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Annals of Biomedical Engineering Dec 2021Ischemic mitral regurgitation (IMR) is particularly challenging to repair with lasting durability due to the complex valvular and subvalvular pathologies resulting from...
Ischemic mitral regurgitation (IMR) is particularly challenging to repair with lasting durability due to the complex valvular and subvalvular pathologies resulting from left ventricular dysfunction. Ex vivo simulation is uniquely suited to quantitatively analyze the repair biomechanics, but advancements are needed to model the nuanced IMR disease state. Here we present a novel IMR model featuring a dilation device with precise dilatation control that preserves annular elasticity to enable accurate ex vivo analysis of surgical repair. Coupled with augmented papillary muscle head positioning, the enhanced heart simulator system successfully modeled IMR pre- and post-surgical intervention and enabled the analysis of adjunctive subvalvular papillary muscle repair to alleviate regurgitation recurrence. The model resulted in an increase in regurgitant fraction: 11.6 ± 1.7% to 36.1 ± 4.4% (p < 0.001). Adjunctive papillary muscle head fusion was analyzed relative to a simple restrictive ring annuloplasty repair and, while both repairs successfully eliminated regurgitation initially, the addition of the adjunctive subvalvular repair reduced regurgitation recurrence: 30.4 ± 5.7% vs. 12.5 ± 2.6% (p = 0.002). Ultimately, this system demonstrates the success of adjunctive papillary muscle head fusion in repairing IMR as well as provides a platform to optimize surgical techniques for increased repair durability.
Topics: Animals; Cardiac Surgical Procedures; Dilatation; Disease Models, Animal; Equipment Design; Hemodynamics; Humans; Mitral Valve Insufficiency; Papillary Muscles; Recurrence; Swine
PubMed: 34734363
DOI: 10.1007/s10439-021-02879-9 -
American Journal of Physiology. Heart... Jun 2013We compared the contractile performance of papillary muscle from a mouse model of hypertrophic cardiomyopathy [α-cardiac actin (ACTC) E99K mutation] with nontransgenic...
We compared the contractile performance of papillary muscle from a mouse model of hypertrophic cardiomyopathy [α-cardiac actin (ACTC) E99K mutation] with nontransgenic (non-TG) littermates. In isometric twitches, ACTC E99K papillary muscle produced three to four times greater force than non-TG muscle under the same conditions independent of stimulation frequency and temperature, whereas maximum isometric force in myofibrils from these muscles was not significantly different. ACTC E99K muscle relaxed slower than non-TG muscle in both papillary muscle (1.4×) and myofibrils (1.7×), whereas the rate of force development after stimulation was the same as non-TG muscle for both electrical stimulation in intact muscle and after a Ca²⁺ jump in myofibrils. The EC₅₀ for Ca²⁺ activation of force in myofibrils was 0.39 ± 0.33 μmol/l in ACTC E99K myofibrils and 0.80 ± 0.11 μmol/l in non-TG myofibrils. There were no significant differences in the amplitude and time course of the Ca²⁺ transient in myocytes from ACTC E99K and non-TG mice. We conclude that hypercontractility is caused by higher myofibrillar Ca²⁺ sensitivity in ACTC E99K muscles. Measurement of the energy (work + heat) released in actively cycling heart muscle showed that for both genotypes, the amount of energy turnover increased with work done but with decreasing efficiency as energy turnover increased. Thus, ACTC E99K mouse heart muscle produced on average 3.3-fold more work than non-TG muscle, and the cost in terms of energy turnover was disproportionately higher than in non-TG muscles. Efficiency for ACTC E99K muscle was in the range of 11-16% and for non-TG muscle was 15-18%.
Topics: Animals; Biomechanical Phenomena; Calcium Signaling; Cardiomegaly; Electric Stimulation; Energy Metabolism; Heart Rate; In Vitro Techniques; Isometric Contraction; Mice; Mice, Transgenic; Myocardial Contraction; Myocytes, Cardiac; Myofibrils; Papillary Muscles; Thermogenesis; Transducers
PubMed: 23604709
DOI: 10.1152/ajpheart.00951.2012 -
General Thoracic and Cardiovascular... Jul 2012In this report we review our experience of operations on mitral regurgitation associated with abnormal papillary muscles/chordae tendineae of the mitral valves and...
