Posteromedial Papillary Muscle Research Articles

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

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. In this study, we evaluated the prognostic value of papillary muscle-free strain in HCM patients. 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. 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.

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. 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. 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. 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.

First experience of focal pulsed field ablation for premature ventricular contractions

Abstract Introduction Pulsed field ablation (PFA) has emerged as a novel strategy to achieve ablation of cardiac tissue. Clinical evidence suggests a remarkable lesion durability and safety profile for AF ablation. Nonetheless, a growing interest exists in broadening its field of application for catheter ablation of ventricular arrhythmias (VA). The CENTAURI system arises as a promising PFA system for targeting VA as it allows pulsed electric field (PEF) delivery via standard, commercially available focal ablation catheters and concomitant coupling with their mapping systems. Purpose To assess, for the first time, the feasibility of focal PFA via the CENTAURI system for premature ventricular complex (PVC) ablation. Methods We conducted a prospective analysis of patients with either high burden (&amp;gt;10%) or symptomatic idiopathic PVC undergoing focal PFA using CENTAURI system at our institution. Procedures were performed between December 2022 and August 2023. Acute and long-term success were defined as no PVC recurrence during a 24h in-hospital monitoring period, and ≥80% burden reduction with absence of symptoms after at least 30 days post-ablation, respectively. PVC monitoring was performed by implantable loop recorder (ILR) or surface ECG Holter monitoring. Results Fourteen patients (age range: 16-87 years; 10 females) were included. Procedures were performed via the CENTAURI system in combination with CARTO 3 system and EnSite X EP system in 4 (28.6%) and 10 cases (71.4%) respectively. Targeted ablation sites were the right ventricular outflow tract (6 cases), right moderator band (2 cases), left postero-medial papillary muscle -PM- (2 cases), and right posterior PM, tricuspid annulus, left posterior fascicle and aortomitral continuity (AMC) in one case. On average, 6.5 applications were delivered to the site of origin with a mean contact force of 11g. Procedural duration and fluoroscopy time were 102 and 8.9 minutes. Two minor complications were observed: one transitory ST depression (solved after i.v. nitrate administration) after repeated applications to AMC, and a femoral pseudoaneurysm. The remaining 12 procedures were uneventful. Although most of the procedures were performed under general anesthesia due to concerns about potential significant muscular contraction, 3 cases (21.4%) were successfully managed with light sedation, without significant muscular contraction nor map shift. Incomplete abolishment of PVC during first 24 h was observed in 2 patients (14.3%). After a median follow-up of 113 days (IQR: 83-188), recurrences were detected in one patient (7.14%). Conclusion Herein we report the feasibility and efficacy of PVC ablation using a focal PEF delivery system (CENTAURI). Furthermore, we describe the possibility of performing PVC ablation with this technology under light sedation, which might be important for minimizing anesthesia impact on PVC burden.Table of characteristicsPVC morphologies

Cardiac Computed Tomography Assessment of the Variation of Papillary Muscle Morphology before Mitral Valve Surgery

Background. The morphology of the papillary muscles of the left ventricle is highly variable. Few studies have investigated papillary muscle morphology using imaging. Objective. This study aimed to assess papillary muscle morphology with primary mitral regurgitation (MR) using cardiac computed tomography (CT). Methods. We examined 116 patients who underwent robotic mitral valve repair for primary MR using preoperative cardiac CT. Papillary muscle morphology was assessed using CT images and compared with operative findings. Results. CT images of papillary muscles were consistent with the operative findings during robotic mitral valve repair in all cases. Both the anterolateral papillary muscle (APM) and posteromedial papillary muscle (PPM) groups were identified in all cases, and the middle papillary muscle (MPM) group was identified in 24.1% of cases. The PPM group had a higher proportion of complex morphologies with more heads and bases than the APM group (head: p&lt;0.001 and base: p&lt;0.001). The PPM group had smaller papillary muscle sizes than the APM group. The MPM group in most patients had one base and one head (78.6%). Papillary muscle sizes were significantly smaller in the order of the APM, PPM, and MPM groups (p&lt;0.001). Conclusions. Cardiac CT allowed clear visualization and accurate assessment of papillary muscle morphology in the left ventricle. It may be useful to obtain the papillary muscle variations preoperatively using CT imaging in procedures involving the papillary muscles such as mitral valve repair.

