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Radiology. Cardiothoracic Imaging Dec 2023Mitral annular disjunction (MAD) refers to atrial displacement of the hinge point of the mitral valve annulus from the ventricular myocardium. MAD leads to paradoxical... (Review)
Review
Mitral annular disjunction (MAD) refers to atrial displacement of the hinge point of the mitral valve annulus from the ventricular myocardium. MAD leads to paradoxical expansion of the annulus in systole and may often be associated with mitral valve prolapse (MVP), leaflet degeneration, myocardial and papillary muscle fibrosis, and, potentially, malignant cardiac arrhythmias. Patients with MAD and MVP may present similarly, and MAD is potentially the missing link in explaining why some patients with MVP experience adverse outcomes. Patients with a 5 mm or longer MAD distance have an elevated risk of malignant cardiac arrhythmia compared with those with a shorter MAD distance. Evaluation for MAD is an important component of cardiac imaging, especially in patients with MVP and unexplained cardiac arrhythmias. Cardiac MRI is an important diagnostic tool that aids in recognizing and quantifying MAD, MVP, and fibrosis in the papillary muscle and myocardium, which may predict and help improve outcomes following electrophysiology procedures and mitral valve surgery. This article reviews the history, pathophysiology, controversy, prevalence, clinical implications, and imaging considerations of MAD, focusing on cardiac MRI. MR-Dynamic Contrast Enhanced, Cardiac, Mitral Valve, Mitral Annular Disjunction, Mitral Valve Prolapse, Floppy Mitral Valve, Cardiac MRI, Arrhythmia, Sudden Cardiac Death, Barlow Valve © RSNA, 2023.
Topics: Humans; Mitral Valve; Mitral Valve Prolapse; Arrhythmias, Cardiac; Papillary Muscles; Fibrosis
PubMed: 38166341
DOI: 10.1148/ryct.230131 -
Medicine Nov 2023Deciding whether to include or exclude the papillary muscles and trabeculae to blood pool is essential, because quantifications of left ventricular (LV) functional...
Deciding whether to include or exclude the papillary muscles and trabeculae to blood pool is essential, because quantifications of left ventricular (LV) functional parameters and myocardial mass are significantly affected. As a result, such inclusion or exclusion might produce different indices for diagnosis and therapy. Using cardiac computed tomography (CT), we obtained standard values of the portion of papillary muscle and trabeculae in normal adults, and to find out how the inclusion or exclusion of papillary muscle and trabeculae affect LV functional parameters depending on the patient group. Excluding the papillary muscles from the LV mass results in easier automated contour detection using CT. The percentage portions of papillary muscle and trabeculae to LV end-diastolic volume (EDV) and LV mass (LVM) were 11.9 ± 5.6% and 20.2 ± 4.3%, respectively, significantly affecting disease diagnosis. Imaging should be consistent at follow-up and include or exclude the papillary muscles and trabeculae to avoid introducing significant differences between measurements.
Topics: Adult; Humans; Papillary Muscles; Ventricular Function, Left; Cross-Sectional Studies; Heart Ventricles; Tomography, X-Ray Computed; Stroke Volume; Reproducibility of Results
PubMed: 37986395
DOI: 10.1097/MD.0000000000036106 -
General Thoracic and Cardiovascular... Sep 2014The surgical strategy for ischemic mitral regurgitation (MR) remains controversial. Ischemic MR is a secondary valve disease caused by left ventricular (LV) remodeling... (Review)
Review
The surgical strategy for ischemic mitral regurgitation (MR) remains controversial. Ischemic MR is a secondary valve disease caused by left ventricular (LV) remodeling and subsequent papillary muscle displacement, usually without structural valve lesions. Reduction annuloplasty is the standard surgical procedure for this condition, though it cannot clearly provide a survival benefit for those with LV dysfunction and is associated with a high prevalence of late recurrence of MR. The valvular procedure alone could be insufficient to treat ischemic MR in terms of long-term survival and the prevention of recurrence because ischemic MR is primarily a ventricular disorder. Thus, recent studies have focused on alternative procedures that target the primary cause of ischemic MR, the papillary muscles and left ventricle. We believe that the appropriate selection of surgical procedures among valvular, subvalvular, and even ventricular ones, considering the severity of LV remodeling for each patient would be more beneficial. Here we review recent studies featuring various surgical approaches to ischemic MR, especially with submitral procedures.
