Interventricular Conduction Delay Research Articles

Cardiac resynchronization therapy guided by interventricular delay: how to choose between biventricular pacing or conduction system pacing

Abstract Background Biventricular pacing (BIV) is gold standard for cardiac resynchronization therapy (CRT). Thirty % of patients result non responder to CRT. Conduction system pacing (CSP) represents a feasible alternative. Interventricular conduction delay (IVCD), as electrical desynchrony marker, is a CRT response predictor. The aim of the study was to assess CRT responder’s incidence when it has been achieved choosing best approach between BIV and CSP according to intraoperative IVCD measurement in patients with HFrEF and LBBB. Methods Ninety-eight patients have been 1:1 randomized in a standard BIV group (control group, CG) and a group in which CRT approach has been chosen based on IVCD evaluation (study group, SG), as reported in Figure 1. If the right ventricular sensed electrogram (RVs)-left ventricular sensed electrogram (LVs) interval was ≥100 ms, the left ventricular lead was left in its original position; otherwise, the lead was removed and CSP was performed instead, as reported in Figure 2. Clinical, EKG and echocardiographic features have been assessed pre- and 6 months post-implant. Echocardiographic and clinical response have been evaluated. Results Twenty-four % of patients in the SG underwent CSP, according to the operative algorithm adopted. CRT responders’ incidence was significantly higher in the SG (echocardiographic criterion: SG 93,9% vs CG 69,8%; clinical criterion SG 87,9% vs CG 62,8%). Patients in SG presented a significant improvement in EF between pre- and post-implant and a significantly reduced End Diastolic Volumes and End Systolic Volumes vs CG. Univariate and multivariate regression analysis showed that enrolment in SG was the only factor consistently associated to CRT response. Conclusion Intraoperative evaluation of IVCD may guide the choice of the best resynchronization approach between BIV and CSP, allowing to achieve a significant improvement of CRT responders’ rate.Figure 1Figure 2

Multicenter hemodynamic assessment of the LOT-CRT strategy: when is one lead enough for resynchronization?

Abstract Background Left bundle branch area pacing (LBBAP) has been postulated as an alternative to traditional cardiac resynchronization therapy via biventricular pacing (BiV) in heart failure patients with wide QRS. Limited data is available regarding the acute hemodynamic response of LBBAP and the combination of LBBAP and coronary venous (LVcv) pacing (LOT-CRT). Purpose We sought to compare the acute hemodynamic and ECG effects of traditional CRT (BiV or LV-only) versus LBBAP and LOT-CRT in CRT candidates with advanced conduction disease. Methods In this multi-centre study (5 EU and 7 US centres), 48 subjects (mean age 65.8 years, 67% males, LV ejection fraction 29.4%) with either nonspecific interventricular conduction delay (NIVCD, n = 29) or left bundle branch block (LBBB; n =19; based upon strict criteria AHA/ACC/HRS plus Strauss) underwent an acute hemodynamic study to determine the % change in +LV dP/dtmax from baseline atrial pacing versus BiV, LBBAP, or LOT-CRT. Each therapy pacing configuration was applied 4 times at 5 different atrioventricular (AV) delays. QRS shortening was assessed using standard 12-lead ECG. Results Successful LBBAP lead implantation was achieved in 27 patients (56%) using current EHRA criteria. Twenty-one patients (44%) were categorized as deep septal pacing (DSP), due to suboptimal lead penetration or advanced left conduction system disease with broad paced QRS complexes and absent V1-r-wave. The increase in AV-optimized dP/dtmax for the different pacing configurations is displayed in the Figure, left panel. LOT-CRT dP/dtmax % improvement was 25.8%, significantly higher than LBBAP configurations (p<0.01), either unipolar-LBBAP (19.3%), or bipolar-LBBAP (16.4%), but not different from BiV (26.4%). QRS shortening was greater in LOT-CRT (29.5ms) vs. unipolar-LBBAP (11.9ms), bipolar-LBBAP (11.7ms), or BiV (18.5ms), all p<0.01. Sub-group analysis indicated the hemodynamic benefit of adding LVcv pacing when LBBAP strategy was pursued (Figure, right panel) depended on obtaining LBBAP rather than DSP (p < 0.01) and baseline QRS duration (p = 0.03). The largest benefit was observed among subjects with a baseline QRS wider than the observed cohort mean (171ms) and DSP only, where LOT-CRT provided 14.5% (5.0-24.1%) greater dP/dtmax improvement and 20.8ms (12.8-28.8ms) greater QRS duration shortening than unipolar DSP. Conclusions In a CRT cohort with advanced conduction disease, LOT-CRT provided greater acute hemodynamic benefit than LBBAP strategy (i.e. including also DSP cases). Patients with wider QRS or suboptimal outcome of LBBAP strategy (DSP) are more likely to benefit from addition of a LVcv lead to implement LOT-CRT.Figure 1

Novel predictors of permanent pacemaker implantation following transcatheter aortic valve replacement.

