Associations of Infarct Size and Regional Myocardial Function Examined by Cardiac Magnetic Resonance Feature Tracking Strain Analysis with the Infarct Location in Patients with Acute ST-Segment Elevation Myocardial Infarction

Objective To quantitatively evaluate the associations of infarct size,regional myocardial function examined by cardiac magnetic resonance feature tracking(CMR-FT)strain analysis with infarct location in patients with ST-segment elevation myocardial infarction(STEMI)treated by primary percutaneous coronary intervention.Methods Cardiac magnetic resonance images were retrospectively analyzed in 95 consecutive STEMI patients with successful reperfusion.The patients were divided into the anterior wall myocardial infarction(AWMI)and nonanterior wall myocardial infarction(NAWMI)groups.Infarct characteristics were assessed by late gadolinium enhancement.Global and regional strains and associated strain rates in the radial,circumferential and longitudinal directions were assessed by CMR-FT based on standard cine images.The associations of infarct size,regional myocardial function examined by CMR-FT strain analysis with infarct location in STEMI patients were evaluated by the Spearman or Pearsonmethod.Results There were 44 patients in the AWMI group and 51 in the NAWMI group.The extent of left ventricular enhanced mass was significantly larger in patients with AWMI compared with the NAWMI group(24.47±11.89,21.06±12.08%LV;t=3.928,P=0.008).In infarct zone analysis,strains in the radial,circumferential and longitudinal directions were remarkably declined in the AWMI group compared with the NAWMI group(z=-20.873,-20.918,-10.357,all P<0.001).The volume(end-systolic volume index),total enhanced mass and extent of enhanced mass of the left ventricular were correlated best with infarct zone strain in the AWMI group(all P<0.001).Conclusion In STEMI patients treated by percutaneous coronary intervention,myocardial damage is more extensive and regional myocardial function in the infarct zone is lower in the AWMI group compared with the NAWMI group.

Evaluation of Sub Clinical Myocardial Systolic Dysfunction Using 2D Global Longitudinal Strain Assessment in Type 2 Diabetes Patients in Sub-Saharan Africa

Background: Heart failure is the commonest cardiovascular complication in type 2 diabetes mellitus. However, subclinical left ventricular dysfunction can’t be detected using 2D echocardiography which is routinely used for cardiac evaluation of diabetic patients. We aimed to determine the prevalence and factors associated to left ventricular global longitudinal strain (LV GLS) impairment in type 2 diabetes Cameroonians patients. Methods: We conducted a cross-sectional study from January 2019 to June 2019, including type 2 diabetes patients with preserved left ventricle ejection fraction. Clinical and echocardiographic data were collected, and LV GLS was assessed using speckle tracking technique, a value ≤ -16% been considered as normal value. Results: We recruited 95 patients, with a mean age of 57.4 ± 11.8 years old and median diabetes duration of 5 [2 - 12] years. Echocardiographic evaluation found 56.3% of left ventricle remodelling, 51.6% of left ventricle diastolic dysfunction and mean left ventricle ejection of 63.3% ± 6.6%. LV GLS impairment was present in 43.2% (95% CI: 32.6 - 53.7) of the participants. After adjustment to all significantly associated factors, Obesity (aOR: 4;95% CI: 1.5 - 10.6) and diastolic dysfunction (aOR: 3.1;95% CI: 1.2 - 8.2) were independent factors associated with LV GLS. Conclusions: Subclinical systolic dysfunction assessed by LV GLS impairment is frequent in diabetic patients. Further research should be carried out more extensively to integrate LV GLS in the type 2 diabetes patients’ routine follow up for a better prognostic outcome, especially in low-incomes countries.

