BACKGROUND:Identifying the risks related to the complications of electrical cardioversion (ECV) can alert the determinaton of rhythm control in patients with atrial fibrillation (AF). METHODS:We retrospectively reviewed 1,058 patients who underwent ECV for persistent or long-standing persistent AF/atrial flutter (AFL) from multiple centers. Patients were classified into the no-complication (1,023 patients) and complication (35 patients) groups based on the following major complications: stroke and/or systemic embolism (SSE), myocardial infarction, major bleeding, implantation of cardiac implantable electronic devices, ventricular tachycardia/fibrillation, and death at 1 year follow-up after ECV. RESULTS:Compared with the no-complication group, the complication group exhibited a higher proportion of female patients (37% vs. 22%), as well as a higher proportion of patients with older age (67 ± 11 vs. 61 ± 10 years), diabetes mellitus (DM) (49% vs. 24%), heart failure (HF) (49% vs. 30%), SSE (23% vs. 9%), high CHA₂DS₂-VASc (CV) score (3.6 ± 1.8 vs. 2.2 ± 1.4), low left ventricular ejection fraction (LVEF) (50 ± 16% vs. 58 ± 21%), and high left atrial volume index (LAVI) (51 ± 26 vs. 40 ± 20 mL/m²). Class I and III antiarrhythmics were less prescribed in the complication group than in the no-complication group (57% vs. 76%). Univariate analysis for complications revealed age (≥ 65 years), female sex, DM, HF, SSE, LVEF (< 50%), LAVI (≥ 40 mL/m²), CV score (≥ 3), bradycardia on Holter (< 60/min), and no antiarrhythmics as risk factors. Among these, multivariate analysis revealed clinical significance of female sex and SSE. CONCLUSION:Female sex and a history of SSE were the most important risk factors of complications in patients with persistent or long-standing persistent AF/AFL who underwent ECV.

BACKGROUND/AIMS:Identifying clinical risk factors of failed electrical cardioversion (ECV) for persistent or long-standing persistent atrial fibrillation (AF) can guide selection of rhythm control. METHODS:A total of 1058 patients who underwent ECV for persistent or long-standing persistent AF at multiple centres were retrospectively reviewed. Patients were divided into three groups: group 1 maintained sinus rhythm (SR) for >1 year, group 2 maintained SR ≤1 year after ECV, and group 3 had failed ECV. SR maintenance was assessed via regular electrocardiography follow-ups or Holter. RESULTS:Group 1, 2 and 3 comprised 315 (30%), 654 (62%), and 89 (8%) patients, respectively. The mean patient age was 61 ± 10 years, with males accounting for 78% (824). Group 3 showed longer AF duration, female dominance, high proportion of patients with history of coronary artery disease (CAD) and heart failure (HF), and increased left atrium (LA) diameter, LA volume index (LAVI), cardiac size, and cardiothoracic ratio. Univariate analysis revealed that AF duration (≥50 months), female sex, history of CAD and HF, increased LA diameter (≥ 45 mm) and LAVI (≥ 45 mL/m2), and no antiarrhythmics were risk factors of failed ECV for persistent or long-standing persistent AF. Among them, AF duration (≥50 months), history of HF, and increased LAVI showed clinical significance in the multivariate analysis. CONCLUSIONS:Longer AF duration, history of HF, and increased LAVI were strongly associated with failed ECV in patients with persistent or long-standing persistent AF.

Background/Aims Although an implantable loop recorder (ILR) is a valuable tool for investigation of unexplained syncope, there are limited data regarding time course to diagnosis and predictors of serious arrhythmias as a cause of unexplained syncope. We sought to investigate diagnosis rate by time period after ILR implantation and identify predictors of serious arrhythmias in patients with unexplained syncope. Methods We identified 394 patients who received ILR implantation for unexplained syncope enrolled in the Korean ILR registry. Results Serious arrhythmias were documented in 205 patients (52.0%). One hundred seventy-two patients (43.7%) had sick sinus-node syndrome (SSS), 24 (6.1%) had atrioventricular block, and nine (2.3%) had ventricular arrhythmia. Of these, 48 (23.4%) and 77 (37.6%) were diagnosed within two weeks and one month after ILR implantation, respectively. Median time to diagnosis was 62 days. In multivariable analysis, left atrial volume index (LAVI) ≥ 34 mL/m2 (hazard ratio [HR] 1.582), hypertension (HR 1.788), sinus bradycardia with a heartrate less than 60 beats per minute (HR 1.762), and LAVI ≥ 34 mL/m2 combined with sinus bradycardia (HR 1.911) were independent predictors of SSS. Cumulative detection rate of SSS was significantly higher in patients with LAVI ≥ 34 mL/m2 than those with LAVI < 34 mL/m2 (p < 0.001). Conclusions More than half of patients with unexplained syncope had serious arrhythmias, and more than one-third of these arrhythmias were diagnosed within one month after ILR implantation. LAVI combined with sinus bradycardia may be a useful predictor of SSS as a cause of unexplained syncope.

