CMU Education
Jessica Lowrey
Created on September 26, 2024
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Transcript
Rhythm Analysis
Fundamentals of rhythm interp
Ventricular Rhythms
Atrial Rhythms
Electrical Conduction
Circulatory System
Heart Parts
Ectopy
Supraventricular Tachycadia
Blocks
EKG fundamentals
Junctional Rhythms
Pacemakers
Parts of the Heart
- Superior & inferior vena cava
- Right Atrium
- Tricuspid valve
- Right ventricle
- Pulmonic valve
- Pulmonary artery
- Pulmonary veins
- Left atrium
- Bicuspid (mitral) valve
- Left ventricle
- Aortic valve
- Aorta
- Interventricular septum
- Sinoatrial node
- Atrioentricular node
- Bundle of His
- Bundle branches
- Purkinje fibers
Blue = deoxygenated blood (low oxygen)
Red= oxygenated blood
Systemic circulation= whole body
Pulmonic circulation= goes to lungs for O2 and back to heart
Pulmonic and Systemic
Circulatory Systems
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Electrical Conduction
Sinoatrial Node (SA)
Atrioventricular Node (AV)
Bundle of His
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Bundle Branches
Purkinje Fibers
Start
Rinse and repeat
Contraction
Systole
depolarization
relaxation
diastole
repolarization
0.04sec
.20sec
1mv
EKG Fundamentals
0.04
0.08
0.12
0.16
0.04
0.04
0.04
0.04
Parameters
PRI (PR interval, atria contraction): 0.12-0.20
QRS (ventricle contraction): 0.08-0.12
QT (ventricle relaxation): Males: 0.350-0.450Females: 0.360-0.460
Sinus Rhythm (60-100)
Sinus Brady <60 bpm
Sinus Tachycardia >100bpm
Normal Sinus
Atrial Rhythms
Normal sinus rhythms includ Sinus rhythm, Sinus brady, Sinus tachycardia, and Sinus Arrhythmia.These originate from the SA (SINoatrial node). The normal sinus p wave will be upright and rounded, measuring 0.12-0.20.Sinus Arrhythmia (SA) is an irregular rhythm that correlates with breathing patterns.
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Sinus Arrhythmia
Ventricular Rhythms
Ventricular Tachycardia
Ventricular Fibrillation
Idioventricular Rhythm
Bundle Branch Blocks
Ectopy
Premature Ventricular Complex (PVC)
Premature Atrial Complex (PAC)
Premature Junctional Complex (PJC)
With an ectopic beat you can have couplets, triplets, bigeminy, trigeminy, and quadgeminy. 4 or more beats is considered a run of VT or SVT.
If you measure two R-R complexes before the premature beat, and then compare it to after the beat, the heart rate will change. This is because the heart has to reset itself and get the atria firing properly again.
Run of VEs (ventricular ectopy)
Run of VEs happen when there's multiple PVCs but the heart rate is below 100 and they don't march out.
PVCs can have three different morphologies. There's positive, where the qrs is pointing up; negative, where the qrs is pointing down; and biphasic, where there is equal parts above and below the isoelectric (base) li.
PACs occur when the an impulse in the atria fires early, and from a place that is not the SA node. The p wave will look different than your sinus p waves.
PJCs originate when the impulse fires form the AV node too early.
Junctional Rhythms
Normal junctional (40-60)
Junctional Tachycardia (>100)
Accelerated Junctional (60-100)
Junctional rhythms can have an inverted p wave, a p wave hidden in the qrs, or retrograde p waves that occur before the t wave. The impulse for junctional rhythms comes from the AV node or Bundle of His. They take over when the SA node fails to pace the heart fast enough.
Junctional Bradycardia (<40)
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Supraventricular Tachycardia
Types of SVT
- AVNRT (AV nodal re-entrant tachycardia)
- AVRT (AV re-entrant tachycardia)
- Ectopic Atrial Tachycardia
- Atrial Flutter
Heart Rates can range from 100-250, depending on the type of SVT
SVT is characterized typically by narrow complexes and sudden onsets and offsets. Theses sudden onsets and offsets can also be seen in afib, however the straight line across the top creating a box shape tells us the rate is regular and is therefore svt or aflutter.
Atrial Tachycardia with block
Any of the SVT rhythms, including flutter, can have atrial tachycardia with a block, where the atrial rate is greater than the ventricular rate. This is usually seen as a p wave in the t wave and a p in front of the qrs.
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Pacemakers
Atrial Pace
Atrial and Ventricular (same time) pace
Ventricular Pace
Paced rhythms can be atrial only, ventricular only, AV sequential, biatrial (both atria), biventricular (both ventricles).They can be continuous or on demand. On demand occurs when the intrinsic (natural) beats of the heart fail. The pacer kicks in and helps beat until the heart can do it by itself again.
biventricular pace
2 pacer spikes in front of the p wave means biatrial pacing, or both atria have a pacer wire in them to help them contract
2 pacer spikes in front of the qrs means both ventricles have pacer wires in them to help them contract
Pacemakers are set at certain high and low limits.