Feature-Tracking Strain Derived from Compressed Sensing Cine Cardiovascular Magnetic Resonance Imaging for Myocardial Infarct Detection: A Feasibility Study

Purpose: This study aimed to use gadolinium-enhanced cardiovascular magnetic resonance (LGE-CMR) scanning to examine the clinical feasibility of feature-tracking strain (FT-strain) analysis on compressed sensing (CS) cine cardiovascular magnetic resonance (CMR) imaging for detecting myocardial infarction (MI). Methods: We enrolled 37 patients who underwent conventional cine CMR, CS cine CMR, and LGE-CMR scanning to assess cardiovascular disease. FT-strain analysis was used to assess peak circumferential strain (p-CS) based on an 18-segment model in both cine CMR imaging modalities. Based on LGE-CMR imaging findings, myocardial segments were classified as remote, adjacent, subendocardial infarcted, and transmural infarcted. The diagnostic performance of p-CS for detecting MI was compared between CS cine CMR imaging and conventional cine CMR imaging using the receiver operating characteristic (ROC) curve analysis. Results: A total of 440 remote, 85 adjacent, 76 subendocardial infarcted, and 65 transmural infarcted segments were diagnosed on LGE-CMR imaging. There were significant between-group differences in p-CS on both conventional and CS cine CMR (p < 0.05 in each) imaging. The sensitivity and specificity of p-CS for identifying MI were 85% and 79% for conventional cine CMR imaging, and 82% and 77% for CS cine CMR imaging, respectively. There was no significant difference between conventional and CS cine CMR imaging in the area under the curve of p-CS (0.89 vs. 0.87, p = 0.15). Conclusion: FT-strain analysis of CS cine CMR imaging may help identify MI;it may be used alongside or instead of conventional CMR imaging.

Relationship of Microvascular Obstruction with Global and Regional Myocardial Function Determined by Cardiac Magnetic Resonance after ST-Segment Elevation Myocardial Infarction

Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(STEMI)patients after percutaneous coronary intervention.Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1-7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study.Based on the presence or absence of MVO on late gadolinium enhancement images,patients were divided into groups with MVO and without MVO.The infarct zone,adjacent zone,and remote zone were determined based on a myocardial 16-segment model.The radial strain(RS),circumferential strain(CS),and longitudinal strain(LS)of the global left ventricle(LV)and the infarct,adjacent,and remote zones were measured by CMRFT from cine images and compared between patients with and without MVO using independent-samples t-test.Logistic regression analysis was used to assess the association of MVO with the impaired LV function.Results A total of 157 STEMI patients(mean age 56.66±11.38 years)were enrolled.MVO was detected in 37.58%(59/157)of STEMI patients,and the mean size of MVO was 3.00±3.76 mL.Compared with patients without MVO(n=98),the MVO group had significantly reduced LV global RS(t=-4.30,P<0.001),global CS(t=4.99,P<0.001),and global LS(t=3.51,P=0.001).The RS and CS of the infarct zone in patients with MVO were significantly reduced(t=-3.38,P=0.001;t=2.64,P=0.01;respectively)and the infarct size was significantly larger(t=8.37,P<0.001)than that of patients without MVO.The presence of LV MVO[OR=4.10,95%CI:2.05-8.19,P<0.001]and its size[OR=1.38,95%CI:1.10-1.72,P=0.01],along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis,while only heart rate(OR=1.08,95%CI:1.03-1.13,P=0.001)and LV infarct size(OR=1.10,95%CI:1.03-1.16,P=0.003)were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.Conclusion The infarct size was larger in STEMI patients with MVO,and MVO deteriorates the global and regional LV myocardial function.

Scimitar Syndrome:Role of Right Atrial Longitudinal Strain.A Case Report

We describe a case of a rare congenital heart disorder,scimitar syndrome,diagnosed in an adult woman presenting with dyspnea on exertion,chest pain and recurrent episodes of pulmonary infections.The hallmark of the syndrome is the presence of an enlarged anomalous pulmonary vein draining into the inferior vena cava.Speckle tracking echocardiography,including the often-forgotten atrial strain evaluation,is a sensitive parameter that should be routinely used for a better clinical and prognostic evaluation of patients with congenital heart disease(CHD).

