Cardiac Rthyms Review Flashcards
1
Q
NSR - Normal Sinus Rhythm
A
- 60-100bpm
- Regular, with minimal variation between R-R
- P-wave present, upright, and precedes each QRS complex (<100ms wide)
- Constant PR interval
2
Q
Sinus Bradycardia
A
- Same morphology as NSR, only the rate differs
- Rt of less than 60bpm
- Rhythm is regular
3
Q
Sinus Tachycardia
A
- Rt of more than 100bpm
- Rhythm regular
- Increases work of the heart
- Tx typically related to underlying cause of tachycardia
4
Q
Sinus Arrhythmia
A
- Slight variation of sinus rhythm
- Brain-bridge reflex: sudden changes in pressure
- Increases stroke volume and BP
- Normal finding in children/ young adults
5
Q
Sinus Arrest
A
- SA node fails to initiate an impulse
- SA node resumes to normal functioning
- Occasional episodes are not significant
- Tx based on the overall HR and tolerance
6
Q
Sinoatrial Block
A
- results from either pacemaker cells or the transitional cells failing to produce on time
- After a dropped beat, the cycle continues on time
-Characteristics:
Rate - varies
Irregular
P waves present, except when dropped
P:QRS - 1:1
QRS width is normal
7
Q
Wandering Atrial Pacemaker
A
- Pacemaker moves from the SA node to various areas within the atria
- Rhythm is slightly irregular
- Pt’s with significant lung disease
- Tx is usually not indicated
8
Q
PAC - Premature Atrial Complex
A
- Existence of a particular complex within another rhythm, also known as ectopic complexes
- Occurs earlier in tme then next expected complex
- Tx usually not indicated
- Disturbs underlying rhythm and resets the SA node
- frequent PAC’s may cause sensation of heart “ skipping a beat “
- Can be caused by anxiety, or excess caffeine
9
Q
SVT - Supra-ventricular Tachycardia
A
- Pacemaker site is above the ventricles
- HR: must exceed 150bpm
- Tx: medication/ electrical therapy
- Characteristics:
Typically P waves not present (buried due to fast rt)
May sometimes appear inverted or retrograde
Reg Rhythm
Narrow QRS (usually less then 120 ms)
Rt typically 140-280bpm
-PSVT - Paroxysmal SXT: an abrupt onset/ offset can be seen
10
Q
Atrial Flutter
A
- Atria contracting at a rt too rapid for the ventricles to match
- Known as flutter or f waves
- Degenerates into atrial fib
- TX: medication or electrical cardio version
- May be fixed/ variable (conduction ratios)
Characteristics:
Atrial rt and ventricular rt will be different (ventricular fraction of the atrial)
Atrial commonly 250-350bpm
P -waves “ saw tooth “ appearance
QRS width is normal
P:QRS ratio - variable, mostly 2:1, but may be higher
11
Q
A - Fib
A
- Rhythm in which the atria fibrillate or quiver without organized contrxn
- Chaotic flirting of numerous atrial pacemaker cells
- Cells depolarize independently
- Usually a sign of a serious heart problem
- Pre-hospital Tx is usually limited to pts with severe symptoms and prolonged transport time
Characteristics:
No discernible P waves
QRS complexes are innervated haphazardly in an irregularly irregular pattern
Ventricular rt is guided by occasional activation from one of the pacemaker sources
QRS width normal
Rt is variable, ventricular response can be fast/ slow
Fibrilatory rt waves may mimic P-waves - this may lead to misinterpretation
12
Q
Multi focal Atrial Tachycardia
A
- Pacemaker moves within the stria
- Rt of more than 100bpm
- Irregular rhythm
- Pts with significant lung disease
- Tx usually not attempted pre hospital
- Typically transitions between frequent PAC’s and atrial fib/ flutter
Characteristics:
HR: > 100bpm, usually 100-150bpm
Irregularly irregular
At least 3 distinct P wave morphologies
Absence of single dominant atrial pacemaker
Some P waves may be non conducted
13
Q
Junctional (Escape) Rhythm
A
- Allows heart to ‘ escape’ from stopping completely
- Rt: 40–60 bpm
- Tx: pacemaker
- Occurs when rt of the supra-ventricular impulses arriving at the AV node or ventricular is less then the intrinsic rt of the ectopic pacemaker
Characteristics:
Junc rhythm with rt of 40-60bpm
QRS complexes typically narrow (<120ms)
No relationship between QRS and preceding atrial activity
Reg Rhythm
P waves may appear inverted, before, during or after the QRS
14
Q
Accelerated Junctional
A
- Junc rhythm with a rt exceeding 60bpm
- less than 100bpm
- Serious condition
- Occurs when junctional pacemaker that is firing the impulses takes over the normal pacing function of the SA node due to damage with normal conduction
Characteristics:
Rt of 60-100bpm
Regular
P wave may be absent, Nate grade, or retrograde
QRS width is normal
P:QRS = 1:1, if absent, none
15
Q
Junctional Tachycardia
A
- Rt exceeds 100bpm
- If the rt exceeds 150 bpm, cardiac output could suffer, leading to SVT
- Same ethology as Junc rhythm, however the rate is > 100bpm
Characteristics;
P waves retrograde
QRS narrow
PR interval short
Reg. Rhythm ‘
16
Q
PJC - Premature Junctional Complex
A
- Existence of a particular complex within another rhythm (ectopic)
- Occurs earlier in time then the next expected sinus complex
- Rarely treated in the pre hospital setting
- Beat prematurely originates in AV node
- Travels thru normal conduction system of ventricles so the QRS complex it creates is identical to others
- Can occur sporadically or as part of a reg grouped pattern (bigeminy/trigeminy)
Characteristics
Narrow QRS either without a preceeding P wave or a retrograde P wave
Occurs sooner than the next beat is expected
17
Q
First Degree HB
A
- Each impulse is delayed slightly longer, impulse eventually passes
- Least serious HB
- Indicates damage to AV node
- Can occur bc of meds,vagal stimulation, disease
Characteristics
Rt - depends on underlying rhythm
Regular
P waves - normal
PR int’s >0.20 sec
18
Q
Second Degree HB (Morbitz Type 1 - Wenckebach)
A
- Impulse is occasionally prevented from proceeding to the ventricles
- Each is delayed a little longer
- intrinsic rt of 60-100bpm
- increasing PRI
- Caused by deceased AV node
-Characteristics
Regularly irregular
Dropped beats
P:QRS - variable
19
Q
Second Degree HB - Type 2
A
- Several impulses are not allowed to continue.