Clinical genetic testing in arrhythmogenic mitral valve prolapse syndrome highlights a potential overlap with familial dilated cardiomyopathy

Abstract Background/Introduction Arrhythmogenic mitral valve prolapse syndrome (AMVPS) is a female-predominant sudden cardiac death (SCD)-predisposing disorder characterized clinically by myxomatous mitral valve prolapse (MVP), inferolateral T-wave inversions and complex ventricular ectopy. However, insights into the pathogenesis and potential genetic basis of AMVPS are currently lacking. Purpose Considering recent case reports that suggest a potential role for genetic cardiomyopathies in the pathogenesis of AMVPS, we sought to determine the yield of pathogenic/likely pathogenic (P/LP) genetic variants in strong evidence cardiomyopathy-susceptibility genes amongst AMVPS patients who underwent clinical genetic testing. Methods In this retrospective study, the medical records of 4,907 patients referred to our cardiovascular genetics clinic was used to identify those patients with a clinical phenotype consistent with AMVPS. After exclusion of individuals with severe mitral valve regurgitation, pertinent clinical, electrocardiographic, imaging and genetic testing data was extracted from the electronic record. For those AMVPS that underwent a form of genetic testing that encompassed 23 Clinical Genome Resource-defined strong/definitive evidence cardiomyopathy-susceptibility genes, ultra-rare (minor allele frequency ≤ 0.00005 in the Genome Aggregation Database [n=141,456 individuals]) non-synonymous variants identified within these genes were adjudicated independently as P, LP or variant of uncertain significance with the assistance of Varsome. The frequency of P/LP variants was then compared to a previously published cohort of 973 ostensibly healthy control exomes. Results Overall, 56 unrelated patients with suspected AMVPS were identified (82% female; average age at presentation of 31 ± 13 years; 32% with a family history of MVP and/or SCD). Of these, 24/56 (43%) underwent a form of clinical genetic testing that encompassed the pre-defined panel of cardiomyopathy-susceptibility genes. In comparison to control exomes (n=973), P/LP variants in strong/definitive evidence cardiomyopathy-susceptibility genes were over-represented in AMVPS patients [4/24 (16.7%) vs 20/973 (2.1%); p=0.002]. Interestingly, this enrichment was driven in large part by an excess number of A-band-localizing P/LP truncating variants in TTN-encoded titin in AMVPS cases [3/24 (12.5%) versus 4/973 (0.4%); p=0.0004]. Conclusion This study provides further evidence that a subset of AMVPS may arise secondary to a "two-hit" model whereby an underlying cardiomyopathic genetic substrate is exacerbated by the mechanical force generated by genetically unrelated myxomatous MVP resulting in maladaptive and ventricular arrhythmia-predisposing fibrosis within the inferobasal left ventricle and posteromedial papillary muscles. Larger studies are needed to better understand the potential role of genetic testing in the diagnosis, risk-stratification and management of patients with suspected AMVPS.

