Killu, Ammar M.

Background: Ventricular tachycardia (VT) is a life-threatening arrhythmia frequently observed in structural heart diseases, including LMNA-related cardiomyopathy, a genetic disorder associated with high risk of sudden cardiac death and progressive systolic dysfunction. While catheter ablation is an established therapeutic option for VT, its efficacy in cardiac laminopathy remains poorly defined. Objectives: To synthesize available evidence on the role and outcomes of VT ablation in patients with cardiac laminopathy. Methods: A systematic review and single-arm meta-analysis was performed in accordance with PRISMA guidelines. PubMed, Embase, and Cochrane databases were searched for studies reporting VT ablation outcomes in LMNA-related cardiomyopathy. An inverse variance random-effects model was applied for meta-analysis of proportions. Results: Seven studies (six cohorts, one abstract) comprising 62 patients (mean age 53.2 ± 9.7 years; 85% male; 88% with implantable cardioverter-defibrillator) were included. An endocardial/endo-epicardial approach was used in 93% of cases. Acute procedural success was achieved in 37% (95% CI: 14–63%; I 2 = 27.4%), and 28% required multiple procedures. Over a median follow-up of 26 (9–35) months, VT recurrence occurred in 91% (95% CI: 76–100%; I 2 = 37.2%). All-cause mortality was 54% (95% CI: 39–70%; I 2 = 28%), predominantly from cardiac causes (51%, 95% CI: 25–76%; I 2 = 53%), and 14% (95% CI: 1–34%; I 2 = 42%) underwent heart transplantation. Conclusions: In LMNA-related cardiomyopathy, catheter ablation is associated with high VT recurrence, limited long-term success, and substantial cardiovascular mortality and transplantation rates, underscoring the importance of ICD implantation and the need for alternative strategies, including variant-specific and molecularly targeted therapies.

Abstract Background/Introduction Multielectrode mapping catheters enhance the speed and accuracy of 3-dimensional data collection. However, with variable catheter configurations, data acquisition and efficiency may differ. We sought to compare the HD Grid X mapping catheter to a multi linear 8-spline catheter (spline catheter) with respect to chamber modeling speed and accuracy in in-vivo and bench setups. Methods In-vivo: In 6 pigs, 4 physicians used each catheter in a randomized order to create unedited models of the left atrium and ventricle (LA and LV) during coronary sinus atrial pacing. A sensor-enabled ablation catheter marked five locations per chamber while applying 10-15g of force. These markers, which denoted the ‘true’ location of the endocardial surface, were compared to the nearest surface location defined by each mapping catheter. Bench: In a tank setup designed to emulate an LA to pulmonary vein (PV) transition, chamber models were created during robotic manipulation of each mapping catheter. Resulting models were compared to a "gold-standard" model generated using robotic manipulation of sensor-enabled ablation catheters. Additionally, a static shape analysis was performed with each catheter held by a fixture in a deformed (HD Grid X catheter-bent 90o degrees; spline catheter-3 splines bunched) and undeformed state. Images of the physical catheters were captured to determine the true catheter shape and were compared to the renderings from the respective electroanatomical mapping systems (EnSite X v3.1 and Carto v7.2). Results In-Vivo: The mean error between the ablation catheter generated points and the models for HD Grid X trended lower than for the spline catheter by 11.7% (p=0.63; 2.57mm, 2.91mm) in the LA. In the LV, the mean error for HD Grid X was 34.4% (p=0.04; 2.04 mm, 3.67mm) less than for the spline catheter. In the LA, time for model creation for HD Grid X trended higher than for the spline catheter by 14.0% (p=0.34; 524s, 451s). However, in the LV, modeling time for HD Grid X was 22.9% (p=0.05; 368s, 478s) less than for the spline catheter. Bench: Compared to the ablation catheter created models, HD Grid X had a median bloat of 1.70mm (5.91mm max) while the spline catheter had 2.53mm (11.45mm max). The RMS error (mm) for the static shape analysis of electrode positions in an undeformed state was 0.60 for HD Grid X and 2.26 for the spline catheter. In a deformed state, the error was 0.82 for HD Grid X and 2.07 for the spline catheter. Conclusion In this translational model, the HD Grid X catheter created faster and more accurate unedited LV model geometry than the spline catheter, with no statistically significant difference noted in the LA. Bench data further supports the enhanced geometry accuracy seen in-vivo with HD Grid X, which may result in superior anatomical delineation, and faster mapping data acquisition times.

