EVALUATION OF THE ROLE OF 3 TESLA MRI AND ECHOCARDIOGRAPHY IN ASSESSING FUNCTIONAL LEFT VENTRICULAR PARAMETERS IN PATIENTS WITH CHRONIC ISCHEMIC CARDIOMYOPATHY

Background Multiple imaging modalities are available to assess dysfunctional yet viable myocardium; these include Echocardiography, Single Photon Emission Computed Tomography (SPECT) Imaging, Positron Emission Tomography (PET) and Cardiac Magnetic Resonance Imaging (CMRI). The aim of this study is to evaluate the role of 3T CMRI and Echocardiography in the evaluation of patients with Ischemic Cardiomyopathy for left ventricular function at both regional and global levels including the calculation of ejection fraction and segmental wall motion abnormalities based on the 17-segment model of the American Heart Association (AHA). Material and Methods This was a Hospital Based Cross Sectional Observational Study, conducted in Department of Cardiology and Department of Radiology, Advanced Cardiac Institute, PT J N M Medical College and Dr. B R A M Hospital between July 2017 to September 2018 in 24 patients with known Ischemic Cardiomyopathy, assessed by Echocardiography and 3T CMRI for Left Ventricular Functions. Results The study showed that the mean LVEF by CMRI was 34.08% and the mean LVEF by Echocardiography was 33.27% with a mean difference of 2.89%, standard deviation of bias was of 0.856 and 95% limits of agreement were 1.212-4.568. A poor to fair level of agreement was noted using Cohen’s Kappa (r) is 0.375, Standard Error (SE) of r is 0.035, P value of < 0.0005. The results showed that CMRI had a sensitivity of 94.7%, specificity of 44.1%, Positive Predictive value (PPV) of 65.5% and Negative Predictive value (NPV) of 88.2%. The Echocardiography had a sensitivity of 80%, specificity of 32.4%, with a PPV of 52.8% and a NPV of 63.2%. CMRI has an Excellent Negative Predictive Value of 88.2% which means that 88.2% of the Vascular Territories without SWMA on CMRI did not have a scar. Conclusions CMRI and Echocardiography are comparable for assessing Global Left Ventricular functions. There is only a fair degree of agreement between CMRI and Echocardiography for analysis of segmental wall motion abnormalities. CMRI may be more accurate in ruling out a scarred myocardium as compared to Echocardiography, owing to High Negative Predictive value.

The Hybrid POCUS-to-Echo Feasibility Study: Provision of Expedited Cardiac Point of Care Ultrasound Service (e-POCUS) by the Echocardiography Lab

Background: Comprehensive transthoracic echocardiography (CTE) provides information vital to the care of acutely ill and unstable patients, but may not be readily available. Cardiac point of care ultrasound (POCUS) is well suited to providing key information at the bedside to expedite decision making. Our objective was to evaluate the feasibility of expedited-POCUS (e-POCUS) provided by the echo lab for internal medicine, cardiology and intensive care services. Methods: A new e-POCUS service was developed by the Kingston Health Sciences Center Echo Lab, whereby focused information relevant to 4 clinical situations (acute heart failure, tamponade, shock and suspected acute valvulopathy) would be provided urgently at the bedside. Requests were acquired over a 4 month period. Sonographers were immediately deployed on request and followed a standard POCUS protocol for each scenario. Staff echocardiographers provided immediate interpretation and arranged for further imaging at their discretion. The response time, diagnostic accuracy and clinical utility of e-POCUS was assessed. Results: A total of 18 patients were evaluated. The average time of an e-POCUS exam was 10 minutes and the average e-POCUS to formal CTE timing was 1.3 days. The agreement between e-POCUS and CTE for the presence of segmental wall motion abnormalities was 83% (Kappa=0.61, p=0.009) and 72% for the detection of right ventricular dilatation (Kappa =0.44, p=0.058). The e-POCUS results altered the working diagnosis in 72% of cases. Conclusion: The provision of an e-POCUS service by the Echo Lab is a feasible workflow solution meeting the demands of a new practice pattern.