Abstract 12522: Non-Ischemic Papillary Muscle Rupture Due to MRSA Myocarditis

Case Presentation: A 46-year-old male with diabetes, ESRD, and recurrent MRSA bacteremia, presented with septic shock and suffered cardiac arrest. Following resuscitation EKG showed inferolateral ischemia. TTE revealed acute mitral valve regurgitation resulting from posteromedial papillary muscle rupture (PMR). An intra-aortic balloon pump was implanted for cardiogenic shock. Coronary angiography revealed right dominant circulation and thrombotic occlusion of a small caliber distal left circumflex artery (LCX). Emergent mitral valve replacement surgery was performed. Pathologic analysis of the excised muscle and leaflet showed marked acute inflammation, bacterial invasion, and myocyte necrosis, confirming non-ischemic rupture due to MRSA myocarditis. Discussion: PMR predominantly occurs after MI, complicating 0.03% of STEMI cases in the reperfusion era. Non-ischemic causes are rare. Coexistence of myocarditis, infective endocarditis (IE), and MI poses a challenge in determining etiology. Establishing causation guides whether to expedite emergent valve surgery or focus on cardiomyocyte salvage by revascularization. The posteromedial papillary muscle is most commonly involved in PMR due to single blood supply from the PDA (most commonly a branch of the RCA, and less commonly the LCX). Coronary angiography, postoperative histopathology, and culture results determined the etiology of PMR was fulminant MRSA bacteremia culminating in myocarditis. Bacterial colonization and resultant inflammation induced physical and mechanical strain leading to complete rupture. The occluded LCX was incidental, and may have been the result of septic embolization, which occurs in up to 65% of left-sided IE. Albeit rare, non-ischemic etiologies must be considered when the anatomic presentation of acute PMR on TTE is incongruent with angiography. Definitive treatment relies on surgical intervention and mechanical circulatory support is often necessary.

Abstract 18126: A Rare Case of a Left Ventricular Papillary Fibroelastoma With an Initial Presentation of Unilateral Vision Loss

A 59-year-old female with hypertension presented with acute onset of decreased vision in the right eye. She reported waking up 3 days prior to admission with sudden onset of shadow in the right eye appearing like a falling curtain which eventually progressed to total visual loss. She also complained of headaches and palpitations. The patient denied pain, nausea, vomiting, photophobia, changes in speech, aphasia, facial weakness, arm or leg weakness or numbness. She states that this is her first experience of vision loss. At the time of admission, she was hypertensive to 170/100s and started on amlodipine 5mg and losartan 25mg. Neurology and ophthalmology were consulted for concerns of stroke and new vision loss. She was started on heparin drip, aspirin 81mg, atorvastatin 80mg, and methylprednisolone 1g. Ocular examination revealed right brachial retinal artery occlusion. MRI brain showed chronic microvascular changes, but no acute intracranial hemorrhage or infarction. CT angiogram of the neck showed mild soft plaque in right carotid bifurcation. Transthoracic echocardiogram revealed a 1.6cm x 1.6cm left ventricular mobile mass which appeared to be attached to the posteromedial papillary muscle and left ventricle ejection fraction of 60%. The patient underwent open heart surgery for removal of the mass. The mass was confirmed to be a papillary fibroelastoma attached to the left ventricular trabeculum. The mitral valve and subvalvular apparatus were not involved. New onset of stroke or acute vision loss is generally a result of thromboembolism. Most times it can be caused by a clot formed in a patient with atrial fibrillation. In other cases, it can be due to a ruptured cholesterol plaque. However, primary cardiac tumors are rare, especially ones on the papillary muscle. We presented a rare case of papillary fibroelastoma that possibly embolized causing acute unilateral vison loss. This case reinforces the importance of cardiac imaging in new stroke or acute vision loss.

Left ventricular fibrosis and CMR tissue characterization of papillary muscles in mitral valve prolapse patients.

