Sinus rhythms and SA node arrythmias (theory 1)

Question 1

Normal sinus rhythm

Answer 1

-intrinsic rate of 60-100 bpm
-regular with minimal variations of R-R intervals
-P wave present, upright and precedes each QRS complex

Question 2

Sinus bradycardia / tachycardia

Answer 2

-rate less than 60 bpm/ greater than 100bpm
-regular rhythm
-normal P wave, PR interval, RR interval and QRS width
-1:1 ratio of P waves to QRS complex

Question 3

Sinus arrythmia

Answer 3

-slight variation of sinus rhythm
-slight change during inspiration due to thorax pressure
-heart beats faster during inspiration then returns to normal during expiration

Question 4

Sinus arrest

Answer 4

-SA node fails to initiate an impulse.
-SA node resumes normal functioning.
-entire PQRST is missing
-Occasional episodes are not significant.
-Treatment based on the overall HR and tolerance

Question 5

SA node arrythmias

Answer 5

-sinus bradycardia
-sinus tachycardia
-sinus arrythmia
-sinus arrest

Question 6

Atrial dysrhythmias

Answer 6

-premature atrial complex
-SVT
-atrial flutter
-AF

Question 7

Premature atrial complex (PAC)

Answer 7

-premature atrial complex, strange looking p wave
-Existence of a particular complex
within another rhythm
-Also known as atrial ectopic
-Occurs earlier in time than the
next expected sinus complex
-Treatment is usually not
indicated

Question 8

Supraventricular tachycardia

Answer 8

-above 150bpm
-narrow QRS complex, but regular
-P wave lost in T wave due to fast rate

Question 9

Atrial flutter

Answer 9

-Atria contract at a rate too rapid for the ventricles to match.
-Known as flutter or F waves (classic saw tooth flutter waves)
-Can have variable ratio of F wave:QRS complex (1:1, 2:1, 3:1 etc)
-Medication or electrical cardioversion
-Can be regular or irregular

Question 10

Atrial fibrillation

Answer 10

-Rhythm in which the atria fibrillate or quiver without organized contraction
-Cells depolarise independently
-rhythm irregularly irregular
-P wave replaced by erratic fibrillatory waves

Question 11

Junctional (AV) rhythms

Answer 11

– If the SA node or atria fails to
initiate an impulse
– AV node can take over
– Impulse travels down through the
conduction system into the
ventricles
– Variations possible
-regular rate of 40-60 bpm
-P waves absent or after QRS, QRST normal

Question 12

Accelerated junctional rhythm

Answer 12

-Junctional rhythm with a rate exceeding the normal range of 60 beats/minute
-Less than 100 beats/minute
-P waves are absent or inverted before or after QRS
-regular rate between 60-100