Approach to managing acute tachyarrhythmia
If identified, correct the cause of the tachyarrhythmia if possible and safe to do so. Consider electrical cardioversion for tachyarrhythmias, especially if the patient is clinically unstable. Procedural sedation is needed before electrical cardioversion—seek advice from an experienced clinician.
A clinically unstable patient with a tachyarrhythmia requires immediate medical attention and urgent electrical cardioversion may be needed. Features of instability include acutely altered mental state, ongoing chest pain, acute left ventricular failure, hypotension or hypoperfusion, acidosis, and other signs of shock. Clinical instability seldom occurs with a heart rate of less than 150 beats per minute. If heart rate is less than 150 beats per minute, other causes of the instability should be considered.
Options for initial management of acute tachyarrhythmias include:
- no specific therapy, or supportive care
- electrical cardioversion
- antiarrhythmic drug therapy
- overdrive pacing.
Initial management depends on an accurate diagnosis of the acute tachyarrhythmia. Take the following into account:
- the current 12-lead ECG and rhythm strip
- past ECGs (keep records of rhythm strips, especially those of transient arrhythmias)
- past pattern of arrhythmias and response to treatment
- risk factors such as age, ischaemia and structural heart disease
- previous electrophysiological studies (if available).
The precise diagnosis may be difficult, particularly for regular wide-complex tachycardia. Seek expert advice if there is uncertainty about the diagnosis.
Options for preventive and long-term management of tachyarrhythmias include:
- no therapy
- catheter ablation
- antiarrhythmic drug therapy
- insertion of a pacemaker and an implantable cardioverter defibrillator (ICD)
- surgery (rarely performed).
All antiarrhythmic drugs can cause adverse effects. They can also have proarrhythmic effects, including an increase in frequency or duration of the first arrhythmia, or development of a new arrhythmia (eg torsades de pointes, which can occur with drugs that prolong the QT interval such as sotalol and other drugs listed in Drugs highly associated with QT-interval prolongation and torsades de pointes). Therefore, consider the option of giving no therapy.
Initial management of any acute tachyarrhythmia gives guidance on the initial management of any acute tachyarrhythmia, and leads on to algorithms for the management of stable acute narrow-complex tachyarrhythmia (Management of stable acute narrow-complex tachyarrhythmia) and stable acute wide-complex tachyarrhythmia (Management of stable acute wide-complex tachyarrhythmia).