Pause-Dependent Paroxysmal Episode of Third-Degree Atrioventricular Block Triggered by Premature Atrial Contraction.

BACKGROUND Paroxysmal third-degree atrioventricular block (AVB) can exhibit a vast array of symptoms, but commonly, paroxysmal AVB leads to presyncope, syncope, or possibly sudden cardiac death. We present a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. CASE REPORT A 65-year-old man with frequent episodes of presyncope and syncope for 3 weeks was admitted to our hospital for further diagnosis. A resting 12-lead electrocardiogram showed an incomplete right bundle branch block, and a 24-h Holter recording showed multiple episodes of third-degree AVB. Intracardiac tracing revealed that the block site was distal, at the infra-His-Purkinje system. CONCLUSIONS This case highlights a rare case of pause-dependent paroxysmal AVB that was triggered by a premature atrial contraction. This type of AVB is an abrupt, unexpected, repetitive block of atrial impulses as they propagate to the ventricles. It is relatively rare, and due to its transient nature, it is often under recognized and can lead to sudden cardiac death.

Discrimination between ventricular tachycardia and wide-QRS preexcited tachycardia.

BACKGROUND: To develop a new algorithm to differentiate ventricular tachycardia (VT) from preexcited tachycardia (pre-ET) according to left bundle branch block (LBBB) and right bundle branch block (RBBB) patterns. METHODS: This study included 67 electrocardiograms (ECGs) with VT and 63 ECGs with pre-ET, collected from our hospital and through PubMed. Of those, 64 were allocated to the derivation cohort and the rest to the validation cohort. The diagnoses of the ECGs were confirmed using an electrophysiological study. Parameters and classifiers from prior algorithms along with the propagation speeds in the early portion of the QRS complex (initial deflection index) in leads V1, V6, aVR, II, and III were manually measured. The performance of the new algorithm was compared with that of prior algorithms. RESULTS: The initial deflection index in lead III was the strongest predictor of pre-ET in LBBB-pattern wide-QRS tachycardia (p = 0.003, AUC 0.805). The initial deflection index in lead V1 was the most powerful predictor of pre-ET in RBBB-pattern wide-QRS tachycardia (p = 0.001, AUC 0.848). Compared to earlier algorithms, those using the initial deflection indexes: lead III in LBBB patterns (cutoff value >0.3) and lead V1 in RBBB patterns (cutoff value ≤0.48), demonstrated superior performance in screening VT, with AUC values of 0.828. The initial deflection indexes proved effective as discriminators between VT and pre-ET in the validation cohort. CONCLUSIONS: In LBBB-pattern wide-QRS tachycardia, the early propagation speed of pre-ET was faster than that in VT. Conversely, in RBBB-pattern wide-QRS tachycardia, it was slower.

Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation.

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

Treatment strategy for heart failure complicated with complete left bundle branch block and atrial tachycardia: a case report.

BACKGROUND: For patients with heart failure combined with complete left bundle branch block, cardiac resynchronization therapy is an important therapeutic method. If these patients also have atrial tachycardia, how to choose a treatment strategy deserves discussion. CASE PRESENTATION: A Chinese woman in her early 70s was admitted due to recurrent episodes of chest distress and asthma for 1 year. Physical and laboratory examinations showed filling of the jugular vein, lung rales, left enlargement of the heart boundary, edema of the lower limbs and elevation of N-terminal pro b-type natriuretic peptide. An electrocardiogram showed atrial tachycardia and a left bundle branch block. An echocardiography revealed enlargement of the left ventricle and left ventricular systolic dysfunction. After obtaining informed consent, the treatment strategy decided upon by the team was to use biventricular cardiac resynchronization therapy treatment and to not intervene for the atrial tachycardia, with left bundle branch area pacing as a backup. Due to twisted and narrow coronary vein branches, traditional biventricular pacing failed, and then, left bundle branch area pacing was attempted successfully. A follow-up echocardiography at 1 year showed improved systolic function. The outcomes for this patient are favorable, but the choice of interventional strategy is worthy of discussion in this case. CONCLUSION: For patients with heart failure combined with left bundle branch block and atrial tachycardia, left bundle branch area pacing can replace traditional biventricular pacing for cardiac resynchronization therapy treatment, and the therapeutic effect is significant. However, multiple factors need to be considered when formulating strategies, including whether there is bundle branch block under sinus rhythm, the success and recurrence rate of atrial tachycardia ablation, the response of cardiac resynchronization therapy, the costs of different strategies, and instrument implantation issues.

