5 Common Dysrhythmias and Treatments
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Article at a Glance
- Five common types of dysrhythmias are symptomatic bradycardia, third-degree atrioventricular block, supraventricular tachycardia, atrial fibrillation, and ventricular tachycardia.
- The provider can assess the type of dysrhythmia a patient has by interpreting the electrocardiogram.
- Read on to learn about treatments for different types of dysrhythmias.
An Overview of Five Common Dysrhythmias
This article provides an overview of common dysrhythmias and their treatments. Dysrhythmia is an abnormality in the electrical rhythm of the heart. The five dysrhythmias covered in this article are:
- Symptomatic bradycardia
- Third-degree atrioventricular (AV) block
- Supraventricular tachycardia (SVT)
- Atrial fibrillation
- Ventricular tachycardia
Dysrhythmia is an abnormality of the electrical rhythm of the heart.
Symptomatic Bradycardia
Symptomatic bradycardia is defined as a heart rate less than 60 beats per minute that elicit signs or symptoms. Patients will typically experience a mental status change or a drop in blood pressure, or both. Atropine is used to treat symptomatic bradycardia.
Atropine blocks innervation from the vagus nerve, stopping any interaction between the vagus nerve and the sinoatrial (SA) node. The vagus nerve slows the heart rate. Therefore, because atropine blocks the innervation from the vagus nerve, it speeds up the heart rate and improves any mental status changes or blood pressure drops.
Related Video – One Quick Question: What are the AFib Criteria?
Third-Degree Atrioventricular Block
Third-degree AV block is also known as complete AV dissociation. In third-degree AV block, there is no communication between the atria and the ventricles. That means both the SA and AV nodes are firing, but they are not in sync. The P waves and QRS complexes are all over the place.
When evaluating an electrocardiogram tracing, it is important to see if the P waves and QRS complexes have any kind of relationship.
The heart rhythm originates in the sinoatrial (SA) node in the right atrium.
The treatment for third-degree AV block is transcutaneous pacing until a permanent pacer is placed.
Drugs, like atropine, are not administered because of the disconnect of electrical signals between the atria and the ventricles. Atropine would affect the SA node but would not affect the AV node or the rest of the heart.
Read: 10 Cardiac Drugs to Know for the Pharmacology Test
Supraventricular Tachycardia
SVT is an umbrella term for any tachycardia that originates above the ventricles. Notable characteristics of an SVT are a fast heart rate and tall, skinny QRS complexes.
The primary goal with SVT is to slow down the heart rate. If a patient’s heart rate is 150 beats per minute, they will have a very low cardiac output. When it comes to treatments, start with the least invasive first. A noninvasive initial treatment is putting ice on the bridge of the patient’s nose to try and stimulate the vagus nerve. Stimulating the vagus nerve slows down the heart rate.
A drug treatment used for SVT is adenosine. Specifically, adenosine is used in paroxysmal SVT, which is an SVT that occurs spontaneously. Adenosine treats SVT by creating a heart block. It stops conduction through the AV node.
When adenosine is administered, the intent is that it will induce a heart block and slow the electrical signals enough so the underlying rhythm can be identified.
It is important to determine if the dysrhythmia is originating from the atrium or the ventricles. Therefore, adenosine is used to slow down the heart rate enough to correctly identify the underlying dysrhythmia.
An important fact about adenosine is that it has an extremely short half-life. The half-life life is 10 seconds, which means the adenosine is essentially out of the system in about 30 seconds. The nurse must push the adenosine very quickly to get the full dose into the patient.
Possible underlying dysrhythmias that could be uncovered with the use of atropine include atrial fibrillation, atrial flutter, or another atrial dysrhythmia.
Related Video – Understanding the Adult Bradycardia with a Pulse Algorithm
Atrial Fibrillation
Atrial fibrillation is an irregular heart rate due to contractions in the atrial chambers of the heart. Most often, the rhythm is fast and causes the patient to experience palpitations. Other times, the rhythm can be slow. Sometimes, the patient may not feel symptoms.
The primary goal of treating atrial fibrillation is to slow the heart rate. Calcium channel blockers (CCBs) and beta-blockers are used to achieve this goal. Cardioversion is also an option for patients who continue to be in atrial fibrillation despite less invasive treatment efforts. The cardioversion procedure will hopefully convert the patient back to a normal sinus rhythm.
Patients with sustained atrial fibrillation need to be considered for anticoagulation. When the heart pumps irregularly, blood can pool in the heart and clot.
The CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, sex category) risk score is used to determine if a patient should be taking an anticoagulant.
Irregular heart rhythms characterize atrial fibrillation.
Ventricular Tachycardia
Ventricular tachycardia (VT) is the deadliest dysrhythmia. VT is a dysrhythmia that originates from the ventricles. The treatment for VT is much different than for other dysrhythmias, as the patient cannot simply be defibrillated.
The goal of VT treatment is to restore a normal heart rhythm. There are several medication and procedure options for treating VT:
- Lidocaine. Lidocaine is used in patients with ventricular tachycardia, particularly in those associated with acute, ischemic myocardial infarction. Lidocaine works to block sodium channels in the heart. Imagine that lidocaine “numbs” the heart. It prevents the ventricles from being overstimulated.
- Amiodarone. Amiodarone is used in the majority of ventricular dysrhythmias.
- Cardioversion. Cardioversion is a treatment option for patients if less invasive methods are unsuccessful in converting the patient back to a normal rhythm.
Cardioversion is a procedure that shocks the heart in an attempt to restore a normal rhythm.
Understanding the causes and treatments of the five common types of dysrhythmias is essential in providing accurate and prompt patient care.
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Editorial Note
ACLS Certification Association (ACA) uses only high-quality medical resources and peer-reviewed studies to support the facts within our articles. Explore our editorial process to learn how our content reflects clinical accuracy and the latest best practices in medicine. As an ACA Authorized Training Center, all content is reviewed for medical accuracy by the ACA Medical Review Board.
More to Learn
Learn about premature junctional contractions (PJCs) and their criteria in our article. Understand these premature beats that arise from the atrioventricular (AV) junction of the heart.
Understand the differences between ST and SVT during an electrocardiogram (ECG) interpretation by reading our comprehensive article.