Cardiac Dysrhythmia by Site of Origin https://www.youtube.com/watch?v=6LrptveKYus

What two segments in a normal PQRST tracing represent a return to baseline?

End of P wave to beginning of Q wave End of S wave to beginning of T wave Also, end of T wave to beginning of next beat (P wave).

What part of the cardiac output equation is impacted by a reduced amount of filling in the ventricles as seen in ventricular tachycardia?

SV and CO

T/F: A NSTEMI is a "Non-ST Elevation Myocardial Infarction"

True

T/F: An example of a ventricular beat is a premature ventricular contraction.

True

T/F: Donald Trump's signature looks like the lethal ventricular rhythm Torsades de Pointes that should be shocked with a defibrillator at 300 joules.

True

T/F: For atrial flutter, each cycle represents one contraction of the atria.

True

T/F: In AV nodal reentrant tachycardia (AVNRT), every time the impulse passes through the node, it is passed down to through the ventricles.

True

T/F: In atrial flutter, the ventricular rate is slower than the atrial rate.

True

T/F: Old myocardial tissue damage can sometimes be seen on ECG tracings

True

T/F: STEMI stands for "ST Elevation Myocardial Infarction"

True

T/F: Sinus bradycardia may be normal in a sleeping person

True

T/F: Sinus tachycardia may be a normal physiological response to aerobic activity?

True

T/F: Sustained V-tach lasting for more than 30 seconds requires immediate intervention.

True

T/F: Torsades is a type of ventricular fibrillation

True

T/F: The atrial and ventricular rates are identical in AV nodal reentrant tachycardia (AVNRT).

True, the rate is also regular and fast

T/F: In atrial flutter, the ECG tracing is characterized by absence of the normal P wave.

True. Instead there are flutter waves or F waves that are present in saw-tooth patterns.

T/F: Heart rate and origin are used to classify cardiac dysrhythmias.

True: An example would be supraventricular (origin) tachycardia (rate)

What is the pathophysiology of ventricular fibrillation?

it is caused by multiple weak ectopic sites in the ventricles

What might a V-Tach look like on ECG?

it is characterized by wide and bizarre looking QRS complexes

In atrial flutter, what structure blocks many of the electrical impulses from conducting through the ventricles?

the AV node

sinus rhythm

the normal (optimal) heart rhythm arising from the sinoatrial node resulting in 60-100 beats per minute

How can you tell if a rhythm is sinus paced (SA node), and therefore a "sinus rhythm?"

the presence of p waves indicate a sinus (SA node) pacing

sinus tachycardia

the sinoatrial (SA) node fires greater than 100 bpm

sinus bradycardia

the sinoatrial (SA) node fires less than 60 times per minute resulting in a heart rate less than 60 bpm

What other rhythm might result from an untreated ventricular tachycardia?

ventricular fibrillation

What types of events/abnormalities can lead to ventricular tachycardia?

structural changes, such as scarring from a previous heart attack or abnormalities in heart muscle

AV nodal reentrant tachycardia (AVNRT)

caused by a small reentrant pathway that directly involves the AV node

If you see an ECG tracing with a sinus paced rhythm, rate of 70, and occasional "wide and bizarre" QRS complexes with different morphologies (shapes), how would you describe it?

"Normal sinus rhythm with occasional multifocal PVCs."

Today you are coving for the cardiology service NP and are discovering that you know more than you thought. You are given a tracing by one of the support staff, Terry, because he is in nursing school and wants to learn more about the rhythm. "I see that the heart rate is quite fast at 200 bpm, the PR interval is normal, as well as the QRS complex. It looks fine except it seems to be missing P waves. Can you help me identify this rhythm?"

"Yes, Terry, what you have is a Supraventricular Tachycardia. Look for rhythm that is regular, with heart rate that is fast (150-250 bpm). Notice that the P wave is merged with t wave. The PR interval is normal (0.12 sec). The QRS is typically normal (.10 sec). PR interval can be difficult to measure."

Why are ventricular rhythms may also be called what?

"lethal rhythms"

A ventricular ectopic pacemaker, will produce a fast ventricular rhythm that ranges from ______ to ______ bpm.

100, 125

What heart rate would you expect to see in AV nodal reentrant tachycardia (AVNRT)?

150-250 bpm

In atrial flutter, the atrial rate is regular and rapid. What is the number of beats per minute that can be observed?

250-400 beats per minute

Ventricular tachycardia is most commonly caused by what?

A single, strong firing site or circuit in one of the ventricles.

What structure is responsible for keeping all electrical signals that are produced in atrial fibrillation from conducting through to reaching the ventricles?

AV node

What is described by the following: Unsynchronized, chaotic electrical signals cause the atria to quiver or "fibrillate" rather than contract?

