ventricular failure

Premature ventricular contractions

ECG characteristics

· P wave : absent

· PR interval : not measurable

· QRS complex : occurs earlier than expected , bizarre

configuration , duration greater than 0.12 sec.

· T wave : occurs opposite direction to QRS complex

· Other : a compensatory pause may follow the T wave.

Possible causes

· Increased catecholamine release

· Hypoxia

· Hypokalaemia

· Hypocalcaemia

· Hypomangnesaemia

· Myocardial infarction / ischaemia

· Hypothermia

· Mechanical irritability i.e. Swan Ganz or pacemaker insertion

· Digoxin toxicity

· Sympathomimetic medication i.e. Adrenaline, Isuprel

· Exercise

· Excessive Alcohol or Caffeine ingestion

· Hypercapnia associated with C.O.A.D

· Cigarette smoking

Treatment

· Resolve the cause

*Maintenance of potassium (Hypokalaemia:- most common cause)

*Maintenance of normothermia

*Sympathomimetic medication induced

Ventricular tachycardia

ECG characteristics

· Atrial rhythm : can not be determined

· Ventricular rhythm : usually regular - may be slightly irregular

· Atrial rate : can not be determined

· Ventricular rate : usually rapid (100 - 200 beats per minute)

· P wave : usually absent , may be obscured by the QRS

complex , retrograde P waves may be seen

· PR interval : not measurable

· QRS complex : duration exceeds 0.12 seconds , bizarre

appearance , usually with increased amplitude

· T wave : direction is opposite QRS complex

· Other : fusion beats , capture beats

Possible causes

· Hypokalaemia, hypocalcaemia, hypomangnesaemia

· Hypothermia

· Acute myocardial infarction / ischaemia

· Rheumatic heart disease

· Mitral valve prolapse

· Congestive heart failure

· Cardiomyopathy

· Pulmonary embolism

· Drug toxicity (Digoxin, Quinidine, Procainamide)

· Hypertensive heart disease

· Cardiac disease

· Ventricular aneurysm

Treatment

· Conscious: - treat cause

perform cough CPR

consider drug therapy (Magnesium, Calcium, Lignocaine, Amiodarone, Bretylium, Procainamide)

cardioversion

· Unconscious: - Defibrillation, and CPR

Treat the cause

Consider drug therapy (Magnesium, Calcium, Lignocaine, Amiodarone, Bretylium, Procainamide)