Implantable Defibrillator Research Articles

Optical control of cardiac electrophysiology by the photochromic ligand azobupivacaine 2.

Patients suffering from ischaemic heart disease and heart failure are at high risk of recurrent ventricular arrhythmias (VAs), eventually leading to sudden cardiac death. While high-voltage shocks delivered by an implantable defibrillator may prevent sudden cardiac death, these interventions themselves impair quality of life and raise both morbidity and mortality, which accentuates the need for developing novel defibrillation techniques. Photopharmacology allows for reversible control of biological processes by light. When relying on synthetic and externally applied chromophores, it renders genetic modification of target cells dispensable and may hence be advantageous over optogenetic approaches. Here, the photochromic ligand azobupivacaine 2 (AB2) was probed as a modulator of cardiac electrophysiology in an ex vivo intact mouse heart model. By reversibly blocking voltage-gated Na+ and K+ channels, photoswitching of AB2 modulated both the ventricular effective refractory period and the conduction velocity in native heart tissue. Moreover, photoswitching of AB2 was able to convert VA into sinus rhythm. The present study provides the first proof of concept that AB2 enables gradual control of cardiac electrophysiology by light. AB2 may hence open the door to the development of an optical defibrillator based on photopharmacology.

Liver Dysfunction as a Rare Presentation of ICD Lead-Induced Tricuspid Regurgitation: A Case Report

Abstract Background Implanted cardiac devices with right ventricular leads can cause tricuspid regurgitation and subsequent heart failure. In these patients, congestive hepatopathy because of tricuspid regurgitation is well documented, however the presentation of liver dysfunction without overt heart failure is rare. Case Summary We report a case of a 56-year-old man with presumed hypertrophic cardiomyopathy, presenting with jaundice without signs of decompensated heart failure, eight years post implantation of dual chamber implantable cardiac defibrillator (ICD). A workup for abnormal liver function, including a liver biopsy, determined congestive hepatopathy as the cause. Cardiac imaging revealed severe tricuspid regurgitation caused by right ventricular ICD lead causing tricuspid valve malposition. Management included both tricuspid valve replacement and extraction of ICD and there was an excellent recovery. Discussion This is a rare case where severe tricuspid regurgitation and congestive hepatopathy secondary to an ICD lead presented with jaundice in the absence of signs of decompensated heart failure. In patients with an implanted cardiac device presenting with signs of liver dysfunction, congestive hepatopathy secondary to tricuspid regurgitation should be considered.

Abstract 4119472: Predictors of Sudden Cardiac Death in Patients with Atrial Fibrillation and No Apparent Risk Factor of Sudden Cardiac Death

Background: Atrial fibrillation (AF) is associated with sudden cardiac death (SCD). It is known that AF is associated with multiple traditional risk factors of SCD, such as coronary artery disease (CAD), history of myocardial infarction (MI), left ventricular hypertrophy (LVH) and low left ventricular ejection fraction (LVEF). However, AF per se could predispose SCD not mediated by these cardiovascular risk factors, and predictors of SCD in AF patients without these apparent SCD risk factors are unknown. Methods: Using the NTUH iMED database, AF patients without apparent SCD risk factors were longitudinal followed up from Jan. 2010 to Dec. 2021. The primary outcome was implantation of implantable cardioverter defibrillator (ICD) due to SCD. Cox regression was used to identify the predictors of SCD. Results: A total of 11250 AF patients without cardiovascular SCD risk factors and LVEF ≥55 % were longitudinally followed up. We first found CHA2DS2-VASc score did not predict SCD event. We found male gender (hazard ratio [HR ] 1.71 [1.05-2.78 ], p =0.032), hyperthyroidism (HR 3.50 [1.40-8.77 ], p=0.007）and paroxysmal AF (PAF)(HR 2.86 [1.63-5.04 ], p<0.001）were associated with higher SCD risks. We created a AFSCD score using these parameters. We found SCD risk incrementally increased with increasing AFSCD score (p <0.001 for trend). Patients with highest score (5 points) had more than 3-fold SCD risk compared with those with 0-point score (1.18 % person-year vs 0.36 %, p<0.001). The C statistic of AFSCD score was significantly higher than CHA2DS2-VASc score (0.64 [0.57-0.70] vs 0.40 [0.33-0.48], p <0.01). Conclusions: Male gender, hyperthyroid AF and PAF were predictors of incident SCD in AF patients and AFSCD scoring scheme based on these risk factors could possibly be implemented in clinical practice.

Abstract 4123563: High Prevalence of Unrecognized Actionable Cardiac Arrhythmias in Patients with Moderate to Severe Chronic Obstructive Pulmonary Disease

Background: Patients with chronic obstructive pulmonary disease (COPD) are at high risk for developing arrhythmias due to hypoxemia, right heart failure and use of beta-agonists inhalers. Symptoms related to arrhythmias can often be masked or confounded by symptoms related to COPD exacerbation and remain undiagnosed. Objective: To identify the incidence of actionable arrhythmias in patients with no prior cardiology follow-up and moderate–severe COPD with continuous monitoring. Methods: An automatic referral for electrophysiology (EP) consult was generated in patients with moderate-severe COPD if they answered yes to one of the following: palpitations, dizziness, abnormal ECG, near syncope. Upon consultation with EP specialist, implantation of loop reorder was discussed (ILR) with the patient. Patients were then monitored for 12 months via remote monitoring. Actionable arrhythmia was defined the arrhythmia that correlated with symptoms triggered by the patient, necessitated adjustment of medications (including initiation of anticoagulation), catheter ablation and implantation of implantable cardiac defibrillator (ICD) or permanent pacemaker (PPM). Results: Out of 62 patients referred 22 (35.5%) agreed to undergo ILR implantation. Of the 22 (50.0% female, 62 ± 9.5 years) patients implanted with an ILR, 15 (68.2%) had an actionable arrhythmia after a mean follow-up of 2.7± .3 months. These included 14 symptomatic events requiring medication adjustment (10 atrial tachycardias, 4 ventricular events), 7 cases of atrial fibrillation (requiring initiation of anticoagulation in all cases and catheter ablation in 1), 1 case of sinus node dysfunction requiring pacemaker implantation, and 1 episodes of sustained ventricular tachycardia requiring ICD implantation. Conclusion: Continuous monitoring had high yield in diagnosing significant arrhythmic events in patients with moderate-severe COPD. Awareness should be raised about the high arrhythmic risk of this population and the role of continuous monitoring should be sought in larger studies.