Diagnostic Dilemma of Syncope: Esophageal Hiatal Hernia and High-risk Bundle-branch Block.

We herein report a complicated case of recurrent syncope accompanying bundle branch block and hiatal hernia of the esophagus. An 83-year-old woman presented with syncope. Echocardiography visualized the left atrium compressed by an esophageal hiatal hernia, which had potential to decrease the cardiac output. Although she underwent esophageal repair surgery, two months after the surgery, she presented to the emergency department again with complaints of syncope. At the return visit, her face was pale and her pulse rate was 30 beats per minute. Electrocardiography showed complete atrioventricular block. On reviewing the patient's previous electrocardiography findings, we found a record of trifascicular block. This case illustrates the importance of predicting atrioventricular blocks in patients with high-risk bundle-branch blocks. Keeping in mind high-risk bundle-branch blocks will help clinicians avoid anchoring bias due to a striking image masquerading as the true diagnosis.

Cardiac MRI of characteristic motion findings in right bundle branch block.

While there have been many descriptions of characteristic motion findings in left bundle branch block (LBBB), there are few published descriptions of such findings in right bundle branch block (RBBB). The purpose of this study was to assess the frequency of particular regional motion findings in cardiac magnetic resonance imaging (CMR) studies of patients with RBBB, compared with normal subjects. We focused on three distinctive motion patterns that can be seen in RBBB during early systole: delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge". The presence and relative magnitude of these findings were independently scored by four experienced observers, in 3-chamber and 4-chamber CMR cines, for both normal subjects and patients with RBBB. These motion patterns were found to be strongly associated with the presence of RBBB. While only moderately sensitive, they were quite specific for RBBB, when present. In particular, with ROC analysis, a combined feature set of the findings in the 4-chamber view had an area under the curve of 0.81.This previously undescribed set of RBBB-associated early-systolic regional motion features (delayed apex-ward motion of the RV base, "reverse septal flash", and "basal bulge") is strongly suggestive of RBBB when present, particularly in the 4-chamber view. Although here evaluated with CMR, it is also likely to be associated with RBBB when seen with other cardiac imaging modalities.

Chagas disease stroke and associated risk factors: A case-control study.

INTRODUCTION: The intricate relationship between Chagas disease and ischemic stroke remains unclear. Limited evidence exists concerning secondary prophylaxis, etiological diagnosis, and stroke-related determinants. This study aims to discern factors linked to stroke in Chagas disease by contrasting patients with and without a history of ischemic stroke. METHODS: Retrospective data from all outpatient Chagas disease patients from two Brazilian hospitals - one Chagas center and one stroke clinic - were examined. Descriptive analyses were conducted to identify stroke-associated factors. Variables were compared between patients with and without ischemic stroke history. RESULTS: Among 678 subjects, 72 had experienced stroke. Univariate associations with stroke included male gender, heart failure, prior or ongoing alcoholism, electrocardiographic features (non-sinus rhythm, left bundle branch, right bundle branch block, left anterosuperior fascicular block, atrial fibrillation), as well as echocardiographic findings indicative of reduced left ventricular ejection fraction and segmental abnormalities. After logistic regression (multivariate analysis), congestive heart failure, right bundle branch block, left anterosuperior divisional block, and atrial fibrillation retained independent associations. CONCLUSION: In this study, cardiac involvement emerged as the predominant factor correlated with stroke in Chagas disease. While atherosclerosis-related risk factors were prevalent, their influence on ischemic stroke in Chagas disease appeared limited.

Self-expanding TAVI using the cusp overlap technique versus the traditional technique: electrocardiogram changes and 1-year cardiovascular outcomes.

