This 66-year-old woman with a history of hypertension is brought to the emergency department four hours after the onset of severe retrosternal chest pain, associated with dyspnea, diaphoresis and nausea:

• Sinus rhythm with successive ectopic ventricular complexes (accelerated idioventricular rhythm), with AV dissociation
• Ventricular rate 70/min.
• Voltage criteria for left ventricular hypertrophy.
• Inferior infarct, age undetermined
• ST elevation in V1 and V2 (sinus-originated complexes), consider septal injury pattern (acuteseptal infarction)
• T wave abnormality, compatible with anterolateral ischemia

The following ECG was 40 minutes later:

• Accelerated Idioventricular Rhythm with AV dissociation, followed by sinus rhythm (2 beats)
• Ventricular rate 78/min.

This tracing shows the end of a run of accelerated idioventricular rhythm with AV dissociation.

Accelerated idioventricular rhythms are commonly seen in patients in the CCU and cardiac ICU, and are very frequent in the first 24 hours after reperfusion. They may be well tolerated, meaning they do not require specific treatment. Often they occur when the atrial rhythm slows down, and subside when the atrial rate increases. 

On arrival in the Emergency Department, the serum troponin and CK of this patient were slightly elevated (41 and 158 mcg/L respectively), but rose to 5289 and 372 mcg/L 8 hours after admission, in keeping with an acute infarction. Coronary angiography revealed severe diffuse disease of the left anterior descending artery with several 70-80% stenoses. The other arteries had no significant stenoses. The patient became symptom-free, and was treated medically.