-
Scientific Reports Sep 2023Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be...
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
Topics: Humans; Animals; Guinea Pigs; Dogs; Anti-Arrhythmia Agents; Ventricular Fibrillation; Calcium; Atrial Fibrillation; Papillary Muscles; Models, Animal
PubMed: 37775650
DOI: 10.1038/s41598-023-41942-4 -
Cardiovascular Journal of AfricaWe aimed to evaluate and compare papillary muscle free strain in hypertrophic cardiomyopathy (HCMP) and hypertensive (HT) patients.
OBJECTIVES
We aimed to evaluate and compare papillary muscle free strain in hypertrophic cardiomyopathy (HCMP) and hypertensive (HT) patients.
METHODS
Global longitudinal strain (GLS), and longitudinal myocardial strain of the anterolateral (ALPM) and posteromedial papillary muscles (PMPM) were obtained in 46 HCMP and 50 HT patients.
RESULTS
Interventricular septum (IVS)/posterior wall (PW) thickness ratio, left ventricular mass index (LVMI), left atrial anteroposterior diameter (LAAP) and mitral E/E' were found to be increased in patients with HCMP compared to HT patients. Left ventricular cavity dimensions were smaller in HCMP patients. GLS of HCMP and HT patients were - 14.52 ± 3.01 and -16.85 ± 1.36%, respectively ( < 0.001). Likewise, ALPM and PMPM free strain values were significantly reduced in HCMP patients over HT patients [-14.00% (-22 to -11%) and -15.5% (-24.02 to -10.16%) vs -23.00% (-24.99 to -19.01%) and -22.30% (-26.48 to -15.95%) ( = 0.016 and = 0.010)], respectively. ALPM free strain showed a statistically significant correlation with GLS, maximal wall thickness, IVS thickness and LVMI. PMPM free strain showed a significant correlation with GLS, IVS thickness and LAAP. The GLS value of - 13.05 had a sensitivity of 61.9% and a specificity of 97.4% for predicting HCMP. ALPM and PMPM free strain values of -15.31 and -17.17% had 63 and 76.9% sensitivity and 85.7 and 76.9% specificity for prediction of HCMP.
CONCLUSIONS
Besides other echocardiographic variables, which were investigated in earlier studies, papillary muscle free strain also could be used in HCMP to distinguish HCMP- from HT-associated hypertrophy.
Topics: Humans; Hypertrophy, Left Ventricular; Papillary Muscles; Myocardial Contraction; Cardiomyopathy, Hypertrophic; Hypertension; Ventricular Function, Left
PubMed: 36947167
DOI: 10.5830/CVJA-2022-070 -
Frontiers in Physiology 2022While the reductionist approach has been fruitful in understanding the molecular basis of muscle function, intact excitable muscle preparations are still important as...
While the reductionist approach has been fruitful in understanding the molecular basis of muscle function, intact excitable muscle preparations are still important as experimental model systems. We present here methods that are useful for preparing cardiac papillary muscle and cardiac slices, which represent macroscopic experimental model systems with fully intact intercellular and intracellular structures. The maintenance of these structures for experimentation have made these model systems especially useful for testing the functional effects of protein mutations and pharmaceutical candidates. We provide solutions recipes for dissection and recording, instructions for removing and preparing the cardiac papillary muscles, as well as instruction for preparing cardiac slices. These instructions are suitable for beginning experimentalists but may be useful for veteran muscle physiologists hoping to reacquaint themselves with macroscopic functional analyses.
PubMed: 35309048
DOI: 10.3389/fphys.2022.817205 -
Diagnostics (Basel, Switzerland) Feb 2020Papillary thyroid cancer (PTC) is the most common type of thyroid malignancy and is characterized by slow growth and an indolent biological behavior. Papillary thyroid... (Review)
Review
Papillary thyroid cancer (PTC) is the most common type of thyroid malignancy and is characterized by slow growth and an indolent biological behavior. Papillary thyroid microcarcinoma is the PTC with the maximum size of the tumor <1cm, considered the most indolent form of thyroid cancer. PTC is usually metastasizes in cervical lymph nodes, lungs and bones and, less commonly, in brain or liver. Skeletal muscle metastases from PTC are extremely rare, a retrospective review of the literature revealed only 13 case reports. Among them, six cases are solitary skeletal muscle metastases, and seven are multiple metastases, most of them being associated with lung lesions. It seems that PTC is prone to metastasizing to the erector spinae and thigh muscles groups with unique cases located in trapezoid, biceps, deltoid, gastrocnemius and rectus abdominis muscles. Although extremely rare, one must bear in mind the fact that muscle metastasis from PTC is possible, and that is the reason we would like to discuss the existing clinical cases and to add a unique case of solitary skeletal muscle metastasis from papillary microcarcinoma.
PubMed: 32059570
DOI: 10.3390/diagnostics10020100 -
Journal of Thoracic Disease Jun 2017Ischemic mitral regurgitation (IMR) is a complex disorder occurring after a myocardial infarction and affecting both the mitral valvular and subvalvular apparati.... (Review)
Review
Ischemic mitral regurgitation (IMR) is a complex disorder occurring after a myocardial infarction and affecting both the mitral valvular and subvalvular apparati. Several abnormalities can be detected in IMR as annular dilatation, leaflet tethering with impaired coaptation and papillary muscle (PM) displacement along a posterior, apical or lateral vectors. Treatments available include, beside myocardial revascularization, mitral-valve repair or chordal-sparing replacement. Repair is normally achieved downsizing the mitral valve annulus with a rigid or semirigid ring. However, considering the involvement of the subvalvular apparatus, techniques addressing the PM have been developed. The rationale at the basis of this strategy relies in the possibility to reduce the interpapillary muscle distance restoring the geometry of the left ventricle (LV) and ultimately resolving the leaflet tethering at the basis of IMR. Subvalvular apparatus surgical approaches include the papillary muscle approximation (PMA), surgical relocation and PM sling. Improved outcomes in terms of postoperative positive left ventricular remodeling and recurrence of mitral regurgitation have been reported, but more investigations are required to confirm the efficacy of subvalvular apparatus surgery. Application of finite element analysis to improve preoperative and intraoperative planning and achieve a correct and durable repair by means of subvalvular surgery is an exciting new avenue in IMR research.
PubMed: 28740718
DOI: 10.21037/jtd.2017.06.98 -
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 -
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