INTRODUCTION AND OBJECTIVES: Transcatheter aortic valve implantation (TAVI) using the cusp overlap technique (COT) has shown a lower pacemaker implantation rate at 30 days. The objective of this study was to compare electrocardiogram changes and clinical outcomes between COT and the traditional technique (TT) at 1 year of follow-up. METHODS: Observational, retrospective, nonrandomized study of consecutive patients undergoing TAVI between January 2015 and January 2021. Patients were matched using a propensity score and the TT was compared with COT. The primary endpoints were electrocardiogram changes and a combined endpoint including pacemaker implantation, hospitalization, or cardiovascular death at 1 year. RESULTS: We included 254 patients. After propensity score matching, 184 patients (92 per group) remained. There were no statistically significant differences in baseline characteristics. At 1 year, COT patients showed a significant reduction in new onset left bundle branch block (49% vs 27%, P=.002) and less P wave (13.1±21.0 msec vs 5.47±12.5 msec; P=.003) and QRS prolongation (29.77±27.0 msec vs 16.38±25.4 msec, P <.001). COT was associated with a significant reduction in the occurrence of the primary endpoint (SHR, 0.39 [IC95%, 0.21-0.76]; P=.005). CONCLUSIONS: At 1 year of follow-up, COT reduced the incidence of new onset left bundle branch block and diminished QRS and P wave widening compared with the TT. COT was also associated with a statistically significant reduction in the occurrence of the combined primary cardiovascular endpoint.

Electrophysiological study in chagasics with syncope and conduction disorder.

BACKGROUND: Investigation of syncope involves the use of electrophysiological study, particularly in patients with cardiac conduction disorder. There is conflicting evidence about the role of electrophysiological study in patients with Chagas disease. OBJECTIVE: The objective of this study was to evaluate the electrophysiological study findings in patients with Chagas disease and bundle branch block and/or divisional block presenting with syncope. METHODS: This is a retrospective study of patients with Chagas disease and cardiac conduction disorder who underwent electrophysiological study from 2017 to 2021 for the investigation of syncope in a tertiary hospital in São Paulo, Brazil. Those with non-interpretable ECG, known coronary artery disease, and/or other cardiomyopathies were excluded. HV interval and electrophysiological study-induced malignant ventricular arrhythmias data were analyzed. RESULTS: A total of 45 patients (60.2±11.29 years, 57.8% males) were included. The mean HV interval was 58.37 ms±10.68; 22.2% of the studied population presented an HV interval of ≥70 ms; and malignant ventricular arrhythmias were induced in 57.8% patients. The use of beta-blockers and amiodarone (p=0.002 and 0.036, respectively), NYHA functional class≥II (p=0.013), wide QRS (p=0.047), increased HV interval (p=0.02), Rassi score >6.5 (p=0.003), and reduced left ventricular ejection fraction (p=0.031) were associated with increased risk of inducible malignant ventricular arrhythmias. CONCLUSION: More than half of the patients with Chagas disease, syncope, and cardiac conduction disorder have inducible malignant ventricular arrhythmias. Prolonged HV interval was observed in only 20% of population. Wide QRS, prolonged HV, reduced ejection fraction, and higher Rassi score were associated with increased risk of malignant ventricular arrhythmias.

Predictors of Trypanosoma cruzi PCR positivity in patients with chronic Chagas disease.

BACKGROUND: A positive Trypanosoma cruzi polymerase chain reaction (PCR) is associated with a worse prognosis in patients with chronic Chagas disease (CD). OBJECTIVES: To study the association of clinical, electrocardiographic, and echocardiographic characteristics and biomarker blood levels with positive T. cruzi PCR in chronic CD. METHODS: This is a single-centre observational cross-sectional study. Positive T. cruzi PCR association with clinical, electrocardiographic, and echocardiographic characteristics, and biomarker blood levels were studied by logistic regression analysis. p values < 0.05 were considered significant. FINDINGS: Among 333 patients with chronic CD (56.4% men; 62 ± 10 years), T. cruzi PCR was positive in 41.1%. Stepwise multivariate logistic regression showed an independent association between positive T. cruzi PCR and diabetes mellitus {odds ratio (OR) 0.53 [95% confidence interval (CI) 0.30-0.93]; p = 0.03}, right bundle branch block [OR 1.78 (95% CI 1.09-2.89); p = 0.02], and history of trypanocidal treatment [OR 0.13 (95% CI 0.04-0.38); p = 0.0002]. Among patients with a history of trypanocidal treatment (n = 39), only four (10%) patients had a positive T. cruzi PCR. MAIN CONCLUSIONS: Among several studied parameters, only diabetes mellitus, right bundle branch block, and history of trypanocidal treatment showed an independent association with positive T. cruzi PCR. History of trypanocidal treatment was a strong protective factor against a positive T. cruzi PCR.

