The Evolving Role of Insertable Cardiac Monitors in Patients with Congenital Heart Disease

Insertable cardiac monitors (ICMs) have been used more frequently and in a wider variety of circumstances in recent years. ICMs are used for symptom-rhythm correlation when patients have potentially arrhythmogenic syncope and for less traditional reasons such as rhythm surveillance in patients with genetic arrhythmia syndromes or other diseases with high arrhythmia risk. ICMs have good diagnostic yield in pediatric patients and in adults with congenital heart disease and have a low rate of complications. Implantation techniques should take patient-specific factors into account to optimize diagnostic yield and minimize risk.

Fate After the Mustard Procedure for d-Transposition of the Great Arteries: Impact of Age, Complexity, and Atrial Tachyarrhythmias: A Single Center Experience

Patients with dextro transposition of the great arteries (d-TGA) after atrial switch procedure are at risk to develop heart failure and arrhythmias during long-term follow-up. The present study aims to add knowledge on the fate of subjects after Mustard procedure during long-term follow-up into adulthood. A single center, retrospective chart review analysis was conducted. All subjects who had Mustard-type atrial switch procedure between 1969 and 1994 at our institution were included. A total of 92 subjects were included. Early postoperative death was reported in 2 subjects. Long-term follow-up was available in 49 survivors. Of those, 6 individuals died during further follow-up. Sudden cardiac death was the most prevalent cause for fatal outcome. Mortality during long-term follow-up was associated with the presence of additional cardiovascular malformations (complex d-TGA). Sinus node dysfunction was observed in 65% of the patients and atrial tachyarrhythmias were common in adult survivors (63%). Implantation of a pacemaker or a cardioverter defibrillator was required in 31% and 45% of those surviving into adulthood. Complications were frequently observed during follow-up after either pacemaker or cardioverter defibrillator implantation (43%) with lead failure being the most frequent complication. The aging population of patients after Mustard procedure is facing challenging problems mainly resulting from a failing systemic right ventricle, presence of associated cardiac malformations and the presence of atrial baffles associated with relevant atrial scars. Age, associated cardiac malformations, and atrial tachyarrhythmias seem to play a major role in determining the fate of patients with d-TGA after atrial switch procedures.

Differences in Androgen Receptor Expression in Human Heart Tissue in Various Types of Cardiomyopathy and in Aortic Valve Stenosis

Background: Sex-specific differences in heart disease outcomes are influenced by the levels of the steroid hormones, estrogen and testosterone. While the roles of estrogen receptors in cardiac disease are well-studied in animals and humans, respective research on androgen receptors (AR) is limited. Here we investigate AR protein and mRNA expression in human myocardium of various cardiac diseases. Methods: AR expression was analyzed by western blotting in myocardium from human non-failing hearts (NF, n = 6) and patients with aortic stenosis (AS, n = 6), hypertrophic cardiomyopathy (HCM, n = 7), dilated cardiomyopathy (DCM, n = 7), and ischemic cardiomyopathy (ICM, n = 7). Using an AR45-specific antibody, a subsequent western blot assessed samples from male and female patients with HCM (n = 10) and DCM (n = 10). The same sample set was probed for full-length AR and AR45 mRNA expression. Immunohistochemistry (IHC) localized AR in myocardium from HCM and AS hearts. Results: Full-length AR was notably enriched in AS and HCM hearts compared to ICM, DCM, and NF. Similarly, AR45 was more abundant in HCM than in DCM. In contrast to the pattern observed for AR protein, full-length AR mRNA levels were lower in HCM compared to DCM, with no discernible difference for the AR45 isoform. Although gender differences in AR expression were not detected in western blots or qRT-PCR, IHC showed stronger nuclear AR signals in males than in females. Conclusions: Our findings indicate disease-specific regulation of AR mRNA and/or AR protein in cardiac hypertrophy, underscoring a potential role in this cardiac pathology.

Leadless epicardial pacing at the left ventricular apex: an animal study

AIMS

State-of-the-art pacemaker implantation technique in infants and small children consists of pace/sense electrodes attached to the epicardium and a pulse generator in the abdominal wall with a significant rate of dysfunction during growth, mostly attributable to lead failure. In order to overcome lead-related problems, feasibility of epicardial implantation of a leadless pacemaker at the left ventricular apex in a growing animal model was studied.

METHODS AND RESULTS

Ten lambs (median body weight 26.8 kg) underwent epicardial implantation of a Micra transcatheter pacing system (TPS) pacemaker (Medtronic Inc., Minneapolis, USA). Using a subxyphoid access, the Micra was introduced through a short, thick-walled tube to increase tissue contact and to prevent tilting from the epicardial surface. The Micra's proprietary delivery system was firmly pressed against the heart, while the Micra was pushed forward out of the sheath allowing the tines to stick into the left ventricular apical epimyocardium. Pacemakers were programmed to VVI 30/min mode. Pacemaker function and integrity was followed for 4 months after implantation. After implantation, median intrinsic R-wave amplitude was 5 mV [interquartile range (IQR) 2.8-7.5], and median pacing impedance was 2235 Ω (IQR 1725-2500), while the median pacing threshold was 2.13 V (IQR 1.25-2.9) at 0.24 ms. During follow-up, 6/10 animals had a significant increase in pacing threshold with loss of capture at maximum output at 0.24 ms in 2/10 animals. After 4 months, median R-wave amplitude had dropped to 2.25 mV (IQR 1.2-3.6), median pacing impedance had decreased to 595 Ω (IQR 575-645), and median pacing threshold had increased to 3.3 V (IQR 1.8-4.5) at 0.24 ms. Explantation of one device revealed deep penetration of the Micra device into the myocardium.

CONCLUSION

Short-term results after epicardial implantation of the Micra TPS at the left ventricular apex in lambs were satisfying. During mid-term follow-up, however, pacing thresholds increased, resulting in loss of capture in 2/10 animals. Penetration of one device into the myocardium was of concern. The concept of epicardial leadless pacing seems very attractive, and the current shape of the Micra TPS makes the device unsuitable for epicardial placement in growing organisms.

Advancing the science of management of arrhythmic disease in children and adult congenital heart disease patients within the last 25 years

This review article reflects how publications in EP Europace have contributed to advancing the science of management of arrhythmic disease in children and adult patients with congenital heart disease within the last 25 years. A special focus is directed to congenital atrioventricular (AV) block, the use of pacemakers, cardiac resynchronization therapy devices, and implantable cardioverter defibrillators in the young with and without congenital heart disease, Wolff-Parkinson-White syndrome, mapping and ablation technology, and understanding of cardiac genomics to untangle arrhythmic sudden death in the young.

