An electrocardiogram, commonly known as an EKG or ECG, is a non-invasive test that measures the electrical activity of the heart. An EKG captures these signals, translating them into wavy lines that healthcare professionals can analyze. This test provides important information about the heart’s rate and rhythm, and can indicate if there are any irregularities or signs of damage. An EKG is a quick, painless procedure that offers valuable insights into heart health.
Patient and Skin Preparation
Before applying EKG electrodes, patient and skin preparation is important for a clear and accurate recording. Explain the procedure to the patient to alleviate anxiety and ensure comfort. The patient should be in a relaxed position, typically lying flat on their back (supine) or in a semi-Fowler’s position, with arms resting at their sides and legs uncrossed. This positioning helps minimize muscle tension and movement that could interfere with EKG signals.
The skin at the electrode placement sites must be clean, dry, and free of oils, lotions, or excessive hair. These substances can create resistance, hindering the electrical signals from reaching the electrodes effectively. If there is significant hair, it may need to be clipped or shaved to ensure good electrode contact.
Cleaning the skin with an alcohol wipe or an abrasive pad helps remove dead skin cells and improve conductivity. Gentle abrasion of the skin surface further reduces skin impedance. This preparation promotes optimal adhesion of the electrodes and helps ensure a high-quality EKG tracing.
Electrode Placement Techniques
Accurate placement of electrodes is important for a standard 12-lead EKG, which uses 10 electrodes to generate 12 different views of the heart’s electrical activity. Four electrodes are placed on the limbs. The right arm (RA) electrode is placed between the right shoulder and elbow, and the left arm (LA) electrode is placed similarly on the left arm. For the legs, the right leg (RL) electrode serves as a ground, and the left leg (LL) electrode is placed on the lower leg. Uniformity in limb lead placement, such as on the forearms and lower legs, is important for consistent readings.
The remaining six electrodes, known as precordial or chest leads (V1-V6), are placed on specific anatomical landmarks across the chest to provide a horizontal view of the heart’s electrical activity. V1 is positioned in the fourth intercostal space (the space between the fourth and fifth ribs) at the right border of the sternum. V2 is placed in the fourth intercostal space at the left border of the sternum. To locate the intercostal spaces, palpate the sternal angle (Angle of Louis), a ridge on the sternum that aligns with the second rib, then count down to the fourth space.
V4 is placed in the fifth intercostal space at the midclavicular line. V3 is then positioned midway between V2 and V4. V5 is placed on the same horizontal level as V4, but along the anterior axillary line. V6 is placed on the same horizontal plane as V4 and V5, extending to the midaxillary line.
For female patients, V3-V6 should be placed under the left breast, avoiding the nipple as a reference point, as nipple location can vary. Ensuring good electrode contact and adhesion by pressing firmly on the electrode after placement helps optimize signal transmission.
Initiating the EKG Recording
Once all electrodes are securely in place, connect the lead wires to the corresponding electrodes and the EKG machine. Each lead wire is color-coded and labeled to match the specific electrode placement. Power on the EKG machine.
Before starting the recording, ensure the EKG machine’s settings are appropriate for a standard reading. This involves checking the speed and gain settings, which are standardized to ensure consistent results. Instruct the patient to remain still and relaxed, and to breathe normally throughout the recording process. Any movement, talking, or deep breathing can introduce interference into the tracing.
Observing the EKG tracing on the machine’s screen provides an initial check for signal quality. A clear, stable baseline indicates good electrode contact and minimal interference. If the tracing appears erratic or unclear, it may be necessary to check electrode connections and skin preparation before proceeding with the final recording. Once a satisfactory tracing is observed, the recording can be initiated, capturing the heart’s electrical activity for analysis.
Addressing Application Issues
Even with careful preparation and placement, issues can arise during EKG application that affect the quality of the recording. These issues manifest as “artifact,” unwanted signals that interfere with the heart’s electrical activity. Common causes of artifact related to application include patient movement, muscle tremor, loose electrodes, and electrical interference from other equipment.
Patient movement, such as shifting or talking, can cause a “wandering baseline,” where the tracing fluctuates slowly. Muscle tremors, which can occur from a nervous or cold patient, or from conditions like Parkinson’s, appear as rapid, irregular fluctuations on the EKG. Loose or dry electrodes, or inadequate skin preparation, can also lead to poor signal quality and artifacts.
Troubleshooting these issues involves several solutions. If the baseline is wandering, instruct the patient to remain still and ensure they are comfortable and warm. For muscle tremor, encouraging relaxation or covering the patient with a blanket can help.
Re-prepping the skin by cleaning and abrading it, or ensuring the electrode gel is moist and electrodes are firmly adhered, can resolve issues related to poor contact. Electrical interference, often appearing as a thick, fuzzy line, can be reduced by moving the EKG machine away from other electrical devices or ensuring lead wires are not crossing power cables. Addressing these application-related problems helps ensure a diagnostic-quality EKG.