Terminal T-wave concordance is associated with SYNTAX score among left bundle branch block patients suspected of acute coronary syndrome without modified Sgarbossa criteria.

BACKGROUND: Timely and precise diagnosis of ischemic cardiac events based on electrocardiogram is challengeable among patients with Left Bundle Branch Block (LBBB). The present study aimed to assess the correlation between SYNTAX score and terminal T-wave morphologies among LBBB patients suspected of Acute Coronary Syndrome (ACS) without modified Sgarbossa criteria. METHOD: This cross-sectional study was conducted on the LBBB patients suspected of ACS without modified Sgarbossa criteria. Binary logistic regression was used to assess the correlation of ischemic heart disease (IHD, SYNTAX score > 0) and SYNTAX score categories with terminal T-wave morphologies including T-wave direction in lead V6 and terminal T-wave concordance in leads I, V5, and V6. RESULT: This study was done on 93 patients with the mean age of 62.4 ± 9.6 years. More than half of the patients were female (58.1%, 95% CI: 47.4% to 68.2%). Among the participants with IHD, the SYNTAX score categories were correlated to discordant terminal T-wave in leads I, V5, and V6 (OR = 5.71, 95% CI: 1.04 to 31.28, p = 0.04). CONCLUSION: Among the LBBB patients with acute ischemic cardiac events without modified Sgarbossa criteria, those with discordant terminal T-waves in leads I, V5, or V6 had higher SYNTAX scores and might require more invasive coronary revascularization techniques such as Coronary Artery Bypass Graft (CABG) surgery.

Transient left bundle branch block associated with very high coronary artery calcium: a case report.

Coronary artery calcium (CAC) is the measure of subclinical coronary artery atherosclerosis most strongly associated with atherosclerotic cardiovascular disease (ASCVD) risk. However, CAC is rarely reported in the inpatient setting to guide chest pain management. We present a case of very high CAC in a 64-year-old woman with hypertension, type 2 diabetes, and hyperlipidemia presenting with dyspnea. Initial electrocardiogram (ECG) demonstrated normal conduction with a heart rate of 76 beats/min, but new T-wave inversions in V1-V4 and a high-sensitivity troponin-I (hsTnI) value of 6 ng/L (normal < 6 ng/L). Repeat ECG in the emergency department showed normal sinus rhythm (heart rate of 80 beats/min); however, it subsequently demonstrated a left bundle branch block (LBBB) with a repeat hsTnI of 7 ng/L. Stress testing with pharmacologic single-photon emission computerized tomography did not show scintigraphic evidence of ischemia but noted extensive CAC and a concern for balanced ischemia. Subsequent coronary computed tomography angiography (CCTA) showed nonobstructive disease and a total Agatston CAC score of 1262. Invasive evaluation with left heart catheterization was deferred given the patient's unchanged symptoms and CCTA findings. Statin therapy was intensified and aspirin, metoprolol succinate, and antihypertension therapies were continued. Initiation of glucose-lowering therapy and lipoprotein(a) testing was strongly recommended on follow-up. Our case suggests that CAC ⩾ 1000 may be incidentally associated with transient LBBB during the workup of coronary artery disease. Here, we specifically show that functional testing that incorporates measurement of CAC burden can help to improve ASCVD-preventive pharmacotherapy initiation and intensification beyond the identification of obstructive disease alone.

Interpreting the ECG in patients with chest pain and right bundle branch block: A case report.

