Pacing-induced cardiomyopathy in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement

BACKGROUND

Chronic right-ventricular (RV) pacing can worsen heart failure in patients with a low ejection fraction (EF), but little is known about pacing-induced cardiomyopathy (PICM) in patients with preserved EF. We aimed to investigate risk factors of PICM in these patients during long-term follow-up.

METHODS

The prospective registry at Chosun University Hospital, South Korea, included de novo patients with preserved EF undergoing transvenous permanent pacemaker (PPM) implantation for atrioventricular blockage from 2017 to 2021. Patients with EF ≥ 50% and expected ventricular pacing ≥ 40% were included. Composite outcomes were cardiac death (pump failure), hospitalization because of heart failure, PICM, and biventricular pacing (BVP) upgrade.

RESULTS

A total of 168 patients (69 men, 76.3 ± 10.4 years) were included. During three years of follow-up, one patient died, 14 were hospitalized, 16 suffered PICM, and two underwent BVP upgrade. PICM were associated with reduced global longitudinal strain (GLS), prolonged paced QRS duration (pQRSd) and diastolic variables (E/e', LAVI). Cox regression analysis identified pQRSd (hazard ratio [HR], 1.111; 95% confidence interval [CI], 1.011-1.222; P = 0.03) and reduced GLS (HR, 1.569; 95% CI, 1.163-2.118; P = 0.003) as independent predictors of PICM. GLS showed high predictive accuracy for PICM, with an area under the curve of 0.84 (95% CI 0.779-0.894; P < 0.001) [GLS -12.0, 62.5% sensitivity, and 86.1% specificity].

CONCLUSION

RV pacing increased the risk of PICM in patients with preserved EF. Reduced GLS and prolonged pQRSd could help identify individuals at high risk of PICM even with preserved EF.

Antiarrhythmic Effect of Artemisinin in an Ex-vivo Model of Brugada Syndrome Induced by NS5806

BACKGROUND AND OBJECTIVES

Brugada syndrome (BrS) is an inherited arrhythmia syndrome that presents as sudden cardiac death (SCD) without structural heart disease. One of the mechanisms of SCD has been suggested to be related to the uneven dispersion of transient outward potassium current (I_to) channels between the epicardium and endocardium, thus inducing ventricular tachyarrhythmia. Artemisinin is widely used as an antimalarial drug. Its antiarrhythmic effect, which includes suppression of I_to channels, has been previously reported. We investigated the effect of artemisinin on the suppression of electrocardiographic manifestations in a canine experimental model of BrS.

METHODS

Transmural pseudo-electrocardiograms and epicardial/endocardial transmembrane action potentials (APs) were recorded from coronary-perfused canine right ventricular wedge preparations (n=8). To mimic the BrS phenotypes, acetylcholine (3 μM), calcium channel blocker verapamil (1 μM), and I_to agonist NS5806 (6-10 μM) were used. Artemisinin (100-150 μM) was then perfused to ameliorate the ventricular tachyarrhythmia in the BrS models.

RESULTS

The provocation agents induced prominent J waves in all the models on the pseudo-electrocardiograms. The epicardial AP dome was attenuated. Ventricular tachyarrhythmia was induced in six out of 8 preparations. Artemisinin suppressed ventricular tachyarrhythmia in all 6 of these preparations and recovered the AP dome of the right ventricular epicardium in all preparations (n=8). J wave areas and epicardial notch indexes were also significantly decreased after artemisinin perfusion.

CONCLUSIONS

Our findings suggest that artemisinin has an antiarrhythmic effect on wedge preparation models of BrS. It might work by inhibition of potassium channels including I_to channels, subsequently suppressing ventricular tachycardia/ventricular fibrillation.

A case of sinus arrest in atrial fibrillation with pulmonary embolism after flecainide ingestion

