-
Heart Rhythm Mar 2023
Topics: Humans; Tachycardia, Ventricular; Electrocardiography
PubMed: 36842790
DOI: 10.1016/j.hrthm.2022.04.010 -
The Journal of Thoracic and... Oct 2022New transapical minimally invasive artificial chordae implantation devices are a promising alternative to traditional open-heart repair, with the potential for decreased...
OBJECTIVE
New transapical minimally invasive artificial chordae implantation devices are a promising alternative to traditional open-heart repair, with the potential for decreased postoperative morbidity and reduced recovery time. However, these devices can place increased stress on the artificial chordae. We designed an artificial papillary muscle to alleviate artificial chordae stresses and thus increase repair durability.
METHODS
The artificial papillary muscle device is a narrow elastic column with an inner core that can be implanted during the minimally invasive transapical procedure via the same ventricular incision site. The device was 3-dimensionally printed in biocompatible silicone for this study. To test efficacy, porcine mitral valves (n = 6) were mounted in a heart simulator, and isolated regurgitation was induced. Each valve was repaired with a polytetrafluoroethylene suture with apical anchoring followed by artificial papillary muscle anchoring. In each case, a high-resolution Fiber Bragg Grating sensor recorded forces on the suture.
RESULTS
Hemodynamic data confirmed that both repairs-with and without the artificial papillary muscle device-were successful in eliminating mitral regurgitation. Both the peak artificial chordae force and the rate of change of force at the onset of systole were significantly lower with the device compared with apical anchoring without the device (P < .001 and P < .001, respectively).
CONCLUSIONS
Our novel artificial papillary muscle could integrate with minimally invasive repairs to shorten the artificial chordae and behave as an elastic damper, thus reducing sharp increases in force. With our device, we have the potential to improve the durability of off-pump transapical mitral valve repair procedures.
Topics: Animals; Chordae Tendineae; Heart Valve Prosthesis Implantation; Mitral Valve; Mitral Valve Insufficiency; Papillary Muscles; Polytetrafluoroethylene; Silicones; Swine
PubMed: 33451843
DOI: 10.1016/j.jtcvs.2020.11.105 -
Journal of Cardiac Surgery Mar 2020The main pathophysiological factor of chronic ischemic mitral regurgitation (MR) is the outward displacement of the papillary muscles (PMs) leading to leaflet tethering.... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND AND AIMS
The main pathophysiological factor of chronic ischemic mitral regurgitation (MR) is the outward displacement of the papillary muscles (PMs) leading to leaflet tethering. For this reason, papillary muscle intervention (PMI) in combination with mitral ring annuloplasty (MRA) has recently been introduced into clinical practice to correct this displacement, and to reduce the recurrence of regurgitation.
METHODS
A meta-analysis was conducted comparing the outcomes of PMI and MRA performed in combination vs MRA performed alone, in terms of MR recurrence and left ventricular reverse remodeling (LVRR). A meta-regression was carried out to investigate the impact of the type of PMI procedure on the outcomes.
RESULTS
MR recurrence in patients undergoing both PMI and MRA was lower than in those who only had MRA (log incidence rate ratio, -0.66; lower-upper limits, -1.13 to 0.20; I = 0.0%; p = .44; Egger's test: intercept 0.35 [-0.78 to 1.51]; p = .42). The group with both PMI and MRA and that with only MRA showed a slightly higher reduction in left ventricular diameters (-5.94%; -8.75% to 3.13%,). However, in both groups, LVRR was <10%. No difference was detected between PM relocation/repositioning and papillary muscle approximation in terms of LVRR (p = .33).
CONCLUSIONS
Using PMI and MRA together has a lower MR recurrence than using MRA alone. No significant LVRR was observed between the two groups nor between the PMI techniques employed.
Topics: Aged; Female; Humans; Male; Middle Aged; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Papillary Muscles; Recurrence; Secondary Prevention; Ventricular Remodeling
PubMed: 31951676
DOI: 10.1111/jocs.14407 -
The Journal of Innovations in Cardiac... May 2021Left bundle branch pacing (LBBP) is emerging as an alternative to His bundle pacing that overcomes the latter's limitations. Several studies have reported on the safety,...