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Heart Blocks
First degree AV block
Delay at AV node creates a long PRI, the space from beginning of P wave to beginning of QRS.
Second Degree AVB Type 1: Wenckebach (Mobitz I)
The delay at the AV node gets longer and longer with each impulse until the impulse fails to meet the ventricles, resulting in a missed QRS.
Second degree AVB type II: Mobitz II (Hay Block)
The delay at the AV node doesn't occur with every impulse, but with varying beats. The p wave will march through on time and the R-R will march before and after.
Third Degree AVB
In a third degree avb, or Complete Heart Block, none of the impulses travel from the atria to the ventricles. The atria beat on their own time and the ventricles take over as the pacemaker of the heart and beat at a rate around 30 beats per minute.
High Grade AVB
High grade AVB is a type of third degree heart block that produces three or more p waves between QRS complexes.
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Calculating HR
Regular
Irregular
Atrial Dysrhythmias
Wandering Atrial Pacemaker/Multifocal Atrial Tachycardia
Atrial Fibrillation
Atrial Flutter
Aberrancy
Wandering Atrial Pacemaker/Multifocal Atrial Tachycardia
WAP characteristics:
- 3 different p waves
- irregular rhythm
- varying PRI
- HR less than 100
MAT:Tachy version of WAP
Atrial Fibrillation
In afib, there is no impulse traveling through the SA or AV nodes. Instead, the impulses are being bounced around chaotically, causing the atria to quiver more than pump. This causes the atria and the ventricles to fall out of sync. If afib is happening at a rate over 100, this is considered RAPID VENTRICULAR RATE (RVR)
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Atrial Flutter
Atrial fibrillation occurs when the impulse gets stuck in a loop around the atria, only letting some impulses through to the ventricles. This creates the sawtooth pattern we see, and the atria beats between 250 and 300 beats per minute.It is also typically very regular and will march on time. The only exception is afl with a variable block.
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Atrial Tachycardia with a Block (ATWB)
Atrial Tachycardia with a block happens when the atria beat faster than the ventricles. This causes P waves to appear inside qrs complexes, inside p waves, and in front of qrs complexes with a variable PRI. Much like in 3rd degree, the p waves will march on time, separate from the ventricles. Atrial tachycardia is a form of SVT, so this is mostly seen in SVT runs.
Aberrancy
Aberrancy occurs when theres an abnormal conduction through the ventricles. The QRS will appear wide and bizarre, similar to ventricular beats; however, they are still atrial.There will be an ectopic p wave associated with each QRS. To determine SVT with aberrancy or VT, measure two R-R cycles before the run, and two after. If they line up, then it's VT. In afib, any aberrant beats will follow Ashman's Phenomenon. This is a long R-R cycle, followed immediately with the quick aberrant beats. This occurs during the rapid rates in afib.Aberrant beats can also appear singularly, as couplets, or triplets like PVCs.
Ventricular Tachycardia
Monomorphic VT- Negative deflection
Monomorphic VT- Positive deflection
Polymorphic VT- Torsades de Pointe (TdP)
Ventricular Tachycardia is caused by the impulse in the SA and AV node to become interrupted and the ventricles take over pacing the heart. There may still be some atrial activity visible in VT runs, and this is called AV dissociation. They will be normal sinus p waves that march on time, but they are typically not seen in runs with a rate over 150.TdP is typically brought on by prolonged QT intervals and R on T phenomenon PVCs.HR for sustained tachycardia and TdP is usually between 150 and 300bpm.
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Ventricular Fibrillation
Just like with Afib, the ventricles can't pump properly , which results in them quivering and producing a squiggly, worm like wave. There is no pulse associated with VF.Coarse VF occurs when the amplitude (how tall) is over 3mm high.Fine VF occurs when the amplitude is less than 3mm.Fine VF is more dangerous than coarse because there is even less ventricular activity associated with it.
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Idioventricular Rhythms
Accelerated Idioventricular Rhythm (AIVR)
Idioventricular Rhythm (IVR)
Idioventricular rhythm occurs when the ventricular rate is faster than the rate of the SA or AV nodes. Idioventricular rhythm is characterized by wide, bizarre qrs complexes and absent p waves (usually hidden). IVR has a rate of a 20-40 bpm and AIVR has a rate between 40 and 100. Usually considered an escape rhythm since it takes over the pacing of the heart.
Bundle Branch Blocks
Bundle branch blocks are caused by a block or delay in the bundle branches, causing the impulse to slow down on one side or the other.QRS measures >0.12, and must be present and identifiable in the V leads.
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SA node
AV node
Bundle of His
Left bundle branch
Right bundle branch
Purkinje Fibers
Non-conducted PACs occur when the impulse from the atria doesn't reach the ventricles. This produces an ectopic p wave, usually burried in the preceding t wave.
Non-conducted PACs
You can also have ventricular escape beats and junctional escape beats that arise to help the heart start pumping appropriately again. Usually ventricular escape beats happen during pauses, while junctional escape beats happen at the offset of afib.
Ventricular escape rhythm/beats
Junctional escape beat