Sarcoma in patients with Lynch syndrome and response to immunotherapy.

BACKGROUND: Lynch syndrome (LS) is an autosomal dominant genetic predisposition to multiple malignancies and is characterized by deficient DNA mismatch repair. Increased incidence of sarcomas is not formally ascribed to LS; however, increasing evidence suggests a preponderance of these malignancies in affected families. Sarcomas typically possess a low tumor mutational burden and incite a poor immune infiltrate, thereby rendering them poorly responsive to immunotherapy. METHODS: We searched the University of California, Los Angeles (UCLA) sarcoma program database for patients with a diagnosis of sarcoma and LS from 2016 to 2023. Three such patients were identified and all three were treated with PD1 blockade. RESULTS: We present three cases of LS-associated sarcomas (two soft tissue sarcoma and one osteosarcoma) with increased tumor mutational burdens. These patients were each treated with an anti-PD1 antibody and experienced a response far superior to that reported for non-LS-associated sarcomas. CONCLUSIONS: Increased mutational burden and immune infiltrate are observed for sarcomas associated with LS. Although unselected patients with sarcoma have demonstrated poor response rates to immunotherapy, our findings suggest that patients with Lynch-associated sarcomas are more likely to respond to treatment with anti-PD1. These patients should be given consideration for immunotherapy.

Novel algorithms improve arrhythmia detection accuracy in insertable cardiac monitors.

INTRODUCTION: Insertable cardiac monitors (ICMs) are commonly used to diagnose cardiac arrhythmias. False detections in the latest ICM systems remain an issue, primarily due to inaccurate R-wave sensing. New discrimination algorithms were developed and tested to reduce false detections of atrial fibrillation (AF), pause, and tachycardia episodes in ICMs. METHODS: Stored electrograms (EGMs) of AF, pause, and tachycardia episodes detected by Abbott Confirm Rx™ ICMs were extracted from the Merlin.net™ Patient Care Network, and manually adjudicated to establish independent training and testing datasets. New discrimination algorithms were developed to reject false episodes due to inaccurate R-wave sensing, P-wave identification, and R-R interval patterns. The performance of these new algorithms was quantified by false positive reduction (FPR) and true positive maintenance (TPM), relative to the existing algorithms. RESULTS: The new AF detection algorithm was trained on 5911 EGMs from 744 devices, resulting in 66.9% FPR and 97.8% TPM. In the testing data set of 1354 EGMs from 119 devices, this algorithm achieved 45.8% FPR and 97.0% TPM. The new pause algorithm was trained on 7178 EGMs from 1490 devices, resulting in 70.9% FPR and 98.7% TPM. In the testing data set of 1442 EGMs from 340 devices, this algorithm achieved 74.4% FPR and 99.3% TPM. The new tachycardia algorithm was trained on 520 EGMs from 204 devices, resulting in 57.0% FPR and 96.6% TPM. In the testing data set of 459 EGMs from 237 devices, this algorithm achieved 57.9% FPR and 96.5% TPM. CONCLUSION: The new algorithms substantially reduced false AF, pause, and tachycardia episodes while maintaining the majority of true arrhythmia episodes detected by the Abbott ICM algorithms that exist today. Implementing these algorithms in the next-generation ICM systems may lead to improved detection accuracy, in-clinic efficiency, and device battery longevity.

Respiratory control minimizes diaphragmatic contraction and dry cough during pulsed-field ablation of atrial fibrillation.

