Anders Kähäri

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.

Coaxial technique for catheterization of the coronary arteries with a very dilated ascending aorta

This article describes a simple yet effective method to catheterize the coronary arteries when the ascending aorta is very dilated. Two catheters are used in a coaxial fashion. It was possible to catheterize a patient with a 9 cm wide ascending aorta. Catheter Cardiovasc Interv 2004;62:32–34.

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.

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).

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.

Estimation of Ejection Fraction and Stroke Volume Using Single- and Biplane Magnetic Resonance Imaging of the Left Cardiac Ventricle

Background: In cardiac magnetic resonance imaging (MRI), left ventricular stroke volume (SV) and ejection fractions (EF) are occasionally calculated using single-plane and biplane ellipsoid models. In previous studies, the calculated SV and EF using single- and biplane ellipsoid models have been compared to reference values calculated from short-axis (SA) images. In these studies, however, it has been emphasized that through-plane motion of the basal SA images represents an important source of error, which may result in incorrect reference values. Purpose: To compare the calculated SV and EF using single-plane and biplane ellipsoid models with SV and EF calculated from SA images in which compensation was made for through-plane motion. Material and Methods: A group of 20 patients who underwent MRI examination were included in the study. SV and EF were calculated using the stack of SA images (which had been compensated for through-plane motion) and compared to the SV and EF calculated according to the single- and biplane ellipsoid models. Results: The mean difference between the single-plane model and the reference was -0.3±6.5 for EF and 7.2±17.1 ml for SV. Corresponding comparison between the biplane method and the reference resulted in a mean difference of 0.3±6.1 for EF and 11.8±14.9 ml for SV. Conclusion: The results from this study show that left ventricular EF can be adequately estimated using the single- and biplane ellipsoid models, while SV tends to be overestimated using both geometrical models.

Calculation of right ventricular stroke volume in short‐axis MR images using the equation of the tricuspid plane

Short‐axis (SA) magnetic resonance (MR) images are commonly planned parallel to the left atrioventricular valve. This orientation leads to oblique slices of the right ventricle (RV) with subsequent difficulties in separating the RV from the right atrium in the SA images. The insertion points of the tricuspid valve (TV) in the myocardium can be clearly identified in the right ventricle long axis (RVLA) and four‐chamber (4CH) views. The purpose of this study was to develop a method that transfers the position of the tricuspid plane, as seen in the RVLA and 4CH views, to the SA images to facilitate the separation of the RV from the atrium. This methodology, termed Dissociating the Right Atrium from the Ventricle Volume (DRAW), was applied in 20 patients for calculations of right ventricular stroke volume (RVSV). The RVSV using DRAW (RVSVDRAW) was compared to left ventricular stroke volumes (LVSV) obtained from flow measurements in the ascending aorta. The RVSV was also determined using the conventional method (RVSVCONV) where the stack of images from the SA views are summarized, and a visual decision is made of the most basal slice to be included in the RV. The mean difference between RVSVDRAW and LVSV was 0·1 ± 12·7 ml, while the mean difference between RVSVCONV and LVSV was 0·33 ± 14·3 ml. Both the intra‐ and interobserver variability were small using the DRAW methodology, 0·6 ± 3·5 and 1·7 ± 2·7 ml, respectively. In conclusion, the DRAW method can be used to facilitate the separation of the RV and the atrium.

Effect on left ventricular mass and geometry in patients with takotsubo cardiomyopathy

Abstract Objectives. Takotsubo cardiomyopathy (TTC) is a condition of transient left ventricular (LV) dysfunction. The effects on LV mass (LVM) and geometry have not been studied enough in TTC. Retrospectively, we analyzed our TTC cohort both by transthoracic echocardiography (TTE) and magnetic resonance imaging (MRI), for comparative purposes. Design. Thirteen women undergoing TTE and MRI, at onset and three months later, were included. LVM was estimated by MRI, and two TTE methods. Segmental wall thickness (SWT) was measured, while radial strain was assessed by TTE. Data analysis included Wilcoxons test (between phases), Mann–Whitney U test and McNemars test (between and within groups). Bland–Altman analyses were used for intertechnique coherence, while interactions regarding TTE were tested using Spearmans coefficient. Results. LVM decreased during recovery (p < 0.05), by MRI and one of the TTE methods; truncated ellipsoid formula (TEF), which also showed relatively better coherence compared with MRI. SWT decreased in two of three sites, by both modalities, but with ambiguous coherence there between. The TEF data interacted partially with a demonstrated increase in radial strain. Conclusions. TTC associates with acute increase in LVM, which appears to be an apical effect, tending to follow the changes in concentric wall motion. MRI and TTE show adequate coherence; primarily for the TEF method regarding LVM.

Cardiovascular magnetic resonance imaging and transthoracic echocardiography in the assessment of stenotic aortic valve area: a comparative study

Background Magnetic resonance (MR) imaging and echocardiography both allow assessment of aortic valve stenosis. In MR the aortic valve area (AvA) is measured using planimetry while in transthoracic echocardiography (TTE) AvA is usually calculated by applying the continuity equation. Purpose To compare the measured stenotic aortic valve areas using five different MR-acquisition alternatives with the corresponding area values calculated by TTE. Material and Methods The aortic valve was imaged in 14 patients, with diagnosed aortic valve stenosis, using balanced steady state free precession (bSSFP) gradient echo (GE) and phase contrast imaging (PC). Three adjacent slices were planned to encompass the aortic valve and the aortic valve area was measured using planimetry. The two sets of complex valued images generated by the PC sequence formed three kinds of images that could be used for aortic valve area measurements: the magnitude image (PC/Mag), the modulus (PCA/M), and phase difference (PCA/P) between the two complex images, respectively. The valve area from TTE was calculated using the continuity equation. A cut-off of<1.0 cm2 was used as a criteria for severe stenosis. Results The mean area differences between the different MR acquisitions and TTE method were −0.05±0.37 cm2 (GE), −0.18±0.46 cm2 (bSSFP), 0.27-0.43 cm2 (PC/Mag), 0.15±0.32 cm2 (PCA/P), and 0.26±0.27 cm2 (PCA/M). The valve area was significantly overestimated using PCA/M that, in turn, implied a significant underestimation of the aortic valve stenosis severity compared to the assessments using TTE. Conclusion The smallest area valve difference between TTE and an MR-acquisition alternative is obtained with gradient echo images. The use of PCA/M leads to significant differences in planimetry measurements of the aortic valve orifice and the gradation of the stenosis severity compared to TTE.