14 hours ago Following facility protocol, the nurse administers supplemental oxygen at 4 L/minute via nasal cannula and pages the physician on call, who orders stat serum cardiac biomarkers, a 12-lead ECG, and sublingual nitroglycerin. A nurse who can independently interpret a 12-lead ECG can anticipate and prepare for any emergency care the patient may need. >> Go To The Portal
The goal of reading an EKG rhythm strip is to determine the rate and rhythm of the patient. This is great for identifying baseline cardiac rhythm as well as any arrhythmias or ectopy that may occur (like a premature beat). A 12-lead EKG also looks at the rate and rhythm, but additionally gives nearly a complete 360° view of the heart.
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EKG 12-Lead Analysis and Interpretation. In this quiz, users are sequentially presented with five analysis questions related to the displayed EKG tracing: Each correct analysis answer is worth one point; there are six analysis questions per tracing.
However, cardiac arrhythmias tend to be transient and episodic, making capture of the 12-lead EKG impractical during these episodes.
The standard EKG leads are denoted as lead I, II, III, aVF, aVR, aVL, V1, V2, V3, V4, V5, V6. Leads I, II, III, aVR, aVL, aVF are denoted the limb leads while the V1, V2, V3, V4, V5, and V6 are precordial leads. Figure 3.
A 12-lead ECG is the gold standard assessment tool that uses electrodes to produce a graphic representation (12 views) of the electrical activity of the heart. It is used to diagnose heart problems such as abnormal electrical activity, heart failure, or heart attacks. It focuses on the left ventricle of the heart:
In the 6-second method, look for the markings (usually short vertical lines) at the top of the rhythm strip or ECG paper. These markings divide the ECG paper into 3-second intervals. Count the number of QRS complexes contained in two interval s (6 seconds) and multiply by 10.
All cardiac cells are electrochemical, meaning they generate electrical energy during depolarization . This electrical energy, called a vector, has strength (measured in millivolts) and direction (measured in degrees from an arbitrary zero point called the electrical axis). Each cardiac cell generates its own microvector. The mathematical average of these microvectors is the mean QRS vector or mean vector, which follows the normal conduction pathway of the heart—downward and to the left. The mean vector flows slightly to the left of the ventricular septum because the left ventricle has more and larger cardiac cells.
The QRS complex may have one, two, or three wave components, depending on the lead and your patient's clinical status. Figure:
Similarly, morbidly obese patients or patients with ascites or an abdominal tumor may have a left axis deviation because of the heart's position in the chest. A right axis deviation is apparent when lead I is negative and lead aVF is upright. The mean vector is abnormally directed to the right side of the heart.
In lead II, the positive electrode is on the left foot and the negative electrode is on the right arm. Because the mean vector flows directly at the positive lead II electrode, this lead usually has the most upright QRS complexes and the most prominent P waves of the entire 12-lead ECG.
Some left bundle-branch blocks will produce a left axis deviation because the cardiac vector flows abnormally from the right side of the heart to the left.
The first part of the cardiac cycle, the P wave appears as a small, semicircular bump (see Tracing a normal ECG waveform ). The wave of depolarization continues through the atria until it encounters the next important structure, the atrioventricular (AV) node, which receives the atrial impulse.
Normal conduction implies normal sinoatrial (SA), atrioventricular (AV), and intraventricular (IV) conduction, whereas a conduction block refers to any obstruction or delay of the flow of electricity along the normal pathways of electrical conduction.
A quick way to calculate the rate is to look at the 10 second ECG strip and count the number of QRS complexes. Multiply this by six as 10 seconds times six equals 60 seconds to arrive at beats/minute.
It is just as important to follow a repeatable pattern or checklist when interpreting a 12-lead EKG. In each lead examine the following:
The EKG Club expert panel accepts 12-lead ECG and EKG cases for review and discussion. The EKG Club expert panel provides an opportunity for EMTs, paramedics, nurses, physicians and other health care providers learn from real patient-based case studies.
In this quiz, users are sequentially presented with five analysis questions related to the displayed EKG tracing:
Each correct analysis answer is worth one point; there are six analysis questions per tracing. Two interpretation questions per tracing are worth an additional two points each.
Take an in-depth look at how the ECG translates the heart's electrical activity into a waveform, and what that waveform tells you about your patient's condition. Part II, appearing in a future issue, will focus on recognizing myocardial infarction and dysrhythmias.
The heart's internal conduction circuit initiates each heartbeat and coordinates all parts of the heart to contract at the proper time. A normal heartbeat is initiated in the sinoatrial (SA) node, a specialized group of cells in the right atrium.
If you examine a 12-lead ECG, you'll notice that some QRS complexes have upward deflections and others have downward deflections. Here's why.
All cardiac cells are electrochemical, meaning they generate electrical energy during depolarization. This electrical energy, called a vector, has strength (measured in millivolts) and direction (measured in degrees from an arbitrary zero point called the electrical axis). Each cardiac cell generates its own microvector.
The mean vector is a representation of the overall electrical properties of the heart. A 12-lead ECG is the electrical record of the mean vector from 12 different monitoring sites (leads) on the surface of the body. As when you look at any object, you need to see all the angles to get a complete picture.
The first six leads of the 12-lead ECG come from four electrodes placed on the patient's arms and legs; the right lower leg electrode is the ground electrode. The limb leads record the mean vector in the up–down and left–right direction along the body's frontal plane.
The six chest or precordial leads lie across the anterior chest and measure the mean vector in the horizontal plane.
Causes includes heart failure, tricuspid valve or mitral valve diseases, pulmonary embolism, cor pulmonale, inferior wall MI, carditis and digoxin toxicity. Management if the patient is unstable with ventricular rate of greater than 150 bpm, prepare for immediate cardioversion.
Sinus Bradycardia. Sinus bradycardia is a heart rate less than 60 beats per minute and originates from the sinus node (as the term “sinus” refers to sinoatrial node). It has the following characteristics. Rate is less than 60 beats per minute.
Atrial flutter is an abnormal rhythm that occurs in the atria of the heart. Atrial flutter has an atrial rhythm that is regular but has an atrial rate of 250 to 400 beats/minute. It has sawtooth appearance. QRS complexes are uniform in shape but often irregular in rate.
Arrhythmia or dysrhythmia are disturbances in the normal cardiac rhythm of the heart which occurs as a result of alterations within the conduction of electrical impulses. These impulses stimulate and coordinate atrial and ventricular myocardial contractions that provide cardiac output. Interpreting EKG. Sinus Tachycardia.
Causes of sinus tachycardia may include exercise, anxiety, fever, drugs, anemia, heart failure, hypovolemia and shock. Sinus tachycardia is often asymptomatic. Management however is directed at the treatment of the primary cause. Carotid sinus pressure (carotid massage) or a beta blocker may be used to reduce heart rate.
First degree AV block is asymptomatic and may be caused by inferior wall MI or ischemia, hyperkalemia, hypokalemia, digoxin toxicity, calcium channel blockers, amiodarone and use of antidysrhythmics. Management includes correction of underlying cause.
Causes includes coronary or valvular heart diseases, atrial ischemia, coronary artery atherosclerosis, heart failure, COPD, electrolyte imbalance and hypoxia.