Sinoatrial block

Sinoatrial Block (SA Block)

Rate	Normal to slow, defined by duration of frequency of block
Rhythm	Irregular when a block occurs
P wave	Upright and uniform, except during the dropped beat
PR interval	Normal (0.12 - 0.20 sec), except during the dropped beat
QRS	Normal (0.06 - 0.10 sec), except during the dropped beat

• Cardiac output will decrease, possibly causing syncope or dizziness.
• Occurs in some multiple of the PP interval.
• After dropped beat, cycles continue on time.