Transitional forestry in New Zealand: re-evaluating the design and management of forest systems through the lens of forest purpose

Forestry management worldwide has become increasingly effective at obtaining high timber yields from productive forests. In New Zealand, a focus on improving an increasingly successful and largely Pinus radiata plantation forestry model over the last 150 years has resulted in some of the most productive timber forests in the temperate zone. In contrast to this success, the full range of forested landscapes across New Zealand, including native forests, are impacted by an array of pressures from introduced pests, diseases, and a changing climate, presenting a collective risk of losses in biological, social and economic value. As the national government policies incentivise reforestation and afforestation, the social acceptability of some forms of newly planted forests is also being challenged. Here, we review relevant literature in the area of integrated forest landscape management to optimise forests as nature-based solutions, presenting 'transitional forestry' as a model design and management paradigm appropriate to a range of forest types, where forest purpose is placed at the heart of decision making. We use New Zealand as a case study region, describing how this purpose-led transitional forestry model can benefit a cross section of forest types, from industrialised forest plantations to dedicated conservation forests and a range of multiple-purpose forests in between. Transitional forestry is an ongoing multi-decade process of change from current 'business-as-usual' forest management to future systems of forest management, embedded across a continuum of forest types. This holistic framework incorporates elements to enhance efficiencies of timber production, improve overall forest landscape resilience, and reduce some potential negative environmental impacts of commercial plantation forestry, while allowing the ecosystem functioning of commercial and non-commercial forests to be maximised, with increased public and biodiversity conservation value. Implementation of transitional forestry addresses tensions that arise between meeting climate mitigation targets and improving biodiversity criteria through afforestation, alongside increasing demand for forest biomass feedstocks to meet the demands of near-term bioenergy and bioeconomy goals. As ambitious government international targets are set for reforestation and afforestation using both native and exotic species, there is an increasing opportunity to make such transitions via integrated thinking that optimises forest values across a continuum of forest types, while embracing the diversity of ways in which such targets can be reached.

Predictors of Delayed Hyponatraemia After Surgery for Pituitary Tumour

Delayed hyponatraemia(DH) is a common complication following trans-sphenoidal surgery(TSS) for pituitary tumour. We evaluated the prevalence of DH following TSS, and assessed the factors associated with DH, including early post-operative diabetes insipidus(EPDI). This retrospective study included 100 TSS for pituitary tumours in 98 patients, over a period of 26 months. Subjects were divided into two groups: those who developed hyponatraemia and those who did not develop hyponatraemia, during post-operative days 4 to 14. The clinical characteristics and peri-operative parameters were compared between the two groups, to identify factors predicting DH. The mean age of the patients was 42.0±13.6 years, 58 (59%) were females and 61 (61%) had functional tumours. Thirty-six patients(36%) developed DH following TSS of whom majority(58%) were diagnosed on post-operative days 7 and 8; only 8/36 (22%) were symptomatic. Syndrome of inappropriate antidiuretic hormone secretion(SIADH) was found to be the most common aetiology of DH. On logistic regression analysis, intra-operative cerebrospinal fluid(CSF) leak (OR 5.0; 95% CI 1.9-13.8; p=0.002), EPDI (OR 3.4; 95% CI 1.3-9.2; p=0.015) and peri-operative steroid use (OR 3.6; 95% CI 1.3-9.8; p=0.014) were found to be significantly associated with DH. In conclusion, EPDI, intra-operative CSF leak and peri-operative steroid use were significant predictors of DH. EPDI predicts moderate to severe hyponatraemia with 80% specificity but has low sensitivity(47%). As most patients have asymptomatic hyponatraemia, serum sodium measurement on POD 7 to 10 would be helpful to identify DH in patients at increased risk.

Multimodal perturbation analyses of cyclin-dependent kinases reveal a network of synthetic lethalities associated with cell-cycle regulation and transcriptional regulation

Cell-cycle control is accomplished by cyclin-dependent kinases (CDKs), motivating extensive research into CDK targeting small-molecule drugs as cancer therapeutics. Here we use combinatorial CRISPR/Cas9 perturbations to uncover an extensive network of functional interdependencies among CDKs and related factors, identifying 43 synthetic-lethal and 12 synergistic interactions. We dissect CDK perturbations using single-cell RNAseq, for which we develop a novel computational framework to precisely quantify cell-cycle effects and diverse cell states orchestrated by specific CDKs. While pairwise disruption of CDK4/6 is synthetic-lethal, only CDK6 is required for normal cell-cycle progression and transcriptional activation. Multiple CDKs (CDK1/7/9/12) are synthetic-lethal in combination with PRMT5, independent of cell-cycle control. In-depth analysis of mRNA expression and splicing patterns provides multiple lines of evidence that the CDK-PRMT5 dependency is due to aberrant transcriptional regulation resulting in premature termination. These inter-dependencies translate to drug-drug synergies, with therapeutic implications in cancer and other diseases.

Leitlinie Myokarditis der Deutschen Gesellschaft für Pädiatrische Kardiologie

This consensus statement presents updated recommendations on diagnosis and treatment of myocarditis in childhood.

Catheter Ablation of Coronary Sinus Accessory Pathways in the Young

BACKGROUND

Accessory atrioventricular pathways (AP) are the most common tachycardia substrate for supraventricular tachycardia (SVT) in the young. Endocardial catheter ablation of AP may be unsuccessful in up to 5% due to a coronary sinus location.

OBJECTIVE

Data on ablation of accessory pathways within the coronary venous system (CVS) in the young is sparse.

METHODS

Analysis of feasibility, outcome, and safety in patients ≤18 years with coronary sinus accessory pathways (CS-AP) and catheter ablation via CVS in a tertiary pediatric electrophysiological referral center (05/2003-12/2021). Control group adjusted for age, weight, and pathway location was established from patients of the prospective European Multicenter Pediatric Ablation Registry who all had endocardial AP ablation.

RESULTS

24 individuals had mapping and intended AP ablation within the CVS (age: 2.7-17.3 years, body weight: 15.0-72.0 kg). Due to proximity to coronary artery, ablation was withheld in 2/24. Overall procedural success was achieved in 20/22 (90.9%) study patients and in 46/48 (95.8%) controls. Coronary artery injury after RF ablation was noted in 2/22 (9%) study patients and in 1/48 (2%) controls. In CVS patients repeat SVT occurred in 5/22 (23%) during a median follow-up of 8.5 years, 4/5 underwent reablation resulting in 94.4% overall success. Controls were free from SVT during follow-up of 12 months as defined by registry protocol.

CONCLUSIONS

Success of CS-AP ablation in the young was comparable to endocardial AP-ablation. Substantial risk of coronary artery injury should be considered when CS-AP ablation is performed in the young.

