[Percutaneous treatment of post-acute myocardial infarction mechanical complications: state of the art]. / Trattamento percutaneo delle complicanze meccaniche dell'infarto miocardico acuto: stato dell'arte.

Left ventricular free wall rupture, ventricular pseudoaneurysm, papillary muscle rupture and ventricular septal rupture are life-threatening mechanical complications of acute myocardial infarction. Despite significant improvements over the last decades in overall mortality for patients with myocardial infarction, the outcome of subjects who develop post-infarction mechanical complications remains poor. Surgical treatment is considered the standard of care. However, percutaneous approaches (such as pericardial fibrin-glue injection for left ventricular free wall rupture, transcatheter edge-to-edge mitral repair for papillary muscle rupture and device closure for ventricular pseudoaneurysm or septal rupture) have been proposed in selected high-risk or inoperable patients, or in subjects with ideal characteristics for feasibility, as therapeutic alternatives to open surgery. The aim of the present review is to provide a comprehensive overview of the percutaneous strategies for the management of post-acute myocardial infarction mechanical complications.

A Rare Case of Intracardiac Lipoma Arising from the Papillary Muscle.

Transthoracic echocardiography and cardiac magnetic resonance imaging revealed a well-defined globular mass attached to the anterolateral papillary muscle. The mass was hyperintense on T1 and T2 weighted images with suppression of signal on fat saturated and short tau inversion recovery (STIR) images. This imaging established the diagnosis of cardiac lipoma attached to the anterolateral papillary muscle, Papillary muscle is a very rare location of lipoma, which is rarely reported in the literature.

Mitral valve repair in ventricular functional mitral regurgitation: a simplified technique of papillary muscles relocation.

Mitral valve repair techniques in ventricular functional mitral regurgitation are controversial due to ongoing debates about long-term repair durability in the setting of left ventricular remodelling. To address the limitations of conventional annuloplasty, subannular techniques, such as papillary muscle relocation, have been developed. However, the limited reproducibility of these techniques has hindered their widespread adoption. In this context, we introduce a simplified and reproducible method for papillary muscle relocation. This method utilizes transoesophageal echocardiographic guidance and premeasured polytetrafluoroethylene loops to streamline the procedure.

Spontaneous Papillary Muscle Rupture: An Uncommon Presentation in the Absence of Myocardial Infarction.

BACKGROUND Papillary muscle rupture (PMR) is a rare complication of myocardial infarction (MI); experiencing PMR without MI makes it even more uncommon, thereby complicating its diagnosis. Therefore, we report a case of spontaneous PMR to raise awareness of this entity. CASE REPORT A 48-year-old man with type 2 diabetes presented to the Emergency Department (ED) after experiencing sudden shortness of breath that began the day before. He had no history of chest trauma, fever, chills, or ischemic chest pain. His vital signs showed stable blood pressure and mild tachycardia. The patient had hypoxemia that did not respond to use of a non-rebreather mask (oxygen saturation 70%). Upon examination, he had increased respiratory rate, altered sensorium, no lower-limb edema, and his chest auscultation revealed bilateral crackles. Chest radiography showed pulmonary edema. Two electrocardiograms (ECG) showed no signs of ST elevation myocardial infarction (STEMI) or RV strain. The patient was intubated but remained hypoxic despite maximum ventilation settings. Transthoracic echocardiography (TTE) performed immediately thereafter revealed acute severe mitral regurgitation with evidence of PMR. A multidisciplinary team approach was adopted early in this case, which resulted in a positive outcome. Eventually, mitral valve replacement was performed, and the patient was discharged home after 17 days, with a favorable neurological outcome. CONCLUSIONS We report a very rare case of spontaneous PMR in a middle-aged man with no evidence of MI, infective endocarditis, or preceding chest trauma. It shows the importance of adopting an early multidisciplinary team approach and showcases the abilities of emergency medicine physicians in early recognition.