Afib (Atrial Fibrillation)

What rhythm can be described this way: Caused by multiple impulses that are randomly initiated from many ectopic sites in the atria?

Atrial Fibrillation (Afib)

What is the most common dysrhythmia?

Atrial conduction abnormalities like paroxysmal atrial fibrillation is the most common type of dysrhythmia. This also include atrial fibrillation.

Name three rhythms that can result in supraventricular tachycardia (SVT).

Atrial flutter, atrial fibrillation, and AV-nodal reentrant tachycardia Caveat - remember that tachycardia is >100 bpm; if A-flutter or Afib are present and the rate is > 100 bpm, it is known as "Atrial flutter" or "Atrial Fibrillation" with a rapid ventricular response. Example: "Afib with RVR."

Why is cardiac output so decreased in ventricular tachycardia?

Because the rate is so fast, there is little time for filling: therefore the very little blood is actually reaching the periphery and vital organs

What a class of drugs can be used to control the heart rate. What drug would you consider for anticoagulation?

Beta blockers, calcium channel blockers heparin warfarin (Coumadin) rivaroxaban (Xarelto) dabigatran (Pradaxa) apixaban (Eliquis) edoxaban (Savaysa) enoxaparin (Lovenox) fondaparinux (Arixtra)

PVCs have the following features:

Broad QRS complex (≥ 120 ms) w/ abnormal morphology Premature: occurs earlier than expected for the next sinus impulse Discordant ST segment & T wave changes

What is the equation for cardiac output (CO)?

CO = HR x SV Cardiac output = heart rate times stroke volume?

How do you treat ventricular fibrillation?

Chest compressions, defibrillator.

T/F: A heart rate of 100 bpm is considered a sinus tachycardia

False. A sinus tachycardia is considered to be a rate greater than 100 bpm

T/F: Atrial fibrillation does not arise from ectopic sites.

False

T/F: In supraventricular tachycardia, the ectopic pacemaker originates from the AV node.

False

T/F: The AV node is the 'pacemaker' of the heart.

False. The SA node is the normal pacemaker of the heart. The AV node serves as a traffic signal, controlling the rate of electrical impulses from the atria allowed to reach the ventricles, limiting the danger of 1 to 1 conduction of fast rhythms from the atrium to the ventricles.

T/F: On ECG tracing, atrial fibrillation is characterized by prominent, steady, evenly spaced P waves and wide QRS complexes.

False: Atrial fibrillation is characterized by absence of P waves and irregular narrow QRS complexes. The baseline may appear undulating or totally flat, depending on the number of ectopic sites.

T/F: Unsynchronized, weak, ectopic ventricular sites that fire randomly, produce a normal cardiac output through reorganized contraction.

False: It causes the ventricles to quiver rather than contract. There is little to no cardiac output.

T/F: If a patient is having PVCs and they must originate from the same ectopic site in the ventricle(s)

False: MultiFocal PVCs is an example of PVs originating from >1 site

T/F: Premature ventricular contractions follow the same conduction pathway as a regular beat, therefore they generally look like any other QRS complex and are difficult to discern.

False: PVCs are typically "wide and bizarre" looking on ECG

T/F: V-tach occuring during a short episode of 30 seconds always causes symptoms.

False: Short runs of V-tach may cause few or no symptoms.

T/F: Because the AV node has the ability to slow signals from the atria, all ventricular beats will be regular during atrial fibrillation.

False: The signals that come through the AV node will be irregular. Remember that there are multiple random ectopic pacemaker firings during atrial fibrillation, therefore the signals making it to the AV node will not be regular. Irregular signals from the atria = irregular conduction through the AV node.

T/F: Ectopic sites of atrial fibrillation are generally found near the septal walls of the atria.

False: They are commonly found near the roots of the pulmonary veins.

T/F: Ventricular dysrhythmias originate at the Bundle of His

False: Ventricular dysrhythmias originate in the ventricles.

T/F: Ventricular rhythms are generally benign and not considered life threatening.

False: Ventricular rhythms are the most dangerous.

T/F: Cardiac arrhythmias that originate from non-SA node sites are normal physiological responses to stressors.

False: they are always clinical. Examples include atrial flutter, atrial fibrillation, and AV nodal reentrant tachycardia.

T/F: All myocardial infarctions show up on the ECG

Fase

In reviewing ECG rhythms, you notice a strip that appears to be a normal sinus rhythm with a rate of 70 bpm, but something is amiss. Honing in on your excellent clinical skills you learned in 502, you notice that the PR interval is prolonged (>0.20 sec). You recognize that the AV node is delaying the signals longer than usual and diagnose a ______________________________.

First degree heart block

During Atrial Fibrillation, ventricular response rates can range from slow to fast. What is considered fast?

