ABSTRACT
Objective To evaluate the value of cardiac MR imaging in chronic ischemie mitral regurgitation (IMR) in patients with myocardial infarction. Methods All patients clinically diagnosed with coronary heart disease and myocardial infarction in our hospital from January 2016 to September 2018 were retrospectively selected, myocardial infarction time more than 3 months and confirmed to have necrotic myocardium by cardiac magnetic resonance examination. All patients underwent echocardiography at the same time. Based on the results of echocardiography, patients were divided into the myocardial infarction group without IMR (40 cases), the mild IMR group (39 cases) and the moderate to severe IMR group (51 cases). Cardiac MR and delayed enhancement (LGE) scan images were analyzed. Cardiac function indexes were measured and left ventricular LGE positive segments were recorded. The indexes of myocardial global longitudinal strain (GLS), global peripheral strain (GCS) and global radial strain (GRS) of left ventricle of IMR patients were measured by feature tracking(FT). Cardiovascular history, coronary artery stenosis and location of myocardial infarction were compared by chi?square test between the without IMR, mild IMR and moderate to severe IMR groups.Univariate analysis of variance was used to compare the measurement data of left ventricular myocardial infarction volume, left heart function and left ventricular myocardial globle strain, and LSD test was used for pair?wise comparison. Results There was no difference in age, sex and cardiovascular history among the three groups. Comparison of myocardial infarction patients in the three groups: (1) There was no statistically significant difference in the myocardial infarction volume between the three groups (P=0.052), while the myocardial infarction volume tended to increase as the grade of mitral regurgitation increased. The number of patients with myocardial infarction in the inferior wall and the inferolateral wall in the moderate to severe IMR group were significantly higher than those of the other two groups (P<0.05), and there was no significant difference in the volume of myocardial infarction between the without IMR group and mild IMR group, and no difference in the number of patients with inferior wall and inferolateral wall. (2) Cardiac function measured by CMR: ejection fraction (EF) was significantly reduced in the moderate to severe IMR group compared with the without IMR group and the mild IMR group (P<0.05), the end diastolic volume (EDV) increased significantly and the end systolic volume (ESV) increased significantly (P<0.05). Mass of myocardium increased significantly (P<0.05); Stroke volume (SV) and cardiac output (CO) there was no significant difference among the three groups. (3) Comparison of the moderate to severe IMR group to the without IMR group and the mild IMR group respectively: left ventricular GLS and GRS decreased (P<0.05), the difference of the GCS was no statistically significant. There was no statistical difference in the three strain values between the without IMR group and the mild IMR group. Conclusion The globe myocardial strain of the left ventricle in myocardial infarction patients with chronic moderate to severe IMR was significantly impaired, the myocardial infarction in the inferior wall and the inferolateral wall in the level of the papillary muscle may be correlated with chronic moderate to severe IMR, and the myocardial infarction volume of the left ventricle may also be related.
ABSTRACT
Objective@#To evaluate the value of cardiac MR imaging in chronic ischemie mitral regurgitation (IMR) in patients with myocardial infarction.@*Methods@#All patients clinically diagnosed with coronary heart disease and myocardial infarction in our hospital from January 2016 to September 2018 were retrospectively selected, myocardial infarction time more than 3 months and confirmed to have necrotic myocardium by cardiac magnetic resonance examination. All patients underwent echocardiography at the same time. Based on the results of echocardiography, patients were divided into the myocardial infarction group without IMR (40 cases), the mild IMR group (39 cases) and the moderate to severe IMR group (51 cases). Cardiac MR and delayed enhancement (LGE) scan images were analyzed. Cardiac function indexes were measured and left ventricular LGE positive segments were recorded. The indexes of myocardial global longitudinal strain (GLS), global peripheral strain (GCS) and global radial strain (GRS) of left ventricle of IMR patients were measured by feature tracking(FT). Cardiovascular history, coronary artery stenosis and location of myocardial infarction were compared by chi-square test between the without IMR, mild IMR and moderate to severe IMR groups.Univariate analysis of variance was used to compare the measurement data of left ventricular myocardial infarction volume, left heart function and left ventricular myocardial globle strain, and LSD test was used for pair-wise comparison.@*Results@#There was no difference in age, sex and cardiovascular history among the three groups. Comparison of myocardial infarction patients in the three groups: (1) There was no statistically significant difference in the myocardial infarction volume between the three groups (P=0.052), while the myocardial infarction volume tended to increase as the grade of mitral regurgitation increased. The number of patients with myocardial infarction in the inferior wall and the inferolateral wall in the moderate to severe IMR group were significantly higher than those of the other two groups (P<0.05), and there was no significant difference in the volume of myocardial infarction between the without IMR group and mild IMR group, and no difference in the number of patients with inferior wall and inferolateral wall. (2) Cardiac function measured by CMR: ejection fraction (EF) was significantly reduced in the moderate to severe IMR group compared with the without IMR group and the mild IMR group (P<0.05), the end diastolic volume (EDV) increased significantly and the end systolic volume (ESV) increased significantly (P<0.05). Mass of myocardium increased significantly (P<0.05); Stroke volume (SV) and cardiac output (CO) there was no significant difference among the three groups. (3) Comparison of the moderate to severe IMR group to the without IMR group and the mild IMR group respectively: left ventricular GLS and GRS decreased (P<0.05), the difference of the GCS was no statistically significant. There was no statistical difference in the three strain values between the without IMR group and the mild IMR group.@*Conclusion@#The globe myocardial strain of the left ventricle in myocardial infarction patients with chronic moderate to severe IMR was significantly impaired, the myocardial infarction in the inferior wall and the inferolateral wall in the level of the papillary muscle may be correlated with chronic moderate to severe IMR, and the myocardial infarction volume of the left ventricle may also be related.