Abstract 4117406: The Safety and Efficacy of Surgical Cardiac Sympathetic Denervation for Ventricular Arrhythmias: An Updated Systematic Review&Meta-Analysis

Objectives: This meta-analysis sought to explore the long-term arrhythmic outcomes of cardiac sympathetic denervation (CS) by measuring event rates of recurrent ventricular arrhythmias (VA) and implantable cardiac defibrillator shocks (ICD) post CSD. Background: The role of sympathetic nervous system in the beginning and continuation of ventricular arrhythmias (VAs) is well known. CS has been associated with improved arrhythmic outcomes in patients with refractory ventricular arrhythmias. However, whether CSD lowers shock event rates after the procedure is still uncertain and therefore, we performed a systematic review and meta-analysis to evaluate this. Methods&Materials: A comprehensive literature search was performed at Medline and Embase until March 2023. Our primary outcome was event rate of ICD shocks at 30 days, 90 days, and 1 year following CS. All analysis was conducted using Comprehensive Meta-Analysis software. Results: The initial search found 1,324 articles. After all articles were examined, a total of 29 studies fit our criteria. ICD shocks 1 year post CSD had a pooled event rate of 66.5% with a 95% confidence interval (CI) of 57.7% to 74.3% and the I-squared (I2) statistics. ICD shocks at 6 months had an event rate at 61.7% with a 95% confidence interval of 53.3% to 69.4% with I2 at 46. VA in one year post CSD had a pooled event rate of 62.5 with a 95% with a CI of 53.3% to 69.1% and I2 at 22%. At 6 months the event rate was 64.2 with a 95% CI of 56.3% to 71.4% with I2 at 33% Mortality from cardiac arrhythmia and classified 0-30 days (short term), 21-364 days (medium term), and >365 days (long term). The pooled event rate for short term morality was 6.8% with a 95% CI of 4.2%-11.0% with I2 at 0%, medium term was 5.2% with a 95% CI of 2.9% to 8.9% with I2 at 0%, and long term was 5.0% with a 95% CI of 2.7% to 9.2% and I2 at 0%. Conclusion: CSD may be an alternative form of therapy that reduces shock event rates and recurrent VA in patients that are refractory to ablation and medical therapy. However larger prospective studies are needed to further evaluate the usefulness and safety of CSD.

Abstract 4138350: Candidemia in Patients with Left Ventricular Assist Device-A Case Series

Introduction: Candidemia is rare but associated, have significant morbidity and mortality. Outcomes are not well-characterized in patients with left ventricular assist devices (LVADs). With an increasing number of patients living with LVADs, we sought to characterize risk factors to help optimize outcomes for this high-risk population. Methods: We retrospectively reviewed records of 97 patients who underwent LVAD implant between January 2012 to May 2024 at Indiana University Health, Indianapolis Indiana. Demographic and clinical data were extracted. Candidemia was defined as a positive blood culture with candida species. Result: We identified three patients with candidemia, with an overall attack rate of 3.09%. All patients had a HeartMate III (HM3) at the time of infection. The mean age of patients was 40.3 years (Range 29.0 – 58.0 years) and mean BMI was 35.7 kg/m 2 (Range, 30.0 – 42.0 kg/m 2 ). One patient grew Candida auris and Candida tropicana, the other patient grew Candida auris and the third patient grew Candida globrata. All patients had an automatic implantable cardiac defibrillation, a peripherally inserted central catheter line, and right heart failure. Two patients had driveline infections (one fungal, one bacterial) while one patient developed LVAD endocarditis with a right ventricular outflow tract vegetation. Two patients had persistently positive blood cultures despite treatment with a multi-drug anti-fungal regimen (Flucytosine, Amphotericin B and micafungin) and expired. The third patient initially cleared her blood cultures after treatment with IV micafungin only but was re-admitted with muti-organ failure and expired. Summarily, all patients with candidemia died with a mortality rate of 100%. None of the patients were candidates for heart transplantation. Average survival from the time of diagnosis of candidemia was 5 months (Range 1.0 – 11.0 months). RHF, chronic DL infection and high BMI were associated with candidemia in our series. Conclusion: Candidemia in LVAD patients, while less common than bacterial infections, carry high mortality without cardiac transplantation (100% mortality in our cohort). Its rare occurrence makes it challenging to identify reversible risk factors, leading to poor survival. Multicenter registries are needed to fully elucidate these risk factors and determine effective treatment strategies.

Abstract 4120249: What Happens to Automated External Defibrillator Rhythm Strips after a Cardiac Arrest?

