| 1. |
- Carlsson, Marcus, et al.
(författare)
-
Atrioventricular plane displacement is the major contributor to left ventricular pumping in healthy adults, athletes, and patients with dilated cardiomyopathy
- 2007
-
Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 292:3, s. 1452-1459
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies using echocardiography in healthy subjects have reported conflicting data regarding the percentage of the stroke volume ( SV) of the left ventricle ( LV) resulting from longitudinal and radial function, respectively. Therefore, the aim was to quantify the percentage of SV explained by longitudinal atrioventricular plane displacement ( AVPD) in controls, athletes, and patients with decreased LV function due to dilated cardiomyopathy ( DCM). Twelve healthy subjects, 12 elite triathletes, and 12 patients with DCM and ejection fraction below 30% were examined by cine magnetic resonance imaging. AVPD and SV were measured in long- and short- axis images, respectively. The percentage of the SV explained by longitudinal function ( SVAVPD%) was calculated as the mean epicardial area of the largest short- axis slices in end diastole multiplied by the AVPD and divided by the SV. SV was higher in athletes [ 140 +/- 4 ml ( mean +/- SE), P = 0.009] and lower in patients ( 72 +/- 7 ml, P < 0.001) when compared with controls ( 116 +/- 6 ml). AVPD was similar in athletes ( 17 +/- 1 mm, P = 0.45) and lower in patients ( 7 +/- 1 mm, P = 0.001) when compared with controls ( 16 +/- 0 mm). SVAVPD% was similar both in athletes ( 57 +/- 2%, P = 0.51) and in patients ( 67 +/- 4%, P = 0.24) when compared with controls ( 60 +/- 2%). In conclusion, longitudinal AVPD is the primary contributor to LV pumping and accounts for similar to 60% of the SV. Although AVPD is less than half in patients with DCM when compared with controls and athletes, the contribution of AVPD to LV function is maintained, which can be explained by the larger short- axis area in DCM.
|
|
| 2. |
- Arvidsson, Per Martin, et al.
(författare)
-
Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements.
- 2013
-
Ingår i: Journal of Applied Physiology. - : American Physiological Society. - 1522-1601 .- 8750-7587. ; 114:10, s. 1472-1481
-
Tidskriftsartikel (refereegranskat)abstract
- Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left and right atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3T, including a four-dimensional phase contrast flow sequence. Mean left atrial (LA) KE was lower than right atrial (RA) KE (1.1±0.1 mJ vs 1.7±0.1 mJ, P<0.01). Three KE peaks were seen in both atria; one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak (P<0.001), and the early diastolic LA peak was larger than the RA peak (P<0.05). Rotational flow contained 46 ± 7% of total KE, and conserved energy better than non-rotational flow did. The KE increase in early diastole was higher in the LA (P<0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement (R2=0.57 for LA and R2=0.64 for RA). Early diastolic KE of the LA correlated with LV mass (R2=0.28), however no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. RV relaxation does not seem to contribute to atrial KE. Instead, atrial KE generated during ventricular systole may be conserved in a hydraulic "flywheel" and transferred to the RV through helical flow, which may contribute to RV filling.
|
|
| 3. |
- Cain, Peter, et al.
(författare)
-
Quantitative polar representation of left ventricular myocardial perfusion, function and viability using SPECT and cardiac magnetic resonance: initial results.
- 2005
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 25:4, s. 215-222
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The clinical management of patients with coronary artery disease (CAD) often involves a complex assessment of the extent and severity of changes in left ventricular (LV) myocardial perfusion, function and viability. We aimed to explore the feasibility of integrative quantitative representation of LV perfusion, function and viability in adjacent polar plots. In order to assess the clinical usefulness of the quantitative methods, we also explored the relationship and determined the agreement between visual scoring and quantitative measurement of regional perfusion and function. Methods: Ten patients with CAD underwent rest and stress 99mTc-tetrofosmin single photon emission computed tomography (SPECT) and cardiac magnetic resonance (CMR) imaging. Software was developed in-house for generating polar plots from semi-automatic quantification of rest and stress perfusion from SPECT, function from cine CMR and viability from delayed contrast enhancement (DE) CMR. The agreement between visual assessment and quantification of both perfusion and function was tested by Kendall's coefficient of concordance (W). Results: Polar plots were created using quantitative data from the semi-automatic analysis of perfusion, function and viability. Kendall's W for agreement between quantitative measurement and visual scoring was 1·0 (P<0·001) for perfusion and 0·85 (P<0·001) for function. Conclusions: Side-by-side quantitative polar representation of LV perfusion, function and viability is feasible and may aid in the complex assessment of these parameters. The agreement between quantitative measurement and visual scoring was very good for both perfusion and function.
|
|
| 4. |
- Carlsson, Marcus, et al.
