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Methods in Molecular Biology (Clifton,... 2021Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to...
Isolated cardiac tissue allows investigators to study mechanisms underlying normal and pathological conditions, which would otherwise be difficult or impossible to perform in vivo. In contrast to ventricular muscle strip preparations, papillary muscles can be prepared without severely damaging the muscle tissue. In this preparation, the isolated papillary muscle is fixed in an environmentally controlled organ bath chamber and electrically stimulated. The evoked twitch force is recorded using a pressure transducer, and parameters such as twitch force amplitude and twitch kinetics are analyzed. A variety of experimental protocols can be performed to investigate the calcium- and frequency-dependent contractility as well as dose-response curves of contractile agents, as well as simulation of pathologic conditions such as acute cardiac ischemia. Mouse papillary muscle preparations have long been the mainstay for studying interactions between intracellular calcium regulation and contractile responses under a number of simulated pathophysiological conditions. These studies are often used to complement in vitro studies performed using isolated neonatal rat cardiac myocytes. In this procedure, we describe how neonatal rat papillary muscles can also be prepared for use in contractile studies.
Topics: Animals; Animals, Newborn; Electric Stimulation; Myocardial Contraction; Myocytes, Cardiac; Papillary Muscles; Rats; Surgical Equipment
PubMed: 34331240
DOI: 10.1007/978-1-0716-1480-8_4 -
European Journal of Cardio-thoracic... Jun 2022
Topics: Humans; Mitral Valve; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Papillary Muscles
PubMed: 35678572
DOI: 10.1093/ejcts/ezac339 -
Echocardiography (Mount Kisco, N.Y.) Jul 2017Acute myocardial infarctions (AMI) continue to be common in the United States. Mechanical complications of AMI can lead to cardiogenic shock (CS) and death. The aim of...
BACKGROUND
Acute myocardial infarctions (AMI) continue to be common in the United States. Mechanical complications of AMI can lead to cardiogenic shock (CS) and death. The aim of this study was to review the cases of papillary muscle ruptures in the setting of myocardial infarctions at a tertiary care center, with a focus on the clinical presentation and echocardiographic diagnosis.
METHODS
This was a retrospective study from January 1, 2000 through December 31, 2014. In all, 22 patients with AMI and papillary muscle rupture (AMI-PMR) who had surgical intervention were identified.
RESULTS
The average age was 70 (±11) with 16 (73%) males. Six patients presented with ST-elevation myocardial infarctions (STEMI) and all underwent emergent revascularization with primary percutaneous coronary intervention (PCI) prior to the diagnosis of AMI-PMR. The other 16 patients presented with a non-STEMI. In total, 17 (77%) of the 22 patients were diagnosed with an AMI-PMR within 7 days from their onset of symptoms. In all, 12 patients (55%) had anterolateral papillary muscle ruptures (ALPMR), and the other 10 had posteromedial papillary muscle ruptures (PMPMR). Ruptures were complete in 10 patients (45%). Patients presented with pulmonary edema early (<7 days) more commonly than late (>14 days). Transthoracic echocardiography was able to demonstrate severe mitral regurgitation in 86% and a definitive or suggestive diagnosis in 93%. All 22 patients survived to operative management, and the overall in-hospital mortality rate was 9%.
CONCLUSION
In conclusion, ischemic papillary muscle ruptures continue to occur, but with prompt diagnosis by echocardiography and rapid surgical management, the mortality rate continues to decline.
Topics: Aged; Aged, 80 and over; Echocardiography; Female; Heart Rupture, Post-Infarction; Humans; Male; Middle Aged; Papillary Muscles; Retrospective Studies
PubMed: 28560714
DOI: 10.1111/echo.13585 -
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 -
European Journal of Cardio-thoracic... Jun 2017Secondary mitral regurgitation (MR) is present in up to half of patients with dilated cardiomyopathy, and is associated with a poor prognosis. It primarily results from... (Review)
Review
Secondary mitral regurgitation (MR) is present in up to half of patients with dilated cardiomyopathy, and is associated with a poor prognosis. It primarily results from progressive left ventricular remodelling, papillary muscle displacement and tethering of the mitral valve leaflets. Mitral valve repair with an undersized ring annuloplasty is the reparative procedure of choice in the treatment of secondary MR. However, this technique is associated with a 30-60% incidence of recurrent moderate or greater MR at mid-term follow-up, which results in progressive deterioration of left ventricular function and increased morbidity. Combined mitral valve repair and papillary muscle approximation has been applied in order to address both the annular and subvalvular dysfunction that coexist in secondary MR, which include graft and suture-based techniques. Herein, we provide a systematic review of the published literature regarding the technical aspects, clinical application, and outcomes of mitral valve repair with combined ring annuloplasty and papillary muscle approximation for the treatment of secondary MR.
