Arrhythmias Flashcards
Palpitations are
Awareness of ones own heart beats
Angina
how is this a common manifestation?
increased demands for oxygen cause chest pain
What mnemonic is used for causes of Arrhythmias?
What does it stand for?
H-hypoxia (COPD)
I- ischemia & irritability ( MI can cause)
S- Sympathetic stimulation (CHF, anxiety, exercise, caffeine, cocaine)
D- drugs
E- electrolyte disturbances (hypokalemia, etc)
B- bradycardia (sick sinus syndrome)
S- stretch (CHF & valvular diseases)
What is helpful when a suspected arrhythmia is infrequent and not likely to be captured on a 12 lead EKG?
Holter Monitor
Worn 24-48 hrs
What if so infrequent even a Holter Monitor won’t pick up?
Event monitor
Multiple recordings can be made over several months
Determining Rate:
1 large square=
2 large squares=
300 beats/min
150 beats/min
Determining Rate:
3 large squares =
4 large squares=
100 beats/ min
75 beats/min
Determining Rate:
5 large squares =
6 large squares=
60 beats/min
50 beats/min
Arrhythmias of Sinus origin can be classified as having….
electrical activity follows usual conduction pathways but is either too fast, too slow, or irregular
Ectopic rhythms can be classified as having…
electrical activity originates from a focus other than the sinus node
Reentrant arrhythmias can be classified as having…
electrical activity trapped within an electrical racetrack
Conduction block arrhythmias can be classified as having…
electrical activity that originates in the sinus node and follows the original pathways but encounters unexpected blocks and delays
Sinus rhythm over 100 beats/min=
Normal or pathological?
Sinus tachycardia
Can be normal or pathological
Causes of sinus tachycardia include:
strenuous exercise CHF severe lung disease hyperthyroidism drugs fever intravascular volume loss pain
Tachycardia in elderly is…
Rare, often can’t get over 140-150
If over this it is probably nonsinus
Sinus rhythm less than 60 beats/min
Sinus Bradycardia
Normal and pathological
Causes of sinus bradycardia include:
early in acute MI enhanced vagal tone drugs hypothyroidism hyperkalemia sick sinus syndrome
Sinus arrhythmia looks like:
most like from:
NSR but slightly irregular
Usually increases in inspiration and decreases in exhalation
Prolonged electrical inactivity
asystole
occurs when the sinus node stops firing or from a sinus node exit block
sinus arrest
what are escape beats?
rescue beats originating outside the sinus node
Sinus node fires between
60-100 times/min
Atrial pacemakers fire between
60-75 times/min
Junctional pacemaker fire between
-where are they located?
46-60 time/min
-located near the AV node
Ventricular pacemakers fire between
30-45 times/min
What pacemaker cells will produce a normal QRS complex?
Atrial and junctional
What pacemaker cells will produce an abnormal or wider QRS complex?
Ventricular pacemakers
What is the most common escape beat?
Junctional
In junctional escape beats a _______ p wave is seen
Usually no p wave sometimes retrograde (atrial depol)
In junctional escape beats the mean electrical axis of the retrograde P wave is ________
reversed 180 degrees from normal p wave
A normal P wave is upright in what leads?
Inverted in what leads?
lead I
aVR
What is a prolonged sinus pause due to failure of the sinus depolarization to be transmitted out of the node into the atria?
Sinus exit block
What causes ectopic rhythms?
Enhanced automaticity of a nonsinus node site
- digitalis toxicity
- beta adrenergic stimulation
Four questions to identify nonsinus arrhythmias:
- Are normal P waves present?
- Are the QRS complexes narrow (.12s)
- What is the relationship between the P waves and QRS complex
- Is the rhythm regular or irregular
Normal P waves with normal p wave axis are indicative of arrhythmias from _____
within the atria
No P waves present are indicative of arrhythmias from_____
AV node or ventricles
Abnormal P wave axis is indicative of arrhythmias from_____
AV node or ventricles
Narrow QRS axis indicates origin or rhythm must be_____
at or above the AV node
A wide QRS complex indicates rhythm must be____
within the ventricles
A single P wave preceding each QRS complex means the rhythm has ______ origin
sinus or other atrial origin
AV dissociation is
Atrial and ventricles are depolarizing/contracting independent of one another
Abnormal P wave that comes too early
otherwise regular
not generally sustained
premature atrial contraction
A small blip (pseudo R') in V1 Regular rhythm P Wave often buried Rate ~150-250 Sudden Onset
Paroxysmal Supraventricular Tachycardia (PSVT)
When is carotid massage contraindicated?
If there is evidence of carotid disease
The flutter waves of atrial flutter are best seen in
Leads II and III
Atrial flutter is generated by a reentrant circuit that runs around_____
annulus of tricuspid valve
Can carotid massage terminate atrial flutter?
No, but it may increase the block
example: 3:1 block to 5:1 block
irregularly irregular ventricle rate between 120-180 bpms, with an absence of p waves is
Atrial fibrillation
What is needed to diagnose multifocal atrial tachycardia (MAT)?
At least 3 different p wave morphologies
What is needed to diagnose wandering atrial pacemakers?
3 different p wave morphologies seen, but there will be two or three beats of each
What is paroxysmal atrial tachycardia?
regular rhythm with rate of 100-200bpm
- initiated by a premature beat
- hard to differentiate from SVT unless you see the start
Differences between PAT and PSVT
PAT has warm up or cool down period
Carotid massage doesn’t affect PAT while it terminates or slows PSVT
A wide and bizarre QRS lasting at least .12seconds and is premature with discordant t wave is a
premature ventricular contraction
-usually followed by prolonged compensatory pause
A run of three or more consecutive PVCs is
ventricular tachycardia (VT)
An EKG showing tracing spasmodic jerks (or an undulating line) with no true QRS complexes is____
Most often seen in_______
Requires_______
Ventricular Fibrillation (VF)
Seen most often in dying hearts
Requires CPR & Defib at once
Prolonged QT intervals can lead to ________
which has QRS complexes that spiral around the baseline
Torsade de Pointes
