Forensic Pathological Diagnosis of Acute and Old Myocardial Infarction Using Fourier Transform Infrared Spectroscopy

OBJECTIVES

Fourier transform infrared spectroscopy (FTIR) was used to analyze myocardial infarction tissues at different stages of pathological change to achieve the forensic pathology diagnosis of acute and old myocardial infarction.

METHODS

FTIR spectra data of early ischemic myocardium, necrotic myocardium, and myocardial fibrous tissue in the left ventricular anterior wall of the sudden death group of atherosclerotic heart disease and the myocardium of the normal control group were collected using hematoxylin-eosin (HE) and immunohistochemistry (IHC) staining as a reference, and the data were analyzed using multivariate statistical analysis.

RESULTS

The mean normalized spectra of control myocardium, early ischemic myocardium and necrotic myocardium were relatively similar, but the mean second derivative spectra were significantly different. The peak intensity of secondary structure of proteins in early ischemic myocardium was significantly higher than in other types of myocardium, and the peak intensity of the α-helix in necrotic myocardium was the lowest. The peaks of amide Ⅰ and amide Ⅱ in the mean normalized spectra of myocardial fibrous tissue significantly shifted towards higher wave numbers, the peak intensities of amide Ⅱ and amide Ⅲ were higher than those of other types of myocardium, and the peak intensities at 1 338, 1 284, 1 238 and 1 204 cm-1 in the mean second derivative spectra were significantly enhanced. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) showed that FTIR could distinguish different types of myocardium.

CONCLUSIONS

FTIR technique has the potential to diagnose acute and old myocardial infarction, and provides a new basis for the analysis of the causes of sudden cardiac death.

Silent Myocardial Infarction: A Case Report

Silent myocardial infarction (SMI) is a type of myocardial infarction (MI) that is asymptomatic or demonstrates mild symptoms; therefore, patients often do not seek medical treatment. SMI cases are often incidentally detected later by electrocardiogram (ECG). We present a case of a 59-year-old overweight woman with prediabetes, primary hypertension, and hypercholesterolemia who presented for herpes zoster (HZ) follow-up; she reported having skipped heartbeats and heart rate fluctuations during the review of systems. On further workup, ECG revealed low voltage QRS complexes, flat QRS complexes, flat T waves, and pathological Q waves, suggesting the diagnosis of SMI. Based on the identified risk factors, including high BMI, prediabetes, primary hypertension, hypercholesterolemia, HZ, and newly diagnosed SMI, the patient was advised to continue with lisinopril 20 mg daily, prescribed atorvastatin 80 mg daily, and was educated about maintaining a healthy diet, exercise, and receiving the shingles vaccination. To prevent the possible risks of poor outcomes such as those following MI, stroke, heart failure, arrhythmias, angina, and shortness of breath (SOB), the patient was referred to the cardiologist for a stress test and further treatment plan.

The detection of viable myocardium by low-dose dobutamine stress speckle tracking echocardiography in patients with old myocardial infarction

PURPOSE

To explore the significance and value of speckle-tracking echocardiography (STE) associated with low-dose dobutamine stress echocardiography (LDDSE) for the detection of viable myocardium (VM) in patients with old myocardial infarction (OMI).

METHODS

We performed STE with LDDSE in 33 hospitalized patients with OMI and left ventricular systolic dysfunction. QLAB software was used to analyze strain (S) and strain rate (Sr). Percutaneous coronary intervention (PCI) was subsequently performed. The movement of each wall segment was observed by routine echocardiography before and after 1, 3, and 6 months of PCI, and improvement was regarded as the gold standard for diagnosing VM.

RESULTS

Compared with semi-quantitative wall-motion analysis combined with LDDSE, the sensitivity, specificity, and accuracy of c-STE (combining the three directions of S and Sr) at LDDSE were 91.6%, 79.5%, and 87.5%, respectively (p < 0.02). Among the deformation parameters, longitudinal strain (LS) and longitudinal strain rate (LSr) had the highest sensitivity, specificity, and accuracy. Upon combining LS and LSr at LDDSE to parallel tests, the sensitivity, specificity, and accuracy were 91.7%, 90%, and 90.6%, respectively. Compared with baseline, LVEF after PCI increased from 43.3% ± 2.6% to 47.3% ± 2.9% (p < 0.001).

CONCLUSIONS

Global strain at LDDSE is superior to semi-quantitative wall-motion analysis with LDDSE for the assessment of VM. When the multivariable analysis and the parallel tests are combined, LS combined with LSr can be considered an independent predictor of VM. LVEF is improved after PCI in patients with VM and OMI. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:545-554, 2016.

Evaluation of myocardial viability in old myocardial infarcted patients with CHF: delayed enhancement MRI vs. low-dose dobutamine stress speckle tracking echocardiography

The aim of this study was to explore the significance of delayed enhancement magnetic resonance imaging (DE-MRI) combined with two-dimensional speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) to assess viable myocardium (VM) in the patients with old myocardial infarction (OMI) associated with congestive heart failure (CHF). Thirty five hospitalized OMI patients with regional wall motion abnormalities and left ventricular ejection fraction (LVEF) < 50% were recruited based on routine echocardiography. The results showed that DE-MRI facilitated the detection of VM, with a sensitivity, specificity and accuracy of 92.41%, 89.19% and 91.32%, respectively. In a parallel test of the two main parameters in STE, the sensitivity, specificity, and accuracy were improved from baseline to LDDSE (71.72% vs. 91.72%, 70.27% vs. 85.14%, and 71.23% vs. 89.50%, P < 0.05). A parallel test involving STE with LDDSE showed high sensitivity for VM. However its specificity and accuracy were lower than DE-MRI, even when combined with LDDSE. Therefore, combining these two methods, improves the sensitivity, specificity and accuracy for assessment of VM. The combination approach is the best option for the evaluation of VM using serial test. It provides further treatment options and prognosis of patients with OMI. LVEF is improved significantly after PCI in OMI patients with VM and CHF.