Left bundle branch pacing (LBBP) is emerging as an alternative to His bundle pacing that overcomes the latter's limitations. Several studies have reported on the safety, efficacy, and electrophysiological properties of LBBP, while postoperative success rates range from 80.5% to 94%. The left posterior fascicle is composed of broad bands of fibers coursing inferiorly and posteriorly toward the papillary muscle, while the anterior fascicle is a thin, tendon-like structure. We report a case of a 70-year-old man in whom left posterior fascicular pacing was done after LBBP failed. We were able to demonstrate all the features of left posterior fascicular capture, including fascicular potential and a left anterior hemiblock pattern, using surface 12-lead electrocardiography. Left posterior fascicular pacing could be an alternative technique when attempts to deploy LBBP fail.
PubMed: 34035980
DOI: 10.19102/icrm.2021.120506 -
Circulation. Cardiovascular Imaging Apr 2023The relation between ventricular arrhythmia and fibrosis in mitral valve prolapse (MVP) is reported, but underlying valve-induced mechanisms remain unknown. We evaluated...
BACKGROUND
The relation between ventricular arrhythmia and fibrosis in mitral valve prolapse (MVP) is reported, but underlying valve-induced mechanisms remain unknown. We evaluated the association between abnormal MVP-related mechanics and myocardial fibrosis, and their association with arrhythmia.
METHODS
We studied 113 patients with MVP with both echocardiogram and gadolinium cardiac magnetic resonance imaging for myocardial fibrosis. Two-dimensional and speckle-tracking echocardiography evaluated mitral regurgitation, superior leaflet and papillary muscle displacement with associated exaggerated basal myocardial systolic curling, and myocardial longitudinal strain. Follow-up assessed arrhythmic events (nonsustained or sustained ventricular tachycardia or ventricular fibrillation).
RESULTS
Myocardial fibrosis was observed in 43 patients with MVP, predominantly in the basal-midventricular inferior-lateral wall and papillary muscles. Patients with MVP with fibrosis had greater mitral regurgitation, prolapse, and superior papillary muscle displacement with basal curling and more impaired inferior-posterior basal strain than those without fibrosis (<0.001). An abnormal strain pattern with distinct peaks pre-end-systole and post-end-systole in inferior-lateral wall was frequent in patients with fibrosis (81 versus 26%, <0.001) but absent in patients without MVP with basal inferior-lateral wall fibrosis (n=20). During median follow-up of 1008 days, 36 of 87 patients with MVP with >6-month follow-up developed ventricular arrhythmias associated (univariable) with fibrosis, greater prolapse, mitral annular disjunction, and double-peak strain. In multivariable analysis, double-peak strain showed incremental risk of arrhythmia over fibrosis.
CONCLUSIONS
Basal inferior-posterior myocardial fibrosis in MVP is associated with abnormal MVP-related myocardial mechanics, which are potentially associated with ventricular arrhythmia. These associations suggest pathophysiological links between MVP-related mechanical abnormalities and myocardial fibrosis, which also may relate to ventricular arrhythmia and offer potential imaging markers of increased arrhythmic risk.
Topics: Humans; Mitral Valve Prolapse; Mitral Valve Insufficiency; Arrhythmias, Cardiac; Papillary Muscles; Fibrosis; Prolapse
PubMed: 37071717
DOI: 10.1161/CIRCIMAGING.122.014963 -
Romanian Journal of Internal Medicine =... Dec 2022We studied by means of echocardiography and cardiac MRI (CMR) the occurrence of an accessory papillary muscle that unites mostly the left ventricle (LV) apex with the...
We studied by means of echocardiography and cardiac MRI (CMR) the occurrence of an accessory papillary muscle that unites mostly the left ventricle (LV) apex with the basal antero-septum in the immediate vicinity of left ventricle outflow tract (LVOT) in patients with and without hypertrophic cardiomyopathy (HOCM). . We included all good quality echocardiography and CMR studies as reviewed by two cardiologists and assessed the occurrence of a contractile papillary muscle situated between the LV apex and antero-septum. A contractile accessory papillary muscle situated between the LV apex and the anteroseptum was seen in 100% of HOCM patients and 62% of control patients (p=0.05) in the CMR images acquired from a total of 9 HOCM and 13 control patients. The same structure was observed in 241 patients representing 69.5% of all-comers echocardiography studies. The age was 69 ± 17 years on average in the echocardiography arm, patients harboring the antero-septal accessory muscle being older (71.6 + 15.7 years old vs 63.5 ± 18.1 for those without, p=0.0005). We exemplify this structure by parasternal long axis still echocardiography images and clips from 24 patients and CMR SSFP still images and a clip from two HOCM patients and one control. . A contractile accessory papillary muscle was observed in more than half of the all-comer echocardiography studies, and in all HOCM patients in the CMR arm. Further research is needed to fully characterize the anatomical and physiological significance as well as the possible structural interventional consequences of this structure attaching in the immediate vicinity of the LVOT in HOCM and control patients.
