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Define pulseless electrical activity full#

Torsades de pointes is a type of polymorphic ventricular tachycardia. When this leads to recurrent contractions without normal repolarisation, it is called torsades de pointes. These afterdepolarisations spread throughout the ventricles, causing a contraction before proper repolarisation. These abnormal spontaneous depolarisations before repolarisation are known as afterdepolarisations. Waiting a long time for repolarisation can result in spontaneous depolarisation in some muscle cells. Repolarisation is a recovery period before the muscle cells are ready to depolarise again.

Depolarisation is the electrical process that leads to heart contraction. It is prolonged at:Ī prolonged QT interval represents prolonged repolarisation of the heart muscle cells ( myocytes) after a contraction. The corrected QT interval ( QTc) estimates the QT interval if the heart rate were 60 beats per minute. The QT interval is from the start of the QRS complex to the end of the T wave. Radiofrequency ablation of the re-entrant rhythm can be a permanent solution. Treatment is similar to atrial fibrillation, including anticoagulation based on the CHA 2 DS 2 -VASc score. There may be 3:1, 4:1 or variable conduction ratios.Ītrial flutter gives a sawtooth appearance on the ECG, with repeated P wave occurring at around 300 per minute, with a narrow complex tachycardia. This often results in two atrial contractions for every one ventricular contraction ( 2:1 conduction), giving a ventricular rate of 150 beats per minute. The signal does not usually enter the ventricles on every lap due to the long refractory period of the atrioventricular node. The atrial rate is usually around 300 beats per minute. The signal goes round and round the atrium without interruption. The electrical signal re-circulates in a self-perpetuating loop due to an extra electrical pathway in the atria. Atrial flutter is caused by a re-entrant rhythm in either atrium. Normally the electrical signal passes through the atria once, stimulating a contraction, then disappears through the atrioventricular node into the ventricles.

Supraventricular tachycardia with bundle branch block (treated as SVT).

Atrial fibrillation with bundle branch block (treated as AF).

Polymorphic ventricular tachycardia, such as torsades de pointes (treated with IV magnesium).

Ventricular tachycardia or unclear cause (treated with IV amiodarone).

The resuscitation guidelines break down broad complex tachycardia into: Intravenous amiodarone is added if initial DC shocks are unsuccessful.īroad complex tachycardia refers to a fast heart rate with a QRS complex duration of more than 0.12 seconds or 3 small squares on an ECG. Patients with life-threatening features, such as loss of consciousness (syncope), heart muscle ischaemia (e.g., chest pain), shock or severe heart failure, are treated with synchronised DC cardioversion under sedation or general anaesthesia.

Atrial flutter (treated with rate control or rhythm control, similar to atrial fibrillation).

Atrial fibrillation (treated with rate control or rhythm control).

Supraventricular tachycardia (treated with vagal manoeuvres and adenosine).

Sinus tachycardia (treatment focuses on the underlying cause).

There are four main differentials of a narrow complex tachycardia: Therefore, the QRS complex will fit within 3 small squares in narrow complex tachycardia. On a normal 25 mm/sec ECG, 0.12 seconds equals 3 small squares. Narrow complex tachycardia refers to a fast heart rate with a QRS complex duration of less than 0.12 seconds.

Asystole (no significant electrical activity).

Pulseless electrical activity (all electrical activity except VF/VT, including sinus rhythm without a pulse).

They are either shockable (meaning defibrillation may be effective) or non-shockable (meaning defibrillation will not be effective). These are the four possible rhythms in a pulseless patient.

Define pulseless electrical activity full#

Attend the relevant courses, follow full guidelines and involve experienced seniors when treating patients. This section is a summary to help with exam preparation and is based on the guidelines from the Resuscitation Council UK from 2021. There are several types of arrhythmia, each with different causes and management options. They result from an interruption to the normal electrical signals that coordinate the contraction of the heart muscle.