Abstract Aims Catheter ablation is commonly performed in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) for management of ventricular arrhythmias (VAs). The impact of catheter ablation on cardiac function is unknown. The aim is to assess the impact of catheter ablation for VAs on cardiac function in patients with ARVC. Methods and results This retrospective study included consecutive patients with ARVC who underwent catheter ablation for VAs. Cardiac and valvular functions were assessed on pre- and post-procedure cardiac imaging. The severities of tricuspid regurgitation, pulmonic regurgitation, right ventricular (RV) enlargement, and RV systolic dysfunction was graded as absent (=0), mild (=1), mild-moderate (=2), moderate (=3), moderate-severe (=4), or severe (=5). Thirty-four patients were included. Median age at the time of ablation was 49 [inter-quartile range (IQR), 23] years, and 10 (29%) patients were female. After a median follow-up of 1 (IQR, 0) day, 11 (34%) patients had worsening RV function, and 4 (12%) patients had worsening left ventricular ejection fraction (LVEF) >5%. Five (15%) patients required inotropic support. After a median follow-up of 6.5 (IQR, 6.4) months, 20 (59%) patients had repeat transthoracic echocardiograms. Among patients with worsening RV function post-ablation, one-sixth (17%) had improvement in the RV function at follow-up. In contrast, among patients who had an acute drop in LVEF post-ablation, two-thirds (67%) had improvement at follow-up. Conclusion Right ventricular dysfunction following catheter ablation in patients with ARVC is common, affecting one-third of patients. Patients undergoing catheter ablation of VAs should be counselled on the potential negative impact of ablation on cardiac function.

ABSTRACT Background Mitral annular disjunction (MAD) carries an increased risk of complex ventricular arrhythmias, which can lead to sudden cardiac death. Many of these patients undergo implantable cardioverter defibrillator (ICD) implantation, but their ICD outcomes are not known. Objective The aim of this study was to assess the outcomes of ICD implantation and the predictors of appropriate ICD therapies in patients with MAD. Methods The study included patients with MAD who underwent ICD implantation. Clinical, electrocardiographic, cardiac imaging, and device therapy data were collected. Results Forty‐nine patients with MAD and ICD were included. Median age was 49 (21) years, and 29 (59%) were female. 13 (27%) patients underwent ICD implantation for primary prevention and 36 (73%) patients for secondary prevention. Over a median follow‐up of 27.3 (35.3) months, 23 (47%) patients received ICD therapies. 18 (37%) patients had appropriate ICD therapies, and 5 (10%) patients had inappropriate ICD shocks. Median time to first appropriate therapy was 22.3 (63.3) months. In patients with a secondary prevention ICD indication, the rate of appropriate ICD therapies was 44%, while in patients with a primary prevention ICD indication, it was 15%. Among patients with appropriate ICD therapies, the first therapies were delivered for monomorphic ventricular tachycardia (VT) in 7 (39%) patients and polymorphic VT or ventricular fibrillation (VF) in 11 (61%) patients. Patients with appropriate ICD therapies were more likely to have a history of SCA ( p = 0.003) and/or low left ventricular ejection fraction (LVEF) ( p = 0.022) before ICD implantation as compared to patients without appropriate ICD therapies. Conclusions In our cohort of patients with MAD and ICD, appropriate ICD therapies were common. Most appropriate ICD therapies were delivered for polymorphic VT or VF. Larger studies are needed to elucidate the mechanisms of VAs and refine risk stratification in MAD.

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.

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.

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterized by fibrofatty replacement of myocardial tissue, creating areas of electrical heterogeneity and increasing the risk of ventricular arrhythmias (VAs) and sudden cardiac death (SCD). Catheter ablation is commonly performed in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) for management of ventricular arrhythmias (VAs). Whether catheter ablation affects cardiac function post-procedurally is uncertain. Research Question: Does catheter ablation for ARVC result in acute change in cardiac function? Goals/Aims: To assess the impact of catheter ablation for VAs on cardiac function in the acute post-procedure setting. Methods: This retrospective study included patients with ARVC who underwent catheter ablation for VAs at Mayo Clinic. Cardiac function was assessed on pre- and post-procedure transthoracic echocardiograms (TTEs). Post-procedure TTEs were obtained within 4 weeks after the ablation procedure. Right ventricular (RV) enlargement and systolic dysfunction were evaluated as continuous variables (0=none, 1=mild, 2=mild-moderate, 3=moderate, 4=moderate-severe, 5=severe). Results: The study included 32 patients who underwent a total of 44 ablations. Mean age at the time of ablation was 49±16 years, and 24 (75%) were male. After a mean follow-up duration of 2.6±5.5 days, there was a significant worsening in mean RV dysfunction (1.6±1.5 to 2.0±1.4, P = 0.001). There were no significant changes in mean left ventricular ejection fraction (LVEF), left ventricular (LV) dimensions, and RV size. 6 (14%) patients had a >5% decline in LVEF, and 14 (32%) patients had worsening RV function. Transient inotropic support was required in 4 (9%) patients. Conclusion(s): This study is the first to assess the acute impact of catheter ablation for VAs on cardiac function in ARVC patients. These results underscore the importance of careful post-procedure monitoring and planning of the ablation target in these patients to avoid excessive ablation and therefore impairment in cardiac function.