Mitral valve prolapse (MVP) is associated with left ventricle (LV) fibrosis, including the papillary muscles (PM), which is in turn linked to malignant arrhythmias. This study aims to evaluate comprehensive tissue characterization of the PM by cardiovascular magnetic resonance (CMR) imaging and its association with LV fibrosis observed by intraoperative biopsies. MVP patients with indication for surgery due to severe mitral regurgitation (n = 19) underwent a preoperative CMR with characterization of the PM: dark-appearance on cine, T1 mapping, conventional bright blood (BB) and dark blood (DB) late gadolinium enhancement (LGE). CMR T1 mapping was performed on 21 healthy volunteers as controls. LV inferobasal myocardial biopsies were obtained in MVP patients and compared to CMR findings. MVP patients (54 ± 10 years old, 14 male) had a dark-appearance of the PM with higher native T1 and extracellular volume (ECV) values compared with healthy volunteers (1096 ± 78ms vs. 994 ± 54ms and 33.9 ± 5.6% vs. 25.9 ± 3.1%, respectively, p < 0.001). Seventeen MVP patients (89.5%) had fibrosis by biopsy. BB-LGE + in LV and PM was identified in 5 (26.3%) patients, while DB-LGE + was observed in LV in 9 (47.4%) and in PM in 15 (78.9%) patients. DB-LGE + in PM was the only technique that showed no difference with detection of LV fibrosis by biopsy. Posteromedial PM was more frequently affected than the anterolateral (73.7% vs. 36.8%, p = 0.039) and correlated with biopsy-proven LV fibrosis (Rho 0.529, p = 0.029). CMR imaging in MVP patients referred for surgery shows a dark-appearance of the PM with higher T1 and ECV values compared with healthy volunteers. The presence of a positive DB-LGE at the posteromedial PM by CMR may serve as a better predictor of biopsy-proven LV inferobasal fibrosis than conventional CMR techniques.

Assessment of papillary muscle free strain in hypertrophic cardiomyopathy and hypertension-induced left ventricular hypertrophy.

We aimed to evaluate and compare papillary muscle free strain in hypertrophic cardiomyopathy (HCMP) and hypertensive (HT) patients. 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. 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 (p < 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%) (p = 0.016 and p = 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. 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.

False Tendons in the Left Ventricle: Implications for Successful Ablation of Left Posterior Fascicular Tachycardias

BackgroundThe anatomical substrate for left posterior fascicular ventricular tachycardia (LPF-VT) is still unclear. ObjectivesThe purpose of this study is to describe the endocavitary substrate of the re-entrant loop of LPF-VT. MethodsA total of 26 consecutive patients with LPF-VT underwent an electrophysiology study and radiofrequency ablation. ResultsIntracardiac echocardiography imaging observed a 100% prevalence of false tendons (FTs) at the left posterior septal region in all patients, and 3 different types of FTs could be classified according to their location. In 22 patients, a P1 potential could be recorded via the multielectrode catheter from a FT. In 4 patients without a recorded P1 during LPF-VT, the earliest P2 potentials were recorded from a FT in 3 patients, and from a muscular connection between 2 posteromedial papillary muscles in 1 patient. Catheter ablation focused on the FTs with P1 or earliest P2 (in patients without P1) was successful in all 26 patients. After 19 ± 8.5 months of follow-up, no patients had recurrence of LPF-VT. ConclusionsFTs provide an electroanatomical substrate for LPF-VT and a “culprit FT” may be identified as the critical structure bridging the macro–re-entrant loop. Targeting the “culprit FT” is a novel anatomical ablation strategy that results in long-term arrhythmia-free survival.

Is catheter-tissue contact force value important for ablation of ventricular arrhythmias originating from the left ventricular papillary muscles?

Good catheter-tissue contact is mandatory to create effective ablation lesions. The minimal contact force value for ablation of arrhythmias originating from the left ventricle is 8.0-10.0 grams but is not known for arrhythmias arising from papillary muscles. To analyze contact force values during successful ablation procedures of arrhythmias originating from the left ventricular papillary muscles. 24 consecutive patients (mean age 57.9 ± 11.9 years, 16 males) underwent ablation of premature ventricular complexes originating from left ventricular papillary muscles with the use of CARTO electro-anatomical system and intracardiac echocardiography. Acute complete abolition of ventricular ectopy was obtained in 23 (96%) patients. The fluoroscopy time was 3.9 ± 3.5 min and procedure duration - 114.8 ± 37.9 min. The mean contact force during successful ablations was 3.0 ± 1.1 grams and 3.18 ± 1.8 grams for antero-lateral and postero-medial papillary muscle, respectively (NS). The mean contact force during a single unsuccessful ablation was 3.0 grams. At control Holter ECG, the mean Ectopy Burden was Reduced in the Antero-Lateral Papillary Muscle Group from 18.0% ± 7.9% to 2.6% ± 2.9% (p = 0.005415) and in the Postero-Medial Papillary Muscle Group - from 34.8% ± 13.7%-1.7% ± 1.3% (p = 0.012694). During Median 27 (IQR: 17-34) Months of Follow-up There one Recurrence of Arrhythmia. The values of contact force for successful ablation of ventricular ectopy originating from the left ventricular papillary muscles may be much lower than those for ablation of other foci which questions the role of contact force measurement when ablating these arrhythmias.