Topics: Cardiac Surgical Procedures; Heart Ventricles; Humans; Mitral Valve Annuloplasty; Mitral Valve Insufficiency; Myocardial Ischemia; Papillary Muscles; Recurrence; Ventricular Dysfunction, Left; Ventricular Remodeling
PubMed: 25022809
DOI: 10.1007/s11748-014-0453-3 -
The Journal of Thoracic and... Jan 2022To categorize and assess the functional significance of anomalous papillary muscles in patients undergoing surgical management of obstructive hypertrophic cardiomyopathy.
OBJECTIVES
To categorize and assess the functional significance of anomalous papillary muscles in patients undergoing surgical management of obstructive hypertrophic cardiomyopathy.
METHODS
We reviewed the records of operations for obstructive hypertrophic cardiomyopathy and identified 73 patients with an anomalous papillary muscle. Anomalous papillary muscles inserting directly into the body of the anterior mitral valve leaflet were classified as type I, those with both direct insertion into the body of the leaflet and attachment to the free edge of the anterior leaflet were categorized as type II, and anomalous papillary muscles inserting into the free edge of the anterior leaflet were grouped as type III. Additionally, we investigated detection rates by preoperative transthoracic echocardiography, intraoperative transesophageal echocardiography, and cardiac magnetic resonance imaging.
RESULTS
The mean age of patients was 51.9 ± 12.3 years, and 49.3% were male. The anomalous papillary muscle was classified as type I in 31.5% of patients, type II in 35.6%, and type III in 32.9%. Only type I and type II anomalous papillary muscles contributed to left ventricular outflow tract obstruction. The anomalous papillary muscle was detected on preoperative transthoracic echocardiography in 11% of patients and by intraoperative transesophageal echocardiography in 27.4% of patients. No anomalous papillary muscles were identified on cardiac magnetic resonance imaging. All patients underwent septal myectomy with or without (n = 34) associated excision of the anomalous papillary muscle. Excision of the papillary muscles was more common in patients with type I and II (76.4% and 80.8%, respectively) when compared with type III (4.2%). Ten patients underwent mitral valve repair, and 1 patient had mitral valve replacement.
CONCLUSIONS
Papillary muscle abnormalities are important findings in patients with obstructive hypertrophic cardiomyopathy but are not identified preoperatively in the majority of patients. Recognition of anomalous papillary muscles intraoperatively and understanding of the morphologic subtypes are critical to adequate gradient relief and preservation of mitral valve function. The optimum approach involves a transaortic extended septal myectomy associated with the resection of the anomalous papillary muscles in patients with type I and II anatomy.
Topics: Cardiac Surgical Procedures; Cardiomyopathy, Hypertrophic; Echocardiography, Transesophageal; Female; Heart Septum; Humans; Intraoperative Complications; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Mitral Valve; Mitral Valve Annuloplasty; Outcome and Process Assessment, Health Care; Papillary Muscles; Postoperative Complications; Preoperative Care; United States
PubMed: 32414597
DOI: 10.1016/j.jtcvs.2020.04.007 -
Journal of Cardiovascular... Dec 2021Myxomatous mitral valve prolapse (MVP) and mitral-annular disjunction (Barlow disease) are at-risk for ventricular arrhythmias (VA). Fibrosis involving the papillary...
BACKGROUND
Myxomatous mitral valve prolapse (MVP) and mitral-annular disjunction (Barlow disease) are at-risk for ventricular arrhythmias (VA). Fibrosis involving the papillary muscles and/or the infero-basal left ventricular (LV) wall was reported at autopsy in sudden cardiac death (SCD) patients with MVP.
OBJECTIVES
We investigated the electrophysiological substrate subtending VA in MVP patients with Barlow disease phenotype.
