What is SA Block
Failure to inititate an impulse from SA node.
Causes of SA Block
• Degenerative changes in elderly.
• Ischaemic heart disease (involving SA node).
• Drugs (digoxin).
• Increased vagal tone (may present like sick sinus syndrome).
Symptoms
• May be asymptomatic.
• Dizziness, giddiness.
Signs
Drop beat and no heart sound at the time of drop beat.
Investigations
• ECG—complete absence of one complex (P-QRS-T).
• Holter monitoring—may show the block.
Treatment of SA Block
• No treatment, if asymptomatic.
• Withdrawal of offensive drug, if any.
• If any syncopal attack or sick sinus syndrome—permanent pacemaker should be given.