Topics: Humans; Middle Aged; Aged; Aged, 80 and over; Papillary Muscles; Heart Ventricles; Ventricular Outflow Obstruction; Echocardiography; Cardiomyopathy, Hypertrophic; Magnetic Resonance Imaging
PubMed: 36178793
DOI: 10.2478/rjim-2022-0017 -
The Journal of Physiology Oct 2022Right-sided myocardial mechanical efficiency (work output/metabolic energy input) in pulmonary hypertension can be severely reduced. We determined the contribution of...
Right-sided myocardial mechanical efficiency (work output/metabolic energy input) in pulmonary hypertension can be severely reduced. We determined the contribution of intrinsic myocardial determinants of efficiency using papillary muscle preparations from monocrotaline-induced pulmonary hypertensive (MCT-PH) rats. The hypothesis tested was that efficiency is reduced by mitochondrial dysfunction in addition to increased activation heat reported previously. Right ventricular muscle preparations were subjected to 5 Hz sinusoidal length changes at 37°C. Work and suprabasal oxygen consumption ( ) were measured before and after cross-bridge inhibition by blebbistatin. Cytosolic cytochrome c concentration, myocyte cross-sectional area, proton permeability of the inner mitochondrial membrane and monoamine oxidase and glucose 6-phosphate dehydrogenase activities and phosphatidylglycerol/cardiolipin contents were determined. Mechanical efficiency ranged from 23% to 11% in control (n = 6) and from 22% to 1% in MCT-PH (n = 15) and correlated with work (r = 0.68, P < 0.0001) but not with (r = 0.004, P = 0.7919). for cross-bridge cycling was proportional to work (r = 0.56, P = 0.0005). Blebbistatin-resistant (r = 0.32, P = 0.0167) and proton permeability of the mitochondrial inner membrane (r = 0.36, P = 0.0110) correlated inversely with efficiency. Together, these variables explained the variance of efficiency (coefficient of multiple determination r = 0.79, P = 0.0001). Cytosolic cytochrome c correlated inversely with work (r = 0.28, P = 0.0391), but not with efficiency (r = 0.20, P = 0.0867). Glucose 6-phosphate dehydrogenase, monoamine oxidase and phosphatidylglycerol/cardiolipin increased in the right ventricular wall of MCT-PH but did not correlate with efficiency. Reduced myocardial efficiency in MCT-PH is a result of activation processes and mitochondrial dysfunction. The variance of work and the ratio of activation heat reported previously and blebbistatin-resistant are discussed. KEY POINTS: Mechanical efficiency of right ventricular myocardium is reduced in pulmonary hypertension. Increased energy use for activation processes has been demonstrated previously, but the contribution of mitochondrial dysfunction is unknown. Work and oxygen consumption are determined during work loops. Oxygen consumption for activation and cross-bridge cycling confirm the previous heat measurements. Cytosolic cytochrome c concentration, proton permeability of the mitochondrial inner membrane and phosphatidylglycerol/cardiolipin are increased in experimental pulmonary hypertension. Reduced work and mechanical efficiency are related to mitochondrial dysfunction. Upregulation of the pentose phosphate pathway and a potential gap in the energy balance suggest mitochondrial dysfunction in right ventricular overload is a resiult of the excessive production of reactive oxygen species.