Apixaban is recommended for patients with atrial fibrillation. Although routine monitoring of plasma concentrations is not typically advised, factors such as ethnicity, sex, and comorbidities can influence these levels. Our study analyzed the plasma apixaban concentrations (PAC) in patients to explore whether these levels, along with underlying conditions, offer enhanced insights for risk stratification. This study analyzed 49 patients with atrial fibrillation who had been taking apixaban for over a month, examined factor Xa levels within 6 h post-administration, and correlated PAC with clinical characteristics such as age, body weight, estimated glomerular filtration rate (eGFR), presence of heart failure, and bleeding events. The mean plasma concentration of apixaban in all patients was 160.3 ± 77.5 ng/mL. Those taking apixaban 5 mg twice daily had higher plasma concentrations than those taking 2.5 mg twice daily (191.2 ± 75.3 ng/mL vs. 137.2 ± 72.0 ng/mL, p = 0.014). Among the patients receiving a reduced dose, renal function and heart failure were significantly associated with plasma concentrations. No factors were associated with the plasma concentrations in patients receiving the standard dose. Notably, reduced-dose patients with heart failure had plasma concentrations comparable to those of individuals receiving the standard dose and exhibited a higher incidence of bleeding than the other groups. PAC measurement revealed that apixaban dosages, classified based on age, body weight, and eGFR, were generally effective. Nonetheless, heart failure may increase plasma levels and correlate with an increased bleeding risk in Korean patients on reduced doses. Therefore, tailoring apixaban prescriptions to account for heart failure and other comorbidities may enhance treatment efficacy.

We sought to compare the diagnostic efficacy of a 72-hour wearable electrocardiography (ECG) patch monitoring with a conventional 24-hour Holter monitoring for the detection of cardiogenic vertigo. We conducted a prospective multicenter study that recruited 47 patients suspected of cardiogenic vertigo in four referral-based university hospitals between November 2019 and April 2022. Patients received simultaneous ambulatory ECG recordings using a 72-hour wearable ECG patch monitoring and a conventional 24-hour Holter monitor. The primary outcome was the detection rate of arrhythmia events during the entire wearing period. The secondary outcomes included device preference and factors affecting the detection of cardiogenic vertigo. During the 72-hour monitoring period, there was no significant difference in the overall detection rate of arrhythmia events between the wearable patch and conventional Holter monitoring (10 of 47 [21.3%] vs. 8 of 47 [17.0%], p = .500) Most patients (46/47) favored a wearable patch over Holter monitoring. The effectiveness of wearable ECG patch monitoring was comparable to conventional Holter monitoring in detecting cardiogenic vertigo. With its extended monitoring capability and patient preference, wearable patch monitoring holds promise as an alternative method for the diagnosis of cardiogenic vertigo. Limitations of this study include small sample size and selection bias.

We sought to compare the diagnostic efficacy of a 72-hour wearable electrocardiography (ECG) patch monitoring with a conventional 24-hour Holter monitoring for the detection of cardiogenic vertigo (CV). We conducted a prospective multicenter study that recruited 47 patients suspected of CV in four referral-based university hospitals between November 2019 and April 2022. Patients received simultaneous ambulatory ECG recordings using a 72-hour wearable ECG patch monitoring and a conventional 24-hour Holter monitor. The primary outcome was the detection rate of arrhythmia events during the entire wearing period. The secondary outcomes included device preference and factors affecting CV detection. During the 72-hour monitoring period, there was no significant difference in the overall detection rate of arrhythmia events between the wearable patch and conventional Holter monitoring (21.3% vs.17.0%, p > .001). Most patients (46/47) favored a wearable patch over Holter monitoring. The detection of CV was associated with a lower frequency of vertigo. The effectiveness of wearable ECG patch monitoring was comparable to conventional Holter monitoring in detecting CV. With its extended monitoring capability and patient preference, wearable patch monitoring holds promise as an alternative method for CV diagnosis.

