Guitars, Paramedics, Linux, and Me

January 13, 2014

Paramedic EKG Study Guide – Part 2

Filed under: EMS — S. Kindley @ 10:15 am
Tags: , , , , ,
EKG

EKG

Rhythm Identification

You can stare at rhythm strips all day, but you’ll never be consistent at correctly identifying the rhythm until you master the criteria of each rhythm. Before you start looking at strips take the time to learn what makes each rhythm unique.

It does take some practice but once you have the hang of it you’ll really increase you accuracy and speed in identifying various rhythms.

For those with experience: This isn’t a learn it once and forget it skill. This is something you should brush up on every once in a while.

Read on for more …

Rhythms – of the ‘I ain’t got no rhythm variety’

Asystole

  • No electrical activity.
  • No rate.
  • No P-Waves.
  • No PRI.
  • No QRS.
  • No T-Wave.
  • No U-Wave.
  • No nuttin’.

Rhythms – of the Sinus variety

Sinus Rhythm

  • R to R is regular.
  • Rate is 60 – 100 bpm.
  • P-Wave is uniform and in front of every QRS Complex.
  • PRI is between 0.12 and 0.20 seconds.
  • QRS Complex measures less than 0.12 seconds.

Sinus Tachycardia

  • R to R is regular.
  • Atrial and Ventricular rates are equal: Heart rate is between 100 – 150.
  • P-Wave is uniform and in front of every QRS Complex.
  • PRI is between 0.12 and 0.20 seconds.
  • QRS Complex measures less than 0.12 seconds.

Sinus Bradycardia

  • R to R is regular
  • Atrial and Ventricular rates are equal: Heart rate is less than 60.
  • P-Wave is uniform and in front of every QRS Complex.
  • PRI is between 0.12 and 0.20 seconds.
  • QRS Complex measures less than 0.12 seconds.

Wandering Pacemaker

  • R to R intervals vary slightly as the pacemaker site changes; the rhythm can be slightly irregular.
  • Atrial and Ventricular rates are equal: Heart rate is usually between 60 – 100, but can be slower.
  • Morphology of the P-Wave changes as the pacemaker site changes but there is 1 in front of every QRS. May be hard to see.
  • PRI will vary slightly as pacemaker site changes. All will be less than 0.12 seconds and no more than 0.20 seconds.
  • QRS Complex measures less than 0.12 seconds.

Sinus Arrhythmia

  • R to R intervals vary, rate changes with patient’s respirations.
  • Atrial and Ventricular rates are equal: Heart rate is usually between 60 – 100, but can be slower.
  • P-Wave is uniform and in front of every QRS Complex.
  • PRI is between 0.12 and 0.20 seconds.
  • QRS Complex measures less than 0.12 seconds.

Rhythms – of the Atrial variety

Atrial Tachycardia

  • R to R intervals are constant and regular.
  • Atrial and Ventricular rates are equal: Heart rate is usually between 150-250 bpm.
  • Usually 1 P-Wave is in front of every QRS Complex. The configuration of the P-Wave will be different than Sinus P-Waves; they may be flattened or notched, and sometimes hidden in the T-Wave of the previous beat.
  • PRI is between 0.12 and 0.20 seconds and constant across the strip but may be difficult to measure if hidden in the previous T-Wave.
  • QRS Complex measures less than 0.12 seconds.

Atrial Flutter

  • Atrial rhythm is regular. Ventricular rhythm will be regular if the AV Node conducts impulses in a consistent pattern. If the pattern varies the ventricular rate will be irregular.
  • Atrial rate is between 250 – 350 beats per minute. Ventricular rate will depend on the ratio of of impulses conducted through to the ventricles.
  • When the atria flutter they produce a series of well defined P-Waves. When seen together these “flutter” waves have a “saw toothed” appearance.
  • PRI is impossible to determine due to the saw toothed flutter of P-Waves and their proximity to the QRS Complex.
  • QRS Complex measures less than 0.12 seconds and can be difficult to measure.

