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[Relationship of left ventricular wall motion to myocardial viability in patients with recent myocardial infarction]
M Narita1, T Kurihara, K Murano
1Department of Internal Medicine, Sumitomo Hospital, Osaka.
Insights
Assessing myocardial perfusion after percutaneous transluminal coronary angioplasty (PTCA) helps differentiate viable from necrotic heart tissue. This study correlated perfusion patterns with left ventricular wall motion in myocardial infarction patients post-PTCA.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Imaging
Background:
- Differentiating viable from necrotic myocardium is crucial for managing patients post-myocardial infarction.
- Left ventricular myocardial perfusion directly influences myocardial wall motion.
- Percutaneous transluminal coronary angioplasty (PTCA) is a common intervention following myocardial infarction.
Purpose of the Study:
- To investigate the relationship between left ventricular myocardial perfusion and left ventricular wall motion.
- To differentiate viable from necrotic myocardium in patients after recent myocardial infarction and successful PTCA.
- To assess changes in perfusion and wall motion before and after PTCA.
Main Methods:
- Studied 21 patients with recent myocardial infarction who underwent successful PTCA.
- Utilized exercise stress thallium-201 tomography (Ex-Tl) and rest 99mTc-gated blood pool tomography.
- Compared myocardial perfusion patterns (normal, redistribution, fixed defect/viable, necrosis) with left ventricular segmental % shortening.
Main Results:
- Normal perfusion segments (88%) showed normal wall motion (mean % shortening 42%).
- Redistribution segments (RD(+)) often exhibited hypokinesis or akinesis (mean % shortening 19%).
- Fixed defect/viable (RD(-)) and necrosis segments showed significant wall motion abnormalities (mean % shortening 12% and severe dysfunction, respectively).
Conclusions:
- Myocardial perfusion patterns correlate significantly with left ventricular wall motion post-PTCA.
- Transient perfusion defects (redistribution) are associated with impaired, but not absent, wall motion.
- Fixed perfusion defects indicate necrotic myocardium with severely compromised wall motion.
Abstract:
The influence of left ventricular myocardial perfusion on left ventricular wall motion in patients with recent myocardial infarction was studied to try to differentiate viable myocardium from necrotic myocardium in 21 patients with initial myocardial infarction who received successful percutaneous transluminal coronary angioplasty (PTCA) 5-8 weeks after the onset. Exercise stress myocardial tomography with 201Tl (Ex-Tl) was performed before (3-5 weeks after acute onset) and after PTCA. Myocardial images were reconstructed into a bull's eye map which was divided into 17 segments. Rest ECG-gated cardiac blood pool tomography with 99mTc was performed before PTCA, and the left ventricular wall was divided into the same 17 segments used in Ex-Tl. The % shortening in each segment was calculated. Myocardial perfusion and % shortening were compared in each myocardial segment. Myocardial perfusion was classified into 4 types by considering whether exercise induced myocardial perfusion abnormality was transient (RD(+)) or persistent (RD(-)) in delayed image; 1) normal perfusion, 2) redistribution (+); RD(+): transient or viability exercise-induced perfusion defect before PTCA, 3) RD(-)/viable: fixed defect before PTCA but normal perfusion after PTCA, and 4) necrosis: fixed defect before and after PTCA. Most normal perfusion segments (88% of 184) showed normal wall motion and mean % shortening was 42 +/- 11%. Only 13 of 73 RD(+) segments showed normal wall motion. Thirty-eight and 19 RD(+) segments showed moderate hypokinesis and severe hypokinesis or akinesis, respectively. Mean % shortening in RD(+) segments was 19 +/- 13%. Thirty-seven of 38 RD(-)/viable segments had wall motion abnormalities, and 20 showed severe hypokinesis or akinesis. Mean % shortening in RD(-) segments was 12 +/- 8%. All 62 necrosis segments showed wall motion abnormalities including 10 with dyskinesis and 42 with akinesis or severe hypokinesis.(ABSTRACT TRUNCATED AT 250 WORDS)