Key Points
- To evaluate regional diastolic and systolic strain rate measurements for differentiating transmural from nontransmural myocardial infarction during dobutamine stress echocardiography.
- Induced chronic circumflex artery occlusion via ameroid constrictors in 23 pigs alongside 5 control pigs without constrictors.
- Performed high-dose dobutamine stress echocardiography to measure systolic strain rates, systolic/postsystolic strain values, and early/late diastolic strain rates.
- Assessed myocardial fibrosis histologically at week 6, categorizing infarcts into nontransmural (n=14) and transmural (n=9).
- Nontransmural infarction exhibited significantly higher systolic strain rate, systolic strain, and postsystolic strain, along with lower early diastolic strain rate compared to transmural infarction (P = 0.01).
- Viability was best predicted by systolic strain rate (ROC area under curve 0.96, P = 0.0003) and early diastolic strain rate at 10 µg/kg/min dobutamine (ROC area under curve 0.94, P = 0.001).
- Diagnostic accuracy for detecting viability was equivalent between early diastolic and systolic strain rate, with sensitivities of 93% vs. 93% and specificities of 96% vs. 94%, respectively.
Structured PICO
PPopulation28 pigs (23 with an ameroid constrictor placed around the circumflex artery inducing chronic vessel occlusion, 5 controls without constrictor)
IInterventionDobutamine stress echocardiography (DSE) with strain rate imaging (systolic and diastolic strain rates)
CComparatorControl pigs without constrictor; comparison between transmural and nontransmural infarction groups
OOutcomeDifferentiation of transmural/nontransmural infarction (viability) and correlation with myocardial fibrosis at week 6surrogate
Diastolic strain rate analysis is equipotent to systolic strain rate parameters for identifying viable myocardium and differentiating nontransmural from transmural myocardial infarction during dobutamine stress echocardiography in a porcine model.