Sinus Arrhythmia - Arrhythmias

Sinus Arrhythmia

·        Normal sinus rhythm: rate 60 to 100 per minute, P wave upright in leads I, II and AVF

·        Sinus tachycardia:

o  ­discharge of sinus node.  Rate is > 100/minute and regular

o  P wave is upright in leads I, II, AVF.  Treat underlying cause

·        Sinus bradycardia:

o  Constant and normal PR interval

o  < 60 bpm: but this is relative. An athlete may normal at 40, and a hypovolaemic patient bradycardic at 65 bpm

o  Causes: SA node disease, ­parasympathetic tone, drug effect

o  Treat if hypotension or ventricular escape beats present

o  Treatment: atropine (0.6 mg) unless MI, transthoracic pacing, dopamine or adrenaline

·        Sick Sinus Syndrome: Common in elderly. Bradycardia +/- arrest, AV block, or SVT alternating with bradycardia/asystole (Tachy-Brady Syndrome). Pace if symptomatic