EKG Analysis and Interpretation

Flashcards based on EKG Analysis and Interpretation lecture notes.

How to calculate heart rate using the 1500 method?

To count the number of small boxes between two R waves and divide 1,500 by that number.

How to calculate heart rate using the sequence method?

To calculate heart rate by dividing 300 by the number of large boxes between R waves.

How to calculate heart rate using the 6-second method?

At the top of the tracing, there are small hash marks indicating 3-second intervals. Between each hash mark are 15 boxes. At the standard print speed, the hash marks and boxes will deliver 3-second intervals. Count the number of QRS complexes in two of the sections (6-second period or 30 boxes) and multiply by 10.

What is the formula for calculating maximum heart rate?

220 - Patient's age = Max heart rate

How is target heart rate calculated?

Calculate the maximum heart rate (220-age), then multiply the maximum heart rate by the percentage you want to limit the rate to.

What does irregular P-P intervals indicate?

Irregular intervals in P waves can indicate atrial dysfunction.

What does irregular R-R intervals indicate?

Irregular intervals in Q waves can indicate ventricular dysfunction.

What are the characteristics of a normal P wave?

The P wave should have a consistent shape throughout the tracing, be positively deflected, and occur before each QRS waveform.

How long of a tracing is needed to assess the regularity of P and QRS waveforms?

A tracing of about 6 to 10 seconds is necessary to assess the regularity of the P and QRS waveforms.

What is a regularly irregular rhythm?

A consistent, noticeable irregular pattern.

What is an irregularly irregular rhythm?

Varies without any consistency throughout the tracing.

How is time and voltage measured on an EKG?

Time is measured horizontally, and voltage (or amplitude) is measured vertically.

What does the P wave represent?

The P wave represents atrial depolarization and begins when the sinoatrial (SA) node fires.

What does the QRS complex represent?

The QRS complex represents ventricular depolarization. (Atrial repolarization is not visible but occurs during this phase.)

What does the J point represent?

The J point represents the exact point in time where ventricular depolarization stops, and ventricular repolarization starts.

What does the T wave represent?

The T wave represents ventricular repolarization.

What does the U wave represent?

The U wave represents a repolarization of the bundle of His and Purkinje fibers.

What does the PR interval represent?

The PR interval represents the time it takes for the SA node to fire, atria to depolarize, and electricity to travel through the AV node-or the time from the beginning of atrial depolarization to the beginning of ventricular depolarization.

-normal range 0.12-0.20

What does the P-P interval represent?

The P-P interval represents the amount of time between atrial depolarization cycles (between P waves).

What does the R-R interval represent?

The R-R interval represents the amount of time between ventricular depolarization cycles (between R waves).

What does the QT interval represent?

The QT interval represents one complete ventricular cycle.

What does the PR segment represent?

The PR segment represents the time between the end of atrial contraction and the beginning of ventricular contraction.

What does the ST segment represent?

The ST segment represents the early phase of ventricular repolarization.

What are the waveform characteristics?

The shapes (or configuration) of the waveforms should be consistent and measure the same voltage throughout the tracing.

What is the function of the SA node?

The SA node is the natural, primary pacemaker and is located within the wall of the right atrium. It sends impulses through the electrical conduction pathway of the heart.

What is the function of the Junctional node?

The secondary pacemaker is the junctional pacemaker located within the atrioventricular tissue or node located at the junction between the atria and ventricles. It fires impulses at a rate of 40 to 60 beats per minute.

What is the function of the Purkinje Fibers?

The final pacemaker is initiated within the Purkinje fibers that stimulate the ventricles. The pacing produced in the ventricles is slow, firing impulses at 20 to 40 beats per minute.

What is Sinus bradycardia?

A normal EKG tracing, but there is heart rate of less than 60/min.

What is Sinus tachycardia?

A normal EKG with the exception of the heart rate greater than 100/min.

What is Sinus dysrhythmia?

A slight irregularity in the rhythm and is most likely associated with normal breathing patterns.

What is Sinus arrest?