PURPOSE
In this report we review our experience of operations on mitral regurgitation associated with abnormal papillary muscles/chordae tendineae of the mitral valves and discussed the clinical characteristics, operative findings, and treatment strategies.
METHODS
Undifferentiated papillary muscle was defined as a hypoplastic chordae tendineae with anomalous formation of papillary muscles attached to the mitral valves directly. Consecutive 87 patients undergoing surgery for mitral regurgitation at our institution were reviewed and 6 of them had undifferentiated papillary muscle.
RESULTS
The underlying mechanism of regurgitation was prolapse at the center of the anterior leaflet in 3 cases and tethering, a wide area of myxomatous degeneration, and annular dilatation in one case, respectively. Five patients underwent mitral valve plasty and 1 patient received replacement. Anomalous formation of chordae tendineae was corrected by resection and suture with transplantation at the tip of the leaflet to which abnormal chordae were attached in 2 cases, while resection and suture with chordal shortening was performed in 1 case, and chordal reconstruction using artificial chordae was employed in 2 cases. There was no operative death, and postoperative echocardiography showed no residual regurgitation in any of the cases.
CONCLUSIONS
Mitral regurgitation associated with undifferentiated papillary muscle resulted from prolapse or tethering and impaired flexibility of leaflets. It was possible to successfully treat the patients by mitral valve plasty unless complex congenital cardiac malformation coexisted. Detailed examinations of attached papillary muscle by echocardiography and intraoperative inspection are necessary and surgical techniques should be selected appropriately in each case.
Topics: Adolescent; Aged; Cell Differentiation; Chordae Tendineae; Female; Heart Defects, Congenital; Heart Valve Prosthesis Implantation; Humans; Japan; Male; Middle Aged; Mitral Valve; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Mitral Valve Prolapse; Papillary Muscles; Treatment Outcome; Ultrasonography
PubMed: 22576650
DOI: 10.1007/s11748-012-0055-x -
The Journal of Thoracic and... Mar 2011To investigate the impact of left ventricular dilatation on right ventricular papillary muscle displacement.
OBJECTIVE
To investigate the impact of left ventricular dilatation on right ventricular papillary muscle displacement.
METHODS
Thirteen patients underwent high-resolution cardiac magnetic resonance imaging at Emory University Hospital: Seven patients with congestive heart failure and a dilated left ventricle composed the dilated left ventricular group, and 6 normal subjects were used as a control. A total of 120 cardiac magnetic resonance imaging slices were acquired in a short-axis view at end diastole for each subject. Cardiac magnetic resonance imaging slices were used to identify the papillary muscle tip position in 3-dimensional coordinates for the septal, posterior, and anterior papillary muscles. The centroid of the papillary muscle coordinates was used as the reference point for comparison between subjects. The relative orientation between the right ventricular papillary muscles was evaluated and compared between the dilated left ventricular group and normal subjects.
RESULTS
Dilatation of the left ventricle resulted in a significant (P = .05) displacement of the septal right ventricular papillary muscle toward the centroid: normal group, 0.0285 ± 0.036 mm/mm versus dilated left ventricular group, 0.1437 ± 0.026 mm/mm. More specifically, the septal papillary muscle significantly (P = .03) moved away from the septal wall (normal group: 0.61 ± 0.09 mm/mm, dilated left ventricular group: 0.379 ± 0.037 mm/mm). Specific locations of all 3 right ventricular papillary muscles were reported for normal subjects and patients with a dilated left ventricle.
CONCLUSIONS
Patients with a dilated left ventricle have significantly increased displacement of the septal right ventricular papillary muscle away from the septum when compared with normal controls. This demonstrates pathophysiologic contribution of the left ventricle to specific papillary muscle alterations within the right ventricle.
