You aren’t the only one that’s a bit terrified of EKGs . . . let’s just clear that up right away. For many nursing students and new nurses, EKG interpretation can be intimidating, to say the least. I remember my first day as a nurse in the ICU . . . monitors were EVERYWHERE. To say that I was overwhelmed is a pretty big understatement.
But the truth is you don’t have to be so scared. In fact, you can interpret ANY heart rhythm in just 5 simple steps. Let me warn you though that you have to follow these steps EXACTLY you can’t skip ahead, you must follow these steps in order.
Normal sinus rhythm is the result of the electrical conduction following the intended course without deviation or alteration in rate. Slight variations in rhythm regularity may be noted with the respiratory cycle.
Okay. . . at this point you should have a basic grasp of how to identify and interpret normal sinus rhythm. This is the BEST place to start. But this is just the beginning. In order to become an EKG master, you need to become comfortable with a wide range of rhythms. Let's dive into how to interpret different rhythms.
When looking at an EKG that is sinus brady, all PQRST waves are within normal measurements meaning that the PR, QRS, and QT intervals all meet the criteria for sinus rhythm. However, when you count out the heart rate it is less than 60 bpm.
Sinus bradycardia can be seen in healthy adults if they are athletic and/or are asleep! Other common causes of sinus brady include:
Patients with sinus bradycardia will likely be asymptomatic, however, it makes sense for patients to exhibit signs and symptoms of cardiac compromise such as:
Transcutaneous pacing should be used if the patient is exhibiting signs and symptoms of poor profusion.
First degree AV block, second degree type 1 AV block, and third degree AV block can be caused by the following issues:
Second degree type 2 (Mobitz), however, is caused by damage to the bundle branch system following an acute anterior Myocardial infarction. It is important to note that second degree type 2 AV block is NOT caused by medications or increased vagal tone.
AV blocks are usually asymptomatic. However, a patient may experience the following:
The main goal of treating AV block usually depends on if the patient is symptomatic or not. If they are not symptomatic and their heart rate is sustaining appropriate profusion, then the goal is to monitor PR intervals and make sure that the heart block conduction system does not worsen. In each specific degree of heart block, you will want to follow the following:
On the EKG, all PQRST wave forms present and the rhythm is regular, just very fast.
Sinus Tachycardia causes decreased cardiac output due to inadequate ventricular filling as well as an increased oxygen demand for the myocardial cells. A patient with sinus tachycardia may have the following signs and symptoms:
The best treatment for sinus tachycardia is to treat the underlying cause. If a patient has a fever, administer antipyretics such as Motrin or Tylenol, or if they have anxiety give them an anti-anxiety medication such as Xanax, Valium or Ativan. If the patient has a narrow QRS complex, then treat them with the following:
If the patient has a wide QRS complex, then treat them with an antiarrhythmic such as Procainamide, Amiodarone, or Sotalol.
Let’s look even closer at Atrial Rhythms. When the sinoatrial (SA) node is not generating proper electrical activity, the hearts atrial tissues or even other tissues of the heart will attempt to generate electrical action potential. This can cause issues with the heart not beating properly, completely, or rhythmically. Watch this video below:
Paroxysmal Supraventricular Tachycardia (PSVT) is a rapid heartbeat that originates in the atria. It is called paroxysmal because it happened intermittently and lasts various lengths of time. PSVT is often just called SVT.
The EKG will show a fast heart rate anywhere from 100 to up to 300 bpm! The QRS is narrow at a regular rhythm. Sometimes the P waves are inverted, this is referred to as retrograde P waves.
A patient can be genetically inclined to have PSVT; Their electrical conduction doesn’t fire normally. It can also be drug-induced; Digoxin and Theophylline can cause PSVT. However, certain behaviors such as alcoholism, caffeine, drug use, or smoking can put you at risk as well.
Patients who have sustained PSVT can have adverse effects such as hypotension due to the inevitable incomplete heartbeats from the fast beating of the heart. As well as over time, the heart will enlarge (Cardiomegaly) and eventually fail (heart failure).
Because PSVT can be treated by the patient by themselves, the first line of treatment involves performing the Valsalva maneuver where the patient holds their breath and bear down as if they were having a bowel movement, or cold water on the face (splashing or submerging). Coughing while positioned sitting forward can also bring someone out of PSVT. In the hospital, a patient may get a carotid massage by a physician, medications such as adenosine (Adenocard) and cardioversion.
The waves are more chaotic and random, the beat is irregular and you can see the atria quivering between the QRS (ventricles pumping). No discernible P waves. The ventricular rate is often 110-160 bpm and the QRS complexes is usually less than 120 ms.
The actual cause of Afib is unknown but research suggests many risk factors that are commonly seen with patients with Afib.
Due to the pooling of blood from incomplete contractions and the quivering of the atria, a patient is likely to form a clot. If the blood clot breaks free it can cause a stroke or pulmonary embolism (PE) and increase the risk of heart failure and death. A patient with Afib may not have any signs or symptoms at all (about 60% do not), however, a patient may feel lightheaded, dizzy, short of breath, as well as experience chest pains, palpitations, and/or weakness. Afib also causes the heart to undergo a process called remodeling where the walls thicken and the heart size increases.
The two main goals of treating Afib is controlling the rate and rhythm and prevention of stroke/pulmonary embolism (PE). Medications can be used to control a patient's rate and rhythm. The most commonly used medication for the rate is adenosine. The two most commonly used medications for rhythm control are diltiazem (Cardizem) and amiodarone (Cordarone). Cardizem is better at controlling the rhythm but can cause hypotension in the patient, whereas amiodarone is better for hemodynamically compromised patients. Anticoagulants are used for stroke and pulmonary emboli prevention. Heparin is the first line, however, Lovenox and warfarin (Coumadin) are also used. If medication has not been successful in controlling the rate or rhythm, the patient may have a medical procedure to correct this arrhythmia.
