Kent Emilsson

Multidisciplinary assessment of tako tsubo cardiomyopathy: a prospective case study

BackgroundThe cause of tako tsubo cardiomyopathy remains unclear. We used a multidisciplinary approach to investigate if a common pathophysiological denominator could be outlined.MethodsWithin 3 days following symptom presentation and again after 3 months we investigated all patients coming to our institution and diagnosed with tako-tsubo cardiomyopathy. Patients underwent extensive biochemical screening. Left ventricular function was evaluated by echocardiography and contrast-enhanced cardiac magnetic resonance imaging. Cardiac autonomic function was studied by heart rate variability and signal-averaged electrocardiogram and posttraumatic stress and depression were investigated by questionnaires (the Posttraumatic Stress Syndrome 10-Questions Inventory, PTSS-10 and the Montgomery-Åsberg depression rating scale, self rated version, MADRS-S).ResultsDuring 2 years, 13 consecutive patients were included. Markers of myocardial damage and heart failure were slightly to moderately elevated and ejection fraction (echocardiography and MRi) was moderately reduced at hospitalization and improved to normal values in all patients. Signal averaged ECG demonstrated a statistically significant shorter duration of the filtered QRS complex in the acute phase as compared to follow-up. In heart rate variability analysis, SDNN and SDANN were shorter acutely compared to follow-up. Two patients fulfilled criteria for posttraumatic stress syndrome while 7 patients were in the borderline zone. There was a statistically significant inverse correlation between PTSS-10 score and QRS duration in the signal-averaged ECG (r = -0.66, P = 0.01).ConclusionsPatients with tako tsubo cardiomyopathy have altered cardiac autonomic function and a high incidence rate of borderline or definite posttraumatic stress syndrome acutely. This is in line with findings in patients with myocardial infarction and does not allow conclusions on cause and effect.

Right ventricular long-axis function in relation to left ventricular systolic function

A decrease in left ventricular (LV) systolic function is accompanied by a decrease in maximal relaxation velocity in LV long‐axis direction, but is it also accompanied by a decrease in right ventricular (RV) long‐axis function? To study this 35 consecutive patients were examined by echocardiography. Ejection fraction (LVEF) and mitral annulus motion (MAM) were used as indices of LV systolic function and tricuspid annulus motion (TAM), that is the systolic shortening in RV long‐axis direction, was used as an index of RV systolic long‐axis function. In the same way the maximal relaxation velocity in LV long‐axis direction, that is the maximal diastolic velocity of MAM (MDV MAM), has been suggested as an index of LV diastolic function the maximal diastolic velocity of TAM (MDV TAM) can be supposed to be an index of RV diastolic function measuring the maximal relaxation velocity in the RV long‐axis direction. A significant positive correlation was found between MDV TAM and MAM (r = 0·64, P<0001) and LVEF (r = 0·54, P = 0·001) and between TAM and the two studied indices of LV systolic function, with the highest correlation to MAM (r = 0·68, P<0·001) and the lowest to LVEF (r = 0·57, P<0·001). Thus, a decrease in LV systolic function is accompanied by a decrease in both systolic and diastolic RV long‐axis function, findings that probably are due to the close anatomical connection between the ventricles and to changes that occur in afterload of the RV secondary to LV systolic dysfunction.

Fast GPU Based Adaptive Filtering of 4D Echocardiography

Time resolved three-dimensional (3D) echocardiography generates four-dimensional (3D+time) data sets that bring new possibilities in clinical practice. Image quality of four-dimensional (4D) echocardiography is however regarded as poorer compared to conventional echocardiography where time-resolved 2D imaging is used. Advanced image processing filtering methods can be used to achieve image improvements but to the cost of heavy data processing. The recent development of graphics processing unit (GPUs) enables highly parallel general purpose computations, that considerably reduces the computational time of advanced image filtering methods. In this study multidimensional adaptive filtering of 4D echocardiography was performed using GPUs. Filtering was done using multiple kernels implemented in OpenCL (open computing language) working on multiple subsets of the data. Our results show a substantial speed increase of up to 74 times, resulting in a total filtering time less than 30 s on a common desktop. This implies that advanced adaptive image processing can be accomplished in conjunction with a clinical examination. Since the presented GPU processor method scales linearly with the number of processing elements, we expect it to continue scaling with the expected future increases in number of processing elements. This should be contrasted with the increases in data set sizes in the near future following the further improvements in ultrasound probes and measuring devices. It is concluded that GPUs facilitate the use of demanding adaptive image filtering techniques that in turn enhance 4D echocardiographic data sets. The presented general methodology of implementing parallelism using GPUs is also applicable for other medical modalities that generate multidimensional data.