METHODS
Twenty-three patients with VA were enrolled, including five with syncope and four with a history of SCD. Unipolar (Uni < 8.3 mV) and bipolar (Bi < 1.5 mV) low-voltage areas were analyzed with electro-anatomical mapping (EAM), and VA inducibility was evaluated with programmed ventricular stimulation (PES). Electrophysiological parameters were correlated with VA patterns, electrocardiogram (ECG) inferior negative T wave (nTW), and late gadolinium enhancement (LGE) assessed by cardiac magnetic resonance.
RESULTS
Premature ventricular complex (PVC) burden was 12 061.9 ± 12 994.6/24 h with a papillary-muscle type (PM-PVC) in 18 patients (68%). Twelve-lead ECG showed nTW in 12 patients (43.5%). A large Uni less than 8.3 mV area (62.4 ± 45.5 cm ) was detected in the basal infero-lateral LV region in 12 (73%) patients, and in the papillary muscles (2.2 ± 2.9 cm ) in 5 (30%) of 15 patients undergoing EAM. A concomitant Bi less than 1.5 mV area (5.0 ± 1.0 cm ) was identified in two patients. A history of SCD, and the presence of nTW, and LGE were associated with a greater Uni less than 8.3 mV extension: (32.8 ± 3.1 cm vs. 9.2 ± 8.7 cm ), nTW (20.1 ± 11.0 vs. 4.1 ± 3.8 cm ), and LGE (19.2 ± 11.7 cm vs. 1.0 ± 2.0 cm , p = .013), respectively. All patients with PM-PVC had a Uni less than 8.3 mV area. Sustained VA (ventricular tachycardia 2 and VF 2) were induced by PES only in four patients (one with resuscitated SCD).
CONCLUSIONS
Low unipolar low voltage areas can be identified with EAM in the basal inferolateral LV region and in the papillary muscles as a potential electrophysiological substrate for VA and SCD in patients with MVP and Barlow disease phenotype.
Topics: Contrast Media; Gadolinium; Humans; Mitral Valve Prolapse; Papillary Muscles; Ventricular Premature Complexes
PubMed: 34664762
DOI: 10.1111/jce.15270 -
Journal of Cardiovascular Translational... Jun 2023Ventricular tachycardia associated with papillary muscle (PM) is often refractory to standard radiofrequency ablation (RFA). The needle-tipped ablation catheter (NT-AC)...
Ventricular tachycardia associated with papillary muscle (PM) is often refractory to standard radiofrequency ablation (RFA). The needle-tipped ablation catheter (NT-AC) has been used to treat deep intramyocardial substrates, but its use for PM has not been characterized. Using an ex vivo experimental platform, both 3 mm and 6 mm NT-AC created larger ablation lesion volumes and depths than open-irrigated ablation catheter did (OI-AC; e.g., 57.12 ± 9.70mm and 2.42 ± 0.22 mm, respectively; p < 0.01 for all comparisons). Longer NT-AC extension (6 mm) resulted in greater ablation lesion volumes and maximum depths (e.g., 333.14 ± 29.13mm and 6.46 ± 0.29 mm, respectively, compared to the shorter 3 mm NT-AC extension, 143.33 ± 12.77mm, and 4.46 ± 0.14 mm; both p < 0.001). There were no steam pops. In conclusion, for PM ablation, the NT-AC was able to achieve ablation lesions that were larger and deeper than with conventional OI-AC. Ablation of PM may be another application for needle-tip ablation. Further studies are warranted to establish long-term safety and efficacy in human studies.
Topics: Humans; Papillary Muscles; Therapeutic Irrigation; Equipment Design; Catheters; Catheter Ablation
PubMed: 36264437
DOI: 10.1007/s12265-022-10331-z -
Journal of the Mechanical Behavior of... Nov 2020The mitral valve (MV) apparatus is a complex mechanical structure including annulus, valve leaflets, papillary muscles (PMs) and connected chordae tendineae. Chordae...
