Arrythmias 1 Flashcards
Normal sinus rhythm Lead 2
Intrinsic rate of 60-100
Regular, with minimal variation in RR intervals
P wave present, positive and preceding QRS
Sinus bradycardia
Regular, minimal variation in RR intervals
P wave is present, positive and precedes each QRS complex
Rate is less than 60 BPM
Sinus tachycardia
Regular, minimal variation in RR interval
P wave is present, positive and preceding QRS
Rate is over 100 BPM
Sinus arrythmia
slight variation of a sinus rhythm
changes in R-R interval in a cyclical fashion corresponding with inspiration and expiration
constant PR and QRS intervals
Sinus arrythmia mechanism
Inspiration decreases vagal tone causing increased sinus rate
Expiration restores vagal tone and decreases sinus rate.
Incidence of SA decreases with age due to decreased baroreceptor reflex sensitivity and decreased carotid distensibility.
Sinus arrest
An entire missing PQRST cycle is missing from an otherwise regular rhythm
Sinus arrest mechanism
SA node fails to initiate a single impulse and will then resume to normal functioning. Occasional episodes are insignificant.
rhythms of the atria definition
rhythms which originate outside of the SA node, originating from any area in the atria.
Premature atrial complex
underlying regular rhythm
premature and abnormally shaped P wave and irregular rhythm on PAC occurrence.
Normal phenomenon not requiring treatment unless Pt has underlying co morbidities.
PAC mechanism
premature beat arising from ectopic pacemaking tissue within atria. ectopic impulses are normally supressed by more rapid impulses from SA node.
PAC classification
Unifocal - originates from a single ectopic
Multifocal - multiple ectopic foci causing varying PAC morphologies
Repeating patterns
Bigeminy - every other beat is PAC
Trigeminy - every third beat
Quadrigeminy - every fourth beat
Couplet - 2 consecutive
triplet - 3 consecutive
supraventricular tachycardia
rate generally above 150 bpm
regular rhythm
P wave lost due to rapid rate and short RR intervals
atrial flutter
regular or irregular
P/F wave :QRS complex ratio varies
SAW TOOTH flutter waves
atrial flutter mechanism
atrial impulse is rapid and atria contract too fast for ventricles to match.
atrial fibrillation
irregularly-irregular rhythm
P wave replaced by erratic fibrillatory waves
QRS present
atrial fibrillation mechanism
due to independent depolarisation of cells, atria quiver without organised contraction.
junctional rhythm
Regular rate of 40-60 bpm
inverted P wave before or after QRS complex
Junctional AV rhythm mechanism
AV node takes over initiating impulse due to SA failure. AV node has a slower intrinsic rate causing decreased heart rate. P wave is inverted due to opposing movement of electrical activity. If ventricles are depolarised first then P wave follows QRS and if depolarisation is simultaneous then P wave is hidden.
