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[Assessment of left ventricular contractile characteristics following coronary artery bypass grafting]
H Imagawa1, T Kobayashi, T Yoshino
1Department of Circulatory Dynamics, Center for Adult Diseases, Osaka, Japan.
Insights
Complete revascularization after coronary artery bypass grafting normalizes left ventricular function. Myocardial infarction can impair systolic function, even with increased preload during exercise.
Area of Science:
- Cardiovascular Surgery
- Cardiac Physiology
- Medical Imaging
Context:
- Assessing left ventricular function post-coronary artery bypass grafting (CABG) is crucial.
- Study included 29 patients categorized by revascularization completeness and myocardial infarction (MI) status.
- Evaluated ejection fraction (EF), systolic pressure/end-systolic volume index (SP/ESVI), and end-diastolic volume index (EDVI) using radionuclide angiography.
Purpose:
- To evaluate left ventricular contractile characteristics after CABG.
- To compare functional parameters between different patient groups (CR/IR, MI-/MI+).
- To determine the relationship between systolic function indices during exercise.
Summary:
- Patients with complete revascularization (CR) and no MI showed normalized EF and SP/ESVI during exercise.
- Incomplete revascularization (IR) or MI led to impaired systolic function, with EF decreasing in the IR.MI(+) group.
- Exercise-induced increases in SP/ESVI correlated significantly with improvements in EF and EDVI.
Impact:
- Complete revascularization and absence of MI are key to restoring normal left ventricular function post-CABG.
- Systolic function can deteriorate during exercise if contractile reserve is compromised, despite increased preload.
- Findings highlight the importance of both surgical success and patient's cardiac history in functional recovery.
Abstract:
The present study was designed to assess a left ventricular function, particularly contractile characteristics following coronary artery bypass grafting (CABG). The subject was 29 post-CABG patient consisting of 4 groups; 6 patients with complete revascularization (CR) and no myocardial infarction (MI) (CR.MI(-) group), with CR and MI (CR.MI(+) group), 5 with incomplete revascularization (IR) and no MI (IR.MI(-) group) and 8 with IR and MI (IR.MI(+) group). Ejection fraction (EF), systolic pressure/end-systolic volume index (SP/ESVI) and end-systolic volume index (EDVI) were evaluated utilizing radionuclide angiography at rest and during exercise (Ex). Increase of SP/ESVI and EF and no change of EDVI during Ex were observed in CR.MI(-) group. Increase of SP/ESVI and no change of EF and EDVI in CR.MI(+) group, no change of SP/ESVI, EF and EDVI in IR.MI(-) group and no change of SP/ESVI and EDVI and decrease of EF in IR.MI(+) group were observed. The SP/ESVI and EF of CR.MI(-) group were respectively highest among 4 groups and showed no difference compared with control group during Ex. Ex-induced increase ratio of SP/ESVI had linear correlations with Ex-induced increment of EF (r = 0.81, p less than 0.001) and Ex-induced increase ratio of EFVI (r = 0.54, p less than 0.005). It is concluded that both CR and no MI lead to normalization of EF and SP/ESVI during Ex. Furthermore, in the case of poor contractile reserve, systolic function may deteriorate in spite of increased preload during Ex.