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Abstract Introduction Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disorder with a pathogenic mutation identified in approximately 50% of cases. The MYH7 and MYBPC3 genes account for over half of these cases, while dozens of other genes can be pathogenic(1). Genetic test results are not independently used to determine which people with HCM benefit from implanted cardiac defibrillators (ICDs)(2, 3). Little is known about the additive role of genetic testing results to existing indications for ICD insertion. Purpose This study aims to examine the interaction between genetic testing results and existing ICD indications and imaging results on defibrillator discharge rates in HCM. Methods Patients who underwent an ICD for HCM, who underwent a cardiac magnetic resonance (CMR) study and who underwent genetic testing were included across 3 sites. The outcome was the incidence rate of appropriate ICD discharges, calculated using cox regression controlling for current age and primary vs secondary prevention. Interaction analysis between genetic risk factors and existing ICD indications, and with CMR quantification of LGE and septal thickness, was performed, and stratum specific estimates calculated using linear computation. Results 177 patients were included in the study, of whom 70 (39.55%) had a pathogenic mutation, 5 (2.82%) had a variant likely pathogenic (VLP), 44 (24.86%) had a variant of undetermined significance (VUS) and 58 (39.55%) had no identifiable mutation. The event rate was 3.32 {2.28 to 4.84) per 100 person years. There was no association between genetic variables and ICD discharge rate. There was an 80% reduction in ICD discharge rate in people who underwent ICD insertion exclusively for family history of sudden cardiac death or for syncope who had no pathogenic or likely pathogenic mutation, however this change was not statistically significant (table 2). Conclusion There is no strong association between genetic characteristics and ICD discharge rates among people with hypertrophic cardiomyopathy with an existing ICD indication. There is a nonsignificant trend towards fewer ICD discharges among people who underwent ICD insertion for family history alone or for a history of syncope and did not have a pathologic variant.Table 1 Table 2

ABSTRACTBackgroundThe factors contributing to sustained ventricular arrhythmias (VAs) >30 days after left ventricular assist device (LVAD) implantation are not well‐established.ObjectivesThis study aimed to predict the factors associated with late sustained VAs after LVAD implantation and develop a predictive score to identify patients with an increased risk of late sustained VAs after the procedure.MethodsWe performed a retrospective cohort study on a training cohort of 623 patients and a validation cohort of 157 patients who underwent LVAD implantation at the Mayo Clinic (Rochester, Phoenix, and Jacksonville) from January 1, 2000, to December 30, 2020. Late sustained VAs were defined as ventricular tachycardia (VT) and ventricular fibrillation (VF) occurring >30 days after the LVAD procedure. Detailed chart reviews of the electronic health records within the Mayo Clinic and outside medical records were performed.ResultsA total of 780 patients were included in our study. Late sustained VAs occurred in 30% (n = 232) of the patients. The significant factors associated with late sustained VAs after LVAD were the history of VAs prior to LVAD (34.1% vs. 23.0%, p < 0.01), implantable cardiac defibrillator (ICD) (87.9% vs. 77.6%, p < 0.01) or cardiac resynchronization therapy (CRT) in situ (43.5% vs. 33.6%, p = 0.008), VT ablation prior to LVAD (5.2% vs. 1.8%, p = 0.010), use of amiodarone (49.1% vs. 38.7%, p = 0.007), use of mexiletine (15.5% vs. 5.7%, p < 0.01), and higher left ventricular end‐diastolic diameter (LVEDD) on echocardiography prior to LVAD implantation (71.4 vs. 68.7 mm, p = 0.002). During follow‐up, the patients who developed late sustained VAs after LVAD had lower survival than those who did not (HR = 1.96, 95% CI:156–2.4, p < 0.001). The average time from LVAD to orthotopic heart transplant was longer among late sustained VAs patients (23 vs. 14 months, p < 0.01). The “VIN” risk score was created to identify four risk groups: low (scores 0), intermediate (score 1), high (score 2), and very high (score 3). The rates of late VA's in the training cohort at 1 year were 9.5%, 14%, 18%, and 25% which was almost similar to the risk of late VA's at validation cohort 10%, 12%, 20%, and 63%, respectively.ConclusionsLate sustained VAs occurred in 30% of the patients who received LVAD and were associated with lower survival. The VIN risk score was developed and validated to stratify patients into low, intermediate, high, and very high risk of late sustained VAs.