Topics: Adult; Aged; Case-Control Studies; Georgia; Heart Failure; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Middle Aged; Papillary Muscles; Predictive Value of Tests; Retrospective Studies; Ventricular Septum; Young Adult
PubMed: 20579666
DOI: 10.1016/j.jtcvs.2010.05.034 -
Pacing and Clinical Electrophysiology :... Apr 2022Catheter ablation of papillary muscle ventricular arrhythmias (PM-VAs) has been associated with unsatisfactory results. Features that may affect acute and long-term...
BACKGROUND
Catheter ablation of papillary muscle ventricular arrhythmias (PM-VAs) has been associated with unsatisfactory results. Features that may affect acute and long-term procedural outcomes are not well established.
OBJECTIVE
To systematically review the available data in the literature assessing efficacy and safety of PM-VAs catheter ablation.
METHODS
An online search of PubMed, Cochrane Registry, Web of Science, Scopus and EMBASE libraries (from inception to March 1, 2021) was performed, in addition to manual screening. Twenty-one observational noncontrolled case-series were considered eligible for the systematic review, including 536 patients.
RESULTS
Postero-medial PM harbored 60.8% of PM-VAs, while antero-lateral PM and right ventricular PMs 34.9% and 4.3% of cases, respectively. The mean acute success rate of the index ablation procedure was 88.1% (95% CI 82.8% to 91.9%, p < .001, I 0%). After a mean follow-up period of 15.5 ± 17.4 months, pooled long-term arrhythmia-free rate was 69.2%, while the pooled long-term success rate after multiple ablation procedure was 84.9%. Overall, procedure complications occurred in nine patients (1.7%) and no procedure-related deaths were reported. The use of intracardiac echocardiography (ICE) as well as contact force sensing (CFS) and irrigated catheters during ablation was associated with higher rates of arrhythmia-freedom at long-term follow-up.
CONCLUSIONS
Catheter ablation is an effective and safe strategy for PM-VAs, with an acute success rate of 88.1%, a long-term success rate of 69.2%, with a relatively low procedural complication rate. The use of ICE, irrigated catheters and catheters with CFS capability was associated with higher rates of arrhythmia-freedom at long-term follow-up.
Topics: Catheter Ablation; Heart Ventricles; Humans; Papillary Muscles; Tachycardia, Ventricular; Treatment Outcome; Ventricular Premature Complexes
PubMed: 35147225
DOI: 10.1111/pace.14462 -
JACC. Clinical Electrophysiology Oct 2020
Topics: Humans; Catheter Ablation; Electrophysiology; Papillary Muscles; Ventricular Premature Complexes
PubMed: 33121668
DOI: 10.1016/j.jacep.2020.08.005 -
Journal of Cardiovascular Magnetic... Nov 2016Functional mitral regurgitation is one of the severe complications of non-ischemic dilated cardiomyopathy (DCM). Non-contrast native T mapping has emerged as a...
BACKGROUND
Functional mitral regurgitation is one of the severe complications of non-ischemic dilated cardiomyopathy (DCM). Non-contrast native T mapping has emerged as a non-invasive method to evaluate myocardial fibrosis. We sought to evaluate the potential relationship between papillary muscle T time and mitral regurgitation in DCM patients.
METHODS
Forty DCM patients (55 ± 13 years) and 20 healthy adult control subjects (54 ± 13 years) were studied. Native T mapping was performed using a slice interleaved T mapping sequence (STONE) which enables acquisition of 5 slices in the short-axis plane within a 90 s free-breathing scan. We measured papillary muscle diameter, length and shortening. DCM patients were allocated into 2 groups based on the presence or absence of functional mitral regurgitation.
RESULTS
Papillary muscle T time was significantly elevated in DCM patients with mitral regurgitation (n = 22) in comparison to those without mitral regurgitation (n = 18) (anterior papillary muscle: 1127 ± 36 msec vs 1063 ± 16 msec, p < 0.05; posterior papillary muscle: 1124 ± 30 msec vs 1062 ± 19 msec, p < 0.05), but LV T time was similar (1129 ± 38 msec vs 1134 ± 58 msec, p = 0.93). Multivariate linear regression analysis showed that papillary muscle native T time (β = 0.10, 95 % CI: 0.05-0.17, p < 0.05) is significantly correlated with mitral regurgitant fraction. Elevated papillary muscle T time was associated with larger diameter, longer length and decreased papillary muscle shortening (all p values <0.05).