Conduction and rhythm abnormalities requiring permanent pacemakers (PPM) are short-term complications following transcatheter aortic valve replacement (TAVR), and their clinical outcomes remain conflicting. Potential novel predictors of post-TAVR PPM, like QRS duration, QTc prolongation, and supraventricular arrhythmias, have been poorly studied. To evaluate the effects of baseline nonspecific interventricular conduction delay and supraventricular arrhythmia on post-TAVR PPM requirement and determine the impact of PPM implantation on clinical outcomes. A retrospective cohort study that identified patients with TAVR between January 1, 2012 to December 31, 2019. The group was dichotomized into those with post-TAVR PPM and those without PPM. Both groups were followed for one year. Out of the 357 patients that met inclusion criteria, the mean age was 80 years, 188 (52.7%) were male, and 57 (16%) had a PPM implantation. Baseline demographics, valve type, and cardiovascular risk factors were similar except for type II diabetes mellitus (DM), which was more prevalent in the PPM cohort (59.6% vs 40.7%; P = 0.009). The PPM cohort had a significantly higher rate of pre-procedure right bundle branch block, prolonged QRS > 120 ms, prolonged QTc > 470 ms, and supraventricular arrhythmias. There was a consistently significant increase in the odds ratio (OR) of PPM implantation for every 20 ms increase in the QRS duration above 100 ms: QRS 101-120 [OR: 2.44; confidence intervals (CI): 1.14-5.25; P = 0.022], QRS 121-140 (OR: 3.25; CI: 1.32-7.98; P = 0.010), QRS 141-160 (OR: 6.98; CI: 3.10-15.61; P < 0.001). After model adjustment for baseline risk factors, the OR remained significant for type II DM (aOR: 2.16; CI: 1.18-3.94; P = 0.012), QRS > 120 (aOR: 2.18; CI: 1.02-4.66; P = 0.045) and marginally significant for supraventricular arrhythmias (aOR: 1.82; CI: 0.97-3.42; P = 0.062). The PPM cohort had a higher adjusted OR of heart failure (HF) hospitalization (aOR: 2.2; CI: 1.1-4.3; P = 0.022) and nonfatal myocardial infarction (MI) (aOR: 3.9; CI: 1.1-14; P = 0.031) without any difference in mortality (aOR: 1.1; CI: 0.5-2.7; P = 0.796) at one year. Pre-TAVR type II DM and QRS duration > 120, regardless of the presence of bundle branch blocks, are predictors of post-TAVR PPM. At 1-year post-TAVR, patients with PPM have higher odds of HF hospitalization and MI.

Biventricular or conduction system pacing for cardiac resynchronization therapy: a proposed treatment algorithm based on interventricular conduction delays

Abstract Background Cardiac resynchronization therapy (CRT) is usually performed with biventricular pacing (BiVP), but recently conduction system pacing (CSP) has been proposed as an alternative in case of unsuccessful coronary sinus lead implantation. However , further evidence is needed to determine when CSP should be used in lieu of BiVP to improve clinical benefit. Purpose To assess the clinical benefit of a treatment algorithm based on interventricular conduction delays (IVCD) to choose between BiVP or CSP in candidates to CRT. Methods Consecutive patients presenting at our Institution from January 2018 to December 2020 with an indication to CRT were prospectively enrolled in the study group (delays-guided resynchronization group, DRG). IVCD were measured after left ventricle (LV) lead positioning in a lateral or posterior-lateral cardiac vein, when feasible, using endocavitary electrogram. Treatment algorithm based on IVCD was used to decide whether to leave LV lead to perform BiVP or pull it out and perform CSP. An historical cohort of patients who underwent CRT from January 2016 to December 2017 independently from IVCD was used as a control group (standard resynchronization group, SRG). The primary endpoint was a composite of cardiovascular mortality, heart failure (HF) hospitalization, or urgent unplanned clinic visits at 1 year after the date of intervention. Results Study population consisted in 292 patients, of which 160 (54.8%) in the DRG and 132 (45.2%) in the SRG. Age, sex, HF etiology, NYHA class, left ventricular ejection fraction and QRS duration and morphology did not differ between the two groups. In the DRG 41 of 160 patients underwent CSP based on treatment algorithm (25.6%). The primary endpoint was significantly reduced in the DRG (35/160, 21.8%) compared to SRG (48/132, 36.4%)(hazard ratio (HR): 1.72; 95% confidence interval (CI):1.12-2.65; p=0.013). Conclusion A treatment algorithm based on IVCD shifted 1 patient every 4 from BiVP to CSP, with consequent reduction in cardiovascular deaths, HF hospitalizations or urgent unplanned clinic visits after implantation. Therefore, its application could be useful to determine whether to perform BiVP or CSP in CRT candidates.Treatment Algorithm

Management of Postprocedural Conduction Disturbances Using a Prespecified Algorithm in the Optimize PRO Study