A 76-year-old female visited the emergency department with complaining of dizziness and syncope. She had a history of paroxysmal atrial fibrillation (AF) and had been prescribed flecainide 50 mg and apixaban 5 mg 12-hourly in another hospital 1 day before the presentation. Upon admission, her electrocardiogram showed profound bradycardia and extremely long sinus arrest, which required temporary cardiac pacing. Within 24 hours, her intrinsic rhythm was restored, and the temporary pacemaker was removed. Transthoracic and transesophageal echocardiography revealed no structural heart disease or thrombus in the left atrial appendage. Cardiac computed tomography showed no coronary artery stenosis, but a pulmonary thrombus in the right pulmonary artery. She underwent an electrophysiology study, and four pulmonary vein (PV) isolations were attempted to treat the paroxysmal AF. A bidirectional PV conduction block was acquired in all PVs despite spontaneous dissociation of PV potential in the right PV. Programmed stimulation following ablation resulted in sinus node dysfunction. After the procedure, the patient did not complain of dizziness and syncope for 72 hours of telemetry monitoring. She was discharged with anticoagulant and did not show any further symptoms for 6 months. Flecainide acetate is a class Ic antiarrhythmics, and its clinical efficacy has been confirmed in several clinical trials. However, it can unmask sinus node dysfunction in asymptomatic patients with paroxysmal AF. Clinicians should screen candidates for sinus nodal diseases when prescribing flecainide.

Impact of diastolic dysfunction in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement

Background

Chronic right-ventricular (RV) pacing can exacerbate heart failure in patients with a low ejection fraction (EF). There is little information on the effects of diastolic dysfunction (DD) in patients with preserved EF undergoing permanent pacemaker (PPM) placement. We aimed to investigate the clinical outcomes in these patients.

Methods

This multicenter, retrospective analysis of PPM use in Chonnam, South Korea, included all patients with preserved EF undergoing transvenous PPM implantation for atrioventricular blockage from 2017 to 2019. Patients were divided into two groups according to DD, which were assessed by including mitral flow velocities (E′ velocity, E/E′ ratio), peak velocity of the tricuspid regurgitant, and left atrial maximum volume index. Composite outcomes were defined as (1) cardiovascular death, and (2) hospitalization by heart failure during the follow-up period.

Results

One hundred sixty-seven patients (66 men; overall mean age, 75.3 ± 11.9 years) were divided into two groups: 125 normal versus 42 DD. Compared with normal subjects, the DD group included older patients (mean age, 79.1 ± 9.9 vs. 74.0 ± 12.3; p = 0.016), and had longer paced QTc interval (pQTc, 168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Fifteen patients were hospitalized and two died. In a Cox proportional regression analysis, DD (hazard ratio [HR], 7.343; 95% confidence interval [CI], 2.035–26.494; p = 0.002) and pQRSd (HR, 1.046; 95% CI, 1.004–1.091; p = 0.033) were independent predictors of composite outcomes.

Conclusion

In patients with DD, RV pacing raised the risk of pacing-induced heart failure despite preserved left-ventricular function. Thus, patients with DD should be monitored intensively.

Clinical outcomes in patients with atrioventricular block undergoing pacemaker: 3-year follow-up

PURPOSE

Left ventricular function can be affected by chronic ventricular pacing. Different right ventricular (RV) pacing sites have shown heterogeneous clinical outcomes. We investigated these factors in patients receiving permanent pacemaker (PPM) implants.

METHODS

This multicenter, retrospective analysis of PPM use in South Korea, included all patients undergoing de novo transvenous PPM implantation for atrioventricular block from 2017 to 2019. Clinical characteristics, 12-lead electrocardiograms, echocardiography, and laboratory parameters were evaluated. Composite outcomes are defined by two coprimary endpoints: (1) hospitalizations and (2) cardiac death by heart failure during follow-up period.

RESULTS

There were 167 patients (66 males; overall mean age 75.3 ± 11.9 years), divided into two groups according to the pacing site: 83 apical RV (RVA) vs. 84 septal RV (RVS). There were no significant baseline differences. Paced QRS duration (pQRSd) increased with RVA (168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Over a median 31-month follow-up, there were 15 hospitalizations and 2 deaths. More patients with RVA were hospitalized or died (16% vs. 5%, respectively; p = 0.049). In Cox proportional regression analysis, pQRSd (hazard ratio [HR] 1.046; 95% confidence interval [CI] 1.004-1.091; p = 0.033), and diastolic dysfunction (HR 7.343; 95% CI 2.035-26.494; p = 0.002) were independent predictors of composite clinical outcomes.

CONCLUSIONS

RVS placement shortened the pQRSd and improved clinical outcomes. However, the determinants of these were pQRSd and diastolic dysfunction. Therefore, clinicians should try to shorten the pQRSd when implanting a PPM, and patients with diastolic dysfunction should be monitored intensively.

