Which part of the ECG would be affected if impulse originated in ventricles?
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During a resting ECG the body must be relaxed (at rest), as the neighboring muscles and nerves also produce electrical tension. The electrodes are attached to predetermined locations on the body, located on the chest, arms and legs, which are connected to the ECG machine via a cable. The electrodes can detect electrical tension of less than a millivolt, which is then transcribed onto graph paper to produce an ECG. Show
Exercise ECG An exercise ECG (or stress ECG) is performed under physical stress, as some changes are only detected when the heart is strained. For example, a resting ECG is particularly unremarkable in the setting of Coronary Artery Disease (CAD). Many heart rhythm disorders or ECG changes can be better detected and diagnosed via an exercise ECG. In addition, an exercise ECG is performed as part of the evaluation of chest pain in certain situations: As with a resting ECG, the electrodes are attached to the skin and are connected to the ECG machine via a cable. The patient is placed on either a treadmill or a stationary bicycle. The level of resistance/speed is increased at regular intervals (usually every 2-3 minutes) until the patient can no longer exercise, the maximum heart rate is reached or symptoms and/or ECG changes indicating stress to the heart are present. The ECG reading, heart rate and blood pressure are continuously monitored during the test, and for a few minutes following, in order to observe the return of the heart rate to its baseline. An exercise ECG should not be performed in the following situations, as it could cause cardiac injury:
Long-term ECG An additional way to measure the activity of the heart is a long-term ECG. This measures the heart’s activity over 24 hours and can therefore detect many changes. The electrodes are attached to the skin and connected to a small mobile recording device via a cable. The gathered data is then interpreted by a physician. Specialized tissues within the heart are capable of generating electrical impulses. These impulses cause the heart muscles to contract. With each contraction, the heart sends blood out to the lungs to pick up oxygen or to the body to deliver oxygen to the cells. The tissues that generate electrical activity are called the sinus node (or sinoatrial node). The sinus node, located in the heart’s upper right chamber (atrium), generates an electrical impulse each fraction of a second. The impulse travels through the atrial muscles, causing them to contract. It then travels to the AV (atrioventricular) node, which is located between the (upper chambers) and the ventricles (lower chambers). The AV atria node is the only pathway for electrical impulses to travel to the ventricles. The AV node conducts the electrical impulses more slowly than other nodes to allow time for the ventricles to receive blood from the atria before they contract and send it out of the heart. If the electrical impulses traveling from the atria to the ventricles come early or late, the balance between blood filling the lower chambers and the timing of the heart’s contraction is disturbed. The result is reduced cardiac output - or a reduced amount of blood ejected from the heart. How Is an ECG Performed?An ECG may be performed at rest or during exercise. During the ECG, small, sticky patches (electrodes) are placed on different areas of the body. Wires leading from the patches to a computer carry a signal that traces the heart’s electrical activity on paper or on a computer. Doctors analyze the ECG to learn more about the heart’s rhythm and condition. How Does an ECG Work?An ECG measures the heart’s electrical activity through electrodes, and a computer translates the heart’s activity into a printed or onscreen readout. You may have seen images of an ECG readout from television or movies: the electrical activity image looks like a line graph with peaks and valleys. An ECG shows three “waves” of signals.
The shape and size of the waves, the time between each wave, and the rate and regularity of beating provide valuable information to doctors. In addition to providing insight into the heart’s rhythm, the ECG helps doctors determine the size of the heart chambers, detect heart muscle damage and identify abnormal levels of certain electrolytes, such as potassium and calcium, in the blood. Is It Safe?Electrocardiograms do not pose any safety risks. Questions to Ask Your Doctor About ElectrocardiogramsThe following questions can help you talk to your physician about having an electrocardiogram. Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors. Which waves on an ECG are produced in the ventricles?The QRS complex refers to the combination of the Q, R, and S waves, and indicates ventricular depolarization and contraction (ventricular systole).
Which part of the ECG represents electrical impulse transmission through the ventricles?The P wave represents the depolarization (contraction) of the atria, the PR segment the transmission of the electrical impulse to the ventricles, the QRS complex represents depolarization (contraction) of the ventricles and the T wave shows the repolarization (relaxation) of the ventricles.
Which wave of the ECG is impacted the most if someone has a problem with ventricular repolarization?Introduction. The T wave on the ECG (T-ECG) represents repolarization of the ventricular myocardium.
What part of ECG is ventricular depolarization?Ventricular depolarization and activation is represented by the QRS complex, whereas ventricular repolarization (VR) is expressed as the interval from the beginning of the QRS complex to the end of the T wave (QT interval).
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