This was always the easiest rhythm for me to pick out because it is so unique. The jagged edges are similar to that of a saw blade, and people refer to it as a saw tooth pattern. The rate is regular but fast.
If untreated can lead to cardiomyopathy, heart failure, and Afib.
Generally speaking, AFlutter itself isn’t life-threatening, however, long term, it can cause complications similar to Afib. The most common treatment for Aflutter is cardioversion and medications.
The rhythm is regular but the rate is fast (above 100 bpm). The QRS complex is widened and P waves can be difficult to identify. This is a very easy rhythm to glance at and interpret due to its characteristic waves.
VTach can occur in patients who have heart diseases such as:
And can be present due to abnormal blood conditions such as:
A patient with VTach could be asymptomatic, however, signs and symptoms include:
If left untreated, VTach can cause sudden cardiac death
The most immediate goal is to slow the heart rate. This is managed through medications (such as Lidocaine, Procainamide, Sotalol, or Amiodarone), defibrillation and possible cardiopulmonary resuscitation (CPR). Chronic long term VTach is treated with an implantable cardioverter defibrillator (ICD).
VFib is easily recognized because of its rapid, chaotic, and irregular nature. The QRS complexes are variable in height and width as well as there are no P waves.
VFib can be caused by:
Ventricular tachycardia will become ventricular fibrillation if it is left untreated. Electrolyte imbalances also can cause VFib because our muscles (the heart is a giant muscle) uses calcium (Ca-) and potassium (K+) to contract and magnesium (Mg) to relax.
Your patient will likely lose consciousness and they will not have a pulse. VFib needs to be recognized and treated immediately because it leads to cardiac arrest and death.
How do you read an ekg strip?
By looking at the waveforms on the EKG graph you look for the P wave followed by the QRS wave and T wave in that specific order.
How to measure an ekg strip?
Each small box is 0.04 seconds and each large box is 0.20 seconds. There are 5 small boxes in a large box (0.04 X 5 = 0.20 seconds).
How many seconds is an ekg strip?
Most EKG strips are 6 seconds, the graph paper has a marking on the top or bottom to indicate every 3 seconds. You can also count the large boxes, 30 large boxes equal 6 seconds, most 12 lead EKGs are 10 seconds long.
What does an abnormal EKG strip look like?
An abnormal EKG strip will not follow the traditional P wave, QRS wave, and T wave order. There could be an additional P wave or an extra QRS complex or an irregular rhythm.
How to calculate a heart rate on an EKG strip?
By counting the R waves on a 6-second strip and multiplying by 10. You can count the small boxes between the R waves and divide 1500 by the number of R waves (1500/20 = 75). Or you can count the large boxes
This is the time you call a code blue, grab the crash cart, and get on the patients’ chest. With VFib, it is super important to defibrillate as soon as possible. For further details about running a code, check out the ACLS algorithm. Check out this awesome website for more helpful information about cardiac rhythms!
When you’re taking care of patients on cardiac monitoring, It’s important to be able to not only identify rhythm changes but also have an idea of some typical interventions for these changes. I’m going to go over a few common ECG changes and typical subsequent nursing interventions.
The 5-step method for rapid EKG interpretation outlines the steps to help you quickly spot arrhythmias with confidence. There are many more factors involved in fully understanding EKGs but this simple 5 step method will help you know exactly where to start. If you work through the 5 steps in order you will be able to look at any strip and quickly notice abnormalities. You can view a PDF chart with essential heart rhythms and their criteria here.
With any strip, you should start with the rate which can be determined (on a 6-second strip) by counting the P waves or the R waves and multiplying by 10. You can also count the number of large boxes between R waves and divide 300 by that number. For example, if you count 5 large boxes between each R wave then your rate would be approximately 60 bpm. Identifying the rate is a good way to determine where the impulse is initiating and can quickly rule out sinus rhythm.
The P wave is representative of atrial depolarization and the wave should have an upward direction, it should be visible, and smooth. If you do not see P waves or they are misshapen you are not dealing with sinus rhythm.
The QRS complex represents ventricular depolarization and should be present. The complex should have a length of 0.06 – 0.12 seconds (1.5 – 3 small squares). Anything out of this range is abnormal.
Every P wave should be followed directly by a QRS. The ratio between P and QRS should be 1:1. This represents the appropriate route of impulse travel. Deviation or alteration from the impulse traveling from SA node through Purkenji fibers in the right direction may be identified with the P:QRS.
The PR interval represents the onset of atrial depolarization and the onset of ventricular depolarization and is a factor in determining how long the impulse is held in the AV node. PR interval analysis is helpful in identifying AV heart blocks. The PR interval should be between 0.12 – 0.20 seconds (3 – 5 small squares).
By looking at the waveforms on the EKG graph you look for the P wave followed by the QRS wave and T wave in that specific order.
Each small box is 0.04 seconds and each large box is 0.20 seconds. There are 5 small boxes in a large box (0.04 X 5 = 0.20 seconds).
Most EKG strips are 6 seconds, the graph paper has a marking on the top or bottom to indicate every 3 seconds. You can also count the large boxes, 30 large boxes equal 6 seconds, and most 12 lead EKGs are 10 seconds long.
An abnormal EKG strip will not follow the traditional P wave, QRS wave, and T wave order. There could be an additional P wave or an extra QRS complex or an irregular rhythm.
By counting the R waves on a 6-second strip and multiplying by 10. You can count the small boxes between the R waves and divide 1500 by the number of R waves (1500/20 = 75). Or you can count the large boxes