AIMS: Pulsed-field ablation (PFA) is a promising new ablation modality to treat atrial fibrillation. However, PFA can cause varying degrees of diaphragmatic contraction and dry cough, especially under conscious sedation. This prospective study presents a method to minimize the impact of PFA on diaphragmatic contraction and dry cough during the procedure. METHODS AND RESULTS: Twenty-eight patients underwent PFA for pulmonary vein (PV) and superior vena cava isolation under conscious sedation. Each patient received two groups of ablations in each vein: the control group allowed PFA application during any phase of respiratory cycle, while the test group used respiratory control, delivering PFA energy only at the end of expiration. A rating score system was developed to assess diaphragmatic contraction and dry cough. A total of 1401 control ablations and 4317 test ablations were performed. The test group had significantly lower scores for diaphragmatic contraction (P < 0.01) and dry cough (P < 0.001) in all PVs compared to the control group. The average relative reductions in scores for all PVs were 33-47% for diaphragmatic contraction and 67-83% for dry cough. The percentage of ablations with scores ≧2 for diaphragmatic contraction decreased significantly from 18.5-28.0% in the control group to 0.4-2.6% in the test group (P < 0.001). For dry cough, the percentage decreased from 11.9-43.7% in the control group to 0.7-2.1% in the test group. CONCLUSION: Pulsed-field ablation application at the end of expiration can reduce the severity of diaphragmatic contraction and eliminate moderate and severe dry cough during PV isolation performed under conscious sedation.

Biological substrate modification suppresses ventricular arrhythmias in a porcine model of chronic ischaemic cardiomyopathy.

AIMS: Cardiomyopathy patients are prone to ventricular arrhythmias (VA) and sudden cardiac death. Current therapies to prevent VA include radiofrequency ablation to destroy slowly conducting pathways of viable myocardium which support re-entry. Here, we tested the reverse concept, namely that boosting local tissue viability in zones of slow conduction might eliminate slow conduction and suppress VA in ischaemic cardiomyopathy. METHODS AND RESULTS: Exosomes are extracellular vesicles laden with bioactive cargo. Exosomes secreted by cardiosphere-derived cells (CDCEXO) reduce scar and improve heart function after intramyocardial delivery. In a VA-prone porcine model of ischaemic cardiomyopathy, we injected CDCEXO or vehicle into zones of delayed conduction defined by electroanatomic mapping. Up to 1-month post-injection, CDCEXO, but not the vehicle, decreased myocardial scar, suppressed slowly conducting electrical pathways, and inhibited VA induction by programmed electrical stimulation. In silico reconstruction of electrical activity based on magnetic resonance images accurately reproduced the suppression of VA inducibility by CDCEXO. Strong anti-fibrotic effects of CDCEXO, evident histologically and by proteomic analysis from pig hearts, were confirmed in a co-culture assay of cardiomyocytes and fibroblasts. CONCLUSION: Biological substrate modification by exosome injection may be worth developing as a non-destructive alternative to conventional ablation for the prevention of recurrent ventricular tachyarrhythmias.

The Prevalence and Outcomes of Unexpected Positive Intraoperative Cultures in Presumed Aseptic Revision Knee Arthroplasty.

BACKGROUND: The prevalence and outcomes of unexpected positive intraoperative cultures (UPC) in presumed aseptic revision total knee arthroplasty (TKA) are unclear. The purpose of this study was to determine the prevalence of UPC and infection-free implant survival in this patient population. Secondly, we aimed to compare the infection-free implant survival between cohorts based on number of UPCs and antibiotic treatment. METHODS: We reviewed our institutional database from 2006 to 2019 for all TKA revisions (n = 1795) to identify all presumed aseptic TKA revisions with intraoperative culture(s). After exclusions, 775 revisions were eligible and those with UPC were included in the Kaplan-Meier analysis to determine infection-free implant survival for the cohorts. RESULTS: The prevalence of UPC was 9.8%. The 2- and 5-year infection-free survival was 97.4% and 95.3%, respectively. The 5-year infection-free survival from the same microorganism as the UPC was 98.7%. Infection-free survival was similar for the 1 versus ≥2 UPC cohorts (P = .416), however was poorer for the cohort treated with antibiotics (P = .021). Only one of 3 subsequent PJI-related implant failures was caused by the same microorganism (polymicrobial) as the UPC. There were no subsequent infections in patients with a single UPC not treated with antibiotics. CONCLUSIONS: The prevalence of UPC was 9.8% and the infection-free implant survival is excellent. Infection-free survivorship from PJI caused by the same UPC microorganism is outstanding. Comparisons between cohorts must be interpreted with caution due to study limitations. A single UPC in patents without other signs of infection does not require antibiotic treatment. LEVEL OF EVIDENCE: IV.