P4349Simple and rapid estimation of left ventricular longitudinal deformation by tissue-tracking mitral annular displacement in single apical view

Background Noninvasive assessment of left ventricular (LV) deformation using global longitudinal strain (GLS) has prognostic value in patients with and without preserved ejection fraction (EF). Application of speckle-tracking technology to the mitral annulus provides rapid and easy assessment of displacement of septal and lateral mitral annulus and mid-point of mitral annular line in single apical view (TMAD) even in poor echo-image quality. TMAD may be used as a simple index of LV longitudinal deformation in patients with and without preserved EF (Figure). Purpose The purpose of this study was to examine whether TMAD can be used as a simple index of LV longitudinal deformation in patients with and without preserved EF. Methods The study population consists of 95 patients without segmental wall motion abnormality, significant valvular diseases, and atrial fibrillation in whom both TMAD and GLS measurements were applied by QLAB software (Philips). We estimated GLS from apical 4- and 2-chamber views and apical longitudinal views, and TMAD from apical 4-chamber view. TMAD was automatically and quickly evaluated as the base-to-apex displacement of septal (TMADsep), lateral (TMADlat), and mid-point of annular line (TMADmid) (Figure). The percentage of M-TMAD to LV length from the mid-point of mitral annuls to the apex at end-diastole (%TMADmid) was also calculated. We compared each TMAD values with GLS values by linear regression analysis, and evluated TMAD values by a receiver operating characteristic (ROC) analysis to detect impaired LV longitudinal deformation (|GLS|<12.0%). Results TMAD was successfully assessed in 94 of 95 patients (99%) while GLS was measured in 84 of 95 patients (87%, p=0.0082 vs TMAD). There were good correlations between each TMAD index and |GLS| (TMADsep:r=0.77, TMADlat:r=0.81, TMADmid:r=0.82, %TMADmid:r=0.87). According to ROC curve, the best cut-off values for TMADsep, TMADlat, TMADmid, and %TMADmid in determining LV longitudinal deformation were 6.8mm, 8.0mm, 7.8mm, and 9.5% respectively (Table). Conclusions The present results suggest that rapid and easy assessment of TMAD in single apical view may be used as a simple index of LV longitudinal deformation.

Left ventricular systolic function

Chapter 6 is subdivided into three sections: global LV systolic function, regional LV systolic function, and cardiomyopathies. In Section 1, commonly used indices of global systolic function, such as fractional area change and ejection fraction, are reviewed, along with their limitations related to oesophageal imaging. The relationship between stroke volume and ejection fraction is explored. Newer techniques such as quantitative 3D imaging and strain-rate imaging are described. In Section 2, the causes of regional systolic dysfunction are reviewed, along with the different aetiologies of real and apparent segmental wall motion abnormalities. Complications of myocardial infarction such as mitral regurgitation, true and false LV aneurysms, and ventricular septal rupture are also dealt with in this section. Section 3 provides an overview of the echocardiographic findings associated with various cardiomyopathies: dilated, hypertrophic, restrictive, acute myocarditis, LV non-compaction, and Takotsubo.

Ventricular Fibrillation-Induced Cardiac Arrest Results in Regional Cardiac Injury Preferentially in Left Anterior Descending Coronary Artery Territory in Piglet Model

Objective. Decreased cardiac function after resuscitation from cardiac arrest (CA) results from global ischemia of the myocardium. In the evolution of postarrest myocardial dysfunction, preferential involvement of any coronary arterial territory is not known. We hypothesized that there is no preferential involvement of any coronary artery during electrical induced ventricular fibrillation (VF) in piglet model. Design. Prospective, randomized controlled study. Methods. 12 piglets were randomized to baseline and electrical induced VF. After 5 min, the animals were resuscitated according to AHA PALS guidelines. After return of spontaneous circulation (ROSC), animals were observed for an additional 4 hours prior to cardiac MRI. Data (mean ± SD) was analyzed using unpaired t-test; p value ≤ 0.05 was considered statistically significant. Results. Segmental wall motion (mm; baseline versus postarrest group) in segment 7 (left anterior descending (LAD)) was 4.68±0.54 versus 3.31±0.64, p=0.0026. In segment 13, it was 3.82±0.96 versus 2.58±0.82, p=0.02. In segment 14, it was 2.42±0.44 versus 1.29±0.99, p=0.028. Conclusion. Postarrest myocardial dysfunction resulted in segmental wall motion defects in the LAD territory. There were no perfusion defects in the involved segments.