(författare)
-
Center of volume and total heart volume variation in healthy subjects and patients before and after coronary bypass surgery.
- 2005
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 25:4, s. 226-233
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Total heart volume variation (THVV) and center of volume variation (COVV) likely affects the efficiency of cardiac pumping, but no study has determined COVV of the heart throughout the cardiac cycle or the effect of surgery on THVV in adults. Therefore, the purposes of this study were to determine COVV in healthy adults and patients with cardiac failure due to ischemic heart disease (IHD), identify any difference in THVV between these two groups, and determine how these parameters are affected by coronary bypass surgery. METHODS: Six healthy volunteers and eight patients before and after surgery were investigated with cardiovascular magnetic resonance imaging. The atrioventricular plane movement (AVPM), THVV and time resolved three-dimensional coordinates of the center of the cardiac volume (COVV) were measured. RESULTS: COVV followed a loop in 3D space that between the end-points was approximately 2 mm with no difference between healthy subjects and patients before surgery (P = 0.093), although AVPM was significantly lower in patients (P = 0.002). However, after surgery the COVV during the cardiac cycle doubled (P = 0.012) and the increase in THVV was significant (P = 0.050), although of very small magnitude, and the AVPM remained unchanged (P = 0.401). CONCLUSION: COVV and THVV were similar in patients and healthy subjects even though AVPM was lower in the patient population. After surgery, however, COVV doubled despite a very small change in THVV and no change in AVPM. Taken together, the results of this study may provide new insights into the energy expenditure and efficiency of cardiac pumping.
|
|
| 5. |
- Carlsson, Marcus, et al.
(författare)
-
Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements
- 2012
-
Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 302:4, s. 893-900
-
Tidskriftsartikel (refereegranskat)abstract
- Carlsson M, Heiberg E, Toger J, Arheden H. Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements. Am J Physiol Heart Circ Physiol 302: H893-H900, 2012. First published December 16, 2011; doi: 10.1152/ajpheart. 00942.2011.-We aimed to quantify kinetic energy (KE) during the entire cardiac cycle of the left ventricle (LV) and right ventricle (RV) using four-dimensional phasecontrast magnetic resonance imaging (MRI). KE was quantified in healthy volunteers (n = 9) using an in-house developed software. Mean KE through the cardiac cycle of the LV and the RV were highly correlated (r(2) = 0.96). Mean KE was related to end-diastolic volume (r(2) = 0.66 for LV and r(2) = 0.74 for RV), end-systolic volume (r(2) = 0.59 and 0.68), and stroke volume (r(2) = 0.55 and 0.60), but not to ejection fraction (r(2) = 0.01, P = not significant for both). Three KE peaks were found in both ventricles, in systole, early diastole, and late diastole. In systole, peak KE in the LV was lower (4.9 +/- 0.4 mJ, P = 0.004) compared with the RV (7.5 +/- 0.8 mJ). In contrast, KE during early diastole was higher in the LV (6.0 +/- 0.6 mJ, P = 0.004) compared with the RV (3.6 +/- 0.4 mJ). The late diastolic peaks were smaller than the systolic and early diastolic peaks (1.3 +/- 0.2 and 1.2 +/- 0.2 mJ). Modeling estimated the proportion of KE to total external work, which comprised similar to 0.3% of LV external work and 3% of RV energy at rest and 3 vs. 24% during peak exercise. The higher early diastolic KE in the LV indicates that LV filling is more dependent on ventricular suction compared with the RV. RV early diastolic filling, on the other hand, may be caused to a higher degree of the return of the atrioventricular plane toward the base of the heart. The difference in ventricular geometry with a longer outflow tract in the RV compared with the LV explains the higher systolic KE in the RV.
|
|
| 6. |
- Carlsson, Marcus, et al.
(författare)
-
Submaximal adenosine-induced coronary hyperaemia with 12 h caffeine abstinence: implications for clinical adenosine perfusion imaging tests.
- 2015
-
Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 35:1, s. 49-56
-
Tidskriftsartikel (refereegranskat)abstract
- Adenosine is widely used as a vasodilator agent in myocardial perfusion imaging. Caffeine inhibits the effect, but the time of caffeine abstinence needed is under discussion and varies from 12 to 24 h. Therefore, our aim was to examine whether the time of caffeine abstinence affects the hyperaemic response using quantification of coronary sinus flow (CS F) with cardiac magnetic resonance (CMR) during adenosine infusion.
|
|
| 7. |
- Carlsson, Marcus, et al.
(författare)
-
The Quantitative Relationship between Longitudinal and Radial Function in Left, Right and Total Heart Pumping in Humans.