Reduction of opioid use after orthopedic surgery: a scoping review.

BACKGROUND: The opioid epidemic is one of the biggest public health crises of our time, and overprescribing of opioids after surgery has the potential to lead to long-term use. The purpose of this review was to identify and summarize the available evidence on interventions aimed at reducing opioid use after orthopedic surgery. METHODS: We searched CENTRAL, Embase and Medline from inception until August 2019 for studies comparing interventions aimed at reducing opioid use after orthopedic surgery to a control group. We recorded demographic data and data on intervention success, and recorded or calculated percent opioid reduction compared to control. RESULTS: We included 141 studies (20 963 patients) in the review, of which 113 (80.1%) were randomized controlled trials (RCTs), 6 (4.3%) were prospective cohort studies, 16 (11.4%) were retrospective cohort studies, 5 (3.6%) were case reports, and 1 (0.7%) was a case series. The majority of studies (95 [67.4%]) had a follow-up duration of 2 days or less. Interventions included the use of local anesthetics and/or nerve blocks (42 studies [29.8%]), nonsteroidal anti-inflammatory drugs (31 [22.0%]), neuropathic pain medications (9 [6.4%]) and multimodal analgesic combinations (25 [17.7%]. In 127 studies (90.1%), a significant decrease in postoperative opioid consumption compared to the control intervention was reported; the median opioid reduction in these studies was 39.7% (range 5%-100%). Despite these reductions in opioid use, the effect on pain scores and on incidence of adverse effects was inconsistent. CONCLUSION: There is a large body of evidence from randomized trials showing the promise of a variety of interventions for reducing opioid use after orthopedic surgery. Rigorously designed RCTs are needed to determine the ideal interventions or combination of interventions for reducing opioid use, for the good of patients, medicine and society.

Catheter ablation for atrial tachycardias: How to interpret the unclear activation map?

BACKGROUND: Post-ablation atrial tachycardias (ATs) are characterized by low-voltage signals that challenge current mapping methods. In this study, we analyzed common mistakes during activation mapping and delineated a mapping strategy for correct interpretation of tachycardia mechanisms in patients with challenging underlying substrate. METHODS AND RESULTS: Thirty-one patients referred for AT ablation were selected for the study. Three types of incorrect activation patterns were identified, which were referred to as unrecognized block line (pseudo-macroreentry and pseudo-fig-8 reentry), incorrect activation timing window of interest (WOI) (chaotic activation), and mis-annotation of complex signals (multiple sites of "early meets late"). Pseudo-macroreentry and chaotic activation occur in focal or localized reentry AT with the error related to the WOI selection (four cases), incorrect annotation of local activation time (six cases), or a previous line of atrial block in (seven cases). Pseudo-fig-8 reentry (five cases) and multiple sites of "early meets late" (nine cases) occur in macroreentrant AT with blocked areas and low-voltage atrial substrate. All ATs were successfully eliminated at the origin site. CONCLUSIONS: We delineated a series of ATs in the setting of a disordered pattern of activation mapping encountered in patients after previous extensive ablation or atriotomy. The algorithm proposed rapidly corrects the activation map and identifies the mechanism of the AT.

Treatment of atypical pacemaker-mediated tachycardia with ablation of the retrograde atrioventricular nodal pathway.

A 25-year-old runner received a single-lead, VDD pacemaker after ablation of AV nodal reentrant tachycardia complicated by intermittent AV block. The rate-adaptive AV delay algorithm (RAAV), which shortens the sensed AV interval (SAV) at faster atrial rates, was programmed to provide a physiologic SAV with exercise. She developed repetitive, atypical, long-RP pacemaker-mediated tachycardia (PMT) because the RAAV shortened the antegrade SAV and retrograde conduction occurred over the slow AV nodal pathway. PMT was refractory to usual programming solutions. Using high-density electroanatomic mapping, we were able to ablate the retrograde limb of PMT without further damaging AV conduction.