Greater than 100 bpm

Your patient has a known bigeminy rhythm but today you notice something different on ECG tracing. You see what looks like only wide and bizarre complexes at a slow rate. What might this be?

Idioventricular rhythm: Look for rhythm that is regular, with heart rate that is slow (20-40 bpm). Notice that the P wave is absent. The PR interval is not measurable. The QRS is typically wide (>0.10 sec), bizarre appearance.

During Atrial Fibrillation, ventricular response rates can range from slow to fast. What is considered slow?

Less than 60 bpm

Explain the normal conduction pattern of the heart as evidenced by the ECG tracing.

P wave - atrial depolarization PR interval - atrial depolarization complete QRS complex - ventricular depolarization (atria repolarize) ST segment - ventricular depolarization complete T wave - ventricular repolarization complete

You notice a rhythm strip that has a normal PQRST complex followed by a wide and bizarre complex that you recognize as a PVC. However, each normal PQRST complex is followed by a PVC at a rate of 1:1. What is this called?

Premature ventricular complex bigeminy, or just "bigeminy."

Break down the following rhythm by describing each term: Atrial Flutter with RVR

RVR - ventricular rate is greater than 100 bpm Atrial Flutter - regular, cyclic firing of the atria

Your patient has been complaining of weakness, dizziness at times, and shortness of breath when climbing steps times one week. You notice an irregular tachycardia when you check the radial pulse, and also notice that the auscultated PMI rate is not equal to the radial rate. The remainder of the exam in noncontributory. You obtain an ECG and diagnose AFib. What are two priorities to consider when treating AFib?

Rate control and anticoagulation

In the simplest terms, what is it about structural changes in the heart that causes deviations from baseline as seen in ST segment depression.

Remember that an ECG is measuring electrical impulses (depolarization/repolarization) over time. If there is an abnormal deflection it probably means that the event is taking longer than expected. Things that slow down conduction include damaged tissue (think MI) or problems with signal handling (left BBB).

Sinus Arrhythmia

Sinus Arrhythmia. Look for rhythm that is irregular, varying with respiration, with heart rate that is normal (60-100 bpm) and rate may increase during inspiration. Notice that the P wave is normal. The PR interval is normal (0.12-0.20 sec). The QRS is typically normal (0.06-0.10 sec). Heart rate frequently increases with inspiration, decreasing with expiration.

Name two things that can cause ST segment depression.

Structural: MI, old ischemia, left ventricular hypertrophy, left bundle branch block Non-structural: effects of drugs such as digoxin

Break down the following rhythm by describing each term: Paroxysmal Supraventricular Tachycardia

Tachycardia: rate > 100 Supraventricular: beats originate in the atria Paroxysmal: sudden recurrence or intensification of symptoms (or event)

Atrial Fibrillation

This tracing is Atrial Fibrillation. Look for rhythm that is irregular, with heart rate that is very fast (> 350 bpm) for atrial, but ventricular rate may be slow, normal or fast. Notice that the P wave is absent - erratic waves are present. The PR interval is absent. The QRS is typically normal but may be widened if there are conduction delays.

During atrial fibrillation, if there are many ectopic sites, how might the baseline appear on ECG?

The baseline may appear flat. This is because there are many sites firing and repolarizing at the same time, therefore they cancel each other out on the tracing.

(T/F) Asystole must always be confirmed in at least one lead to rule out any other dysrhythmias.

True

An 84 years old patient presents to clinic with complaints of unrelenting back pain and shortness of breath. She is pale and diaphoretic. You recognize the this may be a cardiac event and have your patient lie down on the examination table, while your nurse retrieves the AED from the hallway. You are assessing the patient's pulse and you note it to be thready, irregular, and weak. The nurse arrives and applies the AED. During this intervention, the patients stops talking, loses expression, and stares into space. The AED announces "Analyzing rhythm, shock not advised." Why might this be?

The patient has progressed to asystole, therefore it is not a shockable rhythm.

A quivering baseline with no discernable complexes appears on a tracing you are reading. You think ______________________ because: A) "Oh crap!" B) "I wonder what's in the cafeteria for lunch" C) "I need to return Terry's call" D) You don't think, you activate your institution's code blue protocol

The rhythm is ventricular fibrillation Look for rhythm that is highly irregular, with heart rate that is unmeasurable. Notice that the P wave is absent. The PR interval is not measurable. The QRS is typically none. EKG tracings is a wavy line.

On an normal ECG tracing, the ST segment is normally at baseline (not deflected up or down) because it represents a period where during which the ventricles have depolarized but have not repolarized. In layman's terms, what might this mean?