Comparison between circumflex artery motion and mitral annulus motion.

Objective - To compare mitral annulus motion (MAM) with circumflex artery motion (CXM) and the motion amplitude at an endocardial site (representing MAM) with an epicardial site (representing CXM) at the most basal lateral part of the atrioventricular plane (AVP). Design - MAM and CXM were obtained in 28 patients examined by echocardiography and coronary angiography. The motion amplitude epicardially and endocardially was recorded by echocardiography in 13 patients with normal ejection fraction (EF) ( S 0.50) and in 13 patients with decreased EF (< 0.50). Results - CXM was higher than MAM in most patients with normal EF but lower than MAM in most patients with decreased EF. The motion amplitude epicardially was significantly higher ( p < 0.001) than endocardially in patients with normal EF, while there was no significant difference in patients with decreased EF. Conclusion - CXM represents the motion of the epicardial part of the AVP and differs from MAM, which represents the endocardial part of the wall. This must be considered when CXM is used for assessment of left ventricular systolic function.OBJECTIVE To compare mitral annulus motion (MAM) with circumflex artery motion (CXM) and the motion amplitude at an endocardial site (representing MAM) with an epicardial site (representing CXM) at the most basal lateral part of the atrioventricular plane (AVP). DESIGN MAM and CXM were obtained in 28 patients examined by echocardiography and coronary angiography. The motion amplitude epicardially and endocardially was recorded by echocardiography in 13 patients with normal ejection fraction (EF) (> or = 0.50) and in 13 patients with decreased EF (<0.50). RESULTS CXM was higher than MAM in most patients with normal EF but lower than MAM in most patients with decreased EF. The motion amplitude epicardially was significantly higher (p < 0.001) than endocardially in patients with normal EF. while there was no significant difference in patients with decreased EF. CONCLUSION CXM represents the motion of the epicardial part of the AVP and differs from MAM, which represents the endocardial part of the wall. This must be considered when CXM is used for assessment of left ventricular systolic function.

Separating the left cardiac ventricle from the atrium in short axis MR images using the equation of the atrioventricular plane

Short axis (SA) images obtained from cardiac magnetic resonance imaging are used to advantage in the calculation of important clinical parameters such as the ejection fraction and stroke volume (SV). A prerequisite for these calculations is the separation of the left ventricle and the left atrium. When only using the information seen in the SA images this separation can be a source of error due to the through‐plane motion of the basal part of the left ventricle.

Left and right ventricular systolic long-axis function and diastolic function in patients with takotsubo cardiomyopathy

Aims:  Takotsubo cardiomyopathy is characterized by apical wall motion abnormalities without coronary stenosis. Limited information is available on the genesis of the underlying reversible contractile disorder. Our objective in this prospective study was to investigate biventricular changes in systolic long‐axis function and diastolic parameters in the acute phase and after recovery.

Isovolumetric relaxation time of the right ventricle assessed by tissue Doppler imaging

Objectives—The isovolumetric relaxation time of the right ventricle (RV‐IVRT) can be assessed using a method based on ECG and pulsed wave Doppler (PW). Recently pulsed wave Doppler tissue imaging (PW‐DTI) has been introduced in the assessment. Design—RV‐IVRT obtained by the two methods was compared in 20 consecutive patients as was the time from the R wave on the ECG to the onset of tricuspid flow (R‐T), to the closure of the pulmonic valve (R‐P), to the onset of early diastolic motion of the tricuspid annulus tissue (R‐E) and to the end of the systolic motion (R‐S). Results—RV‐IVRT obtained by the PW method was significantly (p < 0.001) shorter than RV‐IVRT obtained by PW‐DTI. R‐S had significantly (p < 0.001) shorter duration than R‐P, while there was no significant difference between R‐E and R‐T. Conclusions—The methods are not measuring the same interval. Only the PW method measures RV‐IVRT according to the usual definition. Different reference values have to be used if the methods are used in the assessment of RV diastolic function.