Topics: Aged; Humans; Middle Aged; Mitral Valve; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Papillary Muscles; Reoperation
PubMed: 28040676
DOI: 10.1093/ejcts/ezw384 -
Medical Engineering & Physics May 2024Early detection of cardiovascular diseases is based on accurate quantification of the left ventricle (LV) function parameters. In this paper, we propose a fully...
OBJECTIVE
Early detection of cardiovascular diseases is based on accurate quantification of the left ventricle (LV) function parameters. In this paper, we propose a fully automatic framework for LV volume and mass quantification from 2D-cine MR images already segmented using U-Net.
METHODS
The general framework consists of three main steps: Data preparation including automatic LV localization using a convolution neural network (CNN) and application of morphological operations to exclude papillary muscles from the LV cavity. The second step consists in automatically extracting the LV contours using U-Net architecture. Finally, by integrating temporal information which is manifested by a spatial motion of myocytes as a third dimension, we calculated LV volume, LV ejection fraction (LVEF) and left ventricle mass (LVM). Based on these parameters, we detected and quantified cardiac contraction abnormalities using Python software.
RESULTS
CNN was trained with 35 patients and tested on 15 patients from the ACDC database with an accuracy of 99,15 %. U-Net architecture was trained using ACDC database and evaluated using local dataset with a Dice similarity coefficient (DSC) of 99,78 % and a Hausdorff Distance (HD) of 4.468 mm (p < 0,001). Quantification results showed a strong correlation with physiological measures with a Pearson correlation coefficient (PCC) of 0,991 for LV volume, 0.962 for LVEF, 0.98 for stroke volume (SV) and 0.923 for LVM after pillars' elimination. Clinically, our method allows regional and accurate identification of pathological myocardial segments and can serve as a diagnostic aid tool of cardiac contraction abnormalities.
CONCLUSION
Experimental results prove the usefulness of the proposed method for LV volume and function quantification and verify its potential clinical applicability.
Topics: Humans; Heart Ventricles; Magnetic Resonance Imaging, Cine; Automation; Papillary Muscles; Image Processing, Computer-Assisted; Organ Size; Male; Middle Aged; Neural Networks, Computer; Female; Stroke Volume
PubMed: 38692762
DOI: 10.1016/j.medengphy.2024.104162 -
The Thoracic and Cardiovascular Surgeon Mar 2022We performed "Papillary muscle heads focalization" for three patients with severe functional mitral regurgitation with severe leaflet tethering (coaptation distance...
We performed "Papillary muscle heads focalization" for three patients with severe functional mitral regurgitation with severe leaflet tethering (coaptation distance ≥1 cm and/or posterior leaflet angle ≥45 degrees). All separated papillary muscle heads were sutured together and both the anterolateral and posteromedial papillary muscles were reconstructed as single head papillary muscles. The stitches are positioned to adjust the levels of mitral leaflet tips, concerning the length of the marginal chordae connected to each head. A downsized annuloplasty is performed concomitantly. At discharge, no patient showed moderate/severe mitral regurgitation. Their coaptation lengths were 7.1, 8.5, and 8.3 mm.
Topics: Humans; Mitral Valve; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Papillary Muscles; Treatment Outcome
PubMed: 33831965
DOI: 10.1055/s-0040-1722730 -
European Radiology Jul 2023The prognostic role of left ventricular (LV) papillary muscle abnormalities in patients with preserved LV systolic ejection fraction (LVEF) is unknown. We sought to...
OBJECTIVES
The prognostic role of left ventricular (LV) papillary muscle abnormalities in patients with preserved LV systolic ejection fraction (LVEF) is unknown. We sought to evaluate the prognosis role of LV papillary muscle abnormalities by CMR in patients with ventricular arrhythmias, preserved LVEF with no cardiac disease.
METHODS
A total of 391 patients with > 500/24 h premature ventricular complexes and/or with non-sustained ventricular tachycardia (NSVT), preserved LVEF, and no cardiac disease were enrolled. Different features of LV papillary muscles were considered: supernumerary muscles, papillary thickness, the attachment, late gadolinium enhancement (LGE). Dark-Paps was defined as end-systolic signal hypointensity of both papillary muscles in early post-contrast cine CMR images. Mitral valve prolapse, mitral annular disjunction (MAD), and myocardial LGE were considered.