Case Report: Non-ischemic Papillary Muscle Rupture due to MRSA Myocarditis with Concurrent Thromboembolic Myocardial Infarction Secondary to Infective Endocarditis.

Non-ischemic papillary muscle rupture (PMR) is rare. PMR caused by myocarditis in the presence of concurrent infective endocarditis (IE) and myocardial infarction (MI) has not been described. We report a 46-year-old male with recurrent MRSA bacteremia who presented in septic shock and suffered cardiac arrest. Echocardiography revealed acute mitral valve regurgitation resulting from posteromedial PMR. An intra-aortic balloon pump was implanted. Angiography revealed thrombotic occlusion of a small distal left circumflex artery. Emergent mitral valve replacement surgery was performed. MRSA myocarditis and IE were diagnosed by tissue cultures. Coexistence of myocarditis, IE, and MI poses a challenge in determining etiology.

Evaluation of the prognostic value of papillary muscle-free strain in patients with hypertrophic cardiomyopathy.

BACKGROUND: The prognosis of hypertrophic cardiomyopathy (HCM) varies from mild disease with a normal life expectancy to heart failure and sudden cardiac death (SCD). The identification of patients who are at high risk for SCD remains challenging. AIMS: In this study, we evaluated the prognostic value of papillary muscle-free strain in HCM patients. METHODS AND RESULTS: Seventy-nine patients with a diagnosis of HCM were included in this study. Patients were divided into low/intermediate-risk (n = 57) and high-risk (n = 22) groups. Two-dimensional (2-D) echocardiography and strain imaging were performed for each patient. The mean age of the study population was 53.85 ± 15.88 years; 47 (59.5%) of them were male. During a mean follow-up duration of 74.45 ± 17.03 months, 12 patients died. A comparison of the low-intermediate and high-SCD risk groups revealed that patients in the high-SCD risk group had greater maximal wall thickness, interventricular septum thickness, posterior wall thickness, and left ventricular mass index (LVMI) and lower (less negative) global longitudinal, anterolateral papillary muscle (ALPM) and posteromedial papillary muscle (PMPM) free strain. Additionally, a history of syncope and ICD implantation were found to be more common in patients with high SCD risk scores. The SCD risk score was positively correlated with the global longitudinal strain, ALPM-free strain, and PMPM-free strain (r = .528, r = .658, and r = .600, respectively; p < .001 for all). Our results showed that the LVMI, presence of syncope, global longitudinal strain, and ALPM-free strain were predictors of death. CONCLUSIONS: Decreased papillary muscle-free strain values might have prognostic value in patients with HCM.

Papillary Muscle Infarction by Cardiac MRI in Patients With Mitral Regurgitation.

