Is accelerated idioventricular rhythm a good marker for reperfusion after streptokinase?

Accelerated idioventricular rhythm (AIVR) is a common arrhythmia observed in patients with ST segment elevation myocardial infarction (MI). It is not clear how much value AIVR has in predicting successful reperfusion, since there have been conflicting data regarding this in the past. Streptokinase (STK) even today is the commonest thrombolytic agent used in the public health care set-up in India.(1) Most data for the use of STK are from the 1990s, which had showed that at best it is effective in only 50% of patients in restoring adequate flow.(2) It is probable that with the current dual-antiplatelet loading dose regimen and other newer medications, this figure could be higher. Also, rescue angioplasty for failed thrombolysis is the standard of care now, unlike before. Hence, we need reliable non-invasive markers to judge successful reperfusion in the present era. While ST segment resolution is the standard marker for reperfusion used in thrombolytic trials, in several instances it is not definitive. An additional marker would thus be very useful, especially in such cases.

This was a prospective observational study carried out at a public teaching hospital. 200 consecutive patients with a diagnosis of acute MI who were given STK within 12h of index pain were included. The STK dose was 1.5 million units, infused over 30min; the ECG was again recorded after 90min of completion of the infusion. Continuous ECG monitoring for the first 24h of ICCU stay was performed and AIVRs during this period were documented. Early AIVR was defined as that occurring within 2h of completing the STK infusion. Echocardiography was performed 24h after presentation. The time course of AIVR was studied vis-a-vis the outcome of thrombolysis.

AIVR was seen in 41% of the patients. Though AIVR was found to have low sensitivity (45%) and specificity (64%) as a predictor of successful thrombolysis, early AIVR was a reliable sign of successful thrombolysis (p<0.05). The sensitivity (45%) of early AIVR was low; however, the specificity (94%) and positive predictive value (94%) were very good.

AIVR is a common arrhythmia in the setting of STEMI receiving thrombolytic therapy. Early AIVR is more common with successful thrombolysis, with an excellent positive predictive value. Thus, early AIVR can be used as an additive criterion to ST segment resolution as a non-invasive marker of successful thrombolysis with STK.