BackgroundLack of standardization in posttranscatheter aortic valve replacement (TAVR) conduction disturbance (CD) identification and treatment may affect permanent pacemaker implantation (PPI) rates and clinical outcomes. The safety and efficacy of a standardized TAVR CD algorithm has not been analyzed. This study analyzes the Optimize PRO post-TAVR CD management algorithm with Evolut PRO/PRO+ valves. MethodsOptimize PRO is a prospective, postmarket study implementing 2 strategies to reduce pacemaker rates: TAVR with cusp overlap technique and a post-TAVR CD algorithm. The 2-hour postprocedural electrocardiogram (ECG) stratified patients to early discharge in the absence of new ECG changes or to CD algorithms for (1) ECG changes with preexisting right or left bundle branch block (LBBB), interventricular conduction delay or first-degree atrioventricular block, (2) new LBBB, or (3) high-degree atrioventricular block (HAVB). ResultsThe interim analysis of the CD cohort consisted of 125/400 TAVR recipients. In the CD cohort, the 30-day new PPI rate was higher (28.1% vs 1.5%; P <.001), and 60 (48%) patients were discharged with a 30-day continuous ECG monitor. At 30 days, 90% of patients discharged with a monitor did not require PPI. Clinical outcomes, including mortality, stroke, bleeding, and reintervention, were similar in patients with and without CDs. No patient experienced sudden cardiac death. ConclusionsEffective management of CDs using a standard algorithm following Evolut TAVR provides similar 30-day safety outcomes to patients without CDs who undergo routine next day discharge. The CD algorithm may provide an effective strategy to recognize arrhythmias early, improve PPI utilization, and facilitate safe monitoring of patients after discharge.

Biventricular or conduction system pacing for cardiac resynchronization therapy: a proposed treatment algorithm based on interventricular conduction delays

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac resynchronization therapy (CRT) is usually performed with biventricular pacing (BiVP), but recently conduction system pacing (CSP) has been proposed as an alternative in case of unsuccessful coronary sinus lead implantation. CSP was performed as His Bundle pacing or Left bundle branch pacing(1). However, further evidence is needed to determine when CSP should be used in lieu of BiVP to improve clinical benefit. Purpose To assess the clinical benefit of a treatment algorithm based on interventricular conduction delays (IVCD) to choose between BiVP or CSP in candidates to CRT(figure1). Methods Consecutive patients presenting at our Institution from January 2018 to December 2020 with an indication to CRT were prospectively enrolled in the study group (delays-guided resynchronization group, DRG). IVCD were measured after left ventricle (LV) lead positioning in a lateral or posterior-lateral cardiac vein, when feasible, using endocavitary electrogram(2). Treatment algorithm based on IVCD was used to decide whether to leave LV lead to perform BiVP or pull it out and perform CSP. Outcomes from the DRG group were compared to a historical cohort of CRT patients (resynchronization standard guide group,SRG). The primary endpoint was a composite of cardiovascular mortality, heart failure (HF) hospitalization, or HF event at 1 year after the date of intervention. Results Study population consisted in 292 patients, of which 160 (54.8%) in the DRG and 132 (45.2%) in the SRG. In the DRG 41 of 160 patients underwent CSP based on treatment algorithm (25.6%). The primary endpoint was significantly reduced in the DRG (35/160, 21.8%) compared to SRG (48/132, 36.4%) (hazard ratio(HR):1.72;95% confidence interval(CI):1.12-2.65;p=0.013)(figure2). Conclusion A treatment algorithm based on IVCD shifted 1 patient every 4 from BiVP to CSP, with consequent reduction in cardiovascular deaths, HF hospitalizations or HF event after implantation. Therefore, its application could be useful to determine whether to perform BiVP or CSP in CRT candidates.

Biventricular or Conduction System Pacing for Cardiac Resynchronization Therapy: A Strategy for Cardiac Resynchronization Based on a Hybrid Approach

Cardiac resynchronization therapy (CRT) is usually performed with biventricular pacing (BiVP), but recently, conduction system pacing (CSP) has been proposed as an alternative in case of BiVP failure. The aim of this study is to define an algorithm to choose between BiVP and CSP resynchronization using the interventricular conduction delays (IVCD) as a guide. Consecutive patients from January 2018 to December 2020 with an indication for CRT were prospectively enrolled in the study group (delays-guided resynchronization group, DRG). A treatment algorithm based on IVCD was used to decide whether to leave the left ventricular (LV) lead to perform BiVP or pull it out and perform CSP. Outcomes from the DRG group were compared to a historical cohort of CRT patients who underwent CRT procedures between January 2016 and December 2017 (resynchronization standard guide group, SRG). The primary endpoint was a composite of cardiovascular mortality, heart failure (HF) hospitalization, or HF event at 1 year after the date of intervention. The study population consisted of 292 patients, of which 160 (54.8%) were in the DRG and 132 (45.2%) in the SRG. In the DRG, 41 of 160 patients underwent CSP based on the treatment algorithm (25.6%). The primary endpoint was significantly higher in the SRG (48/132, 36.4%) compared to the DRG (35/160, 21.8%) (hazard ratio (HR): 1.72; 95% confidence interval (CI): 1.12-2.65; p = 0.013). A treatment algorithm based on IVCD shifted one patient out of every four from BiVP to CSP, with consequent reduction in the primary endpoint after implantation. Therefore, its application could be useful to determine whether to perform BiVP or CSP.