Abstract Background Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with significant morbidity and mortality, posing a considerable burden on healthcare systems. In Republic of Korea, the prevalence and incidence of AF have increased in recent years. There have also been significant changes in the trends of antiarrhythmic drug (AAD) use and procedural treatments for AF. Objectives This study aims to review the trends in AF treatment strategies in Republic of Korea, particularly focusing on the utilization of antiarrhythmic drugs and catheter ablation. Methods The Korean National Health Insurance Service (K-NHIS) data were used to identify AF patients from 2013 to 2022. AAD usage and catheter ablation procedures were analyzed annually. AADs were classified into Class IC and III drugs. Trends in beta-blockers, calcium channel blockers, and digoxin prescriptions were also examined. The primary endpoint was the trend of AAD use and AF catheter ablation (AFCA) over 10 years. Results In 2022, 940,063 patients had a prior diagnosis of AF. From 2013 to 2022, the use of AADs increased from 12.1 to 16.4% among prevalent AF patients. Beta-blockers were the most commonly prescribed rate control medication, while the use of calcium channel blockers and digoxin declined. The frequency of AFCA procedures also increased, from 0.5% of prevalent AF patients in 2013 to 0.7% in 2022. Younger patients, males, and those with lower CHA2DS2-VASc scores were more likely to receive AFCA. Regional variations in treatment patterns were observed, with Seoul exhibiting higher rates of procedural treatments and AAD prescriptions. Conclusions Over the past decade, there has been a significant increase in the use of AADs and AFCA procedures in Republic of Korea. These trends reflect recent advancements in AF management advocating a refined rhythm control strategy.

Premature atrial complex (PAC) and premature ventricular complex (PVC) are the most common arrhythmias. Most of them are benign, whereas some could be an initial sign of any underlying significant heart disease. Evaluation of daily burden and the presence of any association with underlying medical conditions are essential for proper assessment. Recently, newly developed electrocardiogram smart devices are widely available to document arrhythmias and identify correlations with symptoms. Management is required if the daily burden is high, patients are highly symptomatic, or significant structural heart disease is present. Antiarrhythmic drugs (AADs) are the first-line treatment, but if arrhythmias are drug-refractory or the patients are intolerable to AADs, catheter ablation is considered a good alternative in selected cases. In this paper, the proper diagnosis and management for PAC and PVC will be comprehensively reviewed.

Although the adverse effects of long-term use of vitamin K oral anticoagulant (OAC), warfarin, on the coronary vasculature are well-established, it remains unknown whether nonvitamin K oral anticoagulants play a role in the attenuation of plaque progression and coronary calcification. This study aimed to compare the changes in atherosclerotic plaques and calcification of the coronary arteries in patients with atrial fibrillation (AF) treated with edoxaban and warfarin. A total of 150 OAC-naïve patients with AF and atherosclerotic lesions on coronary computed tomography angiography (CCTA) were enrolled and randomly assigned to the edoxaban or warfarin treatment groups. All enrolled patients received rosuvastatin 10 mg and 119 patients completed the entire study protocol. A total of 12 months after the assigned OAC treatment, follow-up CCTA was performed and changes in plaque and calcium volumes of the coronary arteries were analyzed. The baseline characteristics of the 2 groups were well-balanced. The percentage of time in therapeutic range in the warfarin group was 61.1%. Compared with the baseline CCTA, there was a significant reduction in plaque volume after 12 months of OAC and rosuvastatin administration in both groups, and the extent of regression did not differ significantly between the groups. The increase in calcium volume was greater in the warfarin group than in the edoxaban group; however, the difference was not significant. In OAC-naïve patients with AF and atherosclerotic coronary lesions who were treated with moderate-intensity statin, edoxaban use did not have a positive effect on atherosclerotic plaques and coronary calcification compared with warfarin use over a 12-month follow-up period.