BACKGROUND: Papillary muscle (PM) infarction (PMI) detected by cardiac magnetic resonance imaging (CMR) is associated with poor outcomes. Whether PM parameters provide more value for mitral regurgitation (MR) management currently remains unclear. Therefore, we examined the prognostic value of PMI using CMR in patients with MR. METHODS: Between March 2018 and July 2023, we retrospectively enrolled 397 patients with MR undergoing CMR. CMR was used to detect PMI qualitatively and quantitively. We also collected baseline clinical, echocardiography, and follow-up data. RESULTS: Of the 397 patients with MR (52.4 ± 13.9 years), 117 (29.5%) were assigned to the PMI group, with 280 (70.5%) in the non-PMI group. PMI was demonstrated more in the posteromedial PM (PM-PM, 98/117) than in the anterolateral PM (AL-PM, 45/117). Compared with patients without PMI, patients with PMI had a decreased AL-PM (41.5 ± 5.4 vs. 45.6 ± 5.3)/PM-PM diastolic length (35.0 ± 5.2 vs. 37.9 ± 4.0), PM-longitudinal strain (LS, 20.4 ± 6.1 vs. 24.9 ± 4.6), AL-PM-LS (19.7 ± 6.8 vs. 24.7 ± 5.6)/PM-PM-LS (21.2 ± 7.9 vs. 25.2 ± 6.0), and increased inter-PM distance (25.7 ± 8.0 vs. 22.7 ± 6.2, all p < 0.001). Multiple logistic regression analyses identified male sex (odds ratio [OR] = 3.65, 95% confidence interval = 1.881-7.081, p < 0.001) diabetes mellitus (OR/95% CI/p = 2.534/1.13-5.68/0.024), AL-PM diastolic length (OR/95% CI/p = 0.841/0.77-0.92/< 0.001), PM-PM diastolic length (OR/95% CI/p = 0.873/0.79-0.964/0.007), inter-PM distance (OR/95% CI/p = 1.087/1.028-1.15/0.003), AL-PM-LS (OR/95% CI/p = 0.892/0.843-0.94/< 0.001), and PM-PM-LS (OR/95% CI/p = 0.95/0.9-0.992/0.021) as independently associated with PMI. Over a 769 ± 367-day follow-up, 100 (25.2%) patients had arrhythmia. Cox regression analyses indicated that PMI (hazard ratio [HR]/95% CI/p = 1.644/1.062-2.547/0.026), AL-PM-LS (HR/95% CI/p = 0.937/0.903-0.973/0.001), and PM-PM-LS (HR/95% CI/p = 0.933/0.902-0.965/< 0.001) remained independently associated with MR. CONCLUSIONS: The CMR-derived PMI and LS parameters improve the evaluation of PM dysfunction, indicating a high risk for arrhythmia, and provide additive risk stratification for patients with MR.

Preclinical Study of Pulsed Field Ablation of Difficult Ventricular Targets: Intracavitary Mobile Structures, Interventricular Septum, and Left Ventricular Free Wall.

BACKGROUND: Endocardial catheter-based pulsed field ablation (PFA) of the ventricular myocardium is promising. However, little is known about PFA's ability to target intracavitary structures, epicardium, and ways to achieve transmural lesions across thick ventricular tissue. METHODS: A lattice-tip catheter was used to deliver biphasic monopolar PFA to swine ventricles under general anesthesia, with electroanatomical mapping, fluoroscopy and intracardiac echocardiography guidance. We conducted experiments to assess the feasibility and safety of repetitive monopolar PFA applications to ablate (1) intracavitary papillary muscles and moderator bands, (2) epicardial targets, and (3) bipolar PFA for midmyocardial targets in the interventricular septum and left ventricular free wall. RESULTS: (1) Papillary muscles (n=13) were successfully ablated and then evaluated at 2, 7, and 21 days. Nine lesions with stable contact measured 18.3±2.4 mm long, 15.3±1.5 mm wide, and 5.8±1.0 mm deep at 2 days. Chronic lesions demonstrated preserved chordae without mitral regurgitation. Two targeted moderator bands were transmurally ablated without structural disruption. (2) Transatrial saline/carbon dioxide assisted epicardial access was obtained successfully and epicardial monopolar lesions had a mean length, width, and depth of 30.4±4.2, 23.5±4.1, and 9.1±1.9 mm, respectively. (3) Bipolar PFA lesions were delivered across the septum (n=11) and the left ventricular free wall (n=7). Twelve completed bipolar lesions had a mean length, width, and depth of 29.6±5.5, 21.0±7.3, and 14.3±4.7 mm, respectively. Chronically, these lesions demonstrated uniform fibrotic changes without tissue disruption. Bipolar lesions were significantly deeper than the monopolar epicardial lesions. CONCLUSIONS: This in vivo evaluation demonstrates that PFA can successfully ablate intracavitary structures and create deep epicardial lesions and transmural left ventricular lesions.

Automatic left ventricle volume and mass quantification from 2D cine-MRI: Investigating papillary muscle influence.

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.

Biomechanical evaluation of flash-frozen and cryo-sectioned papillary muscle samples by using sinusoidal analysis: cross-bridge kinetics and the effect of partial Ca2+ activation.