Post-operative Atrial Fibrillation Impacts on Outcomes in Transcatheter and Surgical Aortic Valve Replacement

Background: Atrial fibrillation (AF) in severe aortic stenosis (AS) has poor outcomes after transcatheter and surgical aortic valve replacement (TAVR and SAVR, respectively). We compared the incidence of AF after aortic valve replacement (AVR) according to the treatment method and the impact of AF on outcomes.

Methods: We investigated the incidence of AF and clinical outcomes of AVR according to whether AF occurred after TAVR and SAVR after propensity score (PS)-matching for 1 year follow-up. Clinical outcomes were defined as death, stroke, and admission due to heart failure. The composite outcome comprised death, stroke, and admission due to heart failure.

Results: A total of 221 patients with severe AS were enrolled consecutively, 100 of whom underwent TAVR and 121 underwent SAVR. The incidence of newly detected AF was significantly higher in the SAVR group before PS-matching (6.0 vs. 40.5%, P < 0.001) and after PS-matching (7.5 vs. 35.6%, P = 0.001). TAVR and SAVR showed no significant differences in outcomes except in terms of stroke. In the TAVR group, AF history did not affect the outcomes; however, in the SAVR group, AF history affected death (log rank P = 0.038). Post-AVR AF had a worse impact on admission due to heart failure (log rank P = 0.049) and composite outcomes in the SAVR group. Post-AVR AF had a worse impact on admission due to heart failure (log rank P = 0.008) and composite outcome in the TAVR group.

Conclusion: Post-AVR AF could be considered as a predictor of the outcomes of AVR. TAVR might be a favorable treatment option for patients with severe symptomatic AS who are at high-risk for AF development or who have a history of AF because the occurrence of AF was more frequent in the SAVR group.

Screening for Atrial Fibrillation Using a Single Lead ECG Monitoring Device

Atrial fibrillation (AF) is the most common arrhythmia which needs management for stroke prevention. Therefore, it has emphasized the importance of screening for general population to detect AF earlier. We conducted screening for AF in the Chonbuk region in South Korea. Participants who were older than 50 years were enrolled. The screening test used a single lead electrocardiography (ECG) (KardiaBand, AliveCor, CA, USA). Diagnosis of AF was confirmed by electrophysiologists, if the single lead ECG demonstrated AF of more than 30 seconds. We analyzed the prevalence of AF and the characteristics of newly detected AF patients. A total of 2728 participants, 145 (5.3%) participants had already been diagnosed with AF before. The number of screening positive was 55. Among them, 40 participants were confirmed for AF. Male gender and age older than 70 years were the independent risk factors for AF among the screening positive participants. Most of newly detected AF patients were at high risk for stroke which had more than 2 points on the CHA2DS2-VASc score. We followed up with those patients and encouraged them to visit the hospital. As a result, 31 (77.5%) patients started to manage AF. The additional 1.2% of AF was detected by a screening test with a single lead ECG monitor device. Considering most participants of newly detected AF by screening were at high risk for stroke, it was thought that AF was still undertreated. Therefore, screening tests with simple mobile device might be useful for early detection of AF.

Implantable cardioverter defibrillator as a treatment for massive left ventricular fibroma-induced ventricular arrhythmia in a child

Pediatric cardiac tumors are rare. Among these, cardiac fibroma is the second most common. Its clinical manifestations depend on size and location of the tumor and include arrhythmia or obstruction to blood flow. Symptomatic cardiac fibroma is generally treated with surgical resection or cardiac transplantation. We present the case of a 12-year-old boy with a lethal ventricular arrhythmia induced by a remnant tumor that was previously partially resected. An implantable cardioverter defibrillator was inserted as the arrhythmia was resistant to medical treatment. He was discharged in stable condition with an implantable cardioverter defibrillator generator and followed up in the outpatient clinic.

Right Ventricular Longitudinal Conduction Delay in Patients with Brugada Syndrome

BACKGROUND

The mechanism of Brugada syndrome (BrS) is still unclear, with different researchers favoring either the repolarization or depolarization hypothesis. Prolonged longitudinal activation time has been verified in only a small number of human right ventricles (RVs). The purpose of the present study was to demonstrate RV conduction delays in BrS.

METHODS

The RV outflow tract (RVOT)-to-RV apex (RVA) and RVA-to-RVOT conduction times were measured by endocardial stimulation and mapping in 7 patients with BrS and 14 controls.