P155 CT EVIDENCE OF PARTIAL ISCHEMIC PAPILLARY MUSCLE RUPTURE

Abstract A 77–year–old man was referred for coronary CT following an episode of prolonged chest pain that occurred about 30 days earlier, with subsequent onset of dyspnea on moderate exertion. Coronary CT demonstrated right dominance, occlusion of the right coronary artery, as well as severe stenosis of the distal segment of the left anterior descending artery and of the first obtuse marginal branch. CT scan also showed an intraventricular image consistent with partial rupture of the posteromedial papillary muscle (Figure 1). The patient was transferred to the emergency department. An ECG showed signs of inferolateral necrosis. Transthoracic echocardiography confirmed akinesia of the inferior and inferolateral walls and of the basal segment of the inferior septum, with severe mitral valve insufficiency from anterior leaflet prolapse (A3 scallop) from partial rupture of the posteromedial papillary muscle (Figure 2). Transesophageal echocardiography confirmed the diagnosis (Figure 3). The patient was admitted to the CCU and underwent coronarography, which confirmed the severe triple vessel coronary artery disease with occlusion of the right coronary artery, and then urgent mitral valve replacement with bioprosthesis and aortocoronary bypass with saphenous vein grafting to the posterior descending artery. The postoperative course was uneventful. Ischemic papillary muscle rupture is a rare cause of mitral insufficiency. Papillary rupture typically occurs within 5 days of an acute myocardial infarction, and causes mitral insufficiency by prolapse and flail of one or, more rarely, both mitral valve leaflets. The posteromedial papillary muscle is most commonly affected, since the anterolateral papillary muscle has dual supply from the anterior interventricular artery and the circumflex artery. Papillary muscle rupture can be total or partial; however, most cases of partial rupture progress to complete rupture and therefore require urgent surgical treatment. The peculiarity of this case lies in the fact that it is the first case described in the literature of a papillary muscle rupture documented on CT.

PO-05-097 FIRST REPORT OF CRYOABLATION OF NON-PAPILLARY MUSCLE PVCS UNDER DIRECT VISUALIZATION DURING MV REPAIR: INTER-LEAFLET TRIANGLE AND THE AORTO-MITRAL CONTINUITY

Up to 60% of patients with mitral valve prolapse (MVP) have premature ventricular contractions (PVC), usually of papillary muscle (PM) origin. However, one-third of PVCs are of non-PM origin, from areas exposed to annular stress forces. We have previously demonstrated the feasibility of intraoperative cryoablation of PM PVCs under direct visualization during mitral valve (MV) repair. To our knowledge, this is the first report of a similar approach for non-PM PVCs. We present two cases of visually-guided surgical cryoablation of non-PM PVCs at the time of elective MV repair. Both were guided by ECG morphology criteria and hybrid PET/MRI imaging pre-operatively. n/a Case 1 (Figure): 73 year old female with degenerative MVP, severe MR and frequent PVCs (27%). There were two PVC morphologies: the dominant PVC was suggestive of interleaflet triangle (ILT) origin (abrupt V3 transition), and the less frequent PVC was consistent with postero-medial PM origin. Hybrid PET-MRI demonstrated focal uptake of FDG in the LV summit region just under the aortic valve. The patient underwent an uncomplicated MV repair, TV repair and cryoablation of the ILT (open endocardial retrograde approach) and then the posterior PM. Follow up TTE showed normal MV and aortic leaflets function without regurgitation or stenosis. An event monitor at 2 months post-op revealed a PVC burden of 2% (off drugs). Case 2: 76 year old male with degenerative MVP, severe mitral regurgitation (MR) and frequent symptomatic PVCs (24%), suggestive of an aortomitral continuity (AMC) origin. Simultaneous cardiac 18F FDG-PET and MRI with LGE imaging demonstrated focal uptake of FDG in the AMC region, no LGE was detected. The patient underwent an uncomplicated MV repair, TV repair and cryoablation of the AMC. The cryo-application was performed on the atrial side of the mitral annulus with forward pressure to reach the ventricular myocardium. There were no PVCs during post-op monitoring and a 6-month follow-up monitor revealed a PVC burden of 1% (off drugs). Surgical cryoablation of non-PM PVCs under direct visualization at the time of MV surgery, using standard ECG criteria and pre-op Hybrid PET-MRI imaging, is feasible. Further studies are needed to determine the safety and effectiveness of adjunctive PVC cryoablation at the time of MV surgery.