Topics: Animals; Cardiolipins; Cytochromes c; Glucose; Hypertension, Pulmonary; Monoamine Oxidase; Monocrotaline; Oxidoreductases; Oxygen Consumption; Papillary Muscles; Phosphates; Protons; Rats; Rats, Wistar; Reactive Oxygen Species
PubMed: 35993114
DOI: 10.1113/JP282991 -
Structural Heart : the Journal of the... Jun 2022Mitral valve prolapse (MVP) is the most common nonischemic mitral regurgitation etiology and mitral abnormality requiring surgery in the Western world. There is an... (Review)
Review
Mitral valve prolapse (MVP) is the most common nonischemic mitral regurgitation etiology and mitral abnormality requiring surgery in the Western world. There is an increasing awareness that pathological findings in MVP are not confined to the valve tissue; rather, it is a complex disease, involving the mitral valve apparatus, cardiac hemodynamics, and cardiac structure. Imaging has played a fundamental role in the understanding of the diagnosis, prevalence, and consequences of MVP. The diagnosis of MVP by imaging is based upon demonstrating valve leaflets ascending into the left atrium through the saddle-shaped annulus. Transthoracic and transesophageal echocardiography are the primary modalities in the diagnosis and assessment of MVP patients and must include careful assessment of the leaflets, annulus, chords, and papillary muscles. High-spatial-resolution imaging modalities such as cardiac magnetic resonance images and cardiac computed tomography play a secondary role in this regard and can demonstrate the anatomical relation between the mitral valve annulus and leaflet excursion for appropriate diagnosis. Ongoing development of new methods of cardiac imaging can help us to accurately understand the mechanism, diagnose the disease, develop an appropriate treatment plan, and estimate the risk for sudden death. Recently, several new observations with respect to prolapse have been derived from cardiac imaging including three-dimensional echocardiography and tissue-Doppler imaging. The aim of this article is to present these new imaging-derived insights for the diagnosis, risk assessment, treatment, and follow-up of patients with MVP.
PubMed: 37273735
DOI: 10.1016/j.shj.2022.100024 -
BMC Cardiovascular Disorders Aug 2023Fabry disease (FD) is an X-linked genetic lysosomal disease, in which a deficit in the alpha-galactosidase A enzyme results in lysosomal build-up of...
BACKGROUND AND AIMS
Fabry disease (FD) is an X-linked genetic lysosomal disease, in which a deficit in the alpha-galactosidase A enzyme results in lysosomal build-up of globotriaosylceramide in several organs, causing cardiac, renal and cerebrovascular complications. The aim of this study was to assess the prevalence of papillary muscle hypertrophy (PMH) in patients with FD.
METHODS
A group of 63 patients with FD and a positive genetic diagnosis were studied and were divided into two groups: one included 24 patients with FD and LVH and another group included 39 patients with FD and without LVH. Papillary muscles were measured from the left parasternal short axis view, defining PMH as a diastolic thickness greater than 11 mm in any diameter.
RESULTS
Patients with FD and LVH had a high prevalence of anterolateral PMH (66.6%), and such prevalence was lower for the posteromedial PMH (33.3%). However, patients who had not yet developed LVH had a high prevalence of anterolateral PMH (33.3%).
CONCLUSIONS
Patients with FD in the pre-clinical stage (without LVH) have a high prevalence of PMH, especially involving the anterolateral papillary muscle. This finding could be an early marker for the development of LVH, allowing to suspect the disease during its early stages, and begin enzyme replacement therapy in the appropriate patients.
Topics: Humans; Fabry Disease; Papillary Muscles; Prevalence; Hypertrophy; Kidney
PubMed: 37635225
DOI: 10.1186/s12872-023-03463-w -
International Journal of Molecular... Aug 2020Bladder cancer is a heterogeneous disease that is not depicted by current classification systems. It was originally classified into non-muscle invasive and muscle... (Review)
Review
Bladder cancer is a heterogeneous disease that is not depicted by current classification systems. It was originally classified into non-muscle invasive and muscle invasive. However, clinically and genetically variable tumors are summarized within both classes. A definition of three groups may better account for the divergence in prognosis and probably also choice of treatment. The first group represents mostly non-invasive tumors that reoccur but do not progress. Contrarily, the second group represent non-muscle invasive tumors that likely progress to the third group, the muscle invasive tumors. High throughput tumor profiling improved our understanding of the biology of bladder cancer. It allows the identification of molecular subtypes, at least three for non-muscle invasive bladder cancer (Class I, Class II and Class III) and six for muscle-invasive bladder cancer (luminal papillary, luminal non-specified, luminal unstable, stroma-rich, basal/squamous and neuroendocrine-like) with distinct clinical and molecular phenotypes. Molecular subtypes can be potentially used to predict the response to treatment (e.g., neoadjuvant chemotherapy and immune checkpoint inhibitors). Moreover, they may allow to characterize the evolution of bladder cancer through different pathways. However, to move towards precision medicine, the understanding of the biological meaning of these molecular subtypes and differences in the composition of cell subpopulations will be mandatory.
Topics: Animals; Biomarkers, Tumor; Humans; Muscles; Treatment Failure; Urinary Bladder Neoplasms; Urothelium
PubMed: 32784716
DOI: 10.3390/ijms21165670