RESULTS
Dark-Paps was found in 79 (20%) patients and was more frequent in females. It was associated with higher prevalence of mitral valve prolapse and MAD. During a median follow-up of 2534 days, 22 hard cardiac events occurred. At Kaplan-Meier curve analysis, patients with Dark-Paps were at higher risk of events than those without (p < 0.0001). Dark-Paps was significantly associated with hard cardiac events in all the multivariate models. Dark-Paps improved prognostic estimation when added to NSVT (p = 0.0006), to LGE (p = 0.005) and to a model including NSVT+LGE (p = 0.014). Dark-Paps allowed a significant net reclassification when added to NSVT (NRI 0.30, p = 0.03), to LGE (NRI 0.25, p = 0.04), and to NSVT + LGE (NRI 0.32, p = 0.02).
CONCLUSIONS
In LV papillary muscles, Dark-Paps is a novel prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction.
KEY POINTS
• Papillary muscle abnormalities are seen in patients with ventricular arrhythmias and preserved left ventricular ejection fraction. • Early post-contrast hypointensity of papillary muscles in end-systolic cine images (Dark-Paps) is a novel prognostic marker in patients with ventricular arrhythmias and preserved ejection fraction. • Dark-Paps had an additive prognostic role over late gadolinium enhancement and non-sustained ventricular tachycardia.
Topics: Female; Humans; Papillary Muscles; Contrast Media; Stroke Volume; Mitral Valve Prolapse; Prognosis; Ventricular Function, Left; Gadolinium; Magnetic Resonance Imaging, Cine; Arrhythmias, Cardiac; Heart Diseases; Tachycardia, Ventricular; Magnetic Resonance Spectroscopy; Predictive Value of Tests
PubMed: 36692598
DOI: 10.1007/s00330-023-09400-x -
Catheterization and Cardiovascular... Jul 2023Papillary muscle rupture (PMR) is a rare complication of acute myocardial infarction (AMI) associated with high mortality and morbidity. Surgery is the gold-standard... (Review)
Review
Papillary muscle rupture (PMR) is a rare complication of acute myocardial infarction (AMI) associated with high mortality and morbidity. Surgery is the gold-standard treatment for these patients, but it is burdened by a high perioperative risk due to hemodynamic instability. Mitral transcatheter edge-to-edge repair (M-TEER) was reported to be safe and effective in unstable patients with significant mitral regurgitation. However, data in patients with post-AMI PMR are limited to a few case reports. In this review, we summarized all data available regarding percutaneous treatment of post-AMI PMR. These results show that M-TEER is safe and effective in this setting with low in-hospital mortality and complications and high rate of significant mitral regurgitation reduction.
Topics: Humans; Mitral Valve Insufficiency; Mitral Valve; Papillary Muscles; Heart Rupture, Post-Infarction; Treatment Outcome; Myocardial Infarction; Heart Valve Prosthesis Implantation; Heart Failure
PubMed: 37161909
DOI: 10.1002/ccd.30682 -
Heart Rhythm Oct 2023Ventricular arrhythmias (VAs) originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. Reasons may include premature...
BACKGROUND
Ventricular arrhythmias (VAs) originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. Reasons may include premature ventricular complex pleomorphism, structurally abnormal PAPs, or unusual origins of VAs from PAP-myocardial connections (PAP-MYCs).
OBJECTIVE
The purpose of this study was to correlate PAP anatomy with mapping and ablation of PAP VAs.
METHODS
In a series of 43 consecutive patients with frequent PAP arrhythmias referred for ablation, the anatomy and structure of PAPs and VA origins were analyzed using multimodality imaging. Successful ablation sites were analyzed for location on the PAP body or a PAP-MYC.
RESULTS
In a total of 17 of 43 patients (40%), VAs originated from a PAP-MYC (in 5 of 17 patients, the PAP inserted into the mitral valve anulus); and in 41 patients, VAs originated from a PAP body. VAs from a PAP-MYC more often had delayed R-wave transition than did other PAP VAs (69% vs 28%; P < .001). Patients with failed procedures had more PAP-MYCs (24.8 ± 8 PAP-MYCs per patient vs 16 ± 7 PAP-MYCs per patient; P < .001).
CONCLUSION
Multimodality imaging identifies anatomic details of PAPs that facilitate mapping and ablation of VAs. In more than a third of patients with PAP VAs, VAs originate from connections between PAPs and the surrounding myocardium or between other PAPs. VA electrocardiographic morphologies are different when VAs originate from PAP-connection sites as compared with VAs originating from the PAP body.
Topics: Humans; Papillary Muscles; Tachycardia, Ventricular; Ventricular Premature Complexes; Electrocardiography; Mitral Valve; Catheter Ablation; Heart Ventricles
PubMed: 37329938
DOI: 10.1016/j.hrthm.2023.06.009