Background: Following an out of hospital cardiac arrest (OHCA), rhythm strips stored on an automated external defibrillator (AED) help guide important medical decisions, including possible implantable cardioverter defibrillator (ICD) implantation. However, this information is often difficult to obtain. Objective: To evaluate how frequently AED rhythm strips are reviewed following an OHCA prior to placing an ICD. Methods: Using the Cardiac Arrest Registry to Enhance Survival (CARES), we identified patients from 1/2015-12/2023 who were transferred to our institution following an OHCA. Patients were excluded if resuscitation was not attempted, death occurred during the hospitalization or patient identifying information was not available. Results: Of 907 OHCAs identified, 119 patients ( Table 1 ) met the inclusion criteria. The AED rhythm strip was in the electronic medical record on hospital arrival in 22% of cases and only after provider initiation in 6% of cases. None of the rhythm strips from a bystander-only delivered AED shock (n=17) were available on arrival, with only 24% retrieved during the hospitalization, taking 4.5±2.1 days from the date of arrest. Patients with an AED rhythm strip available (n=34) were more likely than those without a rhythm strip (n=85) to have a cardiac MRI (38% v. 13%, p=0.02) and genetic testing (15% v. 1%, p=0.02) done and have an ICD placed (53% v. 27%, p=0.04) or be discharged on a new anti-arrhythmic drug (15% v. 4%, p=0.04). Figure 1 Of the 42 patients who had an ICD placed during the index hospitalization, 54% were implanted without knowing the type of shockable rhythm or confirmation that an appropriate AED shock had been delivered. Conclusion: Rhythm strips help guide clinical decisions when assessing the need for ICD implantation. There is a systems gap in the process of transferring rhythm strips from AEDs to hospital providers following an OHCA.

Desmoplakin Cardiomyopathy in Pediatric Patients: A Distinct, Underrecognized Cohort of Arrhythmogenic Cardiomyopathy.

DSP cardiomyopathy is a distinct subset of arrhythmogenic cardiomyopathy, reported primarily in adults, that has predominantly left ventricular involvement and features of myocarditis. Clinical characteristics, risk stratification, and management of pediatric patients with DSP variants are not well known. We sought to identify phenotypic features and prognosis of pediatric patients with DSP pathogenic or likely pathogenic variants. Multicenter, retrospective study of patients <21 years of age with DSP variants from 6 tertiary pediatric hospitals. Thirty-four patients, including 10 probands with clinical disease and 24 genotype-positive phenotype-negative patients, were included in the study. The majority of probands were initially diagnosed with myocarditis (50%) and had biventricular (60%) or left ventricular predominant (40%) disease. Chest pain was the most common symptom at presentation (30%), and all had troponin elevation. Probands with homozygous or compound heterozygous DSP variants were likely to present at an early age (<13 years) with symptoms of heart failure, severe biventricular involvement, and dermatologic abnormalities. Low-voltage QRS was the most prominent ECG abnormality. Of those who underwent implantable cardioverter defibrillator implantation, 50% received appropriate implantable cardioverter defibrillator therapy and were found to have significant biventricular involvement in addition to severe left ventricular dysfunction with an ejection fraction <35%. DSP cardiomyopathy in children and adolescents has varied phenotypic manifestations based on age and genotype and often can be diagnosed as myocarditis. Severe left ventricular dysfunction and biventricular involvement may be associated with a higher likelihood of malignant ventricular tachyarrhythmia.

Case report - Survival after ECPR for adolescent arrhythmogenic arrest - ECPELLA (ECMO with Impella®)

Abstract Background The combined therapy with venoarterial extracorporeal membrane oxygenation (V-A ECMO) and Impella (ECPella) has been shown to improve survival in acute cardiogenic shock (CS) in adult patient. Only 3 paediatric cases have been reported in a multicentre study. Case summary We present our case, the first described to our knowledge in the UK, of a 15 year old adolescent of Afro-Caribbean descent, weight 75kg, who received E-CPR (extracorporeal cardiopulmonary-resuscitation) and ECPella implantation. The patient suffered a sudden cardiac arrest at home, his mother called for an ambulance who arrived within 10 minutes and commenced life support with a LUCAS device. He received 3 doses of adrenaline and 3 desynchronised shocks for an underlying rhythm of ventricular fibrillation (VF) after which ROSC was achieved. He was then transferred to his local hospital where he had another VF arrest with successful cardioversion and was then transferred to our institution where on arrival he had another VF arrest and received E-CPR (extracorporeal cardiopulmonary-resuscitation) and ECPella implantation under the institutional adult shock program within 3 hours of in-hospital cardiac arrest. Following weaning from ECPella the patient underwent cardiac and brain MRI and serial echocardiograms with complete recovery of ventricular function. After implantation of cardiac defibrillator, he was discharged home without neurological sequelae. He remains asymptomatic from a cardiac perspective, with a normal cardiac examination and with no neurological sequelae at 2 year follow up. Discussion This is the first case description of ECPella use in a child in the United Kingdom and highlighted the importance of timely institution of E-CPR on survival benefit in fatal CS. The outcome success of post-resuscitation ECPella strategy in this adolescent was through collaborative interprofessional engagement of multiple supra-specialists within acute cardiology and critical care across paediatric and adult services and alignment with the institutional adult shock program.