A break in the normal EKG pattern. In this condition, the SA node failed to fire

What is Atrial flutter?

A condition in which the atria are contracting at a rate much faster than the ventricles are contracting.

What is Atrial fibrillation?

There is no organized contraction of the atria. They are in a quivering state, where blood clot formation due to stagnation of the blood in the ventricles is possible.

What are Junctional arrhythmias?

Impulses are being generated at the AV junction, electrical activity to the atria flows backward, which will result in an inverted P wave configuration.

What is Premature junctional complex (PJC)?

An early impulse that occurs before the next expected beat. The P wave could occur before, after, or even buried within the QRS complex, which causes an irregularity in the rhythm.

What is Junctional escape rhythm?

Reflects an impulse originating from the AV node, which is acting as the back-up pacemaker. The atria and ventricles will receive the impulse simultaneously, which can result in an absent P wave-but if recognizable, it will be inverted. The heart rate will not exceed 60/min.

What is Accelerated junctional rhythm?

Same as the escape rhythm, but the rate is 60 to 100/min.

What is Junctional tachycardia rhythm?

The same as the escape and accelerated rhythm, but the heart rate will be between 100 and 150/min.

What is Supraventricular tachycardia (SVT) or narrow complex tachycardia?

The impulse comes from any area above the ventricles. In this situation, the impulse is not following the normal electrical conduction pathway. The heart rate will be greater than 150/min. Due to the rapid nature of the heart rate, P waves are usually not visible.

What are Premature ventricular complexes (PVCS)?

Occur when the ventricles contract out of the normal sequence initiated by an ectopic focal point within the ventricles. A P wave is not visible, and the QRS complex is often wider than normal with an unusual shape.

What is Bigeminy?

PVCs occur every second beat.

What is Trigeminy?

PVCs occur every third beat.

What is Quadgeminy?

PVCS occur every fourth beat.

What is Coupling?

Two PVCs occur back to back.

What is Ventricular tachycardia (VT)?

Three or more PVCs in a row with a ventricular rate greater than 100/min. There is a continuous state of contraction and relaxation of the ventricles, resulting in a poor cardiac output.

What is Ventricular fibrillation (VF)?

An emergency state in which the ventricles are not contracting, but quivering and there is no cardiac output.

What is Idioventricular rhythm?

Occurs when only the ventricular pacemaker is functioning. The ventricular rate will range from 20 to 40/min, and there are no discernible P waves. The QRS complex is wide with an unusual appearance.

What is Agonal rhythm?

Results when all the pacemakers of the heat (SA node, AV node, Purkinje fibers) have failed. The tracing shows a wide, unusual QRS complex with no P or T wave. The ventricular rate is less than 20/min.

What are Heart blocks?

Occur when there is a block somewhere in the electrical conduction pathway, which results in delayed or absent ventricular depolarization.

What is Bundle branch block?

Occurs when there is interference somewhere in one of the bundle branches.

What is First-degree atrioventricular block?

Represents a delay in conduction from the SA node to the AV node. The impulse still travels through the normal pathway but is delayed. As a result, the PR interval will be greater than the normal 0.20 seconds.

What is Second-degree atrioventricular block, type I?

There are nonconducted or blocked impulses from the AV node to the ventricles. As a result, there will be missing QRS complexes. The PR interval will get progressively longer until a QRS is dropped, and then the pattern repeats itself.

What is Second-degree atrioventricular block, type II?

The PR interval remains constant, but during the tracing it is noted that a P wave is present with no QRS complex or T wave. In this situation, the AV node has selectively blocked specific impulses.

What is Third-degree atrioventricular block?

Occurs when all electrical impulses that originate above the ventricles are blocked. There is no pattern to the cardiac cycle as the atria and ventricles are contracting independently.

What are two of the most important interventions for cardiac arrest?

CPR and early defibrillation

What is a Pacemaker spike?

A thin spike at the P wave, QRS complex, or both, depending on the specific pacing needed and programmed.

What is Myocardial ischemia?

Is exhibited through ST segment depression of 1 mm or greater, occurring in two contiguous leads or T wave inversion.