Atrial Fibrillation

  •  Rhythm is unmeasurable; all atrial activity is chaotic. The ventricular rhythm is grossly irregular, having no pattern to it’s irregularity.
  • The atrial rate cannot be measured because it is so chaotic but it is probably above 350 bpm. The ventricular rate is significantly slower because the AV Node blocks most of the impulses. If the ventricular rate is below 100 bpm the rhythm is said to be controlled. If it is over 100 bpm it is said to be uncontrolled.
  • No discernible P-Waves, only fibrillatory waves.
  • PRI is unmeasurable.
  • QRS Complex should be less than 0.12 seconds.

Rhythms – of the Junctional variety

Junctional Escape Rhythm

  • R to R intervals are consistent, the rhythm is regular.
  • Atrial and Ventricular rates are equal; the inherent rate of the AV Junction is 40 – 60 bpm.
  • P-Wave can come before or after the QRS Complex or buried within. If it is visible the P-Wave will be inverted.
  • If the P-Wave is before the QRS the PRI will be less than 0.12 seconds.
  • If the P-Wave is buried within or comes after the QRS Complex there will be no PRI.
  • The QRS Complex will be less than 0.12 seconds.

Accelerated Junctional Rhythm

  • R to R intervals are consistent, the rhythm is regular.
  • Atrial and Ventricular rates are equal. The rate will be faster than the inherent rate, usually in the 60 – 100 bpm range.
  • P-Wave can come before or after the QRS Complex or buried within. If it is visible the P-Wave will be inverted.
  • If the P-Wave is before the QRS the PRI will be less than 0.12 seconds.
  • If the P-Wave is buried within or comes after the QRS Complex there will be no PRI.
  • The QRS Complex will be less than 0.12 seconds.

Junctional Tachycardia

  • R to R intervals are consistent, the rhythm is regular.
  • Atrial and Ventricular rates are equal. The rate will be in the tachycardia range but will not exceed 180 bpm.
  • P-Wave can come before or after the QRS Complex or buried within. If it is visible the P-Wave will be inverted.
  • If the P-Wave is before the QRS the PRI will be less than 0.12 seconds.
  • If the P-Wave is buried within or comes after the QRS Complex there will be no PRI.
  • The QRS Complex will be less than 0.12 seconds.

Rhythms – of the Ventricular variety

Ventricular Tachycardia – V-Tach

  • This rhythm is usually regular but can be slightly irregular.
  • Atrial rate cannot be determined. Ventricular rate is 150 – 250 bpm. If the rate is below 150 it is said to be a slow V-Tach. If the rate exceeds 250 it is said to be Ventricular Flutter.
  • None of the QRS Complexes will be preceded by P-Waves. You may see dissociated P-Waves intermittently across the strip.
  • PRI doesn’t exists since the rhythm originates in the ventricles.
  • QRS Complexes will be wide and bizarre measuring at least 0.12 seconds. It is often difficult to differentiate between the QRS and the T-Wave.

Supraventricular Tachycardia – SVT

*** Clinicians can find it difficult to differentiate V-TACH from SVT. The problem is complex. The clinical distinction is important. V-Tach is potentially life threatening and usually requires immediate treatment whereas SVT is usually less dangerous. ***

*** Wide-QRS Complex Tachycardia of uncertain origin should be considered V-Tach and treated as such until proven otherwise. ***

Ventricular Fibrillation – V-Fib

  • There are no waves or complexes to be analyzed to determine regularity. Totally chaotic baseline.
  • Rate cannot be determined since there are no discernible waves or complexes to measure.
  • There are no P-Waves.
  • There is no PRI.
  • There are no QRS Complexes.

Idioventricular Rhythm

  • This rhythm is usually regular, but less reliable as the heart dies.
  • The ventricular rate is usually 20 – 40 bpm but can be slower.
  • No P-Waves.
  • No PRI.
  • QRS is wide and bizarre measuring at least 0.12 seconds.

Accelerated Idioventricular Rhythm

  • This rhythm is usually regular.
  • The ventricular rate is between 40 – 100 bpm.
  • No P-Waves.
  • No PRI.
  • QRS is wide and bizarre measuring at least 0.12 seconds.