Clinical value of multiple sensors contributing to a composite heart failure ICD monitoring index

Abstract Background The HeartLogic algorithm integrates data from various implantable defibrillator (ICD) sensors to predict impending heart failure (HF) decompensation. The algorithm computes worsening in its sensors and weighs them based on a risk level. These sensors include accelerometer-based first (S1) and third (S3) heart sounds, intrathoracic impedance (TI), respiration rate (RR), the ratio of respiration rate to tidal volume (RSBI), and night heart rate (NHR). Objective This study assessed the relative worsening of ICD sensors at the onset of HeartLogic alerts, their association with patient characteristics and subsequent outcomes. Methods The HeartLogic feature was activated in 568 ICD patients (410 with CRT-D) across 26 centers, with a median follow-up of 26 months [25th–75th percentile: 16–37]. Results During the follow-up, 1200 HeartLogic alerts were recorded in 370 patients. The sensor with the highest worsening (SHW) at the alert onset was S3 (27% of alerts), followed by S3/S1 (25%), TI (16%), RR (15%), and NHR (11%), RSBI (6%). Patients with atrial fibrillation (AF) at implantation and those with chronic kidney disease (CKD) had higher alert prevalence (AF 84% vs. no-AF 58%, CKD 72% vs. no-CKD 59%; both p &amp;lt;0.05) and higher alert rates (AF 1.51/patient-year vs. no-AF 0.88/patient-year, CKD 1.30/patient-year vs. no-CKD 0.89/patient-year; both p &amp;lt;0.05). AF patients had alerts with every sensor as SHW, while CKD patients had alerts primarily with TI, RR, and RSBI as SHW (Figure). In 85% of cases among 247 patients with &amp;gt;1 alert, the SHW changed between successive alerts. Of the 88 (7%) alerts resulting in HF hospitalizations or deaths, a greater proportion featured RR or RSBI (11%) and NHR (11%) as SHW, followed by heart sounds (5%) (both p &amp;lt;0.05). Clinical events were more common with the first alert (12.6%) than subsequent alerts (5.2%, p &amp;lt;0.001). Conclusion HeartLogic alerts are predominantly associated with the highest worsening in heart sounds. Nevertheless, recurrent alerts often involve other sensors, suggesting varied HF progression mechanisms and potential divergent outcomes. The frequency of alerts and the pattern of worsening in ICD sensors are linked to patient characteristics.

The impact of QRS complex fragmentation status before and after cardiac resynchronization therapy with defibrillator implantation: Is it a predictor of arrhythmic events?

Abstract Introduction Cardiac resynchronization therapy with an implantable cardioverter defibrillator (CRT-D) has demonstrated efficacy in reducing mortality, hospitalization for heart failure (HF), and sudden cardiac death among subgroups of patients with HF with reduced ejection fraction (HFrEF). However, this population is highly heterogeneous, necessitating risk stratification. Several clinical findings, including QRS complex fragmentation (QRSf), have been identified as potential prognostic factors for arrhythmic risk. Nonetheless, evidence supporting the prognostic significance of QRSf in patients undergoing CRT-D remains limited. Purpose The aim of this study is to assess whether alterations in QRSf status, before and after CRT-D implantation, can predict arrhythmic events (AE) in patients with HFrEF. Methods This study included consecutive patients underwent CRT-D implantation at our center from October 2009 to December 2022. Demographic, clinical, electrocardiographic and echocardiographic data were obtained from electronic medical records and telephone interviews. QRSf was defined by the presence of various RSR′ patterns, including additional R waves (R′) or notching of the R and S wave in two contiguous leads corresponding to a primary coronary artery territory on a 12-lead electrocardiogram conducted before and after CRT-D implantation. An AE was characterized by appropriate ICD therapy (antitachycardia pacing or shock) for a ventricular arrhythmia or sustained ventricular arrhythmia without the need for ICD therapy. Results A total of 176 patients were included (mean age 69.9 ± 9.6 years with 80.6% male). Ischemic etiology accounted for 54.6% of cases of LV systolic dysfunction, with a mean baseline LVEF of 23.6%. CRT-D was indicated as secondary prevention in 18 patients. At baseline, 114 patients (64.8%) presented QRSf. Following CRT implantation, 17 patients (9.8%) without previous QRSf developed QRSf, while 26 patients (14.9%) resolved QRSf. The median follow-up was 43.6 months (interquartile range 19.5-81.1). During follow-up, 90 patients died and 29 AE occurred (16.5%). Among these, 23 patients had QRSf before and after CRT, whereas 6 AE occurred in patients without QRSf. Multivariate survival analysis using Cox regression demonstrated that the presence of QRSf before and after CRT-D was an independent predictor of AE (HR 3.56; 95% CI 1.00-12.70). Univariate and multivariate Cox regression analyses are presented in Table 1. Kaplan-Meier curves for AE in relation to QRSf status before and after CRT-D are illustrated in Figure 1. Conclusions Our findings suggest that the presence of QRSf and its persistence following CRT-D implantation appears to be an independent predictor of AE after CRT-D implantation in patients with HFrEF. Therefore, these patients would benefit from closer monitoring as they exhibit a heightened risk of arrhythmic events. Nevertheless, further research is warranted to validate these results.Table 1.Cox Regression Analysis.

Sex differences in cardiovascular-related hospital readmissions, adverse events and interventions within 1 year after ST-elevation myocardial infarction