RESULTS

Patients with BrS had a longer PR interval (180 ± 12.6 vs. 142 ± 6.7 ms, P = 0.016). The RVA-to-RVOT conduction time was longer in the patients with BrS than in controls (stimulation at 600 ms, 107 ± 9.9 vs. 73 ± 3.4 ms, P = 0.001; stimulation at 500 ms, 104 ± 12.3 vs. 74 ± 4.2 ms, P = 0.037; stimulation at 400 ms, 107 ±12.2 vs. 73 ± 5.1 ms, P = 0.014). The RVOT-to-RVA conduction time was longer in the patients with BrS than in controls (stimulation at 500 ms, 95 ± 10.3 vs. 62 ± 4.1 ms, P = 0.007; stimulation at 400 ms, 94 ±11.2 vs. 64 ± 4.6 ms, P = 0.027). The difference in longitudinal conduction time was not significant when isoproterenol was administered.

CONCLUSION

The patients with BrS showed an RV longitudinal conduction delay obviously. These findings suggest that RV conduction delay might contribute to generate the BrS phenotype.

Positive chronotropic effects of theophylline and cilostazol in patients with symptomatic sick sinus syndrome who have declined permanent pacing

Pacemakers are more commonly recommended than theophylline for sick sinus syndrome (SSS) treatment. The positive effects of cilostazol on bradyarrhythmias also have been reported. However, no comparison of cilostazol and theophylline has been previously reported found. We retrospectively enrolled SSS patients, who refused a pacemaker implantation. Theophylline or cilostazol was administered, and the heart rate (HR) was evaluated in 4-8 weeks using a digital sphygmomanometer and the electrocardiogram (ECG). A 200-400 mg of theophylline or 100-200 mg of cilostazol were administered per day in 50 and 30 patients, respectively. The baseline HR was 54.8 ± 13.5 beats per minute (bpm) on using sphygmomanometry and 51.9 ± 11.8 bpm using the ECG. In the theophylline group, the HR increased by 12.0 ± 16.3 bpm by sphygmomanometry (P < 0.001) and 8.4 ± 12.0 bpm by the ECG (P < 0.001). In the cilostazol group, the HR increased by 16.8 ± 13.9 bpm by sphygmomanometry (P < 0.001) and 12.4 ± 13.4 bpm using the ECG (P < 0.001). In 15 of the 50 theophylline patients, the medication was switched to cilostazol. The HR increased from 61.4 ± 13.8 bpm to 64.0 ± 12.6 bpm (P = 0.338). Symptoms such as dyspnea, chest discomfort, dizziness, and syncope significantly improved after the administration of the medications. There were no significant differences in the improvement in the symptoms except for dizziness between the two agents. Cilostazol was as effective as theophylline for increasing the HR in SSS patients.

Radiofrequency catheter ablation without radiation exposure in a 13th week pregnant woman with Wolff-Parkinson-White syndrome

A 36-year-old woman with 12-week gestation visited the emergency department, complaining of palpitations. Her electrocardiography (ECG) demonstrated ventricular pre-excitation combined with atrial fibrillation. The polarity of the delta waves in leads V5, V6, I, and aVL were positive and negative in leads V1, III, and aVF, suggesting that the accessory pathway (AP) was located on the right posterior free wall. She did not want to take any medicine to prevent the tachycardia. Moreover, the shortest pre-excited RR interval during the atrial fibrillation was 200 ms, so we decided to ablate the AP without fluoroscopy. An electrophysiology study was performed with guidance of a 3-dimension (3D) navigation system and intracardiac echocardiography (ICE). We ablated the right free wall AP without fluoroscopy. A follow-up ECG no longer exhibited any delta waves. Even in the early period of pregnancy, catheter ablation might be performed safely using ICE and a 3D navigation system without fluoroscopy. Therefore, it could more often be considered as a therapeutic option in pregnant women without concern for radiation exposure.