Tangential stress analysis of myocardial wall by finite element method

A novel method is presented to build the triangular surface model and calculate the tangential stress and strain of myocardial wall ,which can be further used to reflect the left ventricle twisting—a sensitive index to assess the systolic and diastolic function of heart. Firstly, a point distribution model is used to obtain the feature points of the ventricular surface in medical images. Secondly, the surface model is constructed by triangular mesh, and then the subdivision strategy is introduced to refine the model. Thirdly, plane projection and finite element method(FEM) are applied to calculate the tangential stress and strain.Finally, the distribution of tangential modulus of elasticity is discussed. The stimulation results show that the proposed method can be used to compute the tangential stress and strain of myocardial wall effectively and the computing result is consistent with the results mentioned in the literatures.

Hypertrophic cardiomyopathy secondary to deficiency in lysosomeassociated membrane protein-2: A case report

BACKGROUND Danon disease(DD),in which mutations in the X-linked lysosome-associated membrane protein-2(LAMP-2)gene result in hypertrophic cardiomyopathy,is a rare disease,reported primarily in small samples or cases.However,with the development of cardiac magnetic resonance imaging and genetic technology in recent years,the number of reports has increased.CASE SUMMARY We report a case of DD in an adolescent male patient,confirmed by genetic testing.The patient was admitted to our hospital with complaints of a three-year history of chest tightness and shortness of breath.His preliminary clinical diagnosis is hypertrophic cardiomyopathy.Our report includes the patient’s clinical course from hospital admission to death,step-by-step diagnosis,treatment course,and noninvasive imaging features.We highlight how a noninvasive diagnostic approach,based solely on clinical and imaging“red flags”for DD,can be used to achieve a diagnosis of DD with a high degree of confidence.CONCLUSION DD is a very dangerous cardiomyopathy,and it is necessary to achieve early diagnosis and treatment.

Optimal patching locations and orientations for maximum energy harvesting efficiency of ultrathin flexible piezoelectric devices mounted on heart surface

Flexible piezoelectric energy harvesters(PEHs)have gained lots of attention in recent years,because of their potential biomechanical applications,such as powering implantable devices.Several in vivo animal experiments have demonstrated that the output power of a flexible PEH varies remarkably with patching orientations and locations,but the underlying mechanism remains unclear yet.Herein,an electromechanical model for a flexible PEH installed on a beating heart is proposed,and a concise relationship between the output power of the device and myocardium strain is established.The results demonstrate that the patching orientations have a significant impact on the output power of the PEH,and the optimal patching orientations for all patching locations are approximately 15–20 degree for PEHs mounted on the left ventricle.The simple theoretical method provided here would be universally effective for choosing the optimal patching locations and orientations of flexible PEHs installed on a nonhomogeneous deformed surface.

Comprehensive Left Ventricular Mechanics Analysis by Speckle Tracking Echocardiography in COVID-19

Background: Cardiac involvement and the consequences of inflammation induced by SARS-CoV2 infection could have catastrophic long-term consequences. Left ventricular mechanics could identify a specific pattern of myocardial fiber damage in patients infected with COVID-19. To our knowledge there are no publications referring to the global description of ventricular mechanics in patients with COVID-19. Objective: To describe left ventricular mechanics in hospitalized patients with COVID-19. Methods: In this cross-sectional study, we included 40 hospitalized patients with confirmed diagnostic of COVID-19, from April 11, 2020, to September 6, 2020. Demographic and laboratory data, clinical and echocardiographic characteristics were collected, as well as events during hospitalization. Left ventricular deformation was analyzed and reported. Results: Subclinical dysfunction was observed in 82.5% (left ventricular longitudinal strain [LVGLS] -17.05% and global circumferential strain [GCS] -18.6%) of the patients, likewise, the mean twist and apical rotation were preserved, and even increased as part of the compensating mechanism to maintain the ejection fraction. Conclusion: In patients hospitalized with COVID-19, despite having a normal left ventricular ejection fraction, subclinical myocardial damage was found, manifested by a decrease in Global Longitudinal Strain (GLS) and Global Circumferential Strain (GCS). This behavior is similar to that of cardiomyopathies in the early stage of the disease, and given the pathophysiological mechanisms involved in the disease, its long-term consequences should be monitored and evaluated.