Abstract Aims Atrial fibrillation (AF) is the most common cardiac arrhythmia. Although lipoprotein(a) [Lp(a)] is known to be a well-established risk factor for atherosclerotic cardiovascular disease, its role in the development of AF, independent of this association, remains unclear. Methods and results Adult patients from the three Mayo Clinic sites with a baseline Lp(a) and without AF history were included. Patients were categorized into two groups based on their Lp(a) levels: high Lp(a) (≥50 mg/dL) and low Lp(a) (&lt;50 mg/dL). Survival probabilities free from incident AF were compared between Lp(a) groups, during a follow-up period up to 15 years, using the Kaplan–Meier curve and the log-rank test. Multivariable Cox regression analysis was also conducted. A total of 75 376 patients were included (median age: 55 years, 59% males), with a median follow-up duration of 8.8 (inter-quartile range: 3.4, 14.8) years. Incident AF was detected in 5738 (7.6%) patients. Survival probability free from incident AF was significantly lower in patients with elevated Lp(a) (86%) compared with those with low Lp(a) (88%, log-rank P &lt; 0.001). Multivariable analysis adjusted for potential risk factors of AF showed a statistically significant association of elevated Lp(a) with an 11% increase in AF risk (adjusted hazard ratio: 1.11, 95% confidence interval: 1.05–1.18). Conclusion Our study suggests that elevated Lp(a) (≥50 mg/dL) is an independent risk factor for incident AF. Future prospective studies are warranted to validate our results and to test if reducing Lp(a) could mitigate the burden of AF.

Introduction: Tricuspid regurgitation (TR) is a common complication of right ventricle lead extraction (RVLE) in 5 to 10% of cases. This study aims to identify clinical outcomes such as predictors of heart failure hospitalization, need for tricuspid valve intervention, and death among patients with new severe TR after device lead removal (DLR). Methods: Patients who underwent DLR (pacemaker/ICD) between 3/1997 and 3/2024 were identified. Those who had an echocardiogram before and after RVLE with evidence of new severe TR were included. Cox univariable regression controlling for current age was used to assess association with death. Prentice Williams Peterson total time (PWPTT) Cox univariable regression was used to determine the rate of heart failure hospitalization up to three events per subject. Bivariable cox regression was used to control for ejection fraction for ICD and coil removal. Analysis was conducted using Stata IC16. Results: We identified 2,122 people who underwent RVLE, of whom 90 (4.24%) developed new severe TR and were included in the analysis. There were 68 hospitalizations among 38 people at a median of 2 years following lead extraction (IQR 0.57 to 4.5 years). The rate of hospitalization was 11.60 [9.14 to 14.71] per 100 person-years. Removal of an ICD was associated with increased hospitalization (HR 5.48 p<0.001) but not mortality (HR 1.21, p=0.707). Removal of a single coil ICD lead was associated with increased hospitalization rate (HR 3.01, p=0.031) but not mortality (HR =0.51, p=0.380). Removal of dual coil ICD lead was associated with more than a tenfold increase in hospitalization rate (HR 11.55, p=0.001) and four times the mortality rate (HR 4.05, p=0.031) (Figures 1&2). The presence of an abandoned (pacemaker/ICD) lead was associated with increased hospitalization (HR 5.75, p=0.004) and mortality (HR4.95, p=0.034). There was no change in hospitalization rate following tricuspid valve replacement (HR 1.33, p=0.716, n=18). Conclusion: Among people with new severe TR following DLR, the characteristics of the leads are strongly correlated with morbidity and mortality.

Background: Catheter ablation (CA) is an effective treatment for atrial fibrillation (AF), but many patients experience recurrence post-intervention. Evaluating left atrial strain (LAS) to measure LA reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct) could help predict AF recurrence, especially in patients with no evident signs of severe LA myopathy. Goal: This study aims to assess the prognostic value of pre-ablation LAS in both paroxysmal AF (paAF) and persistent AF(peAF) in patients with no evident signs of severe LA myopathy. Methods: This retrospective study encompassed AF patients who underwent their first CA procedure at Mayo Clinic Arizona from October 2018 to February 2022 and had a LAVI <40 ml/m2 and LVEF >55%. Transthoracic echocardiography parameters, including the three LAS phases, were collected using TOMTEC software on the closest date before the CA procedure. Receiver operating characteristic (ROC) curve analysis was used to evaluate the capability of LAS to detect patients with AF recurrence after CA from those without recurrence. Results: Out of 335 AF patients who underwent CA during the study period, 40 cases had LAVI <40 ml/m2 and LVEF >55% (72.5% male; mean age 69.2 ± 8 years). Of these, 15% (6/40) experienced recurrence, while 85% (34/40) maintained sinus rhythm. The mean values of LASr, LAScd, and LASct for all patients were 16.82, 11.23, and 6.87, respectively. ROC analysis indicated that the area under the curve (AUC) for LASr, LAScd, and LASct was 0.582, 0.502, and 0.710, respectively. (Graph 1A, Table 1A) LASct was the only parameter associated with AF recurrence (AUC: 0.71). Additionally, we developed a novel marker termed LAVI-LASct by combining LAVI and LASct values, which demonstrated improved discrimination with an ROC value of 0.74 (Graph 1B). Conclusions: LASct demonstrated predictive capability for AF recurrence in patients with no severe LA dilation and preserved LVEF, potentially due to its ability to detect early atrial dysfunction preceding visible structural changes or myocardial pathology. The addition of LAVI values provided better discrimination for the ROC model. Further research is needed to confirm the clinical relevance of LAS in AF patients undergoing ablation.

