Different types of ECG

Sinus tachycardia

ECG characteristics

· Atrial rhythm : regular

· Ventricular rhythm : regular

· Atrial rate : greater than 100 beats / minute

· Ventricular rate : greater than 100 beats / minute

· P wave : precedes each QRS complex

· PR interval : normal - remains constant at 0.12 to 0.2 seconds

· QRS complex : duration and configuration usually normal

Possible causes

· Increased Catecholamine release (stress, anxiety)

· Exercise

· Volume depletion

· Fever / hypothermia

· Pain

· Alcohol / Caffeine ingestion / Cigarette smoking

· Left ventricular failure / cardiac tamponade

· Pulmonary embolus

· Hyperthyroidism

· Anaemia

Treatment

Treat the cause i.e. IV hydration, analgesia, oxygen therapy, blood transfusion etc.

Atrial fibrillation

ECG characteristics

· Atrial rhythm : grossly irregular

· Ventricular rhythm : grossly irregular

· Atrial rate : almost indiscernible , usually > 400 beats / min

· ventricular rate : 60 to 150 beats / minute

· P wave : absent , erratic 'f ' wave baseline (fibrillatory

Waves) appear, course atrial fibrillation has pronounced 'f'’waves, fine atrial fibrillation has less defined 'f'’ waves

· QRS complex : duration and configuration usually normal

Possible causes

· Increased circulating catecholamines

· Atrial volume overload

· Myocardial irritability following peri-operative handling of the heart

· Rheumatic heart disease

· Constrictive pericarditis

· Valvular disorders-particularly mitral stenosis.

· Congestive heart failure

· Cardiomyopathy

· Hypoxia

· Hypothermia

· Ischaemic heart disease / coronary heart disease

· Chronic obstructive airways disease

· Thyrotoxicosis

· Excessive alcohol / caffeine ingestion

Treatment

Controlled (HR<100) no treatment. Rapid (HR>100) requires treatment to slow the rate.

· Drug therapy (Digoxin, Amiodarone, Verapamil, and Sotolol).

· Cardioversion.

Carotid sinus massage

Atrial flutter

ECG characteristics

· Atrial rhythm : regular

· Atrial rate : regular

· Flutter ( or 'f' ) waves : saw toothed appearance

· QRS complex : duration and configuration usually normal

Possible causes

· Increased catecholamine release

· Atrial volume overload

· Myocardial irritability following peri-operative handling of the heart

Mitral or tricuspid valvular disease

· Cor Pulmonale

· Inferior wall myocardial infarction / ischaemia.

· Myocardial infarction

· Hypoxia

· Hypothermia

· Acute or chronic heart disease

· Excessive alcohol / caffeine ingestion

Treatment

If symptomatic or rapid rate

· Drug therapy (Digoxin, Amiodarone, or Verapamil)

· Elective cardioversion