Abstract 12072: EKG Appearance and Evolution of Baseline EKG-Characteristics in the Worldwide First Genetically Modified Porcine-to-Human Xenotransplant (“Pig Heart-in-Human Body”)

Introduction: The worldwide first genetically modified porcine-to-human cardiac xenotransplantation was performed in January 2022 at the University of Maryland with the recipient surviving for 61 days. Methods: Daily 12- lead ECGs were obtained during the post-operative period. Results: Accepted “pig heart-in-pig body” ECG parameters demonstrate a short PR interval (50-120ms), short QRS (70-90ms) and short QT (260-380ms). However, the first-ever EKG of a genetically modified heart xenotransplant (“pig heart-in-human body”) demonstrated a relatively longer PR interval of 190ms, QRS duration of 138ms and QT of 538ms (in setting of sinus bradycardia, interventricular conduction delay and inferior/antero-lateral T wave inversions; Figure 1). Prolonged intrinsic PR intervals remained stable during the post-operative course with 210±22ms [range 142-246ms]. However, atrial pacing demonstrated evidence of decremental intra-atrial conduction delay/AV-conduction delay most pronounced on day 12 (PR: 380ms). QRS duration remained prolonged with 145±16ms [range 116-192ms] but shortened during the post-operative course (day 21-40 vs 41-60: 148±14ms vs 132±11ms; p&lt;0.001). Increased QT persisted with 509±54ms [range 384-650ms] with dynamic fluctuations (QT nadir around day 14 (428±22ms vs 533±36ms; p&lt;0.001). Conclusions: ECG parameters of the first genetically modified porcine-to-human cardiac xenotransplant (“pig heart-in-human body”) demonstrated prolongation over the usually encountered ECG measurements in the donor (“pig heart- in-pig body”) including changes in cardiac depolarization and repolarization. Prolonged ECG parameters persisted but showed dynamic changes during post-operative period. This provides a first insight into the novel and evolving field of xenotransplanation suggesting a complex interplay of inter-species physiology and porcine denervation in addition to post-surgical and medication-related changes.

Cardiac resynchronization therapy optimization in nonresponders and incomplete responders using electrical dyssynchrony mapping

Nonresponse to cardiac resynchronization therapy (CRT) occurs in ∼30%-50% of patients. There are no well-accepted clinical approaches for optimizing CRT in nonresponders. The purpose of this study was to demonstrate the effect of CRT optimization using electrical dyssynchrony mapping on left ventricular (LV) function, size, and dyssynchrony in selected patients with nonresponse/incomplete response to CRT. We studied 39 patients with underlying left bundle branch block or interventricular conduction delay who had an LV ejection fraction of ≤40% after receiving CRT and had significant electrical dyssynchrony. Electrical dyssynchrony was measured at multiple atrioventricular delays and interventricular delays. The QRS area between combinations of 9 anterior and 9 posterior electrograms (QRS area under the curve) was calculated, and cardiac resynchronization index (CRI) was defined as the percent change in QRS area under the curve compared to native conduction. Electrical dyssynchrony maps depicted CRI over the wide range of settings tested. Patients were programmed to an optimal device setting, and echocardiograms were recorded 5.9 ± 3.7 months postoptimization. CRI increased from 49.4% ± 24.0% to 90.8% ± 10.5%. CRT optimization significantly improved LV ejection fraction from 31.8% ± 4.7% to 36.3% ± 5.9% (P < .001) and LV end-systolic volume from 108.5 ± 37.6 to 98.0 ± 37.5 mL (P = .009). Speckle-tracking measures of LV strain significantly improved by 2.4% ± 4.5% (transverse; P = .002) and 1.0% ± 2.6% (longitudinal; P = .017). Aortic to pulmonic valve opening time, a measure of interventricular dyssynchrony, significantly (P = .040) decreased by 14.9 ± 39.4 ms. CRT optimization of electrical dyssynchrony using a novel electrical dyssynchrony mapping technology significantly improves LV systolic function, LV end-systolic volume, and mechanical dyssynchrony. This methodology offers a noninvasive, practical clinical approach to treating nonresponders and incomplete responders to CRT.

S1137 The Impact of Electrocardiogram Parameters on Cardiovascular Complications at Time of Liver Transplantation

Introduction: Electrocardiogram (ECG) is an integral component of cardiovascular assessment in patients evaluated for liver transplant (LT). However, despite its centrality, there is paucity of data linking ECG interval and rhythm assessment to peri-LT cardiovascular events. Methods: In this retrospective study, the ECG of all patients receiving LT at our institution between 2010-2018 (n=651) were reviewed independently by two cardiologists blinded to clinical data according to the Minnesota classification. Primary outcome included cardiac arrest, new-onset cardiac arrythmia or known arrhythmia requiring change in medication that occurred within 4 weeks of LT. Results: The mean age was 56±10 years and consisted mainly of males (n=478) and Whites (n=469). Leading etiology of cirrhosis was hepatitis C (n=276), followed by NASH (n=120) and alcohol-related liver disease (n=104). At LT evaluation, 633 patients were in sinus rhythm, while atrial fibrillation or flutter was present in 18 subjects. The most common abnormal ECG findings included prolonged QTc (n=347), left ventricular hypertrophy (n=58), right bundle branch block (n=28), and left bundle branch block (n=6). Patients with NASH were more likely to have atrial fibrillation/flutter (5.8% vs. 2.1%; p=0.03), interventricular conduction delay (13.3% vs. 5.1%; p=0.003), and left anterior fascicular block (5.8% vs. 1.3%; p=0.007). The likelihood of primary outcome was 17.3% with the most common arrhythmia being atrial fibrillation (n=53, 8.1%), followed by bradycardia (n=22, 3.4%), supraventricular tachycardia (n=10, 1.5%), and sinus tachycardia (n=9, 1.4%). Primary outcome was more common among patients with dyslipidemia (24.3% vs. 15.5%, p=0.01) and CAD (23.6% vs. 15.0%, p=0.008). After adjusting for gender, BMI, beta blocker use, diabetes, dyslipidemia, statin use, and presence of CAD, age (HR 1.06, p=0.001) and male gender (HR 1.97, p=0.04) were associated with increased risk of post-LT arrythmias. While aspirin (HR 0.37, P=0.02) and prolonged QRS (HR 0.49, p=0.04) were associated with lower risk of cardiovascular events. Conclusion: ECG abnormalities are common among patients with cirrhosis, particularly NASH cirrhosis. It is likely perturbation the bio-clinical profile (older, diabetic, obese, electrolyte abnormalities) that predispose them to developing peri-transplant arrhythmias. Well designed mechanistic studies are required to better understand the pathophysiology to implement targeted peri-transplant therapy to mitigate this risk.