Ecological and health risk assessment of heavy metals: a case study of residential waste sites in Umuahia, South-East Nigeria

This study assessed the human health hazards and ecological risks of heavy metals from waste sites in residential vicinity. The heavy metals analyzed were Cr, Pb, Cd, Ni, Cu, and Zn. A total of 40 soil samples were collected from waste sites in two residential estates located in the urban and suburb areas of Umuahia, Abia state. Results revealed a trend in concentrations of the heavy metals for both sites in the following order: Cu > Ni > Zn > Cr > Cd > Pb. The concentrations of heavy metals were higher in rural soils than in urban soil. The contamination factor (CF) indices for Pb, Cr, Cu, Ni, and Zn were less than 1 for both sites, signifying a low contamination scenario. The contamination factor for Cd (6 > CF) for both sites indicated a very high contamination status. The estimated degree of contamination (Cdeg) was less than the lower threshold of 8.0, denoting a low degree of contamination. Cd was the highest contributor to ecological risk with Er index value of 184.2 among measured heavy metals. The overall potential ecological risk index for urban and rural sites are 187.1 and 196.1 respectively, classifying the sites as moderate risk. The overall non-carcinogenic hazard index values (HI) for adults and children in urban and rural soils are 0.00248, 0.0198 and 0.0028, 0.0223 respectively, which are below the acceptable limit (HI < 1), indicating that the exposed residents are unlikely to experience any apparent adverse health hazards. However, children are more susceptible to non-carcinogenic hazards than adults in the study areas.

Functional regeneration of dilated cardiomyopathy by transcatheter bilateral pulmonary artery banding: first-in-human case series

Background

Dilated cardiomyopathy (DCM) is a leading cause of heart transplantation (HTx) in children. Surgical pulmonary artery banding (PAB) is used worldwide to achieve functional heart regeneration and remodelling.

Case summary

We report for the first-time successful bilateral transcatheter implantation of bilateral pulmonary artery flow restrictors in a case series of three infants with severe DCM based on left-ventricular non-compaction morphology associated with Barth syndrome in one and a non-classified syndrome in another. Functional cardiac regeneration was observed in two patients after almost 6 months of endoluminal banding, and in the neonate with Barth syndrome already after 6 weeks. Accompanied by an improvement in functional class (Class IV to Class I), the left ventricular end-diastolic dimensions z-score normalized, as did the elevated serum brain natriuretic peptide levels. A listing for HTx could be avoided.

Discussion

Percutaneous bilateral endoluminal PAB is a novel minimally invasive approach that enables functional cardiac regeneration in infants with severe DCM and preserved right ventricular function. Interruption of the ventriculo-ventricular interaction, the key mechanism for recovery, is avoided. Intensive care for these critically ill patients is reduced to a minimum. However, investing in 'heart regeneration to avoid transplantation' remains a challenge.

Association and outcomes of vf according to involved coronary artery in STEMI – a nationwide analysis

Background

Ventricular fibrillation (VF) is common in acute ST segment elevation myocardial infarction (STEMI) and is associated with increased in-hospital mortality rate.

Purpose

We sought to investigate the association between VF and artery involved in STEMI

Methods

This is a retrospective observational study of hospitalizations between January 1, 2016 and December 31, 2019, using the National Inpatient Sample (NIS), the largest all-payer public database of hospital care in the United States.

Results

A total of 138,201 patients were primarily hospitalized for STEMI from 2016 to 2019. Among them 12,318 had right coronary artery (RCA) lesions, 427 had left main (LM) lesions, 2381 had left circumflex (LCx) lesions and 12,765 had left anterior descending (LAD) lesions. Mean age of patients with VF and STEMI was 62 years and that with RCA (63 years), LM (65 years), LCx (62 years), LAD (60 years), p&lt;0.001. Females were 30.5% (n=42,231) among all STEMI group and 29.8% (n=3672) RCA, 29% (n=124) LM, 27.4%(n=653) LCx and 28.6%(n=3645) LAD, p&lt;0.001. In-hospital mortality for all patients with STEMI was 7.9%. The in-hospital mortality associated with STEMI there was 5%, 23.4%, 6.6%, 7.1%, (p&lt;0.001) for RCA, LM, LCx and LAD respectively. The incidence of VF among all patients with STEMI was 8.3% (n=11425) and for LM, LAD, LCX, and RCA was 12.9%, 10.7%, 9.2% and 7.9% (p&lt;0.001). Mean hospital length of stay for VF with RCA (6.2 days), LM (5.5 days), LCx (6.9 days) and LAD (7.4 days). After adjusting for age, gender, race, income, comorbidities, hospital teaching status, region and year, patients with STEMI who had VF had higher odds of mortality (aOR 6.4, 95% CI, 6.1 to 6.8; P&lt;0.001). The highest likelihood of mortality observed in patients with VF who had and LCx STEMI (aOR 7.9, CI 95%, 5 to 12.4; p&lt;0.001) followed by RCA STEMI (aOR 7.4, 95% CI 6 to 9.1; p&lt;0.001), and LM STEMI (aOR 6.1, 95% 3.1 to 12; p&lt;0.001).

Conclusion

Highest in-hospital mortality was observed in patients with STEMI who had VF in LCx, followed by RCA and LM. There was higher occurrence of VF in STEMI involving LM.

Funding Acknowledgement

Type of funding sources: None.

Patient activation and health-related quality-of-life in association with smartwatch alerts for atrial fibrillation detection

Background

Smartwatches with various alert systems are becoming increasingly popular in the detection of atrial fibrillation (AF) post stroke, however their impact on psychological well-being remains unknown.

Purpose

Assess the association between smartwatch alerts for detected atrial fibrillation in older stroke survivors and patient activation as well as health-related quality-of-life.

Methods

Data were used from the Pulsewatch study, a multiphase, randomized controlled trial, which enrolled older adults (≥50 years of age) from the UMass Memorial Health System with history of a stroke and no contraindications to anticoagulation, who were given a smartwatch for AF detection. In Phase I, participants were randomized 3:1 (intervention:control) to receive a smartwatch/smartphone pair and an FDA-approved cardiac patch monitor or only the patch (control) to monitor for AF for 14 days. In Phase II, participants were re-randomized 1:1, with the intervention group being offered the smartwatch/smartphone pair for an extra 30 days. Participants were grouped into those receiving at least one alert of a possible abnormal rhythm versus those who did not receive any alerts from their smartwatch. At baseline, 14 days, and 44 days the Consumer Health Activation Index was used to assess patient activation and the Physical and Mental Component Summary of Short-Form Health Survey were utilized to evaluate physical and mental health-related quality-of-life, respectively. Mixed-effects repeated measures linear regression models were used to examine changes in patient activation and physical and mental health-related quality-of-life, in relation to alerts, adjusting for confounding variables including age, sex, race, history of arrhythmias, history of congestive heart failure, history of coronary artery disease, baseline depression, and baseline cognitive impairment, over the study period.

Results

94 participants (64.6±9.1 years of age, 87.2% non-Hispanic white, and 43.6% female) were included in the analysis; 16 of whom received at least one alert. Specifically, twelve participants received 1 to 3 alerts, three participants received 11 to 18, and one participant received 226. In fully adjusted models, receiving alerts was not associated with changes in patient activation or mental health-related quality-of-life (β −1.70, p-value 0.60 and β 2.85, p-value 0.09 respectively), but was associated with a significant reduction in physical health-related quality-of-life (β −4.67, p-value 0.04).