A patient with right bundle branch block (RBBB) presented with chest pain. An ECG showed ST-elevation in leads V1, V2, and aVR, with widespread ST-depression in leads II, aVF, I, aVL, and V4-6. The initial ECG interpretation missed ST-elevation myocardial infarction (STEMI), as ST-elevation thresholds were not reached. Non-urgent angiography showed severe left anterior descending artery stenosis requiring percutaneous coronary intervention. The course was complicated by cardiac arrest necessitating resuscitation and dual chamber pacemaker placement with left bundle branch pacing. This case report outlines the deficiencies of the current voltage criteria for identification of anterior STEMI in patients with RBBB.

Association Between Intensive vs Standard Blood Pressure Control and Incident Left Ventricular Conduction Disease: A Post Hoc Analysis of the SPRINT Randomized Clinical Trial.

Importance: Left ventricular conduction disease predicts heart failure and death, and the only strategies to mitigate its effects involve implantation of a permanent pacemaker. There are currently no proven preventive strategies for this common condition. Objective: To determine the association between targeting intensive blood pressure (BP) control and the risk of developing left ventricular conduction disease. Design, Setting, and Participants: This was a post hoc analysis of the 2-arm multicenter Systolic Blood Pressure Intervention Trial (SPRINT), which recruited participants from 102 sites in the US and Puerto Rico and was conducted from November 2010 until August 2015. Adults 50 years and older with hypertension and at least 1 other cardiovascular risk factor were included. Participants with baseline left ventricular conduction disease, ventricular pacing, or ventricular pre-excitation were excluded for the current analysis. Data were analyzed from November 2021 to November 2022. Intervention: Participants were randomly assigned to a systolic BP target of less than 140 mm Hg (standard treatment group) or less than 120 mm Hg (intensive treatment group). Main Outcome: The primary outcome was incident left ventricular conduction disease, including any fascicular or left bundle-branch block, assessed by serial electrocardiography. Incident right bundle-branch block was examined as a negative control. Results: Among 3918 participants randomized to standard treatment and 3956 to intensive treatment (mean [SD] age, 67.6 [9.2] years; 2815 [36%] female) monitored for a median [IQR] 3.5 (0.02-5.2) years, 203 developed left ventricular conduction disease. Older age (hazard ratio per 10-year increase [HR], 1.42; 95% CI, 1.21-1.67; P < .001), male sex (HR, 2.31; 95% CI, 1.63-3.32; P < .001), and cardiovascular disease (HR, 1.46; 95% CI, 1.06-2.00; P = .02) were associated with a higher risk of left ventricular conduction disease. Assignment to intensive treatment was associated with a 26% lower risk of left ventricular conduction disease (HR, 0.74; 95% CI, 0.56-0.98; P = .04). These results persisted when incident ventricular pacing was included in the outcome and when considering all-cause death as a competing risk. In contrast, no association between randomization assignment and right bundle-branch block was observed (HR, 0.95; 95% CI, 0.71-1.27; P = .75). Conclusions and Relevance: In this study, targeting intensive BP control was associated with lower risk of left ventricular conduction disease in a randomized clinical trial, suggesting that clinically relevant conduction disease may be preventable. Trial Registration: ClinicalTrials.gov Identifier: NCT01206062.

Efectos del tratamiento médico guiado en pacientes con miocardiopatía inducida por bloqueo de rama izquierda / Effects of guideline-directed medical therapy in patients with left bundle branch block-induced cardiomyopathy

Introducción y objetivos La miocardiopatía inducida por el bloqueo de rama izquierda (BRI) se produce en pacientes con BRI de larga duración. Es característico que muestren hiperrespuesta a las terapias de resincronización cardiaca (TRC). Sin embargo, existe poca información sobre su respuesta al tratamiento médico. El objetivo de este estudio es evaluar el cambio en la fracción de eyección del ventrículo izquierdo (FEVI) después de un periodo de 3 meses tras la dosificación del tratamiento médico recomendado por la guía de insuficiencia cardiaca. Métodos Se trata de un análisis retrospectivo, en el que se incluyó a todos los pacientes valorados en la unidad de insuficiencia cardiaca de un hospital universitario español entre 2020 y 2021, que presentaban disfunción ventricular de novo (FEVI <40%) y tenían antecedentes de BRI de larga evolución sin otras posibles causas de miocardiopatía. Resultados Se analizó a un total de 1.497 pacientes, de los que resultaron elegibles 21. El tiempo medio desde el primer diagnóstico de BRI a la primera consulta fue de 4,05±4,1 años. La FEVI media desde la primera consulta hasta el final de la dosificación mejoró del 29,5±5,7% al 32,7±8,6% (p=0,172); ninguno recuperó la función ventricular al final del seguimiento. La clase funcional de la New York Heart Association mejoró de 1,91±0,46 a 1,81±0,53 (p=0,542). Tras el implante del dispositivo de TRC en 8 pacientes, la FEVI mejoró un 18,1±6,4% (p=0,003). Conclusiones El tratamiento médico recomendado por la guía parece ser ineficaz para mejorar la FEVI y la clase funcional en pacientes con insuficiencia cardiaca de novo y miocardiopatía inducida por BRI. Basándose en la respuesta positiva a la TRC en la mejora de la FEVI, el implante temprano de TRC podría ser una estrategia razonable para estos pacientes (AU)