- Can be regular or irregular
- Groups beats with one dropped beet between each group
- PR interval is THE SAME
- Caused by a diseased AV node- typically indicative of worsening cardiac issues, specifically complete heart block
20
Q
3rd Degree HB
A
- All impulses are prevented.
- Ventricles develop their own pacemaker.
-Rate is less than 60 beats/minute. - Nonconducted P waves
- Complete absence of AV conduction
- None of the supraventricular impulses are conducted to the ventricles
- Atria and ventricles firing separately
- Typically a bradycardiac rate
21
Q
Idioventricular Rhythm
A
- Produced by the ventricles
- Usually regular
- May or may not result in a palpable pulse
- Treatment is geared toward improving the cardiac output.
- Occurs when a ventricular focus acts as the primary pacemaker for the heart
QRS complexes are wide and bizarre
Characteristics:
Rate: 20-40 bpm
Regular
P waves- Absent
P:QRS- N/A
QRS Width- wide (>120ms/.120 s), bizarre appearance
“Wide and Slow? Its Idio”
22
Q
AIVR - Accelerated Idioventricular
A
- Faster version of an idioventricular rhythm
- Exceeds 40 beats/minute but remains under 100 beats/minute
- May represent serious cardiac disease
- Antiarrhythmic medications usually not indicated
Characteristics:
Rate of 40-100 bpm
Regular rhythm
P waves- Absent
QRS: Wide (>0.12s), bizarre appearance
23
Q
Ventricular Tachycardia
A
- Rate exceeding 100 beats/minute; QRS complex will measure greater than 0.12 s
- Regular, with no variation between RR intervals
- P waves are not normally visualized.
- QRS complexes are monomorphic.
- Polymorphic
- Extremely serious
- Sustained vs Not sustained:
Sustained- duration of > 30 seconds or requiring intervention due to hemodynamic instability
Non Sustained- 3 or more consecutive ventricular complexes terminating spontaneously in <30 seconds
24
Q
Monomorphic V-Tach
A
- Regular rhythm
- Originated form a single focus within the ventricles
- Produces uniform QRS complexes
- Classified as stable vs. non stable
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25
Q
Polymorphic V-Tach
A
- A form of Ventricular Tachycardia in which there are multiple ventricular foci and the resultant QRS complexes vary in size and shape
- Most common cause is myocardial ischemia
26
Q
Torsades de Pointes
A
- Occurs when there is an underlying prolonged QT interval
- A type of polymorphic VTach
- Axis of the QRS complex changes from positive to negative in a haphazard fashion
- Means “twisting of points”
- Can convert to NSR or V Fibb- treat this vey carefully as it precursor/notifier of death!
27
Q
PVC - Premature Ventricular Complex
A
- Ectopic complexes
- Occurs earlier than the next expected complex
- Unifocal
- Caused by the premature firing of the ventricular cell
- Ventricular pacer fires before the SA node
- This causes the ventricles to be in a refractory state when the normal impulse tries to get through, causing the ventricles do not fire at their normal time
- Underlying pacing rhythm/schedule is not altered, so the beat following the PVC will arrive on time
this is a compensatory pause
28
Q
Multifocal Vs. Unifocal PVC’s
A
Multifocal- arising from 2 or more ectopic foci
Results in multiple QRS morphologies
Unifocal- arising from a single ectopic foci
Results in each PVC looking identical
29
Q
PVC patterns
A
PVC’s can often occur in repeating patterns:
Couplet- two consecutive PVC’s
Bigeminy- every other beat is a PVC
Trigeminy- every third beat is a PVC
Quadrigeminy- every fourth beat is a PVC
30
Q
V fib - Ventricular Fibrilation
A
- Rhythm in which the entire heart is no longer contracting
- Quivering without organized contraction, cardiac chaos, approx. 500 bpm firing
- Random depolarization of many cells
- Rhythm most commonly seen in cardiac arrests
- Responds well to defibrillation
- CPR compressions help make the heart more susceptible to defibrillation.
- Can be course or fine
- Typically in cardiac death, with start as course v fibb and without correction will progress to fine v fibb and then ultimately asystole
31
Q
Asystole
A
“Flatline”
- Entire heart is no longer contracting.
- Many cells have no energy for contraction.
- Generally a confirmation of death
- May be treated in certain circumstances
32
Q
Artificial Pacemaker Rhythms
A
- Obvious on the heart monitor
- Many types exist.
- Ventricular pacemakers are attached to the ventricles only.
- Atrial pacemaker are attached to the atria
- Can have a pacemaker pacing both atria and ventricles
- Typically “Demand” pacemakers
33
Q
Other ECG Abnormalities
A
- Delta wave
- Aberrant conduction
- Pre-excited atrial fibrillation
- Osborne (J) wave
- Electrolyte imbalances
- Hyperkalemia
- Hypokalemia