Conclusions

In a cohort of older stroke survivors who wore smartwatches for up to 44 days, reception of alerts was not significantly associated with changes in patient activation or mental health-related quality-of-life but was significantly related to a decline in physical health-related quality-of-life. Further studies are necessary to explore the use of smartwatches in AF screening and their impact on psychological health and quality-of-life.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): R01HL137734 from the National Heart, Lung, and Blood Institute

Periprocedural outcomes of transcatheter aortic valve replacement (TAVR) in patients with and without cardiac amyloidosis-analysis from 2016–2019 national inpatient sample

Background

Cardiac Amyloidosis is often misdiagnosed due to its non-specific presenting symptoms. There is a lack of evidence on the clinical outcomes in patients with cardiac amyloidosis undergoing transcatheter aortic valve replacement (TAVR).

Purpose

To study periprocedural outcomes in patients hospitalised primarily for TAVR with and without cardiac amyloidosis.

Methods

This is a retrospective observational study involving index hospitalizations for TAVR between January 1, 2016 to December 31, 2019 from the National Inpatient Sample (NIS), the largest all-payer public database of hospital care data in the United States. Our study sample included discharged adult patients (≥18 years) primarily hospitalised for TAVR using ICD-10 codes. Confounders were adjusted using multivariable regression analysis.

Results

During 2016–2019, there were 43270 principal hospitalizations (unweighted sample) identified for TAVR, among them 4999 patients had a history of cardiac amyloidosis. Mean age was 79.3±8.4 years. Among patients hospitalised for TAVR, 54.4% (n=23539) were males, 45.6% (n=19731) were females (p&lt;0.001), 1.71% (n=740) developed cardiogenic shock, 1.53% (n=662) required mechanical ventilation with an in-hospital mortality of 1.3% (n=563). There were 87% Whites, 4.2% Blacks, 4.8% Hispanics, 1.3% Asians, and 2.7% were other races. A total of 23,819 (55.1%) hospitalizations had a Charlson Comorbidity Index (CCI) of three or higher.

After undergoing TAVR, compared to the non-cardiac amyloidosis cohort, the cardiac amyloidosis cohort had less females (27.8% vs 45.6%, p=0.01), had similar age (mean age: 80.2 vs 79.3; p=0.665), higher incidence of congestive heart failure (CHF) (100% vs 74%, p=0.012), higher mechanical ventilation requirement (11.1% vs 1.5%, p=0.001)) but with a similar length of hospital stay (3.9% vs 3.9%, p=0.99). Multivariate regression analysis revealed that TAVR in cardiac amyloidosis cohort did not significantly increase the odds of in-hospital mortality than the non-cardiac amyloidosis cohort (aOR: 5.2; 95% CI: 0.7, 38.3; p=0.103). However, females had higher odds of mortality post-TAVR compared to males (aOR: 1.45; 95% CI: 1.22, 1.73; p&lt;0.001) after controlling for age, sex, race, regional hospital location, hospital bed capacity, income, and CCI. There is an increasing trend of index TAVR hospitalizations with cardiac amyloidosis with 109.4 per 100,000 hospitalizations in 2016, 139.7 per 100,000 in 2017, 157.5 per 100,000 in 2018, 201.4 per 100,000 in 2019 (p trend&lt;0.001).

Conclusions

After TAVR, cardiac amyloidosis is associated with higher incidence of CHF increased need for mechanical ventilation, similar in-hospital mortality rate in comparison to non-cardiac amyloidosis cohort. There was an increasing trend in the index hospitalizations for TAVR with cardiac amyloidosis from 2016–2019.

Funding Acknowledgement

Type of funding sources: None.

Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation

BACKGROUND

Palliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPM_v) may be associated with additional adverse long-term outcomes.

OBJECTIVES

The goal of this study was to quantify the attributable risk of PPM_v in patients with SV, and to identify modifiable risk factors.

METHODS

This international study was sponsored by the Pediatric and Congenital Electrophysiology Society. Centers contributed baseline and longitudinal data for functionally SV patients with PPM_v. Enrollment was at implantation. Controls were matched 1:1 to PPM_v subjects by ventricular morphology and sex, identified within center, and enrolled at matched age. Primary outcome was transplantation or death.

RESULTS

In total, 236 PPM_v subjects and 213 matched controls were identified (22 centers, 9 countries). Median age at enrollment was 5.3 years (quartiles: 1.5-13.2 years), follow-up 6.9 years (3.4-11.6 years). Median percent ventricular pacing (Vp) was 90.8% (25th-75th percentile: 4.3%-100%) in the PPM_v cohort. Across 213 matched pairs, multivariable HR for death/transplant associated with PPM_v was 3.8 (95% CI 1.9-7.6; P < 0.001). Within the PPM_v population, higher Vp (HR: 1.009 per %; P = 0.009), higher QRS z-score (HR: 1.19; P = 0.009) and nonapical lead position (HR: 2.17; P = 0.042) were all associated with death/transplantation.

CONCLUSIONS

PPM_v in patients with SV is associated with increased risk of heart transplantation and death, despite controlling for increased associated morbidity of the PPM_v cohort. Increased Vp, higher QRS z-score, and nonapical ventricular lead position are all associated with higher risk of adverse outcome and may be modifiable risk factors.

Contact Force Guided Radiofrequency Current Application at Developing Myocardium: Summary and Conclusions

BACKGROUND

Catheter contact is one key determinant for lesion size in radiofrequency catheter ablation (RFA). Monitoring of contact force (CF) during RFA has been shown to improve efficacy of RFA in experimental settings as well as in adult patients. Coronary artery narrowing after RFA has been described in experimental settings as well as in children and adults and may be dependent from catheter contact. Value of CF monitoring concerning these issues has not been systematically yet.

OBJECTIVE

Value of high versus low CF during RFA in piglets was studied to assess lesion size and potential coronary artery involvement mimicking RFA in small children.

ANIMALS AND METHODS

RFA with continuous CF monitoring was performed in 24 piglets (median weight 18.5 kg) using a 7F TactiCath Quartz RF ablation catheter (Abbott, Illinois, USA). A total of 7 lesions were induced in each animal applying low (10-20 g) or high (40-60 g) CF. RF energy was delivered with a target temperature of 65 °C at 30 W for 30 seconds. Coronary angiography was performed prior and immediately after RF application. Animals were assigned to repeat coronary angiography followed by heart removal after 48 h (n=12) or 6 months (n=12). Lesions with surrounding myocardium were excised, fixated and stained. Lesion volumes were measured by microscopic planimetry.

RESULTS

A total of 148 RF lesions were identified in the explanted hearts. Only in the subset of lesions at the AV annulus 6 month after ablation, lesion size and number of lesions exhibiting transmural extension were higher in the high CF group compared to low CF. In all other locations CF had no impact on lesion size and mural extension after 48 h as well as after 6 months. Additional parameters as Lesion Size Index and Force Time Integral were also not related to lesion size. Coronary artery damage was present in 2 animals after 48 h and in 1 after 6 months and was not related to CF. This article is protected by copyright. All rights reserved.