Background: Transthyretin cardiac amyloidosis (ATTR-CA) carries an elevated risk of developing ventricular arrhythmias (VA) but there remains limited evidence supporting the role of catheter ablation in this population. Purpose: To assess the safety and efficacy of catheter ablation for VA in ATTR-CA. Methods: An electronic database was used to identify all patients suspected of having ATTR-CA who underwent catheter ablation for VA at our institution between January 2010 and December 2023. Patients who did not meet the diagnosis of ATTR-CA and had a negative workup who underwent catheter ablation for ventricular tachycardia (VT) or premature ventricular contractions (PVCs) were used to form a control group matched for age, sex and left ventricular ejection fraction at a ratio of 2:1. Results: 20 controls and 10 cases of ATTR-CA were identified. Examining the two groups at baseline (Table 1), the mean age at index ablation was 67.7±7.0 and 68.6±8.1 years (p=0.359), mean follow-up time was 4.1±3.1 and 4.2±2.6 years (p=0.494), and the proportion of males was 100% and 90% respectively. The ATTR-CA group had a significantly higher proportion of chronic kidney disease (90% vs. 50%, p=0.032) and prior stroke or thrombotic events compared to the control group (50% vs. 10%, p=0.026) with similar CHA 2 DS 2 VASc scores (4.2±1.6 vs. 3.8±1.3, p=0.233). Both groups had comparable left ventricular ejection fraction (41.4%±14% vs. 46.9%±15.2%, p=0.173), VT/PVCs at presentation (40%/60% vs. 25%/75%, p=0.77), use of antiarrhythmics (70% vs. 60%, p=0.592), and high proportion of atrial fibrillation/flutter (70% vs. 90%, p=0.168). Procedural (261.2±101.2 vs. 265.7±125.6 mins, p=0.449) and total energy delivery time (1442.9±1509.1 vs. 1744.6±956.2 secs, p=0.296) was not significantly different in the two groups. Both groups had a significant decrease in PVC burden postablation with a reduction from 26.8% to 3.8% (p=0.024) and from 27.1% to 13.6% (p=0.028) in the ATTR-CA and control group respectively. A downward trend was seen in antitachycardia pacing events for VT postablation in the ATTR-CA (14.7±9.8 vs. 5.3±6.7, p =0.184) and control (193±387.6 vs. 0.67±1.2. p=0.139) groups. No major complications occurred after ablation (Table 2). Mean time to recurrence post-index ablation was similar between both groups (1620.4±483.8 vs. 1498.8±291.4 days, p=0.987, Figure 1). Conclusions: Catheter ablation appears to be safe and effective for VT and PVCs in patients with ATTR-CA.

Abstract Background The right ventricular moderator band-papillary muscle (RV MB-PM) complex has a rich subendocardial network of purkinje fibers which can lead to ventricular arrhythmias (VA)1. Catheter ablation of such arrhythmias is procedurally challenging and there remains limited studies on long-term procedural success. Purpose We aimed to systematically study RV MB-PM complex VA. Methods A single center retrospective study from January 2013 to December 2023 identified 3249 patients who underwent VA ablation. The RV MB-PM complex was targeted in 47 patients. Acute success was defined as suppression of the targeted VA &gt;=30 minutes post ablation. Long-term success was defined as the absence of symptoms, total PVC burden &lt;5% or improvement in EF in patients presenting with isolated PVCs and as freedom from appropriate ICD therapy in patients presenting with malignant PVCs inducing VF, sustained VT or VT storm. Results Mean age was 51.9 ± 16.7 years and 64% were male. 40 (85%) patients had VA targeted from the MB and 7 (15%) from the PM complex (2 anterior, 2 inferior and 3 septal PM). 34 (72%) had no underlying structural heart disease, 3 (6%) ischemic cardiomyopathy and 10 (21%) non-ischemic cardiomyopathy. No patient had delayed gadolinium enhancement in the RV MB-PM complex. VA were inducible in 42 (89%) of patients and activation mapping was used in 9 (19%), pace mapping in 5 (11%) and a combination of activation and pace mapping used in 33 (70%) patients. Intracardiac echocardiography was used in all cases. Pre-QRS duration was 34.0 ± 10.4 ms. Radiofrequency ablation was used in 37 (78.7%) cases, cryotherapy in 4 (8.51%) cases and a combination of the 2 energy sources in 6 (12.8%) cases. In all cases, acute peri-procedural success was achieved. 24 (51.1%) patients presented with isolated PVCs and were followed up for 4.72 ± 3.55 years after their index procedure. 3 patients underwent repeat catheter ablation targeting the same PVC focus but all patients had long term success with a PVC burden of 16.1 ± 12.5% prior to ablation and 2.40 ± 2.44% at last follow-up. 16 patients underwent ablation for recurrent ICD shocks after initially presenting with PVC induced VF. Patients were followed up for 3.22 ± 2.09 years and 14 (88%) patients remained free from ICD therapy. 7 patients had MB ablation for sustained VT and were followed up for 4.06 ± 3.77 years. 5 (71%) patients remained free from ICD therapy. A purkinje potential was seen in 8% (2/24) cases of isolated PVCs and in 39% (9/23) cases of PVC induced VF or VT (p=0.13). Conclusions RV MB-PM VA commonly present with malignant VF and a purkinje potential is more likely to be seen in these cases suggesting different VA mechanisms to isolated PVCs and catheter ablation is an effective long-term strategy.