Background Although rhythm control could be the best for symptomatic atrial fibrillation (AF), some patients fail to achieve sinus rhythm (SR). This study aimed to identify clinical risk factors of failed electrical cardioversion (ECV). Methods A total of 248 patients who received ECV for persistent AF or atrial flutter (AFL) were retrospectively reviewed. Patients were divided into three groups: Group 1 maintained SR for > 1 year, group 2 maintained SR ≤ 1 year after ECV, and group 3 failed ECV. SR maintenance was assessed using regular electrocardiography or Holter monitoring. Results Patients were divided into group 1 (73, 29%), group 2 (146, 59%), and group 3 (29, 12%). The mean age of patients was 60 ± 10 years, and 197 (79%) were male. Age, sex, and baseline characteristics were similar among groups. However, increased cardiac size, digoxin use, heart failure (HF), and decreased left ventricular ejection fraction (LVEF) were more common in group 3. Univariate analysis of clinical risk factors for failed ECV was increased cardiac size [hazard ratio (HR) 2.14 (95% confidence interval [CI], 1.06–4.34, p = 0.030)], digoxin use [HR 2.66 (95% CI, 1.15–6.14), p = 0.027], HF [HR 2.60 (95% CI, 1.32–5.09), p = 0.005], LVEF < 40% [HR 3.45 (95% CI, 1.00–11.85), p = 0.038], and decreased LVEF [HR 2.49 (95% CI, 1.18–5.25), p = 0.012]. Among them, HF showed clinical significance only by multivariate analysis [HR 3.01 (95% CI, 1.13–7.99), p = 0.027]. Conclusions Increased cardiac size, digoxin use, HF, LVEF < 40%, and decreased LVEF were related to failed ECV for persistent AF or AFL. Among these, HF was the most important risk factor. Further multi-center studies including greater number of participants are planned.

Cancer genetics has to date focused on epithelial malignancies, identifying multiple histotype-specific pathways underlying cancer susceptibility. Sarcomas are rare malignancies predominantly derived from embryonic mesoderm. To identify pathways specific to mesenchymal cancers, we performed whole-genome germline sequencing on 1644 sporadic cases and 3205 matched healthy elderly controls. Using an extreme phenotype design, a combined rare-variant burden and ontologic analysis identified two sarcoma-specific pathways involved in mitotic and telomere functions. Variants in centrosome genes are linked to malignant peripheral nerve sheath and gastrointestinal stromal tumors, whereas heritable defects in the shelterin complex link susceptibility to sarcoma, melanoma, and thyroid cancers. These studies indicate a specific role for heritable defects in mitotic and telomere biology in risk of sarcomas.

BACKGROUND AND OBJECTIVES Previous studies have reported an association between impaired renal function and poor outcomes after radiofrequency catheter ablation in patients with atrial fibrillation (AF). However, outcomes of cryoballoon ablation (CBA) in patients with renal insufficiency are not fully elucidated. This study aimed to compare outcomes of CBA in AF patients with chronic kidney disease (CKD) versus those without CKD and to assess changes in renal function over 12 months following CBA. METHODS A total of 839 patients (65.1% with non-paroxysmal AF [PAF]) who underwent de novo CBA were prospectively enrolled. We divided patients into two groups based on creatinine clearance rate (CCr) and performed intracardiac echocardiography (ICE)-guided contrast agent-free CBA. RESULTS In comparison with patients without CKD (CCr >50, n=722), those with CKD (CCr ≤50, n=117) were older and predominantly female, had a lower body mass index, and showed a higher prevalence of heart failure and hypertension. Mean CHA2DS2-VAS score was significantly higher in CKD group than in non-CKD group. Procedure-related complications were not significantly different between two groups. During a mean follow-up period of 25.4±11.9 months, clinical recurrence occurred in 182 patients (21.7%) and not significantly different between two groups. In multivariate analysis, non-PAF and left atrial size were independent predictors of AF recurrence. CCr levels significantly improved over 12 months after CBA in CKD group. CONCLUSIONS ICE-guided contrast-agent-free CBA showed comparable long-term clinical outcomes without increasing procedure-related complications and improvement of renal function over 12 months following CBA in AF patients with CKD.

