Rhythm of the Month

October - November Rhythm 2011

When first looking at the strip, you will notice two things: first,

the QRSs are narrow or normal in duration (>0.12 seconds), or at

least they look narrow, and there is a regularly irregular rhythm,

giving the look of groups of two. Looking a little closure, you note

all QRS complexes have P waves. Because the QRS complexes

are narrow, the rhythm originates above the ventricles. And because

you see upright P waves in lead II, they are considered to be

normal in their configuration making the first beat of each group

originate in the sinus node; our basic underlying rhythm is sinus rhythm.

But what about the second beat of each group? There are P waves

before each QRS, but they have a slightly different look from the

sinus Ps and their PRIs are slightly longer at approximately 0.20 seconds,

which is normal. The PRIs of the sinus Ps are approximately

0.16 seconds which is normal. The QRSs are normal in width

(0.08 seconds) and look like the sinus QRSs (also 0.08 seconds).

When all the QRSs in a strip look the same and normal width, the

conduction to the ventricles is normal resulting in a narrow or normal

QRS complex. So, the second beat of each group is a PAC or

Premature Atrial Contraction. Because these beats originate in the

atria instead of the sinus node, the P waves have a slightly different

look compared to the sinus P waves. PACs result because there

are irritable foci or places in the atria firing before the next expected

sinus beat, causing them to occur early in the cycle.

If you called this rhythm Sinus rhythm with every other beat a PAC

you would not be incorrect.

But isn’t it easier to say Atrial Bigeminy?

Bigeminy means every other beat is a premature beat following a

sinus beat, thus giving groups of two.

Do you know the difference between Atrial Bigeminy vs. Ventricular Bigeminy?

Interpretation: Atrial Bigeminy

SPECIAL ANNOUNCEMENT

I am pleased to announce we have a winner for the rhythm

contest in August / September 2011 E-Newsletter.

Betsy Stroup, RN of Knoxville, TN had the correct answer,

Atrial Fibrillation, in the winning time of 3 hours and

9 minutes from the time the E-Newsletter was sent.

Congratulations Betsy!!!

I would like to thank everyone who entered this contest

for your time and interest.

There will be future contests so please watch for them in

future editions of “Rhythm Notes”. If you are not currently

receiving our E-Newsletter and would like to, just go to

the home page of this website where you will see an icon

at the top left.

Please be safe, Beth

This is your rhythm for August / September 2011 Contest.

Use the following criteria to interpret this rhythm,

then send your interpretation to This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

If you are the first entry with the correct answer with

the earliest date and time you will win $25.00.

I will personally send you a check. Good luck.

Criteria:

Atrial rhythm: Irregular

Atrial rate: Immeasurable

Ventricular rhythm: Irregular

Ventricular rate: Range is 120 to 240 bpm

PRI: Immeasurable

QRS: 0.04

Comments (1)

May 2011 ROM - April Contest Discussion

This is the criteria given

for April’s rhythm contest.

Atria: Rate is 100 bpm

Rhythm is regular

Ventricles: Rate is 50 bpm

Rhythm is regular

QRS Complex: 0.18 seconds

PRI: 0.16 seconds - constant

As you can see by the atrial and ventricular rates, the

atrial rate is twice as fast as the ventricular rate. Both

rhythms are regular. Because there are twice as many P waves as there

are QRS complexes, there is a block resulting in a 2:1 AV conduction ratio.

The QRS complex is wide since it measures 0.18 seconds.

Because we don’t know the reason for the abnormal width

of the QRS complex, that is all we can say, it is wide.

The length of the PRI is normal, and remains constant.

This is a heart block and if you remember the saying:

“Same, Same, Same, Mobitz II is to blame.” Same,

Same, Same is referring to the PRI staying constant.

So putting it all together, the interpretation is:

Second degree Heart Block – Mobitz II, 2:1 AV Conduction

with a wide QRS complex.

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Rhythm of the Month - Contest - April 2011

Great, you found the right place!