Inability to capture with increasing current strength: Is this near-field or far-field?

We present a case of wide-complex tachycardia in which the clinical electrophysiological diagnosis was considered to be bundle branch re-entry ventricular tachycardia. A series of ventricular entrainment attempts were performed from the left and right ventricular septum to confirm the diagnosis. Entrainment pacing with a general current output (10 mA) was performed from the right ventricular septum with manifest fusion and a post-pacing interval similar to tachycardia cycle length. Thereafter, another entrainment attempt with a greater current output (20 mA) was performed from the same site. Paradoxically, concealed fusion was demonstrated by selective RB capture only, though there was no clear "RB" potential seen. In this case, we attempt to explain and illustrate the mechanism of paradoxical near-field inability to capture with increasing current strength.

Esophageal contraction during cryoablation: A possible protective mechanism.

BACKGROUND: Contraction of the esophagus was observed during cryoablation for paroxysmal atrial fibrillation (PAF). The purpose of this study is to investigate the mechanism of esophageal contraction and the correlation between the contraction and esophageal thermal lesions. METHODS: This prospective study enrolled 64 patients with PAF undergoing second-generation cryoballoon (CB2) ablation for pulmonary vein isolation (PVI). During PVI for the left inferior pulmonary vein, contrast esophagography was performed before and during cryoablation. The sample population was divided into two groups: A (31 patients) and B (33 patients). Group A consisted of patients in whom the distal half of the CB was in proximity to the esophagus, while for group B the esophagus was away from the distal half of the CB. Esophageal contraction was recorded as a variation in the width of the esophageal lumen during PVI. Postablation esophageal endoscopy was done on all patients. RESULTS: The reduction in the width of the esophageal lumen in group A was greater than in group B during freezing (40.12 ± 23.24% vs 8.14 ± 10.35%, P < .001). Following endoscopy, no apparent esophageal lesion was detected in all patients. CONCLUSION: The extent of esophageal contraction is correlated with the positioning of the esophagus at the distal half of the CB. The findings of this study indicate that esophageal contraction during freezing may be a self-protective mechanism.

Invasive therapies for patients with concomitant heart failure and atrial fibrillation.

Atrial fibrillation (AF) and heart failure (HF) are two clinical entities that can present either separately or concurrently. One entity can lead to the other and vice versa as AF can not only be the underlying etiology of HF but also exacerbate HF due to other cardiac diseases. Besides prevention of cerebral and systemic embolism and elimination of AF-related symptoms, restoration of sinus rhythm for AF patients helps to avoid or reduce HF, irrespective of their underlying heart disease. Successful rates of medical therapy for AF are low in persistent AF, and much lower in long-standing AF, while invasive procedures for AF yield promising results. In this review, the authors evaluate the value of invasive therapies for HF patients complicated with non-valvular AF. We examine this clinical problem by interpreting the relationships between these two entities: the mechanism of tachycardia-induced cardiomyopathy (TIC), past opinions about rhythm control and rate control of AF, discrimination of HF-related AF and AF-induced HF, how to identify the AF patients that could benefit from invasive therapies, and how to select invasive therapies for different AF patients and peri-operative treatments.

The influence of cryoballoon manipulation on luminal esophageal temperature during ablation for atrial fibrillation.

