Non Q and "Incomplete Q" Myocardial Infarction After Thrombolysis is Associated to Reinfarction in a Six Months Follow-up

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Abstract

Background

Successful thrombolysis is associated to alimitation of ECG indexes of necrosis.We explored the rate of development of Qwaves at discharge in leads withST segment elevation (STT) on admission and its prognostic implications in the follow-up.

Methods Seven thousand six hundred and five patients (pts) were discharged alive in the International tPA-SK Mortality Trial. We analysed the ECG of pts with ST >_ 0.1 mV in >_ 3 contiguous leads on admission, and excluded pts with bundle branch block, poor quality of the ECG or incomplete follow-up. An index of Q wave development (IQ) in leads withSTT was calculated: (n of leads with discharge in leads with STT on admission / n leads with STTon admission) x 100. Six months follow-up for reinfarction and death was performed. A total of 5253 pts were included. Results 1)Non-Q development, index 0% (non Q MI) was observed in 975 pts (18.6%). 2) Index 10 to 40% "incomplete" Q in 771 patients (14.7%). 3) Index > 40%("complete" Q) in 3507 pts (66.7%). Reinfarction is summarised in the table.                     _{Prevalence   Reinfarction   Odds and IC 95%       p                         (n)     (%)      (n)      (%)   Non Q              975   18.6     60        6.2       1.95(1.39-27) Q Incomplete  771   14.7    45        5.8•      1.84(1.24-26) complete" Q "Complete   3507  66.7    114      3.3         1                     <0.001   p < 0.001 for Q Complete versus Q Incomplete and Non Q}   Death rate was 2.8% in the "Complete" Q group, 3.5% in the "Incomplete" group and 3% in the nonQ group, p (NS). Reinfarction was associated with mortality during follow-up. Death rate was 28%in219 pts with reinfarction and 1.8% pts without it (p< 0.001). Conclusions Non-Q MI or incomplete Q development after thrombolysis at discharge predicts a higher risk of reinfarction during the six months follow-up