Long-term prognostic impact of dobutamine stress echocardiography in patients with Kawasaki disease and coronary artery lesions: a 15-year follow-up study

OBJECTIVES

This study sought to determine the prognostic value of dobutamine stress echocardiography (DSE) over a 15-year follow-up for predicting cardiac events in adolescent Kawasaki disease (KD) patients with coronary artery lesions (CALs).

BACKGROUND

Although DSE is an established technique for the detection of coronary artery disease, its prognostic value to predict cardiac events in adolescent KD patients with CALs is unknown.

METHODS

Fifty-eight adolescent KD patients, including 36 patients with CALs documented by coronary angiography, and 22 patients with normal coronary arteries documented by echocardiography who underwent DSE were reviewed at initial testing (mean age: 13.6 years) and at 15 years' follow-up. Follow-up events were tabulated as major adverse cardiac events (MACEs) that included cardiac death, nonfatal myocardial infarction, and revascularization.

RESULTS

During a mean follow-up of 14.7 years, there were 16 patients with MACEs (acute myocardial infarction: n = 1; old myocardial infarction: n = 7; coronary artery bypass grafting: n = 4; percutaneous coronary intervention: n = 4). Significant coronary artery disease (CAD) (>70% coronary stenosis) was detected in 31.0% of patients at initial testing and 42.1% at follow-up. However, there were no significant differences in wall motion score indices (WMSI) at peak DSE between initial testing and follow-up (p = 0.762). Five of 6 patients (85%) with false-positive DSE results (WMSI: ≥1.25) at initial testing, who had giant aneurysms without CAD, developed CAD with MACEs during follow-up. Cumulative event-free survival rate to 15 years was 25.0% in patients with WMSI ≥1.25 and 91.7% in patients with WMSI <1.25. Cox regression analysis showed the grade of peak WMSI at initial testing to be the only independent predictor of MACEs (relative risk: 3.28; 95% confidence interval: 1.73 to 6.20).

CONCLUSIONS

DSE provided independent prognostic information up to 15 years in adolescent KD survivors.

Value of the frontal planar QRS-T angle on cardiac dysfunction in patients with old myocardial infarction

OBJECTIVES

To explore a method of surface electrocardiogram for assessing cardiac dysfunction in patients with old myocardial infarction.

METHODS

1000 patients with old myocardial infarction in Anzhen hospital were analyzed retrospectively. The planar QRS-T angle was calculated automatically according to QRS-wave and T-wave vectors by the electrocardiogram machine.

RESULTS

Among these 1000 patients, 822 (82.2%) were male and 178 (17.8%) were female, the mean age was 59.3±10.5 years (34~89 years). The average planar QRS-T angle was 88.5±50.6°. The planar QRS-T angle and LVEF was negative correlation (r=-0.406, p<0.01), the lower the LVEF, the better the relationship with planar QRS-T angle. QRS-T angle>90° had optimal sensitivity and specificity (76%, 74%) in diagnosis of cardiac dysfunction.

CONCLUSION

The planar QRS-T angle and LVEF of patients with old myocardial infarction is negative correlation, the larger the planar QRS-T angle, the lower the LVEF. The planar QRS-T angle may be an easier and more feasible index for assessing cardiac dysfunction in patients with old myocardial infarction.

Magnetic resonance imaging of old myocardial infarction in young patients with a history of Kawasaki disease

BACKGROUND

On magnetic resonance imaging (MRI) using gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) as contrast medium, images of infarct regions are enhanced in acute myocardial infarction (AMI). In old myocardial infarction (OMI), thinning of the myocardial walls is present, but images are no longer enhanced by Gd-DTPA. On the other hand, MI in children with a history of Kawasaki disease (KD), several differences from adult MI are observed.

HYPOTHESIS

The aim of this study was to evaluate the lesions that result from OMI in children with a history of KD using MRI with Gd-DTPA as a contrast medium.

METHODS

The subjects were 16 young patients with a history of KD who were diagnosed as having OMI. Of these, both thinning of the myocardial wall and MRI enhancement by Gd-DTPA were observed in 4 cases, thinning alone was observed in 6 cases, Gd-DTPA image enhancement alone was observed in 3 cases, and neither thinning nor Gd-DTPA image enhancement was observed in 3 cases.

RESULTS

The Gd-DTPA-image-enhanced, OMI-induced lesions observed in patients with KD were different from those observed in adults; this might be attributable to histologic differences.

CONCLUSION

Magnetic resonance imaging using Gd-DTPA can evaluate myocardial thinning and presence of circulation noninvasively at the same time and is considered to be useful for long-term follow up of the patients with KD and OMI.