Analysis of heart displacement during thoracic radiotherapy based on electrocardiograph-gated 4-dimensional magnetic resonance imaging.

Periodic cardiac movement may expose the heart to radiation field induced damage, leading to radiation-induced heart disease (RIHD). Studies have proven that delineation of the heart based on planning CT fails to show the real margin of the substructures and a compensatory margin should be applied. The purpose of this study was to quantify the dynamic changes and the compensatory extension range by breath-hold and electrocardiogram gated 4-dimensional magnetic resonance imaging (4D-MRI), which had the advantage of discriminating soft tissues. Eventually, 15 patients with oesophageal or lung cancers were enrolled, including one female and nine males aged from 59 to 77 years from December 10th, 2018, to March 4th, 2020. The displacement of the heart and its substructures was measured through a fusion volume and the compensatory expansion range was calculated by expending the boundary on the planning CT to that of the fusion volume. The differences were tested through the Kruskal-Wallis H test and were considered significant at a two-side P<0.05. The extent of movement of heart and its substructures during one cardiac cycle were approximately 4.0-26.1 millimetre (mm) in anterior-posterior (AP), left-right (LR), and cranial-caudal (CC) axes, and the compensatory margins should be applied to planning CT by extending the margins by 1.7, 3.6, 1.8, 3.0, 2.1, and 2.9 centimetres (cm) for pericardium; 1.2, 2.5, 1.0, 2.8, 1.8, and 3.3 cm for heart; 3.8, 3.4, 3.1, 2.8, 0.9, and 2.0 cm for interatrial septum; 3.3, 4.9, 2.0, 4.1, 1.1, and 2.9 cm for interventricular septum; 2.2, 3.0, 1.1, 5.3, 1.8, and 2.4 cm for left ventricular muscle (LVM); 5.9, 3.4, 2.1, 6.1, 5.4, and 3.6 cm for antero-lateral papillary muscle (ALPM); and 6.6, 2.9, 2.6, 6.6, 3.9, and 4.8 cm for postero-medial papillary muscle (PMPM) in anterior, posterior, left, right, cranial, and caudal directions, respectively. Periodic cardiac activity causes obvious displacement of the heart and its substructures, and the motion amplitude of substructures differs. Extending a certain margin as the compensatory extension to represent the organs at risk (OAR) and then limiting the dose-volume parameters could be performed in clinical practice.

Combination of Intracardiac Echocardiography and Contact Force Sensing for Left Ventricular Papillary Muscle Arrhythmias.

The catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricular (LV) papillary muscles (PMs) is challenging. This study sought to address whether the combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) can improve the acute and long-term ablation outcomes of left ventricular papillary muscle arrhythmias. From May 2015 to August 2022, a total of thirty-three patients underwent catheter ablation for LV PM arrhythmias: VAs were located in anterolateral PMs in 11 and posteromedial PMs in 22. A combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) was used in 21 of the 33 procedures. A mean of 6.93 ± 4.91 for lesions was used per patient, comparable between the CFS/ICE and no ICE/CFS (4.90 ± 2.23 vs. 10.17 ± 5.89; p = 0.011). The mean CF achieved in the ICE/CFS group was 7.52 ± 3.31 g. Less X-ray time was used in the combination group (CFS/ICE: 165.67 ± 47.80 S vs. no ICE/CFS: 365.00 ± 183.73 S; p < 0.001). An acute success rate of 100% was achieved for the ICE/CFS group (n = 22) and 66.67% for the no ICE/CFS group (n = 8). VA recurrence at the 11.21 ± 7.21-month follow-up was 14.2% for the ICE/CFS group and 50% for the no ICE/CFS group (p = 0.04). No severe complications occurred in all patients. The combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) could provide precise geometries of cardiac endocavitary structures and accurate contact information for the catheter during ablation, which improved acute and long-term ablation outcomes. The routine adoption of this strategy should be considered to improve the outcomes of LV PM VA ablation.

A rapid wide complex tachycardia

A rapid wide complex tachycardia

Does papillary muscle free strain has predictive value in risk stratification of patients with hypertrophic cardiomyopathy?

Papillary muscle free strain has not been evaluated previously in hypertrophic cardiomyopathy (HCMP) patients. Our aim was to evaluate free papillary muscle free strain in HCMP patients and to find whether it has a value for prediction of sudden cardiac death (SCD) risk score. Transthoracic echocardiography with tissue Doppler imaging, 2-D speckle tracking imaging (STI) of 55 HCMP patients and 45 controls were performed. HCMP patients were further divided into two groups according to their SCD risk score. Patients with risk score of less than 6 points constituted low/intermediate risk group, whereas patients with risk score of greater or equal to 6 points constituted high risk group. Interventricular septum, posterior wall, and left ventricular mass index were significantly higher, whereas mitral E/A ratio was significantly lower in HCMP patients compared to controls. Longitudinal apical 4C, 2C, 3C, global longitudinal LV strain, anterolateral papillary muscle (ALPM), posteromedial papillary muscle (PMPM) free strain were significantly reduced in HCMP group compared to control group. Global longitudinal strain and ALPM free strain were significantly lower in patients with high SCD risk score (-14.6 (-17.4 - -13.1) vs -11.6 (-13.2 - -10.1), p = 0.001 and -17.1 (-20.3 - -14.0) vs -9.2 (-12.6 - -7.5), p<0.001, respectively. Global longitudinal strain and ALPM free strain were statistically significantly correlated with SCD risk score (r = 0.480, p<0.001 and r = 0.462, p<0.001, respectively). Global longitudinal strain value of -12.60% had a sensitivity of 73.3% and specificity of 82.5% for predicting high SCD risk score (AUC: 0.787, 95% CI: 00.643-0.930, p = 0.001). ALPM free strain value of -12.95% had 66.7% sensitivity and 77.5% specificity for predicting high SCD risk score (AUC: 0.766, 95% CI: 0.626-0.905, p = 0.003). Papillary muscle free strain was reduced in HCMP patients. It might be used in risk stratification of these patients.

Papillary Muscle Involvement during Acute Myocardial Infarction: Detection by Cardiovascular Magnetic Resonance Using T1 Mapping Technique and Papillary Longitudinal Strain