We examined the integrity of flash-frozen and cryo-sectioned cardiac muscle preparations (introduced by Feng and Jin, 2020) by assessing tension transients in response to sinusoidal length changes at varying frequencies (1-100 Hz) at 25 °C. Using 70-µm-thick sections, we isolated fiber preparations to study cross-bridge (CB) kinetics: preparations were activated by saturating Ca2+ as well as varying concentrations of ATP and phosphate (Pi). Our results showed that, compared to ordinary skinned fibers, in-series stiffness decreased to 1/2, which resulted in a decrease of isometric tension to 62%, but CB kinetics and Ca2+ sensitivity were little affected. The pCa study demonstrated that the rate constant of the force generation step (2πb) is proportionate to [Ca2+] at < 5 µM, suggesting that the activation mechanism can be described by a simple second order reaction. We also found that tension, stiffness, and magnitude parameters are related to [Ca2+] by the Hill equation, with a cooperativity coefficient of 4-5, which is consistent with the fact that Ca2+ activation mechanisms involve cooperative multimolecular interactions. Our results support the long-held hypothesis that Process C (Phase 2) represents the CB detachment step, and Process B (Phase 3) represents the force generation step. Moreover, we discovered that constant H may represent the work-performing step in cardiac preparations. Our experiments demonstrate excellent CB kinetics with two well-defined exponentials that can be more distinguished than those found using ordinary skinned fibers. Flash-frozen and cryo-sectioned preparations are especially suitable for multi-institutional collaborations nationally and internationally because of their ease of transportation.

Percutaneous retrieval of an embolized Watchman device on a papillary muscle in the left ventricle.

The use of left atrial appendage occlusion (LAAO) devices have gained prominence as an alternative to long-term anticoagulation therapy in patients with atrial fibrillation at risk of stroke and high risk of bleeding. While these devices have shown efficacy in reducing stroke risk, there have been reported cases of embolization of the Watchman device. There are very few cases of successful percutaneous retrieval of embolized Watchman devices from the left ventricle (LV), as many of these cases require open heart surgery for safe removal. We are presenting a case of an 80-year-old male whose Watchman device embolized to the LV and was entrapped on the LV papillary muscle that was then successfully retrieved via percutaneous methods, which shows the percutaneous options remain a viable strategy to retrieve LAAO devices from the LV.

Mid-term outcomes of right ventricular papillary muscle approximation for severe functional tricuspid regurgitation.

OBJECTIVES: Recurrence of tricuspid regurgitation (TR) after tricuspid annuloplasty can occur in cases where a dilated right ventricle exists and subsequent leaflet tethering follows. We previously reported a new technique of the right ventricular papillary muscle approximation (RV-PMA) for functional TR associated with leaflet tethering. The objective of this study is to elucidate the mid-term outcomes and evaluate the durability of RV-PMA. METHODS: Between January 2014 and March 2023, we applied RV-PMA in 20 patients of advanced functional TR with severe leaflet tethering. The indication of the technique was severe TR with leaflet tethering height >8 mm, and/or a right ventricular end-diastolic diameter >45 mm. The patients were followed up with echocardiography before discharge and at annual interval thereafter. RESULTS: There was no perioperative mortality. In the echocardiography performed before discharge, TR was decreased to mild or less in 85%, and a significant improvement in right ventricular end-diastolic diameter and tethering height were achieved (53-45 mm and 11.1-4.4 mm, respectively). Furthermore, during the median 3-year follow-up period, TR was kept controlled mild or less in 80% of the cases. CONCLUSIONS: RV-PMA is considered to be a safe, effective and durable technique as an additional approach for tricuspid annuloplasty.

Current management of tricuspid regurgitation: a focus on the spiral suspension approach.