Outer contour and radial changes of the cardiac left ventricle : A magnetic resonance imaging study

Earlier studies have shown a ±5% end-systolic decrease in the volume encompassed by the pericardial sack, manifesting as a radial diminution of the pericardial/epicardial contour of the left ventricle (LV).The aim of this study was to measure this radial displacement at different segmental levels of the LV and try to find out were it is as greatest and to calculate regional myocardial volume changes as a reference in healthy subjects.Eleven healthy subjects were examined by magnetic resonance imaging. Images were acquired using an ECG-triggered balanced fast field echo pulse sequence. The epicardial borders of the LV wall were delineated in end-diastole (ED) and end-systole (ES). Regional changes of the LV wall were analysed at three different levels (base, mid and apex) by dividing the myocardium into segments.The volumes obtained as the differences between the outer volume of the left ventricle at ED and ES at different slice levels were found to be greatest at the base of the heart and lowest at apex. The relative inward motion, that is the motion in short-axis direction of the epicardial border of the myocardium from ED to ES towards the centre of the LV, was greatest at the base and lowest at the mid level, something that has to be taken into account when measuring the LV during clinical exams. There was a significant difference in the relative inward motion between the segments at apex (p < 0.0001), mid (p = 0.036) and at base level (p < 0.0001).

Comparison between aortic annulus motion and mitral annulus motion obtained using echocardiography.

Earlier studies have shown that the aortic root, in analogy with the mitral annulus, moves towards the left ventricular apex during systole. However, there are no earlier studies comparing the amplitude of the aortic annulus motion (AAM) with that of the mitral annulus (MAM), which was the main aim of the study. Another aim was to study the intra‐ and interobserver reproducibility (IIOR) of measuring AAM with M‐mode and 2‐D echocardiography as it is not obvious which of the methods that should be used. Twenty‐one healthy subjects were examined by echocardiography. AAM and MAM were measured at different sites. IIOR was measured in 10 of the subjects. There was no significant difference between average AAM (15·3 ± 1·5 mm) and average MAM (15·6 ± 1·5 mm) and there was a rather good agreement between the variables. There was also no significant difference between AAM at the septal site (16·3 ± 2 mm) and average MAM, but a significant difference between AAM at the lateral site (14·2 ± 1·6 mm) and average MAM (P<0·001) and between the both sites of measuring AAM (P<0·001). The significant difference between the two sites of measuring AAM may have anatomical reasons but may also depend on difficulties in measuring AAM at the septal site where it has lower reproducibility than at the lateral site. IIOR of measuring AAM was good when using M‐mode but poor when using 2‐D echocardiography and AAM should preferably be measured using M‐mode and not using 2‐D echocardiography.

Flow and peak velocity measurements in patients with aortic valve stenosis using phase contrast MR accelerated with k-t BLAST

OBJECTIVE To investigate the accuracy of velocity measurements in patients with aortic valve stenosis using phase contrast (PC) imaging accelerated with SENSE (Sensitivity Encoding) and k-t BLAST (Broad-use Linear Acquisition Speed-up Technique). METHODS Accelerated quantitative breath hold PC measurements, using SENSE and k-t BLAST, were performed in twelve patients whose aortic valve stenosis had been initially diagnosed using echocardiography. Stroke volume (SV) and peak velocity measurements were performed on each subject in three adjacent slices using both accelerating methods. RESULTS The peak velocities measured with PC MRI using SENSE were -8.0±9.5% lower (p<0.01) compared to the peak velocities measured with k-t BLAST and the correlation was r=0.83. The stroke volumes when using SENSE were slightly higher 0.4±17.1 ml compared to the SV obtained using k-t BLAST but the difference was not significant (p>0.05). CONCLUSIONS In this study higher peak velocities were measured in patients with aortic stenosis when combining k-t BLAST with PC MRI compared to PC MRI using SENSE. A probable explanation of this difference is the higher temporal resolution achieved in the k-t BLAST measurement. There was, however, no significant difference between calculated SV based on PC MRI using SENSE and k-t BLAST, respectively.