B-PO03-067 PACEMAKER EXIT-BLOCK AFTER RADIOABLATION FOR VT CAUSING INAPPROPRIATE ICD SHOCKS AND BRADYCARDIC ARREST

Stereotactic body radiation therapy (SBRT) is an emerging tool for the treatment of VT where catheter ablation has failed or is technically not feasible. Knowledge of the acute and chronic electrophysiologic sequelae, including changes in functioning of device therapy, is an evolving area. We report the first known case of inappropriate ICD shocks and severe bradycardia due to exit-block in a pacemaker dependent patient as a late-onset phenomenon following successful SBRT for VT. NA NA A 54-year-old female with a history of scar-related VT despite amiodarone therapy and chemical sympathectomy underwent successful SBRT for VT seven months prior. She was pacemaker dependent (CRT-D) with stable thresholds post-SBRT. She presented to hospital with multiple episodes of conscious ICD shocks due to R-wave double counting and misclassification as VF from interventricular conduction delay or RV loss of capture (LOC). At testing, LV and RV pacing thresholds were measured to be stable however. She later experienced severe bradycardic episodes due to intermittent LV and RV LOC that was stabilised by programming her CRT to maximum output. Definitive treatment was with insertion of a new transcutaneous RV lead and removal of LV lead. This is the first known case of delayed-onset exit-block occurring following SBRT for VT with sequelae of inappropriate ICD shocks and profound bradycardia due to dynamic conduction delay, variable pacing threshold and interplay with CRT programming. It is important that the electrophysiology team is aware of these issues.

Electrocardiographic Findings and In-Hospital Mortality of COVID-19 Patients; a Retrospective Cohort Study.

Background:Although current evidence points to the possible prognostic value of electrocardiographic (ECG) findings for in-hospital mortality of COVID-19 patients, most of these studies have been performed on a small sample size. In this study, our aim was to investigate the ECG changes as prognostic indicators of in-hospital mortality.Methods:In a retrospective cohort study, the findings of the first and the second ECGs of COVID-19 patients were extracted and changes in the ECGs were examined. Any abnormal finding in the second ECG that wasn’t present in the initial ECG at the time of admission was defined as an ECG change. ECGs were interpreted by a cardiologist and the prognostic value of abnormal ECG findings for in-hospital mortality of COVID-19 patients was evaluated using multivariate analysis and the report of the relative risk (RR).Results:Data of the ECGs recorded at the time of admission were extracted from the files of 893 patients; likewise, the second ECGs could be extracted from the records of 328 patients who had an initial ECG. The presence of sinus tachycardia (RR = 2.342; p <0.001), supraventricular arrhythmia (RR = 1.688; p = 0.001), ventricular arrhythmia (RR = 1.854; p = 0.011), interventricular conduction delays (RR = 1.608; p = 0.009), and abnormal R wave progression (RR = 1.766; p = 0.001) at the time of admission were independent prognostic factors for in-hospital mortality. In the second ECG, sinus tachycardia (RR = 2.222; p <0.001), supraventricular arrhythmia (RR = 1.632; p <0.001), abnormal R wave progression (RR = 2.151; p = 0.009), and abnormal T wave (RR = 1.590; p = 0.001) were also independent prognostic factors of in-hospital mortality. Moreover, by comparing the first and the second ECGs, it was found that the incidence of supraventricular arrhythmia (RR = 1.973; p = 0.005) and ST segment elevation/depression (RR = 2.296; p <0.001) during hospitalization (ECG novel changes) are two independent prognostic factors of in-hospital mortality in COVID-19 patients.Conclusion:Due to the fact that using electrocardiographic data is easy and accessible and it is easy to continuously monitor patients with this tool, ECGs can be useful in identifying high-risk COVID-19 patients for mortality.