Catheter ablation of atrial fibrillation using 2nd-generation cryoballoon in congenital heart disease patients - significance of RF ablation of additional atrial macro-reentrant tachycardia

Background

Prevalence of atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD). Experience using the cryoballoon to achieve pulmonary vein isolation (PVI) in adult CHD patients is limited. The aim of the present study was to assess the value of PVI by cryoballoon in adult CHD patients and to evaluate the significance of additional radiofrequency (RF) ablation of atrial tachycardia (AT).

Patients and methods

Prospective data analysis; all patients with CHD and AF and PVI using the cryoballoon from January 2017 through November 2021 were included.

Results

Nineteen patients with various types of CHD were included. Median age was 58 (IQR 47–63) years. A total of 12/19 (63%) patients had had RF ablation of right atrial AT before. Median procedure duration was 225 (IQR 196–261) min. Median fluoroscopy time was 12.3 (IQR 5.2–19.5) min and median freeze time was 32 (IQR 28–36.3) min. Procedural success was achieved in all patients. Additional RF catheter ablation of intraatrial reentrant tachycardia within the left atrium was performed in 3/19 (16%) subjects and within the right atrium in 6/19 (32%) patients. Median follow-up was 26 (IQR 9–49) months. Excluding a 90-day blanking period, recurrence of AF was observed in 6/19 subjects (32%). After one redo procedure deploying RF energy only, 84% of all patients remained free from recurrence. Phrenic nerve palsy was observed in 1 subject.

Conclusion

Results after PVI using the cryoballoon plus additional RF ablation of AT were promising (84% success including one redo procedure). Success of AF ablation was unsatisfactory in all patients who had no additional AT ablation. Ablation of any AT in these patients should therefore be considered in addition to PVI.

Morbidity and mortality in adults with congenital heart defects in the third and fourth life decade

Objectives

The population of adults with congenital heart defects (ACHD) is continuously growing. Data on morbidity and mortality of ACHD are limited. This longitudinal observational study examined a group of ACHD with surgically corrected or palliated congenital heart defects (CHD) during a 15-year period.

Methods

ACHD that had participated in the initial study were invited for a follow-up examination. Mortality and hospitalization data were compared with a healthy control group.

Results

From 05/2017 to 04/2019 a total of 249/364 (68%) ACHD participated in the follow-up study: 21% had mild, 60% moderate and 19% severe CHD. During the observational period, 290 health incidents occurred (cardiac catheterization 37%, cardiovascular surgery 27%, electrophysiological study/ablation 20%, catheter interventional treatment 14%, non-cardiac surgery 3%). Events were more frequent in ACHD with moderate (53%) and severe (87%) compared to those with mild CHD (p < 0.001). 24 individuals died at a median age of 43 years during the observation period. 29% of them had moderate and 71% severe CHD corresponding to a mortality rate of 0%, 0.29% and 1.68% per patient-year in ACHD with mild, moderate and severe CHD. Long-term survival was significantly reduced in patients with severe CHD in comparison to individuals with mild and moderate CHD (p < 0.001).

Conclusion

After correction or palliation of CHD, there was remarkable ongoing morbidity and mortality in ACHD patients over the 15-year observation period, particularly in individuals with moderate and severe CHD when compared with the general population. Thus, life-long special care is required for all surgically corrected or palliated ACHD patients.

Graphical abstract

Repeat Radiofrequency Catheter Ablation of Atrial Tachycardias in Patients with Congenital Heart Disease

INTRODUCTION

Atrial tachycardias (AT) in patients with congenital heart disease (CHD) are significantly contributing to morbidity and mortality. Aim of this study was to evaluate the long-term course of CHD patients requiring repeat ablation procedures (RAP) of AT.

PATIENTS AND METHODS

All 144 patients with CHD who had undergone ablation of AT at our center between January 2003 and October 2018 were enrolled. Patients were classified according to complexity of CHD: complex CHD (cCHD), moderate CHD (mCHD) and simple CHD (sCHD).

RESULTS

A total of 101 RAP were performed in 64 patients. One RAP was performed in n=40, two in n=13, three in n=10 and 5 in n=1. Acute success rate was 82% (83/101) and was not associated with complexity of CHD (p=1.0). Number of procedures was lower in patients with sCHD than in patients with mCHD and cCHD (sCHD 1.3±0.6, mCHD 1.8±1.0 and cCHD 1.8±1.1, p=0.04). RAP were most frequent in patients after Fontan palliation or Atrial switch procedure (2.0±1.1 (n=41) vs. 1.6±0.9 all others, p=0.016) and in patients with multiple unstable AT´s (2.5±1.1 (n=11) vs. 1.7±1.0, p=0.008). Major complications occurred in 4/101 procedures. Complete follow-up was available in 125 patients. Since last RAP 73% of the patients were in sinus/atrial rhythm and 34/125 patients (27%) with AT recurrence did not require re-ablation with mean follow-up of 52±40 months.

CONCLUSIONS

Recurrences after ablation of AT in CHD patients were frequent. After RAP promising long-term results could be achieved. Data encourage repetitive ablation procedures in this patient population. This article is protected by copyright. All rights reserved.

A Review of the EUSO-Balloon Pathfinder for the JEM-EUSO Program

EUSO-Balloon is a pathfinder for JEM-EUSO, the mission concept of a spaceborne observatory which is designed to observe Ultra-High Energy Cosmic Ray (UHECR)-induced Extensive Air Showers (EAS) by detecting their UltraViolet (UV) light tracks "from above." On August 25, 2014, EUSO-Balloon was launched from Timmins Stratospheric Balloon Base (Ontario, Canada) by the balloon division of the French Space Agency CNES. After reaching a floating altitude of 38 km, EUSO-Balloon imaged the UV light in the wavelength range ∼290-500 nm for more than 5 hours using the key technologies of JEM-EUSO. The flight allowed a good understanding of the performance of the detector to be developed, giving insights into possible improvements to be applied to future missions. A detailed measurement of the photoelectron counts in different atmospheric and ground conditions was achieved. By means of the simulation of the instrument response and by assuming atmospheric models, the absolute intensity of diffuse light was estimated. The instrument detected hundreds of laser tracks with similar characteristics to EASs shot by a helicopter flying underneath. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. The reconstruction of the direction of the laser tracks was performed. In this work, a review of the main results obtained by EUSO-Balloon is presented as well as implications for future space-based observations of UHECRs.

