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Updated: Oct 11, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Relation among exercise-induced ventricular arrhythmias, myocardial ischemia, and viability late after acute
A Elhendy1, F B Sozzi, R T van Domburg
1Thoraxcenter, University Hospital-Dijkzigt, Rotterdam, The Netherlands. ElHendy.Abdou@mayo.edu
Insights
Exercise-induced ventricular arrhythmia (VA) in patients post-myocardial infarction is linked to increased peri-infarction ischemia and multivessel disease. Myocardial ischemia in dysfunctional areas is a key cause of VA.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiac Imaging
Background:
- Late assessment after acute myocardial infarction (MI) is crucial for understanding long-term outcomes.
- Exercise stress testing combined with single-photon emission computed tomography (SPECT) provides insights into myocardial perfusion and viability.
Purpose of the Study:
- To investigate the relationship between exercise-induced ventricular arrhythmia (VA) and scintigraphic markers of myocardial ischemia and viability.
- To identify predictors of VA in patients with a history of MI.
Main Methods:
- 171 patients (mean 4.1 years post-MI) underwent exercise stress testing and Methoxyisobutyl Isonitrile (MIBI) SPECT.
- Ischemia was defined by reversible perfusion defects; viability by MIBI uptake in dyssynergic segments.
- Exercise-induced VA was recorded and correlated with perfusion and viability data.
Main Results:
- Exercise-induced VA occurred in 27% of patients.
- Patients with VA showed a higher prevalence of infarct-related artery stenosis, peri-infarction ischemia, and multivessel ischemia.
- Reversible defects were more frequent in patients with VA (40% vs 16%).
- Viable myocardial segments were significantly higher in patients with VA (80% vs 69%).
Conclusions:
- Exercise-induced VA late after MI is associated with increased peri-infarction ischemia and multivessel coronary artery disease.
- Myocardial ischemia within dysfunctional (dyssynergic) segments is a primary mechanism for VA development in this population.
Abstract:
This study assesses the relation between exercise-induced ventricular arrhythmia (VA) and scintigraphic markers of myocardial ischemia and viability in patients referred for exercise stress testing late after acute myocardial infarction. We studied 171 patients (144 men, age 57 +/- 10 years) with resting wall motion abnormalities by exercise stress testing in conjunction with methoxyisobutyl isonitrile (MIBI) single-photon emission computed tomography at a mean of 4.1 years after myocardial infarction. Ischemia was defined as reversible perfusion abnormalities. Myocardial viability was considered in myocardial segments with resting wall motion abnormalities in the presence of normal perfusion, a reversible defect or a fixed defect with regional MIBI uptake > or = 50% of maximal uptake. Exercise-induced VA occurred in 46 patients (27%). Patients with VA had a higher prevalence of infarct-related artery stenosis (43 [93%] vs 93 [74%], p < 0.01), peri-infarction ischemia (32 [70%] vs 54 [43%], p < 0.005), and ischemia in > or = 2 vascular regions (20 [43%] vs 27 [22%], p < 0.01) than patients without VA. Reversible defects were detected in 39 of 97 dyssynergic segments (40%) in patients with versus 40 of 248 dyssynergic segments (16%) in patients without VA (p < 0.0001). In dyssynergic segments without reversible perfusion abnormalities, the percent resting MIBI uptake was > or = 50% in 39 of 58 segments (67%) in patients with versus 63% in 131 of 208 segments in patients without VA (p = NS). The percentage of viable segments was 80% and 69% in patients with and without VA, respectively (p < 0.05). It is concluded that patients with exercise-induced VA late after myocardial infarction have a higher prevalence of ischemia in the peri-infarction zone and in multivessel distribution. Myocardial ischemia in the dyssynergic myocardium appears to be a major mechanism underlying the occurrence of VA in these patients.
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