The indication for surgery for tricuspid regurgitation (TR) has reached a major turning point. It has become clear that the presence of moderate or severe TR alone worsens the prognosis of life, and the previous guidelines of Japanese Circulation Society, in which the indication for surgery was recommended at the timing of "right heart failure difficult to treat medically," now recommends surgery with a trigger of "repeated right heart failure" in the 2020 edition. In addition, a new repair technique targeting at subvalvular structure has been developed for end-stage TR to overcome a high TR recurrence rate that is associated with severe right ventricular enlargement and leaflet tethering. This review focuses on the spiral suspension technique, in which the papillary muscles are spirally suspended towards the septal leaflet annulus to correct tethering and enhances the understanding of its application in the context of TR management.

Interpapillary muscle distance independently predicts recurrent mitral regurgitation.

OBJECTIVE: Ischaemic secondary mitral regurgitation (ISMR) after surgery is due to the displacement of papillary muscles resulting from progressive enlargement of the left ventricle end-diastolic diameter (LVEDD). Our aim was to prove that if the interpapillary muscle distance (IPMD) is surgically stabilized, an increase in LVEDD will not lead to a recurrence of ischaemic mitral regurgitation (MR). METHODS: Ninety-six patients with ISMR, who underwent surgical revascularisation and annuloplasty, were randomly assigned in a 1:1 ratio to undergo papillary muscle approximation (PMA). At the 5-year follow-up, we assessed the correlation between PMA and echocardiographic improvements, the effect size of PMA on echocardiographic improvements, and a prediction model for recurrent MR using inferential tree analysis. RESULTS: There was a significant correlation between PMA and enhancements in both the α and ß angles (Spearman's rho > 0.7, p < 0.01). The α angle represents the angle between the annular plane and either the A2 annular-coaptation line or the P2 annular-coaptation line. The ß angle indicates the angle between the annular plane and either the A2 annular-leaflet tip line or the P2 annular-leaflet tip line. PMA led to substantial improvements in LVEDD, tenting area, α and ß angles, with a large effect size (Hedge's g ≥ 8, 95% CI ORs ≠ 1). The most reliable predictor of recurrent MR grade was the interpapillary distance, as only patients with an interpapillary distance greater than 40 mm developed ≥ 3 + grade MR. For patients with an IPMD of 40 mm or less, the best predictor of recurrent MR grade was LVEDD. Among the patients, only those with LVEDD greater than 62 mm showed moderate (2+) MR, while only those with LVEDD less than or equal to 62 mm had absent to mild (1+) MR. CONCLUSION: Prediction of recurrent ischaemic MR is not independent of progressive LVEDD increase. PMA-based surgical procedure stabilises IPMD.

Multimodality imaging for the diagnosis of left ventricular apical hypoplasia: A case presentation and review of the literatures.

Left ventricular apical hypoplasia is a rare malformation recently described congenital abnormality characterized by: (1) truncation of the left ventricle, with the septum projecting toward the right ventricle; (2) abnormal papillary muscle originating from the flattened left ventricular apex; (3) a narrow right ventricle encompassing the periapical area of the left ventricle; (4) fatty infiltration of the apex of the left ventricle. We reported a case of LVAH and reviewed the patient's clinical presentation. And its morphologic characteristics were revealed by multimodality imaging, including echocardiography and cardiac magnetic resonance imaging. Additionally, we reviewed 41 cases from 32 reports to summarize the pathogenesis and analyzed the imaging manifestations of LVAH in this study, aiming to provide new ideas for the diagnosis and clinical management of LVAH patients.

Hypertrophic Cardiomyopathy: Preadolescence, Mitral Valve Disease, and Midventricular Obstruction.

Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM.

Minimally Invasive Mitral Valve Repair Using Transcatheter Chordal Attachments.

The advent of transcatheter mitral chordal replacement techniques has offered an alternative approach that is less invasive and may be more suitable for select patients compared with surgical repair. These systems involve introducing artificial chordae, via catheter, to replace or supplement damaged or elongated natural chordae. These artificial chordae are anchored at one end to the mitral leaflet and the other end to the papillary muscle or directly to the left ventricular apex, restoring the leaflet's coaptation and reducing regurgitation. Early trials and studies suggest promising results in terms of safety and efficacy in reducing MR severity and improving symptoms.