Abstract Introduction Reducing cardiovascular (CV)-related hospital readmissions as well as adverse events following ST- elevation myocardial infarction (STEMI) is a critical goal to improve outcomes as well as quality of life and reduce healthcare costs. We aimed to study the rates of CV-related readmissions, adverse events and interventions after STEMI in women and men. Methods We included STEMI patients from the Acute Myocardial Infarction in Switzerland (AMIS) Plus registry, who underwent percutaneous coronary intervention (PCI) between 2013 and 2022 and participated in a telephone-based follow-up (FU) interview 1-year after hospital admission. Patients were asked if they had hospital readmissions (if yes: planned/emergency/both) during FU for any CV reason, if they suffered a reinfarction or stroke and if they had any or several of the following interventions: PCI, coronary artery bypass graft, pacemaker and/or defibrillator implantation. These self-reported data were analysed using descriptive statistics and logistic regression models were used to study the relationship between patient characteristics and hospital readmissions. Results Of 4388 PCI-treated STEMI patients contacted for FU, 275 (6.3%) were unreachable, 118 (2.7%) died, and 223 (5.1%) had no data on readmissions; therefore 3772 patients (78.4% men, 21.6% women) were analysed. Women were older (mean (SD) age at event: 68.4 (12.0) vs. 62.5 (11.5) years) while the Charlson Comorbidity Index (CCI) was similar (CCI&amp;gt;1: 14.0% vs. 12.1%, n.s.). The mean rate of patients readmitted for CV reasons was 22.1%; 20.4% for women and 22.6% for men (p=0.198). Overall, 8.8% had at least one emergency and 13.9% at least one planned readmission. The occurrence of a planned readmission was significantly lower in women (11.1% vs. 14.7%, p=0.008). Patients with a readmission had during the index hospitalisation higher rates of in-hospital complications (18% vs. 14%), heart failure (NYHA III+IV) (2.2% vs. 0.8%), diabetes (18% vs. 14%) and peripheral arterial disease (3.9% vs. 2.5%). A multivariable adjusted model that included these factors together with age and sex identified heart failure (OR: 2.5, CI 1.34-4.66, p=0.004) and in-hospital complications (OR:1.4, CI 1.12-1.70, p=0.003) as independent predictors of hospital readmission. The rates of the analysed adverse events and interventions were similar between sexes except that women had less often a PCI during the FU period (13.2% vs. 16.6%, p=0.026). Conclusion Over the last 10 years, on average 1 in 5 patients had at least one CV-related readmission within 1 year after PCI-treated STEMI, while no overall sex-difference was found. Heart failure and in-hospital complications were independent predictors of readmission. Women had less often planned hospital readmissions and additional PCIs.

Prognostic yield of echocardiographic measures of cardiac structure and function in HFrEF patients with vs without an ICD or CRT-D

Abstract Background Selected echocardiographic measures of cardiac structure and function are known to be associated with mortality in patients with Heart Failure with reduced Left Ventricular (LV) Ejection Fraction (HFrEF). Whether the predictive ability of measures of cardiac structure and function remain after implantation of an Implantable Cardioverter Defibrillator (ICD) or Cardiac Resynchronization Therapy-Defibrillator (CRT-D) is unknown among patients with HFrEF. Purpose To compare the predictive ability of echocardiographic measures of cardiac structure and function in HFrEF patients with or without an ICD/CRT-D. Methods Echocardiographic examinations were performed between 2003 and 2013 and retrieved from 2168 patients with HFrEF. Patients that had an ICD or CRT-D implanted during follow-up were identified through registries. The endpoint was all-cause mortality and follow-up was 100% to date. Images were analyzed offline in accordance with current guidelines. Associations were assessed by Cox multivariable regression and Cox univariable interaction models. Results After a median of 169 days, 677 patients had an ICD or CRT-D implanted. In total, 68% vs 80% of patients with and without an ICD, respectively, were men (p&amp;lt;0.001) and the median age were 70 vs 71 years (p=0.192). There was a significant difference in resting heart rate (median 74 vs 69, p&amp;lt;0.001) and frequency of ischemic heart disease (64% vs 81%, p&amp;lt;0.001) between the groups. Patients with an ICD had a higher mortality rate (69 per 1000 people/year vs 92 per 1000 people/year, p&amp;lt;0.001) and died significantly faster (median 9.3 vs 8.2 years, p&amp;lt;0.001). Patients with an ICD had higher Left Atrial (LA) End Systolic Volume (59.2 vs 67.3, p&amp;lt;0.001), LA Volume Index (28.5 vs 33.9, p&amp;lt;0.001), LV End Diastolic Volume (137.7 vs 153.7, p&amp;lt;0.001), and LV Mass Index (114.5 vs 124.5, p&amp;lt;0.001), as well as lower LA strain (9.8 vs 6.3, p&amp;lt;0.001) and TAPSE (2.0 vs 1.7, p&amp;lt;0.001). In patients without an ICD, Right Ventricular strain was associated with mortality (HR = 1.05 per 1% decrease mm/m2 [1.005, 1.11] when adjusting for covariates whereas in patients with an ICD, LA Volume Index (HR 1.14 per 1 increase [1.03, 1.25], and LV Ejection Fraction (HR 0.96 per 1% increase [0.92, 0.99]) were associated with mortality when adjusting for covariates. ICD/CRT-D implantation significantly modified the prognostic yield of LV End Diastolic Volume (HR per 1 ml increase: 0.99 without vs 1.01 with an ICD/CRT-D, p=0.005) and LV Mass Index (HR per 1 g/m2 increase: 1.00 without and 1.01 with an ICD/CRT-D, p=0.031). Conclusion Different echocardiographic measures were stronger prognosticators in HFrEF patients with and without an ICD or CRT-D, respectively, and ICD implantation modified the prognostic yield of LV End Diastolic Volume and LV Mass Index in HFrEF patients.Table 1Forest plot

Prevalence, characteristics, and long-term outcomes of patients with mitral annular disjunction undergoing surgery for degenerative mitral regurgitation