There is a dearth of studies investigating whether the combination of low-intensity statins with ezetimibe can reduce the risk of diabetes in patients requiring statin therapy. Therefore, we aimed to evaluate the effects of combination therapy on the prevention of glycated hemoglobin (HbA1c) elevation in patients without diabetes. Sixty-eight patients were randomly assigned in a 1:1 ratio to receive a combination of low-intensity rosuvastatin (5 mg/day) and ezetimibe (10 mg/day) or high-intensity rosuvastatin (20 mg/day). The primary endpoint was the absolute difference in the HbA1c levels at 12 weeks. The HbA1c level showed an overall elevation of 0.11% at 12 weeks compared to that at baseline (mean ± standard deviation: 5.78 ± 0.3%, 95% confidence interval [CI]: 5.86–6.07, p = 0.044). The HbA1c levels did not differ between the groups at 12 weeks (least square mean difference: 0.001, 95% CI: 0.164–0.16, p = 0.999). Our study found that the combination of low-intensity rosuvastatin and ezetimibe did not yield significant differences in HbA1c levels compared to high-intensity rosuvastatin alone after 12 weeks in patients without diabetes. This suggests that the combination of low-intensity rosuvastatin and ezetimibe may not be an effective strategy for preventing HbA1c elevation in patients without diabetes requiring statins.

Background and Objectives: Left atrial hypertension is one of the pathophysiologies of heart failure with preserved ejection fraction. We hypothesized that left atrial pressure response (LAPR) to incremental pacing is higher in patients with atrial fibrillation (AF) and can predict left ventricular diastolic dysfunction. Materials and Methods: Patients requiring left atrial access as a part of a therapeutic procedure for AF (n = 204, AF group) or supraventricular tachycardia (n = 34, control group) were analyzed (male n = 183, 54 ± 12 years old). LAPR was measured during incremental pacing. Results: Baseline left atrial pressure and LAPR at all pacing rates were not different between the AF and control groups. They were higher in patients with a high E/e' (≥ 8) than in those with a low E/e' (<8). LAPR at a pacing interval of 400 ms and E/e' were positively correlated (r = 0.373, p < 0.001). Body mass index and a high E/e' were independent predictors of pacing-induced left atrial hypertension. Conclusions: LAPR to incremental pacing was constant regardless of AF. The non-invasive echocardiographic marker E/e' reflected pacing-induced left atrial hypertension.

Aims The development of intracardiac echocardiography (ICE) has enabled fluoroless atrial fibrillation (AF) ablation using three-dimensional electroanatomical mapping systems. However, fluoroless cryoballoon ablation (CBA) remains challenging, mainly because of the lack of a visual mapping system. Hence, this study aimed to investigate the safety and efficacy of fluoroless CBA for AF under ICE guidance. Methods and results Patients (n = 100) who underwent CBA for paroxysmal AF were randomly assigned to zero-fluoroscopic (Zero-X) and conventional groups. Intracardiac echocardiography was used to guide the transseptal puncture and catheter and balloon manipulation in all enrolled patients. The patients were prospectively followed for 12 months after CBA. The mean age was 60.4 years, and the left atrial (LA) size was 39.4 mm. Pulmonary vein isolation (PVI) was achieved in all patients. In the Zero-X group, fluoroscopy was used in only one patient because of unstable phrenic nerve capture during right-sided PVI. The procedure time and LA indwelling time in the Zero-X group were not statistically different compared with that in the conventional group. Fluoroscopic time (9.0 vs. 0.008 min) and radiation exposure (29.4 vs. 0.02 mGy) were significantly shorter in the Zero-X group than in the conventional group (P < 0.001). The complication rate did not differ between the two groups. During a mean follow-up of 663.3 +/- 172.3 days, the recurrence rate was similar (16.0 vs. 18.0%; P = 0.841) between the groups. Multivariate analysis revealed that LA size was the only independent predictor of clinical recurrence. Conclusion Intracardiac echocardiography-guided fluoroless CBA for AF was a feasible strategy without compromising acute and long-term success or complication rates.

Abstract Background We investigated the effect of nicorandil on infarct size, cardiac function assessed by cardiac magnetic resonance imaging (CMR) and outcomes in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI). Methods In a prospective, randomised, controlled trial, 83 patients with STEMI receiving primary PCI were randomised into the nicorandil (n =  40) or placebo (n  =  43) groups. Nicorandil was administered in the emergency room before primary PCI as an intravenous bolus of 4 mg followed by a continuous infusion of 6 mg/h for 24 h and as 2-mg intracoronary injections prior to balloon dilatation and coronary stenting. Nicorandil was continued orally at 10–20 mg/d for 6 months. Infarct size and cardiac function were measured by CMR at 5 d and 6 months after primary PCI. Furthermore, major adverse cardiac events (MACEs) including all-cause death, nonfatal myocardial infarction (MI), any revascularisation, stroke, and definite/probable stent thrombosis (ST) were compared. Results There were no significant differences in baseline clinical characteristics between the groups. Infarct size at baseline and 6 months as well as infarct size changes during 6 months as measured by CMR were similar between the groups. Similarly, other CMR parameters were comparable at baseline and 6 months between the groups. MACEs occurred in four patients (4.8%) during 6 months. No significant difference in the risk of MACEs was observed between the groups. Conclusions Treatment with nicorandil for 6 months after primary PCI was not associated with any improvement in infarct size, CMR-determined cardiac function, and outcomes in STEMI patients.