Introduction and objectives Left bundle branch block (LBBB)-induced cardiomyopathy occurs in patients with long-standing LBBB. These patients characteristically exhibit hyperresponsiveness to cardiac resynchronization therapies (CRT). However, there is scarce information on their response to medical treatment. The aim of this study was to assess the change in left ventricular ejection fraction (LVEF) after a 3-month period following titration of guideline-directed medical therapy for heart failure. Methods This retrospective analysis included all patients assessed in the heart failure unit of a Spanish University Hospital between 2020 and 2021, who presented with de novo ventricular dysfunction (LVEF <40%) and had a history of long-standing LBBB with no other possible causes of cardiomyopathy. Results A total of 1497 patients were analyzed, of which 21 were finally eligible. Mean time from first diagnosis of LBBB to first consultation was 4.05± 4.1 years. Mean LVEF from first consultation to end of titration improved from 29.5±5.7% to 32.7±8.6% (P = .172), but none had recovered ventricular function at the end of follow-up. New York Heart Association functional class improved from 1.91±0.46 to 1.81±0.53 (P=.542). After CRT device implantation in 8 patients, LVEF improved by 18.1±6.4% (P=.003). Conclusions Guideline-directed medical therapy seems to be ineffective in improving LVEF and functional class in patients with de novo heart failure and LBBB-induced cardiomyopathy. Based on a positive response to CRT on LVEF improvement, early CRT implantation could be a reasonable strategy for these patients (AU)

Conduction Disturbances and Arrhythmia Risk After Septal Reduction Therapy with Alternative Agents: A Pilot Study with EVOH-DMSO and Systematic Review.

OBJECTIVE: Surgical septal myectomy and alcohol septal ablation are recommended treatment modalities for alleviating Left ventricular outflow tract (LVOT) gradient in obstructive HCM. Alcohol septal ablation offers advantages over surgery in many ways. However, it is associated with some life-threatening complications. For this purpose, our center used alternative agents for septal artery embolization. This study compared and evaluated conduction system defects and arrhythmia risk after EVOH-DMSO septal ablation with other alternative agents and alcohol septal ablation. METHODS: Twenty-five patients who received septal reduction therapy with EVOH-DMSO were analyzed retrospectively, and all non-alcoholic agent's septal ablation studies were systematically reviewed and compared. RESULTS: Twenty-five patients (52% female; mean age: 55.8 ± 17.1) with symptomatic obstructive HCM were enrolled. The Peak LVOT gradient was significantly reduced after the procedure (68 vs. 20 mmHg; P <0.001). During the 12-month follow-up, no mortality occurred. The complete atrioventricular block was noted in 2 (8%) patients. The incidence of right bundle branch block (RBBB) increased after the procedure (pre-procedural 2 patients (8%), post-procedural 9 patients (36%) P = 0.002). On ECG and Holter monitorization, no sustained ventricular tachyarrhythmia occurred during follow-up, and no change was found in the frequency of atrial fibrillation. We systematically compared EVOH-DMSO to other non-alcohol agents, and we found that EVOH-DMSO can cause conduction system problems more commonly than other non-alcohol agents. CONCLUSION: EVOH-DMSO could cause conduction system problems more common than other non-alcohol agents but less than alcohol septal ablation.