Not Really A Rhythm Itself – Ectopic Beats

Premature Atrial Contraction – PAC

  • Since this is a single premature ectopic beat it will interrupt the regularity of the underlying rhythm. R to R will be irregular.
  • Overall heart rate depends on rate of underlying rhythm.
  • P-Wave of the premature beat will have a different morphology than the P-Waves of the rest of the strip. The ectopic beat will have a P-Wave, but it can be flattened, notched, or otherwise unusual. It may be hidden within the T-Wave of the preceding complex.
  • PRI measurement 0.12 – 0.20 but can be prolonged; the PRI of the ectopic beat will probably be different from the PRI measurements of the other complexes.
  • QRS Complex measures less than 0.12 seconds.

Premature Junctional Contraction – PJC

  • Since this is a single premature ectopic beat it will interrupt the regularity of the underlying rhythm. R to R will be irregular.
  • Overall heart rate depends on rate of underlying rhythm.
  • P-Wave can come before or after the QRS Complex or buried within. If it is visible the P-Wave will be inverted.
  • If the P-Wave is before the QRS the PRI will be less than 0.12 seconds.
  • If the P-Wave is buried within or comes after the QRS Complex there will be no PRI.
  • The QRS Complex will be less than 0.12 seconds.

Premature Ventricular Contraction – PVC

  • The underlying rhythm can be regular or irregular. The ectopic PVC will interrupt the regularity of the underlying rhythm (Unless the PVC is interpolated. An interpolated premature ventricular contraction is one where the overall pace and rhythm of the heart is not altered by the ectopic beat because retrograde conduction of the PVC does not completely penetrate the AV Node).
  • The Rate is determined by underlying rhythm. PVC themselves are not usually used to determine the rate as they frequently do not produce a pulse.
  • The ectopic beat is not preceded by a P-Wave. You may see a coincidental P-Wave near the PVC, but it is dissociated.
  • No PRI since the ectopic beat comes from a lower focus.
  • The QRS Complex will be wide and bizarre, measuring at least 0.12 seconds. The configuration will differ from that of the underlying QRS Complexes. The T-Wave is frequently in the opposite direction from the QRS Complex.

Heart Blocks

First Degree Heart Block

  • Regularity depends on underlying rhythm.
  • Rate depends on the underlying rhythm.
  • P-Waves upright and uniform and followed by a QRS Complex.
  • PRI will be constant but always greater than 0.20 seconds across the strip.
  • QRS Complex will be less than 0.12 seconds.

Second Degree Heart Block – Type 1 (a.k.a. “Wenkebach”)

  • R to R interval is irregular in a pattern of grouped beating (meaning the R to R interval gets progressively shorter as the PRI gets progressively longer).
  • Atrial rate is normal but the ventricular rate is usually slightly slower because some beats are not conducted.
  • P-Waves are upright and uniform. Some P-Waves are not followed by a QRS Complex.
  • PRI gets progressively longer until one P-Wave is not followed by a QRS Complex. Then the cycle starts again.
  • QRS Complex measurement will be less than 0.12 seconds.

Second Degree Heart Block – Type 2 (a.k.a. “Classic”)

  • If conduction ratio is consistent the R to R interval will be consistent and the rhythm will be regular. If the conduction ratio varies the R to R will be irregular.
  • Atrial rate is usually normal. Since many of the atrial impulses are blocked, the ventricular rate will usually be in the Bradycardia range. Often one half, one third, or one fourth of the Atrial rate.
  • P-Waves are upright and uniform. There are always more P-Waves than QRS Complexes.
  • PRI on conducted beats will be constant across the strip although it might be longer than a normal PRI measurement.
  • QRS Complex measurement will be less than 0.12 seconds.

Third Degree Heart Block (a.k.a. “Complete Heart Block”)

  • Both Atrial and Ventricular foci are firing regularly, thus P to P intervals and R to R intervals are regular.
  • Atrial rate usually in the normal range. The ventricular rate will be slower. If a junctional focus is controlling the ventricles the rate will be 40 – 60 bpm. If the focus is ventricular the rate will be 20 – 40 bpm.
  • P-Waves upright and uniform. There are more P-Waves than QRS Complexes.
  • Since the block at the AV Node is complete, none of the atrial impulses are conducted to the ventricles. There is no PRI. The P-Waves have no relationship to the QRS Complexes. You may occasionally see a P-Wave superimposed upon the QRS Complex.
  • QRS Complex will be less than 0.12 if the ventricles are controlled by a junctional focus. If the focus is ventricular then the QRS Complex will measure 0.12 seconds or greater.
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