Background:The balance of stroke risk reduction and potential bleeding risk associated with antithrombotic treatment (ATT) remains unclear in atrial fibrillation (AF) at non-gender CHA2DS2-VASc scores 0-1. A net clinical benefit (NCB) analysis of ATT may guide stroke prevention strategies in AF with non-gender CHA2DS2-VASc scores 0-1. Methods:This multi-center cohort study evaluated the clinical outcomes of treatment with a single antiplatelet (SAPT), vitamin K antagonist (VKA), and non-VKA oral anticoagulant (NOAC) in non-gender CHA2DS2-VASc score 0-1 and further stratified by biomarker-based ABCD score (Age [≥60 years], B-type natriuretic peptide [BNP] or N-terminal pro-BNP [≥300 pg/mL], creatinine clearance [<50 mL/min], and dimension of the left atrium [≥45 mm]). The primary outcome was the NCB of ATT, including composite thrombotic events (ischemic stroke, systemic embolism, and myocardial infarction) and major bleeding events. Results:We included 2465 patients (age 56.2 ± 9.5 years; female 27.0%) followed-up for 4.0 ± 2.8 years, of whom 661 (26.8%) were treated with SAPT; 423 (17.2%) with VKA; and 1040 (42.2%) with NOAC. With detailed risk stratification using the ABCD score, NOAC showed a significant positive NCB compared with the other ATTs (SAPT vs. NOAC, NCB 2.01, 95% confidence interval [CI] 0.37-4.66; VKA vs. NOAC, NCB 2.38, 95% CI 0.56-5.40) in ABCD score ≥1. ATT failed to show a positive NCB in patients with truly low stroke risk (ABCD score = 0). Conclusions:In the Korean AF cohort at non-gender CHA2DS2-VASc scores 0-1, NOAC showed significant NCB advantages over VKA or SAPT with ABCD score ≥1.

Introduction: Several algorithms have been proposed to reduce unnecessary right ventricular (RV) pacing, and their operations are based on two different mechanisms: (i) atrioventricular (AV) hysteresis (AVH) and (ii) DDD to AAI pacing mode change. Hypothesis: The purpose of our study was to evaluate the efficacy and safety of two ventricular pacing suppression algorithms: Intrinsic Rhythm Support (IRS) plus algorithm (using AVH, IRSplus) and VP suppression (DDD to AAI mode change) algorithm (VpS). Methods: This was a multicenter, randomized study conducted in 11 tertiary hospitals in South Korea. Patients with sinus node dysfunction and receiving dual-chamber permanent pacemaker implantation were included in this study. After the implantation, patients maintained a fixed AV interval for three months. The AV conduction time was determined as the "atrial pacing to ventricular sensing interval" observed from the marker channel during the PPM implantation was set as the sensed AV delay. The paced AV delay was set to be the sensed AV delay+30ms. Subsequently, patients were randomly assigned to either the VpS or IRSplus algorithm group and were followed for 12 months with assessments every 6 months. Results: A total of 118 patients were enrolled, and the total RV pacing percentage (Vp%) of the patients during the 3 months with a fixed AV interval was 10.9±16.0 on average. They were randomly assigned to VpS and IRSplus groups, with 62 and 56 patients in each group. Six months later, the average Vp% was 14.6±18.8 to 2.7±6.0, P<0.001 and 6.8±10.9 to 1.1±4.0, P<0.001 for the VpS and IRSplus groups, respectively. This trend was maintained for additional 6 months (VpS group: 4.6±9.5; IRSplus group: 1.2±3.8). The effects of algorithms were more pronounced in groups with an intrinsic PR interval of < 200ms, and the IRSplus showed better efficacy (Figure). Conclusions: The two ventricular pacing suppression algorithms were effective in reducing Vp% compared to the fixed AV interval.