Background: Right ventricular pacing (RVP) can have adverse cardiac effects and cause pacing induced cardiomyopathy (PiCM). His bundle pacing (HBP)&Left Bundle Branch area pacing (LBBAP) mimic physiologic conduction (PhysioP) and maintain biventricular synchrony. Hypothesis and Aims: Reduced left ventricular (LV) systolic function reserve in the presence of normal baseline LV ejection fraction (EF) could precede development of RV PiCM. Our aim was to compare the effects of RVP vs. PhysioP on bicycle exercise cardiopulmonary performance in patients with normal LVEF who required pacing for bradyarrhythmias. Methods: Patients with sinus rhythm and RVP or PhysioP&ventricular pacing burden of >70% who completed cardiopulmonary exercise test and simultaneous stress echocardiography (SE) were included. Pulmonary gas exchange was calculated using Ventilation/CO2 production at rest and during exercise. Changes in LV size, EF, longitudinal strain and diastolic function and gas exchange parameters were compared post and pre exercise in the 2 groups. Results: 25 of 29 patients completed the study [68 ± 23 yrs, 48% M; LVEF 56±5%, 11 RVP, 14 PhysioP]. There was no difference in baseline demographic&clinical variables, exercise duration, rest and peak heart rate and blood pressure between 2 groups. Pacing duration was 2.61±1.48 yrs in RVP vs. 0.84±0.67 yrs (p=0.003) in the Physio group. Resting echocardiographic parameters ( Table 1A) were comparable. Compared to RVP, reduction in LV end-diastolic volume (EDV) 3.4±14.1 ml vs. -23.1±18.1ml, p=0.006)&LV end-systolic volume (ESV -5.7±11.6 ml vs. -18.0±9.5ml, p=0.01) was more pronounced in the PhysioP group. Changes in LVEF, LV strain&diastolic function were not different between the 2 groups ( Table 1B ). There were no significant differences in changes in pulmonary gas exchange parameters in the 2 groups. Conclusions: In patients with normal LVEF and pacemaker dependent, RVP is associated with impaired but PhysioP with preserved LV systolic function reserve, which can be detected by exercise SE. SE may help identify patients at risk for RV PiCM. Benefit of PhysioP needs to be determined by larger studies with longer follow-up.

Background: New-onset atrial fibrillation (AF) is common among kidney transplant (KTx) recipients and is associated with reduced patient survival. Predictors of AF after KTx are not well understood, although AF can be associated with traditional and non-traditional risk factors. While artificial intelligence-enabled electrocardiography (AI-ECG) has shown promise in predicting incident AF, its predictive and prognostic implications in the KTx population have not yet been evaluated. Hypothesis: AI-ECG can predict new-onset AF and carries prognostic implications in patients undergoing KTx. Aims: To evaluate the clinical implications of applying AI-ECG to the preoperative ECGs of recipients of a KTx. Methods: Patients without a history of AF who underwent KTx at three referral centers between 2011 and 2021, with at least one preoperative ECG, were included in this retrospective study. Preoperative ECGs were analyzed using a previously developed AI-ECG algorithm to estimate the probabilities of new-onset AF. Based on these probabilities, patients were categorized into two groups: high and low probability of incident AF. The optimal cut-off value for the AI-ECG tool was determined using ROC analysis. The incidence of new-onset AF and mortality at 5 years post KTx were compared between these two groups using univariate and multivariate Cox regression analyses. Results: In total, 6246 patients were included (mean age 52.9 ±14.3 years, 58.7% males). A pre-transplant AI-ECG probability of AF >10% was identified as the most accurate cutoff point to distinguish between patients at low risk and high risk of incident AF (ROC = 0.72). The study found that a preoperative AI-ECG high risk of AF demonstrated not only a strong association with new-onset AF (HR 2.54, 95%CI 2.02-3.19, p<0.001 on multivariable analysis, Figure 1A ) but was also associated with an increased risk of mortality both on univariate (HR 2.73, 95%CI 2.34-3.18, p<0.001) and multivariate (HR 1.57, 95%CI 1.29-1.91, p<0.001 ) analysis at 5-year follow-up ( Figure 1B ). Conclusion: The application of AI-ECG to a single widely available test may help assess the risk of new-onset AF and mortality in patients undergoing KTx. Accurate risk stratification may identify a high-risk subgroup of transplant recipients who can benefit from closer AF monitoring, risk factor modification, and early management.

