Definition
When the heart rate is greater than 100/min in sinus ( rhythm.
Causes
1. Physiological—anxiety, emotion, exercise, pain, pregnancy.
2. Pathological—
–– Anaemia.
–– Fever.
–– Thyrotoxicosis.
–– Shock (except vasovagal attack in which bradycardia is present).
–– Heart failure.
–– Sick sinus syndrome.
–– Bleeding and hypovolaemia.
–– Chronic constrictive pericarditis.
–– Acute anterior myocardial infarction (bradycardia is common in inferior myocardial
infarction).
–– Drugs (salbutamol, atropine, adrenaline, isoprenaline, ephedrine, propantheline, thyroxine).
Symptoms
• Palpitation.
• Features of primary disease, if any.
ECG shows
• Heart rate— >100 beats/minute.
• P, QRS and T—normal.
• Rhythm—regular.
Treatment
• If symptomatic—beta-blocker (propranolol, atenolol) or rate-limiting calcium channel
blocker( verapamil).
• Treatment of primary cause, if any.