Mitral valve prolapse - it"s possible to stratify prognosis in these patients?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Mitral valve prolapse (MVP) is one of the most frequent causes of mitral valve disease in developed countries, traditionally with a benign prognosis, however some patients develop arrythmias and significant mitral regurgitation (MR) with need of intervention. Herein our purpose was to establish clinical, electrocardiographic and echocardiographic predictors of arrythmias, mitral valve intervention (MVI) and hospitalization in MVP patients to better characterize the prognosis in these patients. Methods Single-center retrospective study of consecutive patients with MVP documented in transthoracic echocardiogram between January 2014 and October 2019. MVP was defined as systolic displacement of the mitral leaflet into the left atrium ≥ 2 mm from the mitral annular plane. Demographic, clinical, echocardiographic, electrocardiographic data were collected as well as adverse events at follow-up. The results were obtained using Chi-square and Student-t tests; predictors were found with logistic regression. Results 247 patients were included (mean age 62.9 ± 18 years, 61% males), most with MVP involving the posterior leaflet (48.6%). 40% were symptomatic, 47.4% had more than moderate MR, and 25% had interventricular conduction delay in the ECG. During a mean follow-up of 30 ± 19 months, 38% had arrythmias, 27.1% needed mitral valve intervention (95% surgery and 5% percutaneous), 27.1% had atrial fibrillation (AF), 3.4% had ventricular arrythmias, 19.2% had ventricular premature beats, 13.3% had hospital admission for cardiovascular cause and 8.5% (n = 21) died. 9.3% of the patients had mitral annulus disjunction (MAD). Palpitations (p = 0.018), AF (p &amp;lt; 0.001), significant MR (p &amp;lt; 0.001), higher NYHA class (p = 0.016), systolic pulmonary artery pressure (SPAP) (p &amp;lt; 0.001), LV mass (p &amp;lt; 0.001), QTc (p = 0.01) and MAD maximum distance (p = 0.02) associated with MVI. MAD maximum distance value presented an excellent capacity to predict the MVI (AUC 0.85 p = 0.019); the best cut-off was 11,5 mm (Sens = 80%; Spec = 83%). AF was a predictor of hospitalization in univariate analysis (OR = 2.57, CI95% 1.15-5.75, p = 0.022). Regarding arrhythmic events, we found association with aortic root dilatation (p = 0.032), NYHA III-IV (p = 0.013), age and LV mass (both with p &amp;lt; 0.001). In multivariate analysis, LV mass (OR = 1.02, CI95% 1.005-1.027, p = 0.005) and age (OR = 1.038, CI95% 1.004-1.053, p = 0.021) were independent predictors of arrythmias. In this sample, MAD was not associated with arrythmias. Conclusion Opposing to previous studies in our population, MAD was not associated with arrythmias but had an excellent capacity to predict MVI. Age and LV hypertrophy were independent predictors of arrythmias in our patients. Larger studies are needed to better stratify patients with MVP, as its association with arrhythmias, hospitalization and the need for intervention is not negligible.

The Prevalence and Short-Term Outcomes of Ventricular Dyssynchrony after Right Ventricular Pacing

Objective: Long-term right ventricular pacing has been associated with an increased risk of heart failure and cardiomyopathy. The pathophysiology of cardiomyopathy associated with right ventricular pacing remains unclear. We aim to evaluate the burden and short-term outcomes of ventricular dyssynchrony after immediate permanent pacemaker implantation. Materials and Methods: This prospective cohort study examined consecutive patients who had permanent pacemaker implantation at Vajira Hospital in 2019. Left ventricular systolic function, specifically left ventricular ejection fraction (LVEF) and echocardiographic ventricular dyssynchrony parameters were assessed. The endpoints included the prevalence of ventricular dyssynchrony, new-onset cardiomyopathy, heart failure, and death. The correlation between QRS complex duration, the burden of ventricular pacing, and echocardiographic ventricular dyssynchrony was measured. Results: Thirty-six consecutive patients underwent pacemaker implantation. The prevalence of mechanical ventricular dyssynchrony was 22.2% using the interventricular conduction delay method, 41.7% using LV pre-ejection period method, and 11.1% using the septal posterior wall motion abnormality method. Electrical ventricular dyssynchrony was 86.1% and new-onset cardiomyopathy was 17.1% after 3 months of permanent pacemaker implantation. The right ventricular pacing of more than 20% was significantly associated with cardiomyopathy (p < 0.022) and heart failure (log-rank, p = 0.049) within 3 months. But heart failure was not associated with mechanical ventricular dyssynchrony parameters (log-rank, p = 0.610; hazard ratio [HR], 1.53; 95% confidence interval [CI], 0.29 - 7.96; p = 0.613 for IVMD and log-rank, p = 0.398; HR, 0.04; 95% CI, 0.01 - 3316.7 for SPWMD). Conclusion: Mechanical and electrical ventricular dyssynchrony are common findings in right ventricular pacing. High-burden right ventricular pacing after 3 months of permanent pacemaker implantation is often associated with cardiomyopathy and heart failure, but mechanical and electrical ventricular dyssynchrony does not predict a short-term decline in left ventricular systolic function and heart failure.