Abstract Background Congenital Heart Disease (CHD) is associated with development of atrial fibrillation (AF) at an early age. With increased survival of this cohort into adulthood, the prevalence of concurrent CHD and AF is expected to increase over the next several decades. Little is known about the utility of clinical risk factors or prediction models in determining bleeding or stroke rates in adults with CHD and AF. Purpose This study aims to measure the performance of the CHADSVASC and HASBLED scores in a cohort of people with CHD. The association between traditional stroke and bleeding risk factors, as well as CHD-specific factors, will be quantified. Methods Patients age 18 or older attending one of three centers in the USA were included in this study if they had a history of AF on ECG, holter monitor or device interrogation, in addition to a diagnosis of Tetralogy of Fallot (TOF), Double Outlet Right Ventricle (DORV), or Pulmonary Atresia with Intact Ventricular Septum (PA-IVS). Outcomes were major bleeding event, and stroke rate. Analysis was conducted using cox univariable regression controlling for current age. Receiver operator curve and c-statistics were produced for the CHADSVASC and HASBLED scores respectively. Results 326 people were included in this study, of whom 161 (49.5%) had TOF secondary to Pulmonic Stenosis, 126 (38.8%) had TOF secondary to Pulmonary Atresia, 25 (7.7%) had DORV, and 155 (47.7%) had PA-IVS. 227 people used warfarin (79.4%), 28 (9.8%) used apixaban, 9 (3.1%) used Rivaroxaban, 3 (1%) used Edoxaban, and 5 (1.7%) used Enoxaparin for a period of at least 30 days during the study. 13 (4.5%) people didn’t receive anticoagulation during the study. 26 people had a stroke (8.8%) while 85 people (28.6%) had a major bleeding event. Only the CHADSVASC score was significantly associated with stroke rates (HR 2.103, 95% CI 1.555 to 2.844, p&lt;0.001). Clinical variables, such as subtype of CHD, prior conduit placement or unifocalization were not associated with stroke or major bleeding events. C-statistic for the CHADSVASC score in predicting stroke events was 0.755 (Figure 1). C-statistic for the HASBLED score in predicting major bleeding was 0.442 (Figure 2). Conclusions Among people with CHD and AF, the CHADSVASC score can robustly predict stroke events. Other clinical variables are less valuable in predicting either bleeding or strokes. The HASBLED score likely doesn’t have a role in predicting major bleeding episodes in this cohort.

Abstract Aims : Direct oral anticoagulants (DOACs) are widely used for stroke prevention in people with non-valvular atrial fibrillation/flutter (NVAF). Anticoagulants have different bleeding profiles. Apixaban is associated with the lowest bleeding risk. This study evaluates the interaction between DOAC used and right ventricular systolic pressure (RVSP) on echocardiogram and bleeding rates. It was hypothesized that pulmonary hypertension may be associated with excess bleeding based on anticoagulant-specific pharmacologic profiles. Methods & Results : A retrospective analysis of a database was conducted. Multivariable regression models for bleeding rates were developed using a causative analysis approach among participants who had undergone an echocardiogram, and interaction terms for DOAC choice were incorporated. Stratum specific estimates were calculated using linear computation. Patients taking Apixaban had lower bleeding rates than those taking Rivaroxaban and Dabigatran. Among those without pulmonary hypertension, there was no difference in bleeding rates. Where RVSP was ≥45mmHg, there was a 90% increase in bleeding rates with use of Dabigatran (HR 1.99, p=0.024) and Rivaroxaban (HR 1.86, p=0.042) compared to Apixaban (Figure 1). Conclusions : Elevated RVSP is associated with excess bleeding in patients taking Rivaroxaban and Dabigatran, but not Apixaban, after controlling for confounding variables.