG, you will be advised to lie down and relax for about five minutes. A series of electrodes, placed onto your skin with small sticky pads, will record the electrical activity in your heart throughout this period.
"ECG can be absolutely normal in a case of heart disease you have, you can have all the three arteries blocked and yet your ECG can be absolutely normal. The accuracy of ECG to predict a heart attack is only 33%.
Abnormal ECG Findings Caused by Anxiety
In patients without a known clinical history of anxiety or other mental health concerns, short-term nervousness can also disrupt ECG readings. In one case study from the Egyptian Journal of Critical Care Medicine, such apprehension led to reported quadrigeminy in all ECG leads.
Many kinds of abnormalities can often be seen on an ECG. They include a previous heart attack (myocardial infarction), an abnormal heart rhythm (arrhythmia), an inadequate supply of blood and oxygen to the heart (ischemia), and excessive thickening (hypertrophy) of the heart's muscular walls.
Don't eat or drink anything but water for 4 hours before the test. Don't drink or eat anything with caffeine (such as cola, chocolate, coffee, tea, or medications) for 24 hours before. Don't smoke the day of the test. Caffeine and nicotine might affect the results.
An ECG Can Recognize the Signs of Blocked Arteries. But for further accurecy a CT coronary angiogram can reveal plaque buildup and identify blockages in the arteries, which can lead to a heart attack.
Numerous factors can lead to false-positive and false-negative results, including use of medications, conduction system disease, Left ventricular hypertrophy and other conditions that affect repolarization, valvular heart disease, gender, and testing equipment.
Echocardiograms also provide highly accurate information on heart valve function. They can be used to identify leaky or tight heart valves. While the EKG can provide clues to many of these diagnoses, the echocardiogram is considered much more accurate for heart structure and function.