Abstract Background Mitral valve prolapse (MVP) is associated with progressive mitral regurgitation (MR) requiring surgical repair. A subset of patients with MVP may also suffer from malignant ventricular arrhythmias (VAs), especially in the presence of mitral annular disjunction (MAD). Purpose To assess the prevalence, associated characteristics, and long-term outcomes of patients with MVP with and without MAD undergoing mitral valve surgery for degenerative MR. Methods Patients with MVP and moderate-to-severe or severe degenerative MR undergoing mitral valve surgery between 2010-2022 at a university hospital in Sweden were included. MAD length was measured on echocardiograms at end-systole from the insertion of the posterior leaflet on the detached mitral annulus to the border of the bulging left ventricle. Patient demographics and clinical outcomes were collected from medical records. The primary endpoint consisted of VAs, defined as sustained- or non-sustained ventricular tachycardia or high burden of premature ventricular complexes causing hospitalizations or ablation or identified at Holter monitoring. Other endpoints included sudden cardiac death, all-cause mortality, new onset postoperative atrial fibrillation, stroke, mitral valve reoperation, endocarditis, new or worsened heart failure, myocardial infarction and implantation of permanent pacemaker or cardiac defibrillator. Results Of 599 patients undergoing mitral valve surgery, 96 (16%) had preoperative MAD, with a median (Q1, Q3) MAD length of 8.0 (5.0-10.0) mm. Compared with patients without MAD, patients with MAD were younger (55 vs 63 years), more likely to be female (31% vs 17%), to have diffuse myxomatous valve disease (66% vs 25%) and bileaflet prolapse (57% vs 17%). Most patients underwent mitral valve repair (84% vs 80%). No patient had residual MAD after surgical repair. At a mean follow up time of 5.8 ± 3.5 years after mitral valve repair, VAs were more common in patients with pre-operative MAD (10% vs 2% (adjusted HR 4.52, 95% CI 1.57-13.0)) (Figure 1). There were no significant differences in the risks of other clinical outcomes. Conclusions MAD was associated with almost a 5-fold increased long-term risk of VAs after mitral valve repair despite successful anatomical correction of MAD. These findings highlight the importance of increased awareness of VAs in patients with MAD also after mitral valve surgery.

Left atrial strain predicts adverse events in hypertrophic cardiomyopathy: preliminary results from a CMR study

Abstract Background Hypertrophic cardiomyopathy (HCM) is associated with an increased risk of major adverse cardiovascular events (MACE), however, current risk stratification methods are imperfect. Left atrial global longitudinal strain (LA GLS) is an increasingly acknowledged predictive parameter, yet its potential role in HCM is not well defined. Purpose This study aims to investigate the prognostic role of cardiac magnetic resonance (CMR)-derived LA GLS for the occurrence of MACE in patients with HCM. Methods A retrospective, single-centre, CMR study of HCM patients was conducted. Clinical data was collected from electronic medical record and CMR images were analysed by two blinded investigators. LA GLS was derived from CMR two-chamber cine images by a semiautomatic method, and was categorized according to its median value. The endpoint was a composite of MACE, including all-cause death, sudden cardiac death (SCD), sustained and non-sustained ventricular tachycardias (VT), appropriate implantable cardiac defibrillator (ICD) shocks, heart failure (HF) hospitalization, and new-onset atrial fibrillation (AF). Cox regression analysis was performed. The preliminary results of the study are now reported. Results A total of 54 HCM patients were included, mean age was 58.5 years ± 15.9 and 38.9% were female. Average maximal wall thickness (MWT) was 18.0 mm ± 3.9, 37% had left ventricular outflow obstruction (LVOTO) and 45.1% had positive late gadolinium enhancement (LGE). After a mean follow-up of 6.9 ± 3.0 years, 26 patients (48.1%) experienced the composite endpoint. Figure 1 shows the clinical and CMR differences according to the occurrence of MACE. LA GLS was significantly lower in patients with MACE compared to those without (26.5 ± 19% vs 36.7 ± 13%, p=0.026), with a moderate predictive value (AUC = 0.68, Figure 2A). Multivariate Cox regression analysis revealed that a decrease in LA GLS (HR 1.09 per each 1% decrease, 95% CI 1.03-1.15, p=0.002), the presence of LGE (HR 6.9, 95% CI 1.7-28, p=0.007), the presence of LVOTO (HR 3.4, 95% CI 1.12-10.2, p=0.031) and an increase in MWT (HR 1.23 per each 1mm increase, 95% CI 1.05-1.45, p=0.011) were independently associated with MACE. Among low-risk HCM patients (absence of LGE or LVOTO, or MWT below our median value), LA GLS had an additional prognostic role, and those with an LA GLS above the median value (LA GLS&amp;gt;29.7%) presented a remarkably favourable prognosis (Figure 2B-D). Conclusions CMR-derived LA GLS is a predictor of outcomes in HCM beyond established imaging prognostic factors. Particularly, LA GLS appears to be useful in risk-stratifying low-risk HCM patients: those with normal LA GLS show an excellent prognosis. If confirmed in larger studies, LA GLS could be used to individualise HCM management.Figure 2

Incidence of systolic heart failure and need for implantable cardiac defibrillators in patients with atrial fibrillation who had catheter ablation versus antiarrhythmic medical therapy