The mitral valve (MV) apparatus is a complex mechanical structure including annulus, valve leaflets, papillary muscles (PMs) and connected chordae tendineae. Chordae anchor to the papillary muscles to help the valve open and close properly during one cardiac cycle. It is of paramount importance to understand the functional, mechanical, and microstructural properties of mitral valve chordae and connecting PMs. In particular, little is known about the biomechanical properties of the anterior and posterior papillary muscle and corresponding chords. In this work, we performed uniaxial and biaxial tensile tests on the anterolateral (APM) and posteromedial papillary muscle (PPM), and their respective corresponding chordae tendineae, chordae and chordae, in porcine hearts. Histology was carried out to link the microstructure and macro-mechanical behavior of the chordae and PMs. Our results demonstrate that chordae are less in number, but significantly longer and stiffer than chordae. These different biomechanical properties may be partially explained by the higher collagen core ratio and larger collagen fibril density of chordae No significant mechanical or microstructural differences were observed along the circumferential and longitudinal directions of APM and PPM samples. Data measured on chordae and PMs were further fitted with the Ogden and reduced Holzapfel - Ogden strain energy functions, respectively. This study presents the first comparative anatomical, mechanical, and structural dataset of porcine mitral valve chordae and related PMs. Results indicate that a PM based classification of chordae will need to be considered in the analysis of the MV function or planning a surgical treatment, which will also help developing more precise computational models of MV.
Topics: Animals; Chordae Tendineae; Collagen; Mitral Valve; Mitral Valve Insufficiency; Papillary Muscles; Swine
PubMed: 32835989
DOI: 10.1016/j.jmbbm.2020.104011 -
The Annals of Thoracic Surgery Sep 2018Septal myectomy has been the mainstay of the surgical treatment of obstructive hypertrophic cardiomyopathy (HCM); however, recently there is growing appreciation for... (Observational Study)
Observational Study
BACKGROUND
Septal myectomy has been the mainstay of the surgical treatment of obstructive hypertrophic cardiomyopathy (HCM); however, recently there is growing appreciation for associated mitral valve abnormalities that contribute to left ventricular outflow tract (LVOT) obstruction. In this study, we describe our experience with combined papillary muscle realignment (PMR) and septal myectomy for the treatment of obstructive HCM.
METHODS
We identified 44 patients undergoing surgery for obstructive HCM whose anatomy was amenable to combined PMR and septal myectomy at our institution over a 20-month period. All patients underwent resting and stress echocardiography preoperatively and postoperatively. Demographic, clinical, and imaging data were prospectively collected in a cardiac surgery database.
RESULTS
Patient age ranged broadly, with mean age of 54 (range, 18 to 76) years. Preoperatively, 70% of patients were New York Heart Association functional class III or IV, the mean stress LVOT gradient was 144 mm Hg, and severe mitral regurgitation (MR) with stress was seen in 81%. Additional procedures included division of myocardial bands (50%) and chordae (43%) and resection of accessory papillary muscles (25%). Following the procedure, mean resting and stress gradients were reduced to normal (12 and 27 mm Hg, respectively; p < 0.0001). No patient had severe MR and only 3 (6.8%) had moderate MR (p < 0.0001). Mean length of stay was 6 days and there were no mortalities.
CONCLUSIONS
Septal myectomy combined with PMR is a safe, highly effective, and reproducible procedure that reliably relieves LVOT obstruction and corrects MR without the need for mitral valve repair or replacement.
Topics: Academic Medical Centers; Adolescent; Adult; Aged; Cardiomyopathy, Hypertrophic; Cohort Studies; Databases, Factual; Echocardiography, Transesophageal; Female; Follow-Up Studies; Heart Septum; Hospital Mortality; Humans; Male; Middle Aged; Papillary Muscles; Retrospective Studies; Risk Assessment; Severity of Illness Index; Statistics, Nonparametric; Survival Rate; Time Factors; Treatment Outcome; Ventricular Outflow Obstruction; Young Adult
PubMed: 29753818
DOI: 10.1016/j.athoracsur.2018.04.026 -
JACC. Cardiovascular Imaging Sep 2019This study sought to define interpapillary muscle dyssynchrony as a major contributing factor in functional mitral regurgitation (FMR) and prove the reversibility of FMR... (Observational Study)
Observational Study
OBJECTIVES
This study sought to define interpapillary muscle dyssynchrony as a major contributing factor in functional mitral regurgitation (FMR) and prove the reversibility of FMR by interpapillary muscle resynchronization.