CONCLUSIONS
In DCM, papillary muscle native T time is significantly elevated and related to mitral regurgitant fraction.
Topics: Adult; Aged; Cardiomyopathy, Dilated; Case-Control Studies; Chi-Square Distribution; Contrast Media; Female; Fibrosis; Humans; Linear Models; Magnetic Resonance Imaging, Cine; Male; Meglumine; Middle Aged; Mitral Valve; Mitral Valve Insufficiency; Multivariate Analysis; Myocardial Contraction; Organometallic Compounds; Papillary Muscles; Predictive Value of Tests; Risk Factors; Severity of Illness Index; Time Factors; Ventricular Function, Left
PubMed: 27846845
DOI: 10.1186/s12968-016-0301-y -
Folia Morphologica Aug 2013The septomarginal trabecula is present in all human hearts as well as in the hearts of other primates. It usually connects the interventricular septum with the anterior... (Comparative Study)
Comparative Study
The septomarginal trabecula is present in all human hearts as well as in the hearts of other primates. It usually connects the interventricular septum with the anterior papillary muscle, although there are many variations in how this is achieved. The object of the analyses was to estimate the bilateral topography of the septomarginal trabecula and the anterior papillary muscle in the context of the ontogeny and phylogeny of primates. A total of 138 hearts were examined from number of different non-human primates. The presence of the septomarginal trabecula was confirmed in 94.9% of cases, although not in the hearts of Lemur varius. Four configurations could be distinguished by defining the location of the septomarginal trabecula and its relation to the anterior papillary muscle.For the hearts of the Strepsirrhini and the majority of Platyrrhini neither structure was related, whereas in all examined representatives of Homino idea they had fused and created morphologically varying forms. On the basis of these results,a concept was developed for the sequence of changes which the topography of the septomarginal trabecula and the anterior papillary muscle undergo during ontogeny and phylogeny.
Topics: Animals; Heart Ventricles; Humans; Papillary Muscles; Primates
PubMed: 24068681
DOI: 10.5603/fm.2013.0034 -
Circulation Journal : Official Journal... Jul 2022
Topics: Abscess; Heart Rupture, Post-Infarction; Humans; Mitral Valve Insufficiency; Papillary Muscles
PubMed: 35228470
DOI: 10.1253/circj.CJ-22-0038 -
Journal of Veterinary Internal Medicine 2007Papillary muscle hypertrophy can occur in conjunction with, or as the only indication of, hypertrophic cardiomyopathy or other diseases that result in left ventricular...
BACKGROUND
Papillary muscle hypertrophy can occur in conjunction with, or as the only indication of, hypertrophic cardiomyopathy or other diseases that result in left ventricular concentric hypertrophy (LVCH). Assessment of papillary muscle size is usually subjective because objective measures have not been reported.
HYPOTHESIS
The study hypothesis was that papillary muscle dimensions are different between normal cats and cats with LVCH.
ANIMALS
Echocardiograms from 44 normal cats and 40 cats with LVCH were included in the study.
METHODS
All measurements were taken from the right parasternal short-axis view at the level of the papillary muscles at end-diastole. Three methods were used to assess papillary muscle size: the area subtraction method, the direct area trace method, and the diameter method. Measurements were compared between cat groups and method comparisons were made among methods for area determination.
RESULTS
Cats with LVCH were older and had significantly greater left ventricular septal and free wall thicknesses and larger left atrial measurements than normal cats (P < .0006). Papillary muscle measurements were significantly greater by all measurement methods in cats with LVCH than in cats with normal echocardiograms (P < .0001). The area subtraction method and direct area trace method showed moderate agreement.
CONCLUSIONS AND CLINICAL IMPORTANCE
Papillary muscle measurements were larger for LVCH cats than normal cats; however, some overlap was present. The establishment of these objective measures adds to the echocardiographic examination of cats.
Topics: Animals; Cat Diseases; Cats; Echocardiography; Hypertrophy, Left Ventricular; Papillary Muscles
PubMed: 17708393
DOI: 10.1892/0891-6640(2007)21[737:pmmicw]2.0.co;2