Papillary muscle (PPM) involvement in myocardial infarction (MI) increases the risk of secondary mitral valve regurgitation or PPM rupture and may be diagnosed using late gadolinium enhancement (LGE) imaging. The native T1-mapping (nT1) technique and PPM longitudinal strain (PPM-ls) have been used to identify PPM infarction (iPPM) without the use of the contrast agent. This study aimed to assess the diagnostic performance of nT1 and PPM-ls in the identification of iPPM. Forty-six patients, who performed CMR within 14-30 days after MI, were retrospectively enrolled: sixteen showed signs of iPPM on LGE images. nT1 values were measured within the infarcted area (IA), remote myocardium (RM), blood pool (BP), and anterolateral and posteromedial PPMs and compared using ANOVA. PPM-ls values have been assessed on cineMR images as the percentage of shortening between end-diastolic and end-systolic phases. Higher nT1 values and lower PPM-ls were found in infarcted compared to non-infarcted PPMs (nT1: 1219.3 ± 102.5 ms vs. 1052.2 ± 80.5 ms and 17.6 ± 6.3% vs. 21.6 ± 4.3%; p-value < 0.001 for both), with no significant differences between the nT1 of infarcted PPMs and IA and between the non-infarcted PPMs and RM. ROC analysis demonstrated an excellent discriminatory power for nT1 in detecting the iPPM (AUC = 0.874; 95% CI: 0.784-0.963; p < 0.001). nT1 and PPM-ls are valid tools in assessing iPPM with the advantage of avoiding contrast media administration.

Catheter ablation of idiopathic left fascicular ventricular tachycardia: Implications of false tendons for mapping and ablation.

The anatomical substrate for idiopathic left ventricular tachycardia (ILVT) remains speculative. Purkinje networks surrounding false tendons (FTs) might be involved in the reentrant circuit of ILVT. The objective was to evaluate the anatomical and electrophysiological features of false tendons FTs in relation to ILVT. Intracardiac echocardiography (ICE) was conducted on patients with ILVT. The relationship of the FTs with ILVT was determined using electro-anatomical mapping. Electrophysiological evaluation and radiofrequency ablation were conducted in 23 consecutive patients with ILVT. FTs were identified in 19/23 cases (82.6%) with P1 potentials during VT recorded at the FT in 14 of these patients (73.7%). Three FT types were identified. In type 1, the FT attached the septum to the base of the posteromedial papillary muscle (PPM) (4/19); type 2 FTs ran between the septum and the PPM apex (3/19), while in type 3, the connection occurred between the septum and apex (11/19) or between the septum and the LV free wall (1/19). The effective ILVT ablation sites were situated at the FT-PPM (3/19) and the FT-septum (16/19) attachment sites. This series demonstrates the association between Purkinje fibers and FTs during catheter ablation of ILVT and verifies that left ventricular FTs are an important substrate in this type of tachycardia.

The Mechanism and Natural History of Mitral Regurgitation in Cardiac Sarcoidosis

Cardiac sarcoidosis (CS) is an infl/ammatory cardiomyopathy that can present with mitral regurgitation (MR), but few studies describe the mechanisms and natural history of MR in CS. We queried an institutional registry of 512 patients with CS for moderate or greater MR at diagnosis. Baseline demographic and echocardiography (TTE) data were collected. MR was classified by Carpentier type. Positron emission tomography was analyzed for 2-deoxy-2-[fluorine-18] fluoro-d-glucose (FDG) avidity of anterolateral and posteromedial papillary muscles. Follow-up TTE and positron emission tomography imaging of patients treated with immunosuppression was analyzed for MR severity and FDG avidity changes. Fifty-four patients were identified. Mean left ventricular ejection fraction was 39.3%, effective regurgitant orifice 0.34cm2, and MR regurgitant volume 46.3ml. Carpentier type I was the most common MR mechanism (46.3%). Forty-one patients had follow-up TTE (median follow-up 1.7 years, interquartile range 2.6 years). Evaluating preprocedural follow-up TTE only, MR severity was significantly reduced, with 37% of patients showing reduction by at least 1 severity grade (p=0.04). With postprocedural TTE included, 61% of patients showed alleviation of MR severity with mean decrease in grade-0.98 (p <0.001). Sixty-eight percent of patients had anterolateral/posteromedial FDG avidity. Papillary muscle FDG avidity resolved in 80% of patients (n=20, median follow-up 1.6 years, interquartile range 2.5 years). In conclusion, Carpentier type I functional MR is the most common MR mechanism in CS. MR severity and papillary muscle FDG avidity decrease after treatment, and MR resolution is further strengthened by procedural intervention in a minority of patients, suggesting an overall favorable natural history of MR in CS.