BACKGROUND
Mechanistic features of FMR include papillary muscle displacement due to left ventricular remodeling. Intraventricular conduction delay might further augment this condition by introducing interpapillary muscle dyssynchrony.
METHODS
We enrolled 269 chronic heart failure with reduced ejection fraction patients with conduction delay and comprehensively assessed dyssynchrony by complementary echocardiographic techniques covering the entire spectrum of dyssynchrony.
RESULTS
Patients with severe FMR had markedly increased interpapillary longitudinal dyssynchrony (160 ms [interquartile range (IQR): 120 to 200 ms]) compared with those with moderate (70 ms [IQR: 40 to 110 ms]), no, or mild FMR (60 ms [IQR: 30 to 100 ms]; p < 0.001). Increased interpapillary muscle dyssynchrony was correlated with regurgitant volume (r = 0.50; p < 0.001) and vena contracta width (r = 0.49; p < 0.001). Restoration of longitudinal papillary muscle synchronicity by cardiac resynchronization therapy was correlated with FMR regression, as reflected by the reduction in regurgitant volume (r = 0.46; p < 0.001) and vena contracta width (r = 0.58; p < 0.001). Conversely, the improvement of FMR was associated with improved interpapillary radial (p = 0.006) and longitudinal (p < 0.001) dyssynchrony. The improvement of dyssynchrony-mediated FMR signified a better prognosis compared with no improvement in FMR during the 8-year follow-up period even after comprehensive adjustment by a bootstrap-selected confounder model (adjusted hazard ratio: 0.41; 95% confidence interval: 0.18 to 0.91; p = 0.028). The results remained virtually unchanged after adjustment for left bundle branch block.
CONCLUSIONS
Intraventricular dyssynchrony introduces unequal contraction by papillary muscle bearing walls, which has an adverse effect on FMR. Cardiac resynchronization therapy can effectively restore interpapillary balance and thus create a less tented leaflet configuration, resulting in a clinically meaningful reduction of FMR. The restoration of papillary muscle synchronicity in dyssynchrony-mediated FMR translates into a significantly better prognosis.
Topics: Aged; Cardiac Resynchronization Therapy; Chronic Disease; Female; Heart Failure; Humans; Male; Middle Aged; Mitral Valve; Mitral Valve Insufficiency; Myocardial Contraction; Papillary Muscles; Recovery of Function; Stroke Volume; Treatment Outcome; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling
PubMed: 30121264
DOI: 10.1016/j.jcmg.2018.06.013 -
Methods in Molecular Biology (Clifton,... 2018Ischemic mitral regurgitation (IMR) is a common complication of ischemic heart disease that doubles mortality after myocardial infarction and is a major driving factor...
Ischemic mitral regurgitation (IMR) is a common complication of ischemic heart disease that doubles mortality after myocardial infarction and is a major driving factor increasing heart failure. IMR is caused by left ventricular (LV) remodeling which displaces the papillary muscles that tether the mitral valve leaflets and restrict their closure. IMR frequently recurs even after surgical treatment. Failed repair associates with lack of reduction or increase in LV remodeling, and increased heart failure and related readmissions. Understanding mechanistic and molecular mechanisms of IMR has largely attributed to the development of large animal models. Newly developed therapeutic interventions targeted to the primary causes can also be tested in these models. The sheep is one of the most suitable models for the development of IMR. In this chapter, we describe the protocols for inducing IMR in sheep using surgical ligation of obtuse marginal branches. After successful posterior myocardial infarction involving posterior papillary muscle, animals develop significant mitral regurgitation around 2 months after the surgery.
Topics: Animals; Disease Models, Animal; Echocardiography; Mitral Valve; Mitral Valve Insufficiency; Myocardial Infarction; Myocardial Ischemia; Papillary Muscles; Sheep
PubMed: 29987829
DOI: 10.1007/978-1-4939-8597-5_23