Abstract 15474: New Onset Left Bundle Branch Block Secondary to Severe Hyperkalemia

Case presentation: A 79-year-old female with history of renal failure on hemodialysis (HD) presented with generalized weakness. Her last HD was 3 days ago. On examination, she was vitally stable. Blood tests demonstrated a potassium (K+) of 8.3 mmol/L, confirmed on repeat testing. ECG revealed wide QRS, tall T waves and a new left bundle branch block (Figure 1). She was immediately treated with calcium chloride, insulin, dextrose and polystyrene sulfonate. The patient was admitted to the ICU and underwent emergent HD. Repeat K+ post HD reversed to 4.0 mmol/L and ECG reflected normal sinus rhythm with resolution of ST-T wave changes (Figure 2). Discussion: Hyperkalemia can lead to cardiac arrhythmias and sudden death. The ECG changes are dependent on severity of hyperkalemia. It can vary from narrow based, peaked T waves to ventricular fibrillation. Hyperkalemia can also lead to interventricular conduction delays, which, with severity, can take the form of right or left bundle branch block (LLLB). The conduction delay from hyperkalemia usually lasts only in initial or terminal portions as opposed to throughout the QRS complex as seen in bundle branch block disease. Association of LLLB with hyperkalemia is an uncommon but important occurrence and has only scarcely been reported in literature. Its prevalence remains unknown. With the growing use of renin-angiotensin aldosterone system inhibitors, more patients are prone to experience life threatening electrolyte disturbances. A thorough knowledge of the ECG manifestations related to hyperkalemia is crucial to ensure emergent treatment. This may result in improved outcomes in such patients with cardiovascular and renal diseases.

Abstract 14876: Predictors of Permanent Pacemaker Insertion After TAVR: A Systematic Review and Meta-Analysis

Introduction: Transcatheter Aortic Valve Replacement (TAVR) has evolved as the standard of care for patient with severe aortic stenosis. Conduction abnormalities leading to permanent pacemaker (PPM) implantation is one of the most common complication after TAVR. The aim of this analysis is to evaluate the predictors associated with increased risk of PPM implantation after TAVR. Methods: A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify relevant trials. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. Results: 37 observational studies with 71455 patients were identified. The incidence of PPM implantation after TAVR in our analysis was 22%. The risk of PPM implantation after TAVR was more in men, it increased with increasing age, and in patients with diabetes mellitus, presence of right bundle branch block , baseline atrioventricular conduction block, and left anterior fascicular block. Significant predictors of PPM insertion post TAVR included the presence of high calcium volume in the area below left and non-coronary cusp, use of self-expandable valve over balloon-expandable valve, depth of implant, valve size/annulus size, pre-dilatation balloon valvuloplasty and post-implant balloon dilation. However, the risk did not increase with atrial fibrillation, left bundle branch block, baseline interventricular conduction delay, change in QRS duration after the procedure and with the presence of high calcium in the area below right coronary cusp. Conclusions: Our meta-analysis identified 14 factors that were significantly associated with increased risk of PPM insertion after TAVR. Early identification of high-risk populations and targeting modifiable risk factors can help to reduce the rate of PPM insertion after TAVR.

Abstract 15641: Fever. The True Unmasker of My Disease

Introduction: The most common etiology of sudden cardiac death (SCD) from ventricular tachyarrhythmias (VTA) is an acute ischemic event from coronary artery disease (CAD; followed by genetic syndromes, including Brugada Syndrome (BS). The presentation of SCD with an ECG showing RBBB pattern with ST segment elevation (STSE) in leads V1-V3 in healthy patients and in the absence electrolyte imbalances, CAD, or structural heart disease is known as BS. It can be triggered by abundant meals, excessive alcohol intake, cocaine, local anesthetics, tricyclic antidepressants, lithium, propofol and fevers. Case Presentation: 29 y/o woman presenting with atypical chest pain, malaise, and a remote history of a syncopal episode. She denied family history of SCD. She was febrile to 100.4 o F, tachycardic, with regular heart sounds and no murmurs. Laboratory work up was normal. ECG from two years ago showed nonspecific interventricular conduction delay. ECG on admission showed STSE in anterior precordial leads which disappeared with resolution of her fever. Due to the Brugada-like pattern in her ECG and remote history of syncope, AICD placement was recommended. Flecainide challenge was not pursued, since the patient was amenable to AICD. Genetic counseling and testing were provided to her family members. Discussion: Most patients with BS are healthy adults between 30-40 y/o without significant medical history. A defect in the sodium channel SCN5A, results in a loss of homogeneity in the myocardial action potential. This mutant channel may be exaggerated when exposed to supraphysiologic temperatures, unmasking BS and elevating the risk of VTA and SCD. BS is carried through generations in an autosomal dominant fashion. Medical management alone is ineffective and not recommended. AICD is the only effective treatment for prevention of SCD. Conclusion: BS is an identifiable and preventable cause of death. In patients presenting with multiple syncopal episodes or aborted VTA’s, in the absence of significant cardiovascular history, and with known or equivocal family history of SCD, the diagnosis of BS must be considered. Health providers across all practice settings should have the skill of identifying its clinical and ECG presentation in order to decrease the rate of SCD.