BACKGROUND: Esophageal injury is related to a reduction in luminal esophageal temperature (LET) in second-generation cryoballoon (CB) ablation; however, methods to prevent these reductions in temperature have not been well characterized. METHODS: Esophageal temperature was continuously monitored using a LET probe in patients undergoing pulmonary vein (PV) isolation using the second-generation CB. A rotational maneuver of the CB was performed if the initial ablation resulted in a decrease of more than 4℃ in LET. The refrigerant injector near the distal CB pole was used as a fluoroscopic marker to measure the nearest distance between the CB and the LET probe. RESULTS: A total of 52 consecutive patients were enrolled in this study. The rotation was applied in 19 patients and 20 PVs (seven left superior pulmonary veins [LSPVs], seven left inferior PVs [LIPVs], and six right inferior PVs [RIPVs]) with a reduction in LET of more than 4℃ during freezing. The nadir temperature of CB applications was similar before and after CB rotation in all PVs. There was significant difference in the minimum LET before and after rotation during freezing in LSPVs (28.4 ± 3.7 vs 32.4 ± 2.3℃, P = .02), LIPVs (28.4 ± 1.4 vs 32.6 ± 2.7, P = .01) and RIPVs (26.1 ± 4.3 vs 34.0 ± 1.3℃, P = .002). The differences in mean balloon to LET distance were measured for all veins before and after rotation; LSPV (right anterior oblique [RAO], 11.0 ± 1.7 vs 13.8 ± 4.5 mm, P = .05); LIPV (RAO, 10.7 ± 4.3 vs 14.6 ± 6.1 mm, P = .03); RIPV (LAO, 11.8 ± 5.5 vs 14.2 ± 5.7 mm, P = .01). CONCLUSIONS: CB rotational maneuvers during ablation can prevent significant reduction in LET and may prevent esophageal injury during the procedure.

Radiofrequency catheter ablation at the non-coronary cusp for the treatment of para-hisian accessory pathways.

AIMS: Radiofrequency catheter ablation (RFCA) is well established as a definitive therapy of accessory pathways (APs). Successful RFCA of anteroseptal APs at the non-coronary cusp (NCC) have been reported in several case reports. We aimed to evaluate the prevalence, safety, efficacy, and long-term outcome of RFCA at the NCC for the treatment of para-hisian APs. METHODS AND RESULTS: Our study included 17 patients (58.8% female, mean age 46.9 ± 15.9 years) with para-hisian APs. We performed two different ablation approaches which targeted at either the right anterior septum (RAS) (n = 10) or the NCC (n = 7) as the initial target. We compared safety, efficacy, and long-term outcome between these two approaches. The para-hisian APs were successfully ablated in 15 patients and damaged in 1 patient, for the remaining patients, the ablation was abandoned for the suspicion of no atrioventricular conduction. Considering all ablation sites of the para-hisian APs, radiofrequency (RF) delivered at the NCC had a higher success rate (11/12 vs. 5/12, P < 0.05) and a lower complication rate (0/12 vs. 4/12, P < 0.05) compared with the RAS. During a mean follow-up period of 22.4 ± 15.0 months, all the patients were free of arrhythmias without any anti-arrhythmic drugs. CONCLUSION: Para-hisian APs can be safely and effectively ablated at the NCC. Compared with the ablation at the RAS, RF delivered at the NCC has a higher immediate success, lower complication rate, and good long-term outcome.

Correlation of scar in cardiac MRI and high-resolution contact mapping of left ventricle in a chronic infarct model.

BACKGROUND: Endocardial mapping for scars and abnormal electrograms forms the most essential component of ventricular tachycardia ablation. The utility of ultra-high resolution mapping of ventricular scar was assessed using a multielectrode contact mapping system in a chronic canine infarct model. METHODS: Chronic infarcts were created in five anesthetized dogs by ligating the left anterior descending coronary artery. Late gadolinium-enhanced magnetic resonance imaging (LGE MRI) was obtained 4.9 ± 0.9 months after infarction, with three-dimensional (3D) gadolinium enhancement signal intensity maps at 1-mm and 5-mm depths from the endocardium. Ultra-high resolution electroanatomical maps were created using a novel mapping system (Rhythmia Mapping System, Rhythmia Medical/Boston Scientific, Marlborough, MA, USA) Rhythmia Medical, Boston Scientific, Marlborough, MA, USA with an 8.5F catheter with mini-basket electrode array (64 tiny electrodes, 2.5-mm spacing, center-to-center). RESULTS: The maps contained 7,754 ± 1,960 electrograms per animal with a mean resolution of 2.8 ± 0.6 mm. Low bipolar voltage (<2 mV) correlated closely with scar on the LGE MRI and the 3D signal intensity map (1-mm depth). The scar areas between the MRI signal intensity map and electroanatomic map matched at 87.7% of sites. Bipolar and unipolar voltages, compared in 592 electrograms from four MRI-defined scar types (endocardial scar, epicardial scar, mottled transmural scar, and dense transmural scar) as well as normal tissue, were significantly different. A unipolar voltage of <13 mV correlated with transmural extension of scar in MRI. Electrograms exhibiting isolated late potentials (ILPs) were manually annotated and ILP maps were created showing ILP location and timing. ILPs were identified in 203 ± 159 electrograms per dog (within low-voltage areas) and ILP maps showed gradation in timing of ILPs at different locations in the scar. CONCLUSIONS: Ultra-high resolution contact electroanatomical mapping accurately localizes ventricular scar and abnormal myocardial tissue in this chronic canine infarct model. The high fidelity electrograms provided clear identification of the very low amplitude ILPs within the scar tissue and has the potential to quickly identify targets for ablation.