- 2007
-
Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 293:1, s. 636-644
-
Tidskriftsartikel (refereegranskat)abstract
- The total heart volume variation (THVV) during systole has been proposed to be caused by radial function of the ventricles, but definitive data for both ventricles have not been presented. Furthermore, the right ventricle (RV) has been suggested to have a greater longitudinal pumping component than the left ventricle (LV). Therefore, we aimed to compare the stroke volume (SV) generated by radial function to the volume variation of the left, right, and total heart. To do this, we also needed to develop a new method for measuring the contribution of the longitudinal atrioventricular plane displacement (AVPD) to the RVSV (RVSVAVPD). For our study, 11 volunteers underwent cine MRI in the short- and long-axis planes and MRI flow measurement in all vessels leading to and from the heart. The left, right, and total heart showed correlations between volume variation from flow measurements and radial function calculated as SV minus the longitudinal function (r = 0.81, P < 0.01; r = 0.80, P < 0.01; and r = 0.92, P < 0.001, respectively). Compared with the LV, the RV had a greater AVPD (23.4 +/- 0.8 vs. 16.4 +/- 0.5 mm), center of volume movement (13.0 +/- 0.7 vs. 7.8 +/- 0.4 mm), and, RVSVAVPD (82 +/- 2% vs. 60 +/- 2%) (P < 0.001 for all). We found that THVV is predominantly caused by radial function of the ventricles. Longitudinal AVPD accounts for similar to 80% of the RVSV, compared with similar to 60% for the LVSV. This difference explains the larger portion of THVV found on the left side of the heart.
|
|
| 8. |
- Carlsson, Marcus, et al.
(författare)
-
Total heart volume variation throughout the cardiac cycle in man.
- 2004
-
Ingår i: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 287:1, s. 243-250
-
Tidskriftsartikel (refereegranskat)abstract
- Variations in total heart volume (atria plus ventricles) during a cardiac cycle affect efficiency of cardiac pumping. The goals of this study were to confirm the presence, extent, and contributors of total heart volume variation during the cardiac cycle in healthy volunteers with the use of MRI. Eight healthy volunteers were examined by MRI at rest. Changes in total cardiac volume throughout the cardiac cycle were calculated using the following methods: 1) planimetry derived from gradient-echo cine images and 2) flow-sensitive sequences to quantify flow in all vessels leading to and from the heart. The maximum total heart volume diminished during systole by 8.2 +/- 0.8% (SEM, range 4.8-10.6%) measured by method 1 and 8.8 +/- 1.0% (SEM, range 5.6-11.8%) by method 2 with good agreement between the methods [difference according to Bland-Altman analysis -0.6% +/- 1.0% (SD), intraclass correlation coefficient = 0.999]. This decrease in volume is predominantly explained by variation at the midcardiac level at the widest diameter of the heart with a left-sided predominance. In the short axis of the heart, the change of slice volume was proportional to the end-diastolic slice volume. The present study has confirmed the presence of total heart volume variation that predominantly occurs in the region of atrioventricular plane movement and on the left side. The total heart volume variation may relate to the efficiency of energy use by the heart to minimize displacement of surrounding tissue while accounting for the energy required to draw blood into the atria during ventricular systole.
|
|
| 9. |
|
|
| 10. |
- Edlund, Jonathan, et al.
(författare)
-
Validation and quantification of left ventricular function during exercise and free breathing from real-time cardiac magnetic resonance images
- 2022
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Exercise cardiovascular magnetic resonance (CMR) can unmask cardiac pathology not evident at rest. Real-time CMR in free breathing can be used, but respiratory motion may compromise quantification of left ventricular (LV) function. We aimed to develop and validate a post-processing algorithm that semi-automatically sorts real-time CMR images according to breathing to facilitate quantification of LV function in free breathing exercise. A semi-automatic algorithm utilizing manifold learning (Laplacian Eigenmaps) was developed for respiratory sorting. Feasibility was tested in eight healthy volunteers and eight patients who underwent ECG-gated and real-time CMR at rest. Additionally, volunteers performed exercise CMR at 60% of maximum heart rate. The algorithm was validated for exercise by comparing LV mass during exercise to rest. Respiratory sorting to end expiration and end inspiration (processing time 20 to 40 min) succeeded in all research participants. Bias ± SD for LV mass was 0 ± 5 g when comparing real-time CMR at rest, and 0 ± 7 g when comparing real-time CMR during exercise to ECG-gated at rest. This study presents a semi-automatic algorithm to retrospectively perform respiratory sorting in free breathing real-time CMR. This can facilitate implementation of exercise CMR with non-ECG-gated free breathing real-time imaging, without any additional physiological input.
|
|
