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Updated: Mar 13, 2026
Histological Quantification of Chronic Myocardial Infarct in Rats
Published on: December 11, 2016
Assessment of the longitudinal changes in infarct heterogeneity post myocardial infarction
Idan Roifman1, Nilesh R Ghugre2,3,4, Tasnim Vira2
1Sunnybrook Research Institute, Schulich Heart Program, Sunnybrook Health Sciences Centre and the University of Toronto, 2075 Bayview Avenue, room M 315b, Toronto, ON, M4N-3M5, Canada. idan.roifman@utoronto.ca.
Background:
Infarct heterogeneity, as assessed by determination of the peri-infarct zone (PIZ) by cardiac magnetic resonance imaging, has been shown to be an independent predictor for the development of cardiac arrhythmias and mortality post myocardial infarction (MI). The temporal evolution of the PIZ post MI is currently unknown. Thus, the main objective of our study was to describe the temporal evolution of the PIZ over a 6 month time period in contemporarily managed ST elevation myocardial infarction (STEMI) patients. Further, given the poor prognosis associated with microvascular obstruction (MVO) post STEMI, we sought to compare the temporal evolution of the PIZ in patients with and without MVO. We hypothesized that patients with MVO would show a relative persistence of PIZ over time when compared to those without MVO.
Methods:
Twenty-one patients post primary percutaneous coronary intervention were enrolled and treated with evidence based therapy. Each patient had three cardiac MRI scans at 48 h, 3 weeks and 6 months post infarction. Repeated Measures Analysis of Variance (ANOVA) was used to assess the evolution of core infarct size and peri-infarct zone size across the three time frames.
Results:
The patients in this study were predominantly male, with ~40 % LAD territory infarction and a mean LVEF of 46 ± 7 %. Core infarct size and PIZ size both decreased significantly across the three time frames. The presence of microvascular obstruction (MVO), a known adverse prognostic factor, influenced PIZ size. Both patients with and without MVO had a significant reduction in core infarct size over time. Patients with MVO did not have a significant change in PIZ size over time (11.9 ± 6.8 %, 12.2 ± 7.5 %, 10.7 ± 6.6 % p = 0.77). In contrast, non-MVO patients did have a significant decrease in PIZ size over time (7.0 ± 5.5 %, 7.1 ± 6.5 %, 2.7 ± 2.6 %, p = 0.01).
Conclusions:
Peri-infarct zone size, like core infarct size, varies depending upon the timing of measurement. Patients with MVO displayed a persistence of the PIZ over time.
Insights
The peri-infarct zone (PIZ) in ST-elevation myocardial infarction (STEMI) patients shrinks over time. However, PIZ persistence is observed in patients with microvascular obstruction (MVO), indicating poorer outcomes.
Area of Science:
- Cardiology
- Medical Imaging
- Cardiovascular Research
Background:
- Peri-infarct zone (PIZ) size post myocardial infarction (MI) is a predictor of arrhythmias and mortality.
- The temporal changes of the PIZ after MI are not well understood.
- Microvascular obstruction (MVO) is associated with a poor prognosis in ST-elevation MI (STEMI) patients.
Purpose of the Study:
- To investigate the temporal evolution of the PIZ over six months in STEMI patients.
- To compare PIZ changes in STEMI patients with and without MVO.
- To test the hypothesis that MVO leads to PIZ persistence.
Main Methods:
- Cardiac MRI was used to assess PIZ size in 21 STEMI patients at 48 hours, 3 weeks, and 6 months post-MI.
- Patients received standard evidence-based therapy post-primary percutaneous coronary intervention.
- Repeated Measures ANOVA was employed to analyze changes in infarct and PIZ size over time.
Main Results:
- Both core infarct size and PIZ size significantly decreased over the 6-month study period.
- STEMI patients with MVO showed no significant change in PIZ size over time (11.9% to 10.7%).
- STEMI patients without MVO demonstrated a significant reduction in PIZ size over time (7.0% to 2.7%).
Conclusions:
- PIZ size, similar to core infarct size, changes over time and is influenced by MVO.
- STEMI patients with MVO exhibit a persistent PIZ, suggesting a potential mechanism for their adverse outcomes.
- These findings highlight the prognostic significance of MVO in modulating infarct healing and PIZ dynamics.
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