Proteomic mapping of atrial and ventricular heart tissue in patients with aortic valve stenosis

Aortic valve stenosis (AVS) is one of the most common valve diseases in the world. However, detailed biological understanding of the myocardial changes in AVS hearts on the proteome level is still lacking. Proteomic studies using high-resolution mass spectrometry of formalin-fixed and paraffin-embedded (FFPE) human myocardial tissue of AVS-patients are very rare due to methodical issues. To overcome these issues this study used high resolution mass spectrometry in combination with a stem cell-derived cardiac specific protein quantification-standard to profile the proteomes of 17 atrial and 29 left ventricular myocardial FFPE human myocardial tissue samples from AVS-patients. In our proteomic analysis we quantified a median of 1980 (range 1495–2281) proteins in every single sample and identified significant upregulation of 239 proteins in atrial and 54 proteins in ventricular myocardium. We compared the proteins with published data. Well studied proteins reflect disease-related changes in AVS, such as cardiac hypertrophy, development of fibrosis, impairment of mitochondria and downregulated blood supply. In summary, we provide both a workflow for quantitative proteomics of human FFPE heart tissue and a comprehensive proteomic resource for AVS induced changes in the human myocardium.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Developed in collaboration with and endorsed by the Heart Rhythm Society (HRS), the American College of Cardiology (ACC), the American Heart Association (AHA), and the Association for European Paediatric and Congenital Cardiology (AEPC) Endorsed by the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS)

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

1080 An Audit on Compliance with Recommended Duration of Surgical Antimicrobial Prophylaxis in St. Vincent’s University Hospital, Dublin, Ireland

Aim

Surgical site infection (SSI) is a common healthcare-associated infection, and a frequent cause of post-operative morbidity. SSI comprises any infection of the operative incision, cavity or involved organ, that occurs within the 30-day post-operative period. Antimicrobial prophylaxis is critical in reducing SSIs. Our aim was to assess adherence to the recommended surgical antimicrobial prophylaxis guidelines in St. Vincent’s University Hospital (SVUH), as part of the hospital antimicrobial stewardship programme. Compliance of surgical services was measured against the recommended regimens described in the SVUH Antimicrobial Guidelines.

Method

Data on duration and choice of prophylaxis were prospectively gathered on inpatients undergoing elective surgery during a three-week period between August-September 2020. Patients undergoing transplant procedures, inpatients in the intensive care unit, and patients who moved off-site postoperatively were excluded.

Results

Eighty-one patients were included. Sixty-four (79%) were compliant with prophylaxis duration, while seventeen (21%) were not. Reasons for extended prophylaxis included three (18%) cases where there were intra-operative complications and five (29%) cases of routine prescribing of an additional 24-hour coverage. Nine (53%) did not document the reason for extended cover.

Conclusions

Compliance with recommended duration of prophylaxis improved in comparison to prior audits. Among patients receiving extended prophylaxis, documentation of the indication was poor. Patients with evidence of post-operative infection may be better served with targeted antimicrobial therapy rather than extended prophylaxis. One reason for extended prophylaxis may be due to difficulty accessing guidelines on recommended prophylaxis duration, hence a targeted smartphone application was introduced to improve accessibility.

Impaired Exercise Tolerance in Repaired Tetralogy of Fallot Is Associated With Impaired Biventricular Contractile Reserve: An Exercise-Stress Real-Time Cardiovascular Magnetic Resonance Study

BACKGROUND

Correction of tetralogy of Fallot (cTOF) often results in pulmonary valve pathology and right ventricular (RV) dysfunction. Reduced exercise capacity in cTOF patients cannot be explained by these findings alone. We aimed to explore why cTOF patients exhibit impaired exercise capacity with the aid of a comprehensive cardiopulmonary exercise testing (CPET) and real-time cardiovascular magnetic resonance exercise testing (CMR-ET) protocol.

METHODS

Thirty three cTOF patients and 35 matched healthy controls underwent CPET and CMR-ET in a prospective case-control study. Real-time steady-state free precession cine and phase-contrast sequences were obtained during incremental supine in-scanner cycling at 50, 70, and 90 W. RV and left ventricle (LV) volumes and pulmonary blood flow (Qp) were calculated. Differences of CPET and CMR-ET between cTOF versus controls and correlations between CPET and CMR-ET parameters in cTOF were evaluated statistically for all CMR exercise levels using Mann-Whitney U and Spearman rank-order correlation tests.

RESULTS

CPET capacity was significantly lower in cTOF than in controls. cTOF patients exhibited not only significantly reduced Qp and RV function but also lower LV function on CMR-ET. Higher CPET values in cTOF correlated with higher Qp (Qp 90 W versus carbon dioxide ventilatory equivalent %: R=-0.519, P<0.05), higher LV-end-diastolic volume indexed to body surface area (LV-end-diastolic volume indexed to body surface area at 50 W versus oxygen uptake in % at maximum exercise on CPET R=0.452, P<0.05), and change in LV ejection fraction (EF; LV-EF at 90 W versus Watt %: r=-0.463, P<0.05). No correlation was found with regard to RV-EF. Significant RV-LV interaction was observed during CMR-ET (RV-EF versus LV-EF at 50 W and 70 W: r=0.66, P<0.02 and r=0.52, P<0.05, respectively).

CONCLUSIONS

Impaired exercise capacity in cTOF resulted from a reduction in not only RV, but also LV function. cTOF with good exercise capacity on CPET demonstrated higher LV reserve and pulmonary blood flow during incremental CMR-ET. Apart from RV parameters, CMR-ET-derived LV function could be a valuable tool to stratify cTOF patients for pulmonary valve replacement.

Pediatric catheter ablation at the beginning of the 21st century: results from the European Multicenter Pediatric Catheter Ablation Registry 'EUROPA'

AIMS

Contemporary data from prospective multicentre registries on catheter ablation in pediatric patients are sparse. Aim of the European Pediatric Catheter Ablation Registry EUROPA was to contribute data to fill this gap of knowledge.

METHODS AND RESULTS

From July 2012 to June 2017, data on catheter ablation in pediatric patients (≤18 years of age) including a 1-year follow-up from five European pediatric EP centres were collected prospectively. A total of 683 patients (mean age 12.4 ± 3.9 years, mean body weight 50.2 ± 19 kg) were enrolled. Target tachycardia was WPW/atrioventricular-nodal re-entrant tachycardia (AVRT) in 380 (55.7%) patients, AVNRT in 230 (33.8%) patients, ventricular tachycardia (VT) in 24 (3.5) patients, focal atrial tachycardia (FAT) in 20 (2.9%) patients, IART in 14 (2%) patients, and junctional ectopic tachycardia in 3 (0.45) patients. Overall procedural success was 95.6%. Compared with all other substrates, success was significantly lower in FAT patients (80%, n = 16, P = 0.001). Mean procedure duration was 136 ± 67 min and mean fluoroscopy time was 4.9 ± 6.8 min. Major complications occurred in 0.7% of the patients. No persisting AV block requiring permanent pacing was reported. At 1-year follow-up (605/683 patients, 95%), tachycardia recurrence was reported in 7.8% of patients. Recurrence after VT ablation (33%) was significantly higher (P = 0.001) than after ablation of all other substrates.

CONCLUSION

The present study proves overall high efficacy and safety of catheter ablation of various tachycardia substrates in pediatric patients. Of note, complication rate was exceptionally low. Long-term success was high except for patients after VT ablation.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary

Guidelines for the implantation of cardiac implantable electronic devices (CIEDs) have evolved since publication of the initial ACC/AHA pacemaker guidelines in 1984 [1]. CIEDs have evolved to include novel forms of cardiac pacing, the development of implantable cardioverter defibrillators (ICDs) and the introduction of devices for long term monitoring of heart rhythm and other physiologic parameters. In view of the increasing complexity of both devices and patients, practice guidelines, by necessity, have become increasingly specific. In 2018, the ACC/AHA/HRS published Guidelines on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay [2], which were specific recommendations for patients >18 years of age. This age-specific threshold was established in view of the differing indications for CIEDs in young patients as well as size-specific technology factors. Therefore, the following document was developed to update and further delineate indications for the use and management of CIEDs in pediatric patients, defined as ≤21 years of age, with recognition that there is often overlap in the care of patents between 18 and 21 years of age.