The ventricles are taking longer to depolarize

First Degree Heart Block

This tracing is First Degree Heart Block. Look for rhythm that is regular, with heart rate that is the underlying rate. Notice that the P wave is normal. The PR interval is prolonged (>0.20 sec). The QRS is typically normal (0.06-0.10 sec). A first degree AV block occurs when electrical impulses moving through the Atrioventricular (AV) node are delayed (but not blocked). First degree indicates slowed conduction without missed beats..

Idioventricular Rhythm

This tracing is Idioventricular Rhythm. Look for rhythm that is regular, with heart rate that is slow (20-40 bpm). Notice that the P wave is absent. The PR interval is not measurable. The QRS is typically wide (>0.10 sec), bizarre appearance. Wandering baseline artifact can be seen in this tracing.

Pacemaker Single Chamber Atrial

This tracing is Pacemaker Single Chamber Atrial. Look for rhythm that is regular, with heart rate that is 60 bpm. Notice that the P wave is normal. The PR interval is normal. The QRS is typically normal.

After identifying a dangerous rhythm, acting quickly, and saving your patient's life, you continue to assess ECG rhythms, wondering why you ever agreed to cover for the cardiac NP. You glance up and notice that a patient who just returned from surgery has a rather bizarre looking strip with straight lines preceding the complexes. There are no P waves. You remark: A) "Who is drawing lines on my tracings?" B) "Oh this must be the new ECGs software glitch I heard about." C) "These PVCs have a life of their own." D) "I'm so glad Ms. Rhythm got her ventricular pacemaker today."

This tracing is Pacemaker Single Chamber Ventricular

Premature Junctional Complex

This tracing is Premature Junctional Complex. Look for rhythm that is regular with premature beats, with heart rate that is the underlying rate. Notice that the P wave is present before, during (hidden) or after qrs, if visible it is inverted. The PR interval is absent or short. The QRS is typically normal (0.06-0.10 sec).

Premature Ventricular Complex

This tracing is Premature Ventricular Complex. Look for rhythm that is irregular, with heart rate that is the underlying rate. Notice that the P wave is absent. The PR interval is not measurable. The QRS is typically wide (> 0.10 sec), bizarre appearance. Two PVCs together are termed a couplet while three PVCs in a row with a fast rhythm is ventricular tachycardia.

Second Degree Heart Block Type I

This tracing is Second Degree Heart Block Type I. Look for rhythm that is irregular but with progressively longer pr interval lengthening, with heart rate that is the underlying rate. Notice that the P wave is normal. The PR interval is progressively longer until a qrs complex is missed, then cycle repeats. The QRS is typically normal (0.06-0.10 sec).

Second Degree Heart Block Type II

This tracing is Second Degree Heart Block Type II. Look for rhythm that is regular (atrial) and irregular (ventricular), with heart rate that is characterized by atrial rate usually faster than ventricular rate (usually slow). Notice that the P wave is normal form, but more p waves than qrs complexes. The PR interval is normal or prolonged. The QRS is typically normal or wide.

Wandering Atrial Pacemaker

This tracing is Wandering Atrial Pacemaker. Look for rhythm that is may be irregular, with heart rate that is normal (60-100 bpm). Notice that the P wave is changing shape and size from beat to beat (at least three different forms). The PR interval is variable. The QRS is typically normal (0.06-0.10 sec). T wave normal. If heart rate exceeds 100 bpm, then rhythm may be multifocal atrial tachycardia (MAP).

Why does sustained V-tach require immediate intervention?

To prevent cardiac arrest

What rhythm is characterized by it's name meaning "twisting of the points?"

Torsades de Pointes

Zofran (ondansetron) has been linked to what life-threatening dysrhythmia?

Torsades de Pointes

Does ventricular tachycardia reduce cardiac output?

Yes

What is the physiology of atrial flutter?

an electrical impulse that travels around in a localized, self-perpetuating loop, most commonly located in the right atrium

What is an example of a reentrant pathway?

atrial flutter

Why is a fast ventricular rate a problem?

because it does not allow the ventricles time to fill properly, therefore cardiac output is reduced

A experienced colleague reading an ECG strip determines the rhythm to be atrial fibrillation. You notice an absence of P waves and irregular, narrow QRS complexes. You expect to see an undulating baseline, but instead it is flat. Why does this happen?

because there are many sites firing and repolarizing at the same time, therefore they cancel each other out on the tracing

What is a complication of V-tach?

cardiac arrest

What physiologic changes would you expect in a patient who is experiencing an acute onset of reduced cardiac output?

drop in blood pressure, shortness of breath, dizziness, syncope and collapse, nausea/vomiting (not inclusive)

How is V-fib characterized?

irregular, random waveforms of varying amplitude, with no identifiable P wave, QRS complex, or T wave

AV nodal reentrant tachycardia (AVNRT)

regular rhythm with narrow QRS complex with no P wave seen