Transesophageal echocardiographic predictors of intraventricular conduction delay in patients undergoing transcatheter aortic valve replacement

Introduction Patient anatomical features, such as shorter membranous septum (MS) length, on computed tomography have been shown to predict conduction abnormalities after transcatheter aortic valve replacement (TAVR). This relationship has not yet been evaluated using transesophageal echocardiography (TEE). Our hypothesis is that the distance from the aortic annulus to the septal bulge, a surrogate of MS distance and length, will be associated with a new interventricular conduction delay and heart block post-TAVR. Likewise, we hypothesize an implantation depth of the valve closer to the septal bulge will also predict post-TAVR interventricular conduction delay. Methods Comprehensive intraprocedural echocardiographic data were analyzed retrospectively on 88 patients who underwent TAVR under general anesthesia with TEE. Pre-procedural MS distance and post-procedural implantation depth (quantified as the inferior border of valve to septal bulge) were measured in the mid-esophageal long axis view of the aortic valve in mid-systole. EKGs were evaluated pre-TAVR and immediately post-valve deployment. Univariate logistic regression was used to identify predictors of a need for post-operative pacemaker (PM) implantation and new bundle branch block (BBB). Results The population consisted of 88 patients undergoing TAVR with TEE from 2017-2018 at our institution. The median age was 84, 45/88 (51.1%) were female. After TAVR, 7/88 (7.9%) had PPM placed and 21/88 (23.8%) had a new bundle branch block, transient or permanent. MS length was inversely associated with the risk of developing an interventricular conduction delay after TAVR (OR=0.19, CI 0.05-0.75, p=0.018). As shown in Table 1, the implantation distance was inversely associated with the need for a pacemaker or developing a new interventricular conduction delay after TAVR (OR=0.19, Cl 0.06-0.6, p=0.006). Discussion MS length and valve implantation depth on intraprocedural TEE are inversely associated with the risk of developing conduction abnormalities post-TAVR. TEE assessment may be comparable to CT in predicting post-TAVI high-grade atrioventricular block, and has the additional benefit of being performed intraprocedurally in selected patients.

P1462Incidence of ventricular arrhythmias in cardiac resynchronization therapy and implantable cardioverter-defibrillator patients

Abstract Introduction Implantation of a cardiac resynchronization therapy combined with cardioverter-defibrillator (CRT-D) is now common practice. Our study looked at the occurrence of the first adequate CRT-D therapy with respect to gender, treatment indication (primary or secondary prevention of sudden cardiac death) and the etiology of heart failure in long-term follow-up. Methods In the database of CRT-D patients implanted between 2005 and 2013 we analyzed the occurrence of treated episodes of ventricular arrhythmia (first shock or anti-tachycardic pacing). Results 250 patients (22.8% females) with left bundle branch block or non-specific interventricular conduction delay were enrolled. 80% of patients were implanted in the primary and 20% in the secondary prevention of sudden cardiac death. During the follow-up of 5.5 ± 2.5 years, 46.4% of patients died for cardiac (25.6%) or non-cardiac (20.8%) reasons. CRT-D therapy occurred in 33.2% of patients (20.8% shock). In patients implanted in the primary prevention of sudden cardiac death the incidence of therapies was 25.5% vs. 64.0% in patients implanted in the secondary prevention of sudden cardiac death (P˂0.00001). The incidence of therapies between the group of patients with coronary artery disease and other causes of heart failure did not differ (33.3% vs. 32.9%, P = NS). Women were at a significantly lower risk of adequate shock (women 10.5% vs. men 23.8%, P = 0.01). Conclusion Adequate CRT-D therapy occurred in a quarter of patients implanted in the primary prevention of sudden cardiac death. In patients implanted in the secondary prevention of sudden cardiac death the incidence of therapies is significantly more frequent. The female gender predicts significantly lower incidence of adequate shock. Abstract Figure. Adequate shock therapy

1255 Previously unknown ventricular arrhythmia in a globally delayed pediatric patient with tuberous sclerosis

Abstract Introduction We present a case of previously unknown ventricular ectopy in a pediatric patient who is globally delayed. As the patient is non-verbal, it is possible the patient may have ultimately experienced heart failure or a lethal arrhythmia were it not for the polysomnogram (PSG). Report of Case A four year old female with Tuberous Sclerosis (TS) was referred to our pediatric sleep center for snoring. Her past medical history includes intracardiac tumors, daily seizures, and global developmental delay. Initial PSG showed moderate obstructive sleep apnea defined by an obstructive Apnea-Hypopnea Index of 6.89 and no cardiac arrhythmias. Positive airway pressure titration study was performed one year later. Premature ventricular contractions were noticed during the setup while patient was awake. Intermittent couplets and triplets occurred during sleep as well as a prolonged run of bigeminy that initiated during a period of wake after sleep onset and persisted into non-rapid eye movement sleep. She was escorted to the emergency room where a 12-lead electrocardiogram (EKG) showed sinus rhythm with non-specific interventricular conduction delay and right ventricular hypertrophy. She was discharged with a Holter monitor and subsequent analyses was concerning for frequent ventricular couplets and non-sustained runs of ventricular tachycardia. She required admission to initiate anti-arrhythmic therapy. Imaging revealed stable intracardiac tumors, but revealed scarring within sites of intramyocardial lesions. She failed different anti-arrhythmic agents before settling with amiodarone. Conclusion Sleep disordered breathing (SDB) can cause or worsen cardiac arrhythmias. This case highlights the importance of routine surveillance in patients with both known cardiac disease who have or are at risk of having significant cardiac arrhythmias and suspected SDB. Additionally, current guidelines for TS patients recommend EKG once every 3 to 5 years. This case may also highlight the importance of increased cardiac surveillance in this population group.