This document is an abbreviated expert consensus statement (ECS) intended to focus primarily on the indications for CIEDs in the setting of specific disease/diagnostic categories. This document will also provide guidance regarding the management of lead systems and follow-up evaluation for pediatric patients with CIEDs. The recommendations are presented in an abbreviated modular format, with each section including the complete table of recommendations along with a brief synopsis of supportive text and select references to provide some context for the recommendations. This document is not intended to provide an exhaustive discussion of the basis for each of the recommendations, which are further addressed in the comprehensive PACES-CIED document [3], with further data easily accessible in electronic searches or textbooks.

Abstract 1130: First-in-class KAT6A/KAT6B inhibitor CTx-648 (PF-9363) demonstrates potent anti-tumor activity in ER+ breast cancer with KAT6A dysregulation

KAT6A is a lysine histone acetyltransferase (HAT) of the MYST family of HATs. KAT6A, and its paralog KAT6B, have been shown to acetylate histone H3K23Ac and regulate diverse biological processes, including transcription, cell-cycle progression, stem cell maintenance and development. Molecular dysregulation of KAT6A has been observed in several cancers, including amplifications in breast, lung, ovarian cancer along with oncogenic fusions in AML. In breast cancer, KAT6A is amplified as part of the 8p11 amplicon in 10-15% of the patient population, which correlates with a worse clinical outcome in the estrogen receptor+ (ER+) subtype. Here we present identification of a first-in-class potent KAT6A/KAT6B tool inhibitor CTx-648 (PF-9363), that possesses high selectivity versus other MYST family members (KAT7, KAT5, KAT8) and other KATs, demonstrating anti-tumor activity in breast cancer. Using genetic and pharmacological approaches, we have demonstrated several ER+ breast cancer cell lines including KAT6A amplified and over-expressing models, are dependent on KAT6A enzymatic function. Epigenomic profiling studies using bulk and nascent RNA-seq combined with ATAC-seq revealed CTx-648 leads to downregulation of a specific set of genes involved in ESR1 pathway, cell cycle and stem cell pathways. In vivo target validation studies showed strong anti-tumor activity of CTx-648 in several ER+ breast cancer cell line and patient-derived xenograft models, including models harboring endocrine therapy resistance ESR1 mutations, highlighting promise for this novel therapy in ER+ breast cancer population. Based on the strength of the pre-clinical data, a selective KAT6 inhibitor (PF-07248144) is now commencing a Phase 1 clinical study in Advanced or Metastatic Solid Tumors.

Citation Format: Shikhar Sharma, Jay Chung, Sean Uryu, Amanda Rickard, Natalie Nady, Showkhin Khan, Zhenxiong Wang, Yong Zhang, Haikuo Zhang, Pei-Pei Kung, Eric Greenwald, Karen Maegley, Patrick Bingham, Hieu Lam, Ylva E. Bozikis, Hendrik Falk, Elizabeth Allan, Vicky M. Avery, Miriam S. Butler, Michelle A. Camerino, Catalina Carrasco-Pozo, Susan A. Charman, Melissa J. Davis, Mark A. Dawson, Dawson Sarah-Jane, Melanie de Silva, Matthew L. Dennis, Olan Dolezal, Rachel Lagiakos, Geoffrey J. Lindeman, Laura MacPherson, Stewart Nuttall, Thomas S. Peat, Bin Ren, Alexandra E. Stupple, Elliot Surgenor, Chin Wee Tan, Tim Thomas, Jane E. Visvader, Anne K. Voss, Francois Vaillant, Karen L. White, James Whittle, Yuqing Yang, Soroor Hediyeh-Zadeh, Paul A. Stupple, Ian P. Street, Brendon J. Monahan, Thomas Paul. First-in-class KAT6A/KAT6B inhibitor CTx-648 (PF-9363) demonstrates potent anti-tumor activity in ER+ breast cancer with KAT6A dysregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1130.

Abstract 1160: SAM competitive PRMT5 inhibitor PF06939999 demonstrates antitumor activity in splicing dysregulated NSCLC with decreased liability of drug resistance

Protein arginine methyltransferase 5 (PRMT5) overexpression in hematological and solid tumors promotes symmetrical di-methyl arginine (SDMA) on cellular proteins involved in important cancer functions including cell cycle regulation, mRNA splicing, cell differentiation, cell signaling, and apoptosis. PRMT5 methyltransferase function has been linked with high rates of tumor cell proliferation and decreased overall survival, and PRMT5 inhibitors are currently being explored as an approach for targeting cancer-specific dependencies due to PRMT5 catalytic function. Here we describe the discovery of potent and selective S-adenosylmethionine (SAM) competitive PRMT5 inhibitors, including the clinical candidate PF-06939999. Acquired resistance mechanisms were explored through the development of drug resistant cell lines. Our data highlight compound-specific resistance mutations in the PRMT5 enzyme that demonstrate structural constraints in the co-factor binding site that prevent emergence of complete resistance to SAM site inhibitors. PRMT5 inhibition by PF-06939999 treatment reduced proliferation of NSCLC cancer cells, with dose-dependent decreases in SDMA levels and changes in alternative splicing of numerous pre-mRNAs. Drug sensitivity associates with cancer pathways including MYC, cell cycle and splicing. Translation of efficacy in mouse tumor xenograft models with splicing mutations provides rationale for therapeutic use of PF-06939999 for treatment of splicing dysregulated NSCLC.

Citation Format: Kristen Jensen-Pergakes, John Tatlock, Karen Maegley, Indrawan McAlpine, Michele McTigue, Tao Xie, Christopher Dillon, Yuli Wang, Shinji Yamazaki, Noah Spiegel, Manli Shi, Amy Nemeth, Natalie Miller, Eleanore Hendrickson, Hieu Lam, John Sherrill, Wei Liu, Ya-Li Deng, Chi-Yeh Chung, Elizabeth A. McMillan, Prakash Palde, Alexei Brooun, John Braganza, Susan E. Kephart, Robert Kumpf, Ryan Patman, Eugene Rui, Stephanie Scales, Michelle Tran-Dube, Fen Wang, Martin Wythes, Thomas Paul. SAM competitive PRMT5 inhibitor PF06939999 demonstrates antitumor activity in splicing dysregulated NSCLC with decreased liability of drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1160.

Audit of drug-drug interactions and adverse drug reactions due to polypharmacy in older cancer patients: First report from India

Background

In elderly people, the body's metabolic processes are not optimal and pharmacokinetics and pharmacodynamic profile of drugs are compromised or reduced. Under these conditions, the concomitant use of diverse classes of drugs can potentially increase the risk of adverse reactions and drug interactions. This will consequentially affect the already debilitated organ system. As far as the authors are aware, there are no studies addressing the drug-drug interactions and adverse drug reactions due to polypharmacy in older patients with cancer and therefore, we conducted this study.