Abstract Background The CASTLE-AF trial demonstrated that patients with atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF) who underwent catheter ablation (CA) showed improved patient outcomes. These outcomes included a reduction in all-cause mortality and heart failure hospitalizations along with an improvement in left ventricular ejection fraction, when compared to those receiving medical therapy alone. However, there is no data regarding development of novel HFrEF and the need for implantable cardiac defibrillator (ICD) in patients with AF who underwent CA vs. those on antiarrhythmic therapy (AAD). Purpose This study aims to assess if there is a difference in the development of HFrEF and the need for ICD intervention amongst AF patients who underwent CA vs. those on AAD. We hypothesize that patients with AF who underwent CA will have a decrease in the development of HFrEF and mitigation in the need for ICD intervention compared to AAD alone. Methods A large retrospective, multicentre database was utilized to identify patients aged 18-80 with AF from 2017-2023. Two cohorts were subsequently established based on treatment received: 1) CA vs. 2) AAD (amiodarone, flecainide, dronedarone, dofetilide, propafenone, sotalol). Patients with crossover between the groups were excluded. Student’s t-test was performed to compare baseline characteristics between cohorts. Relevant comorbidities, atrial fibrillation types, and cardiovascular medications were used for propensity matching. Kaplan Meier curves were calculated to compare outcomes at 5 years such as HFrEF development, ICD implantation, mortality, and hospitalizations. Results Patients that underwent CA (n=32,774) and AAD (n=345,882) were propensity matched yielding 32,670 patients per cohort. CA demonstrated a significantly decreased need for ICD intervention compared to AAD (1.69% vs. 3.28%; HR=0.559; 95% CI [0.503, 0.621], log rank p&amp;lt;0.0001). Secondary outcomes showed significant reduction in development of systolic heart failure (4.83% vs. 10.60%; HR=0.499; 95% CI [0.467, 0.533], log rank p&amp;lt;0.0001), overall hospitalizations (12.03% vs. 27.32%; HR=0.440; 95% CI [0.420, 0.461], log rank p&amp;lt;0.0001), and all-cause mortality (2.38% vs. 14.19%; HR=0.188; 95% CI [0.174, 0.203], log rank p&amp;lt;0.0001) with catheter ablation. Conclusions Patients that underwent CA had a significant reduction in development of systolic heart failure and mitigation in the need for ICD implantation when compared to those on AAD alone. Randomized clinical trials are needed to better understand this relationship and to further define which subpopulation of atrial fibrillation patients would derive the most benefit from CA.

Assessing the impact of implantable loop recorder placement on anxiety level

Abstract Background Anxiety is a prolonged state of apprehension or worry that can be an independent predictor of cardiovascular events, associated with a 48% increased risk of cardiac death. About one-third of patients with arrhythmias present with high anxiety levels, and subsequently worse quality of life. In our experience of patient care, many patients feel anxious about the possibility of an arrhythmia that could lead to their demise, especially if their symptoms are undiagnosed. Purpose Our project aims to explore the change in patients’ anxiety levels following implantable loop recorder (ILR) placement. Methods This is a survey-based observational study that was performed in an outpatient clinic and hospital using validated General Anxiety Disorder-7 (GAD-7) questionnaires. Individuals who met indications to undergo ILR implantation including palpitations, syncope, subclinical atrial fibrillation, and cryptogenic stroke underwent baseline assessment of anxiety prior to implantation. Individuals had repeat assessments at 6 weeks and 12 weeks post-implantation to evaluate the effect of ILR placement. Results Our study included 50 individuals. Out of the initial subjects, 10/25 females and 11/25 males were lost to follow-up. The average initial GAD-7 score was 3.3 (Range 0, 15), average 6-week score was 1.6 (Range 0, 14), and average 12-week score was 0.9 (Range 0, 10). Total decrease in GAD-7 score after 6 weeks of having ILR was 50%. Total decrease in GAD-7 score after 12 weeks of ILR was statistically significant at 73% (P=0.03). Females showed greater improvement of GAD-7 scores in comparison to males at 6 weeks (67% vs 36%) and 12 weeks (81% vs 66%). Conclusion Studies have suggested an overall decreased level of anxiety in patients receiving implantable devices that have the potential to treat arrhythmias such as implantable cardiac defibrillators and pacemakers. Our results suggest that the benefit may extend to implantable devices that seek to provide further diagnostic information and aid in the prognostication of disease burden. As seen in our study population, GAD-7 scores showed dramatic improvement with greater percentage in female than male population. After the placement of loop recorders, many patients experience a sense of security with having a device that monitors them. Our study is the first to address the association between ILR and anxiety. Future studies evaluating this association would help increase the power of the study.Figure 1:Bar graph of GAD-7 Scores

Impact of SLGT2 inhibitors treatment initiation on the reduction of atrial and ventricular arrhythmias in patients with implanted cardiac defibrillator

Abstract Introduction Sodium-glucose cotransporter type 2 inhibitors (SGLT2i) have been associated with improved prognosis in patients with heart failure; however, their impact on atrial arrhythmic (AA) and ventricular arrhythmic (VA) events is not fully understood. Methods Retrospective multicentric study of heart failure patients with implantable cardiac defibrillator device (ICD) from 2015 to 2020 with or without cardiac resynchronization therapy (CRT) receiving SGLT2 inhibitors. Device-registered arrhythmic events were analyzed and compared in two time periods for each patient: one year before and one year after starting SGLT2i. Relevant VA were defined as the occurrence of any sustained VT (SVT) (&amp;gt;30 seconds), ventricular fibrillation (VF), or appropriate therapy (antitachycardia pacing or shock). All VA included all the relevant VA and the occurrence of non-sustained ventricular tachycardia (NSVT). AA included atrial fibrillation (AF) burden, and episodes of more than 24 hour of AF. Results A total of 195 patients (66.8 [61.3-73.1] years, 18.5% women) were included. A reduction was observed in the percentage of patients with any VA (pre: 52.3% vs post: 30.3%; P &amp;lt; 0.001) and clinically relevant VA (excluding NSVT) (pre: 21.5% vs post 8.7%; P &amp;lt; 0.001) in the post-SGLT2i period. There was also a reduction in the number of episodes per patient/year of NSVT (pre: 2 (1-5) vs post: 1 (0-2); P &amp;lt; .001), and SVT (pre: 1 (1-3) vs post: 0 (0-2); p = 0.046). This protective effect was also observed after controlling confusion factors (Any VA: OR 0.35 (0,24-0,50); p&amp;lt;0.001 and relevant VA: OR 0.30 (0,17-0,52); p&amp;lt;0.001). However, no differences were observed in the prevalence of AA (24.7% vs 18.8%; P = 0.117) or the burden of atrial fibrillation (pre: 0% (0-0.1) vs post 0% (0-0); p = 0.097). Conclusions Following the initiation of SGLT2i treatment, a reduction in the percentage of patients with relevant VA was observed. However, this effect was not observed for AA.Figure 1Figure 2