Spatial analysis and characteristics of persistent late potentials after ablation of scar-related VT substrate: Implications for late potential elimination as a procedural endpoint with high-resolution mapping.

BACKGROUND: Late potential (LP) elimination has been proposed as a surrogate endpoint for scar-related ventricular tachycardia (VT) ablation procedures. The characteristics, distribution, and predictors of persistent late potentials (pLPs) after ablation have not been studied. OBJECTIVE: The purpose of this study was to characterize the spatial distribution and features of pLP after catheter ablation of VT substrate with high-resolution mapping. METHODS: Cases of scar-related VT ablation with adequate pre- and postablation electroanatomic maps (EAMs) acquired exclusively using a high-density grid catheter were reviewed from 2021 to 2023. RESULTS: A total of 62 EAMs (pre- and postablation) from 31 cases using a high-density grid catheter were reviewed. pLPs were observed in 19 cases (61%) after ablation. New LP, spatially distinct from preablation LP, at the periphery of the ablation area comprised the majority of pLPs (16/19 [84%]). Isolated pLPs were more prevalent than fractionated pLPs, with a median amplitude of 0.26 mV (0.09-0.59 mV). The presence of pLP was associated with a significantly lower left ventricular ejection fraction (LVEF) and septal ablation but not low voltage, LP, or ablation area compared to absence of pLP (22.8% ± 7.8% vs 31.5% ± 8.0%, P = .008 for LVEF; 83% vs 44%, P = .033 for septal ablation). CONCLUSION: Formation of spatially distinct new LP after targeted VT ablation is common, especially in patients with lower LVEF and septal substrate independent of ablation burden. This finding highlights the limitations of complete LP elimination as an endpoint to VT ablation procedures.

Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients.

BACKGROUND: Autonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF). OBJECTIVE: The purpose of this study was to test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters. METHODS: Simultaneous recording of SKNA and electrocardiogram (neuECG) recording was performed over 7 days in patients with PAF. RESULTS: In study 1, 8 patients (7 men and 1 woman; age 62 ± 8 years) had 124 episodes of PAF. An SKNA burst toggled both on and off PAF in 8 episodes (6.5%) (type 1), toggled on but not off in 12 episodes (9.7%) (type 2), and toggled on a PAC cluster followed by PAF in 4 episodes (3.2%) (type 3). The duration of these PAF episodes was <10 minutes. The remaining 100 episodes (80.6%) were associated with active SKNA bursts throughout PAF (type 4) and lasted longer than type 1 (P = .0185) and type 2 (P = .0027) PAF. There were 47 PAC clusters. Among them, 24 (51.1%) were toggled on and off, and 23 (48.9%) were toggled on but not off by an SKNA burst. In study 2, 17 patients (9 men and 8 women; age 58 ± 12 years) had <10 minutes of PAF (4, 8, 0, and 31 of types 1, 2, 3, and 4, respectively). There were significant circadian variations of all types of PAF. CONCLUSION: A single SKNA burst can toggle short-duration PAF and PAC cluster episodes on and off. The absence of continued SKNA after the onset might have affected the maintenance of these arrhythmias.