Accelerated idioventricular rhythm

Background

• Results when rate of an ectopic ventricular pacemaker exceeds sinus node
• Usually benign,self limiting

Causes

• Reperfusion phase of acute myocardial infarction (most common cause)
• Beta-sympathomimetics (isoprenaline or adrenaline)
• Drug toxicity, especially digoxin, cocaine and volatile anaesthetics such as desflurane
• Electrolyte abnormalities
• Cardiomyopathy
• congenital heart disease
• myocarditis
• Return of spontaneous circulation (ROSC) following cardiac arrest
• Athletic heart

Clinical Features

• Asymptomatic or palpitations

Diagnosis

ECG features

• Regular rhythm
• Rate 50-110 bpm
• Three or more ventricular complexes
• QRS complexes >120ms
• Fusion and capture beats

Management

• AIVR is a benign rhythm in most settings and does not usually require treatment
• Self limiting and resolves when sinus rate exceeds that of the ventricular foci
• Anti-arrhythmics may cause precipitous haemodynamic deterioration and should be avoided
• Treat the underlying cause: e.g. correct electrolytes, restore myocardial perfusion
• Patients with low-cardiac-output states (e.g. severe biventricular failure) may benefit from restoration of AV synchrony to restore atrial kick – in this case atropine may be trialled to increase sinus rate and AV conduction

Disposition

• Normally outpatient

External Links

• http://lifeinthefastlane.com/ecg-library/aivr/