Accuracy of a non-invasive mapping system for the localisation of re-entrant VT site of origin and its relationship to myocardial scar on cross-sectional imaging

Abstract Introduction View in ventricular onset (VIVO) is a non-invasive mapping system used for localising the site of earliest activation in ventricular arrhythmia, utilising a mathematical algorithm, patient specific cardiac model (constructed using cross-sectional imaging data), 3D images of the patient’s torso (for localising surface electrodes), and a 12-lead electrocardiogram (ECG).(1, 2) Several publications have examined its role in the localisation of premature ventricular contractions (PVCs), and a 5 patient case series assessed its role in scar related re-entrant VT.(1-4) However, its validity in a larger cohort and of the relationship to the relevant myocardial scar has not been investigated. Objective Assess the accuracy of the VIVO mapping system in localising the VT-SoO for patients with scar related re-entrant VT and its relationship to the relevant myocardial scar on cross-sectional imaging. Methods 20 patients with structural heart disease (18 ischaemic cardiomyopathy (ICM), 1 dilated cardiomyopathy (DCM), 1 hypertrophic cardiomyopathy (HCM)) (Male n=18, 63±14 years) and recent cross-sectional cardiac imaging, were recruited over a 16-month period (table 1). All patients had a clinical indication for VT ablation and were on optimal medical therapy, 19 had an implantable cardiac defibrillator. Invasive electro-anatomical mapping (EAM) was performed with the Advisor HD Grid multipolar catheter and maps were generated using Omnipolar electrograms (EGMs). The VT-SoO was identified using an activation- or pace-map by an experienced operator and the location defined using the American heart association’s 17 segment model of the left ventricle during the procedure.(5) VIVO maps were reviewed by a second independent operator and a segment allocated, scar segments were obtained from cross-sectional imaging. A "complete match" was defined as exact segment concordance between allocated segments, "partial match" as adjacent segments, and "no match" if it does not satisfy either of those requirements. Results Mean left ventricular ejection fraction was 35.5 ± 10.6%. Mean procedure time was 242 ± 70 minutes, with a mean ablation time of 20 ± 11.1 minutes. A total of 32 re-entrant VTs were mapped. The VT exit site was identified in all cases (11 activation-map; 21 pace-map). A complete match between the EAM and VIVO map was seen in 75% of VTs and partial match in a further 15% (table 2). The VT-SoO was located withing the myocardial scar (or directly adjacent to is) in 83% of accurately mapped VTs. Procedural success (defined as freedom from device treated episodes) was seen in 90% of patients at mean follow up of 7.3 ± 4.7 months. Conclusion VIVO non-invasive mapping system was able to accurately map the VT-SoO in scar dependent VT, and identify the relevant myocardial scar as seen on cross sectional imaging. Further research assessing its ability to accurately identify relevant ablation targets is ongoing.

Smaller intrinsic QRS area and smaller reduction of QRS area during cardiac resynchronisation therapy are associated with higher risk of ventricular arrhythmias and appropriate ICD therapy

Abstract Background Cardiac resynchronisation therapy (CRT) patients are at high risk for ventricular arrhythmias (VAs), and little is known about which characteristics are associated with an increased risk for arrhythmic events. Purpose To investigate the association between QRS area parameters and the risk for VAs in patients with heart failure undergoing primary preventive CRT with defibrillator (CRT-D) implantation. Methods All patients receiving CRT-D between 2015 and 2020 at a large-volume tertiary care center were retrospectively evaluated. Digital 12-lead electrocardiograms (ECGs) were collected before and after CRT implantation. Patients were included if they had native LBBB and were implanted with a primary preventive CRT-D. Kors’ regression transformation was used to derive vectorcardiographic QRS area from the 12-lead ECGs. QRS area parameters were analysed in relation to a primary endpoint of first appropriate ICD therapy, i.e., ATP or shock therapy. Results 177 patients with LBBB (68.9 years [60.7–73.8]; 21.5% female; 52.9% New York Heart Association (NYHA) class III-IV; LVEF 25.9±6.3%) were followed over a median follow-up time of 2.5 years [1.6–3.0] after CRT-D implantation. 27 patients reached the primary endpoint. The median pre-CRT QRS area was 134.5 μVs [102.3–163.8]. Multivariable Cox regression identified a small pre-CRT QRS area (HR, per 10 μVs decrease, 1.30; [1.12–1.51]; p=&amp;lt;.001) and a small post-CRT reduction in QRS area (HR, per 10 μVs decrease, 1.30; [1.13–1.49]; p=&amp;lt;.001) as independent predictors of an increased risk of appropriate ICD therapy. In analyses with a scoring variable combining pre-CRT QRS area and QRS area reduction both above or below median, the combination of a small pre-CRT QRS area and a small QRS area reduction was strongly associated with an increased risk of reaching the endpoint (HR, per point increase, 2.47; [1.2–4.9]; p=0.01). Conclusion A small intrinsic QRS area, by itself or in combination with a small reduction of post-CRT QRS area, was strongly associated with a higher risk of ventricular arrhythmias in this cohort of CRT-D treated patients. In conjunction with other parameters, further risk stratification for arrhythmic events could be achieved by assessing QRS area data pre- and post-CRT.Figure 1.K-M pre-CRT QRS area quartilesFigure 2.K-M QRS area score