The criteria is as follows:

Atria: Rate is 100 bpm

Rhythm is regular

Ventricles: Rate is 50 bpm

Rhythm is regular

QRS Complex: 0.18 seconds

PRI: 0.16 seconds - constant

If you think you know the name of this rhythm, just email your

complete interpretation to This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Again, good luck and thank you for your participation.

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Rhythm of the Month - March 2011

This rhythm is the most common abnormal rhythm seen in the population at large. It has potentially serious complications if not diagnosed and treated early. Most of you will be able to tell what the rhythm is by just this information. But…can you recognize the rhythm and differentiate it from other rhythms, say Atrial Flutter, if you see the two rhythms side by side? My many years of teaching cardiac rhythms have taught me these two rhythms are the most difficult for folks to learn and differentiate. All three strips shown here are the same rhythm, but with different rates.

If you think this months’ Rhythm of the Month is Atrial Fibrillation (also known as A-Fib), then you are absolutely right. Congratulations! For those of you that are not quite sure or don’t know, let’s take a closer look.

The Mechanism: The two upper chambers, the atria, beat chaotically and irregularly, out of synch with the two lower chambers, the ventricles. The rhythm for the ventricles is what we call irregularly irregular. With this pattern the whole rhythm is irregular. The atrial rhythm at the baseline is wavy, unorganized, and chaotic with no organized P waves as we know them associated with the QRSs. The ventricular rhythm will always be irregular and the QRS complex can be either narrow or wide. There is no P to P / R to R association. No PRIs are measurable.

Potential Complications: Because the atria are not pumping in an organized, effective manner, the atrial kick is lost, decreasing the total cardiac output by as much a 15% to 20%. Many patients will experience symptoms with the loss of the atrial kick. Formation of emboli behind the valve leaflets could break off leading to complications such as stroke, pulmonary embolus, deep vein thrombosis, or heart attack.

This rhythm in itself is usually not life threatening, but it is considered a serious rhythm. Its recognition and treatment should be initiated early, especially if the patient is symptomatic.

Possible Treatment: If onsetof this rhythm is less than 48 hours, synchronized cardioversion may be attempted. If onset occurred more than 48 hours prior to seeking treatment, then anticoagulants are initiated. Other treatments may include: chemical cardioversion with medications, Catheter Radiofrequency Ablation, Pacemaker and Mini Maze Procedure.

Interpretation: Atrial Fibrillation

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Rhythm of the Month February 2011

ROM Feb. 2011

These two rhythms are similar but different.

The question is how are they different?

Both are sinus rhythms originating in the sinus node, the normal pacemaker of the heart. And, they both have PQRST wave forms missing. When there is an interruption in the rhythm (missing wave forms), a pause is created and you should ask yourself, what is the cause of the pause?

Let’s first take a closer look at Figure 1. The pacemaker cells of the sinus node fail to initiate an electrical impulse for one or more beats. Anytime the SA node fails to initiate an impulse, the AV node or ventricles should assume responsibility of pacing the heart; this is known as an escape pacemaker site. If there is no escape rhythm present, then you will see absent PQRST complexes on the EKG or no electrical activity. In figure 1, one or more cardiac cycles are missing.

Now take a look at Figure 2. Again there are missing wave forms without an escape beat or rhythm. In this example, the pacemaker cells within the SA node initiate an impulse but it is blocked as it exits the SA node. Because impulses are generated at regular intervals, the rhythm of the SA node is not affected. If you marched the P waves with calipers (yes I am a huge believer in caliper usage) from left to right, you will notice the rhythm stays right on target as you go across the strip. The impulse is blocked as it exits the SA node. The atria are not activated, resulting in the PQRST complex as missing. The SA node, not realizing an impulse was blocked, continues to fire at its’ regular rate, thus the beat following the pause, occurs right on time.

Interpretation: Figure 1 - Sinus Rhythm with Sinus Arrest

Figure 2 - Sinus Rhythm with Sino-atrio Exit Block

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