Methods

This was an observational chart-based study and was carried out in a tertiary care cancer hospital. The data concerning prescription of all prescribed medications were noted down from the medication chart of the patient in the wards.

Results

The most common drug-to-drug interaction that could have happened was due to the combination of theophylline with budesonide (26.10%). Adverse drug reactions were noted during the course of time, the most common being nausea and vomiting (71.9%).

Conclusions

As the geriatric population is increasing, the need to address medical problems among aged patients with cancer is the need of the hour. The adverse drug reactions and drug interactions that have occurred were lesser when compared to published observations.

Computation of distribution of relaxation times by Tikhonov regularization for Li ion batteries: usage of L-curve method

In this paper, the distribution of relaxation times (DRTs) functions are calculated numerically in Matlab for synthetic impedance data from single parallel \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$RC$$\end{document}RC circuit and two parallel \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$RC$$\end{document}RC circuits connected in series, experimental impedance data from supercapacitors and α-LiFeO₂ anode based Li ion batteries. The quality of the impedance data is checked with the Kramers–Krönig (KK) relations. The DRTs are calculated within the KK compatible regime for all the systems using Tikhonov regularization (TR) method. Here we use a fast and simple L-curve method to estimate the TR parameter (λ) for regularization of the Fredholm integral equations of first kind in impedance. Estimation of the regularization parameters are performed effectively from the offset of the global corner of the L-curve rather than simply using the global corner. The physical significances of DRT peaks are also discussed by calculating the effective resistances and capacitances coupled with peak fitting program. For instance, two peaks in the DRTs justify the electrical double layer capacitance and ion diffusion phenomena for supercapacitors in low to intermediate frequencies respectively. Moreover, the surface film effect, Li/electrolyte and electrode/electrolyte charge transfer related processes are identified for α-LiFeO₂ anode based Li-ion batteries. This estimation of the offset of the global corner extends the L-curve approach coupled with the Tikhonov regularization in the field of electrochemistry and can also be applied in similar process detection methods.

[Fetal ECG and arrhythmias]

The normal fetal heart rate ranges between 110 und 180 beats per minute (bpm). Intrauterine arrhythmias are not an uncommon finding. Fetal echocardiography (ECG) allows for correct diagnosis of the arrhythmia, which is prerequisite for decision making and treatment. Most fetal rhythm disturbances are the result of premature atrial contractions and are of little clinical significance. Intrauterine bradycardias (heart rate < 110 bpm) result from sinus node dysfunction, complete AV block and nonconducted atrial bigeminy. Isolated complete heart block related to maternal anti-SSA/Ro or SSB/La auto-antibodies is irreversible in almost all fetuses. Anti-inflammatory therapy and chronotropic medication may improve outcome. Newborn babies often require pacemaker implantation to augment cardiac output. Intrauterine tachycardias (heart rate > 180 bpm) are most commonly related to supraventricular tachycardia and atrial flutter. Specific antiarrhythmic medication is available to stop the arrhythmia and to prevent hemodynamic deterioration.

Infection prevention in catheter-interventional treatment of children and adults

Catheter-interventional treatment is a growing field in pediatric cardiology and cardiology, replacing an increasing number of operations. This article provides an overview of the general practice of hygienic measures and antimicrobial prophylaxis in the cardiac catheterization laboratory to prevent post-procedural infection, particularly if foreign material is utilized.

Safety of Transseptal Puncture for Access to the Left Atrium in Infants and Children

Transseptal puncture (TSP) is a standard procedure to obtain access to the left heart. However, data on TSP in infants and children particularly with congenital heart defects (CHD) is sparse. Safety and efficacy of TSP in infants and children < 18 years with normal cardiac anatomy and with CHD were assessed. 327 TSP were performed in a total of 300 individuals < 18 years from 10/2002 to 09/2018 in our tertiary pediatric referral center. Median age at TSP was 11.9 years (IQR 7.8-15; range: first day of life to 17.9 years). 13 subjects were < 1 year. Median body weight was 43.8 kg (IQR 26.9-60; range: 1.8-121 kg). CHD was present in 28/327 (8.6%) procedures. TSP could be successfully performed in 323/327 (98.8%) procedures and was abandoned in 4 procedures due to imminent or incurred complications. Major complications occurred in 4 patients. 3 of these 4 subjects were ≤ 1 year of age and required TSP for enlargement of a restrictive atrial septal defect in complex CHD. Two of these babies deceased within 48 h after TSP attempt. The third baby needed urgent surgery in the cath lab. Pericardial effusion requiring drainage was noted in the forth patient (> 1 year) who was discharged well later. Minor complications emerged in 5 patients. The youngest of these individuals (0.3 years, 5.8 kg) developed small pericardial effusion after anterograde ballon valvuloplasty for critical aortic stenosis. The remaining 4/5 patients developed small pericardial effusion after ablation of a left-sided accessory atrioventricular pathway (6.1-12.2 years, 15.6-34.0 kg). TSP for access to the left heart was safe and effective in children and adolescents > 1 year of age. However, TSP was a high-risk procedure in small infants with a restrictive interatrial septum with need for enlargement of interatrial communication.

Epicardial implantation of a leadless pacemaker in a lamb model

BACKGROUND

Pacemaker used in small children typically consist of an abdominally placed generator and epicardially affixed leads, making such a system prone to lead dysfunction during growth. Aim of this study was to investigate the feasibility of epicardial pacing with a leadless pacemaker in a lamb model.

ANIMALS AND METHODS

Seventeen lambs underwent epicardial implantation of a Micra transcatheter pacing system (TPS) (Medtronic, Minneapolis, MN, USA) via left-lateral thoracotomy to the left ventricle (LV) surface (n = 11/17) and to the left atrial appendage (n = 6). Ventricular devices were fixated with the tines within the pericardium, whereas the tines of the atrial devices penetrated the myocardium of the left atrial appendage. After 31 weeks, animals were sacrificed and hearts were explanted for histological analysis.

RESULTS

Following implantation, median P/R amplitude was 4.25/5.5 mV while median pacing threshold was 1.1/1.9 V at 0.24 ms. After 31 weeks, median P/R amplitude was 3.3/4.2 mV. Median atrial pacing threshold was 0.5/0.24 ms. Eight of 10 ventricular pacemakers had lost capture at standard impulse width even at maximum impulse amplitude. On explantation, firm adhesion of the device to the thoracic wall and dislodgement of the electrode tip was found in those ventricular devices.

CONCLUSIONS

Firm fixation of the Micra electrode to the epicardial surface as applied to the atrial devices resulted in excellent electrical properties during midterm follow up. Pericardial fixation as in the ventricular devices was associated with loss of capture. Therefore, it is important to embed the tines in the myocardium and to choose an alternative implantation site allowing for safe fixation of the Micra TPS in a position perpendicular to ventricular epimyocardium.