Accelerated idioventricular rhythm in the post-thrombolytic era: incidence, prognostic implications, and modulating mechanisms after direct percutaneous coronary intervention.

BACKGROUND: In the thrombolytic era, the occurrence of accelerated idioventricular rhythm (AIR) has been proposed to be a specific marker for successful reperfusion. The incidence, prognostic implications, and potential modulating mechanisms of AIR after successful restoration of antegrade flow by means of modern reperfusion therapy (i.e., direct percutaneous coronary intervention (PCI)) has thus far not been investigated.
METHODS: We prospectively investigated 125 consecutive patients undergoing direct PCI for a first acute myocardial infarction (AMI). The incidence of AIR was determined from 24-hour Holter monitoring, initiated prior to PCI.
RESULTS: AIR appeared in 19 patients (15.2%). There were no significant differences between patients with or without AIR regarding baseline clinical characteristics. The incidence of AIR was not different between patients with TIMI 2 and 3 flow (13% vs 16%). There were no differences in the incidence of major cardiac events within 12-month follow-up in patients with and without AIR. Patients with AIR exhibited higher mean R-R intervals (mean 24-hour R-R interval: 871.3 +/- 121 vs 796.4 +/- 100 ms, P < 0.01), higher hourly mean values of heart rate variability (SDNN, 64.7 +/- 26 vs 49.4 +/- 20 ms, P < 0.01; rMSSD, 29.3 +/- 15 vs 22.0 +/- 12 ms, P < 0.01) and lower serum norepinephrine concentrations (60 minute after PCI, 478.9 +/- 357 vs 649.0 +/- 499 pg/ml, P < 0.05).
CONCLUSIONS: Our findings indicate that AIR is an nonspecific marker for reperfusion of the infarct-related artery in AMI and thus, predate previous observations of the thrombolytic era. Even though, AIR was associated with higher tonic vagal tone and lower sympathetic activity, the occurrence of AIR had no prognostic impact on the clinical course and was not able to discriminate between complete and incomplete reperfusion.