Transmural conduction time in an early repolarization syndrome model

In the pathological aspect of J wave syndrome, delayed depolarization is defined as the difference in local conduction velocity of the ventricular myocardium. If polymorphic ventricular tachycardia is induced without local conduction velocity heterogeneity, this contradicts the delayed depolarization theory. In the present study, the transmural conduction time at was evaluated at several transmural locations in a canine early repolarization model. The transmural pseudo-electrocardiogram and endocardial/epicardial action potentials were recorded from coronary-perfused canine left ventricular wedge preparations (n=18). The I_to agonist NS5806 (9-10 µM), Ca²⁺ channel blocker verapamil (2 µM) and acetylcholine (ACh) (2 µM) were used to pharmacologically mimic early repolarization syndrome genotypes. The transmural conduction times were measured at five fixed epicardial unipolar electrodes before and after the perfusion of provocative agents. The transmural conduction time was defined as the time from endocardial stimulation to the maximal negative deflection (dV/dt) of the endocardial electrogram at the unipolar electrode. Polymorphic ventricular tachycardia developed in 14/18 preparations. In the transmembrane action potentials, there was no definite delayed phase 0 upstroke in any induced polymorphic ventricular tachycardia preparations. In all preparations, the transmural conduction time increased significantly after perfusing the I_to agonist NS5806, verapamil and Ach; however, the increase was only 2.6±0.4 msec, and dispersion of the transmural conduction time did not exhibit significant heterogeneity (7.16±0.93 vs. 7.76±1.21 msec; P=0.240). In the early repolarization model, polymorphic ventricular tachycardia was induced without any regional conduction velocity heterogeneity. This finding suggests that local depolarization heterogeneity would not be a major contributor to the generation of ventricular arrhythmia in the early repolarization syndrome wedge preparation model.

Defibrillation threshold testing during implantable cardioverter defibrillator implantation: 5-year follow-up

PURPOSE

Defibrillation threshold (DFT) testing is a routine practice in some Asian countries for patients receiving an implantable cardioverter defibrillator (ICD). However, there are few long-term data about the necessity of intraoperative DFT testing in an Asian population. We investigated the safety of DFT testing and the long-term clinical outcomes in Asian patients undergoing ICD implantation.

METHODS

All patients undergoing de novo transvenous ICD implantation were randomized to undergo periprocedural DFT testing. The study included 67 patients (50 males; 51.5 ± 16.9 years) who underwent ICD implantation with (n = 33) or without (n = 34) intraoperative DFT testing between March 2012 and February 2014. We compared first-shock success, composite safety end points (the sum of complications recorded at 30 days), arrhythmic death, and all-cause mortality.

RESULTS

The baseline clinical characteristics and the procedural-related adverse event rate (3.0% with DFT vs. 0% with non-DFT, p = 0.214) did not differ between groups. The programmed output of the first shock was lower in the DFT testing group (22.9 ± 4.4 J vs. 25.3 ± 5.4 J, p = 0.007). However, there were no significant differences between groups for all-cause mortality (12.1% vs. 17.6%, p = 0.526) or first-shock success rate for ventricular arrhythmia (100% vs. 88.2%, p = 0.471).

CONCLUSIONS

There were no between-group differences in periprocedural safety, complications, and long-term clinical outcomes. Our results suggest that DFT testing in Asian patients allows reduction of the programmed output of the first shock, but does not affect long-term clinical outcomes.

P279 Standard dose of rivaroxaban in Asian patients with atrial fibrillation: 20ms vs.15mg? Off label dose reduction of rivaroxaban should be avoided

Background

Rivaroxaban emerged as potential alternatives to warfarin for the prevention of thromboembolisim in patients with atrial fibrillation (AF). Because of the concern for the risk of major bleeding with rivaroxaban in Asian patients, off label rivaroxaban dose reduction to15mg is common in Asian real-world practice. We aimed to set standard rivaroxaban dose in Asian patients with AF by comparison between on-label rivaroxaban 20mg and off-label reduced rivaroxaban dose 15mg.

Methods

A total of 2,208 consecutive non-valvular AF patients were enrolled between 2011 and 2017. After propensity score matching, both warfarin (n = 804) and rivaroxaban group (n = 804) had comparable baseline characteristics. Rivaroxaban group was further divided into on-label rivaroxaban 20mg group (n = 390) and off-label reduced rivaroxaban 15mg group (n = 333). Efficacy outcome was stroke/systemic embolism. Safety outcome was major bleeding. Primary net clinical benefit (NCB) was defined as the composite of stroke, systemic embolism, major bleeding and all-cause mortality. Secondary NCB was defined as the composite of stroke, systemic embolism and major bleeding. Patients were followed upto one-year or until the first occurrence of any study outcomes.

Results

Both Rivaroxaban groups had comparable efficacy compared to warfarin. However, both on-label rivaroxaban 20mg (hazard ratio [HR] 0.40, 95% confidence interval [CI] 0.18-0.90, p = 0.026) and off-label reduced rivaroxaban 15mg (HR 0.37, 95% CI 0.16-0.88, p = 0.025) significantly reduced major bleeding. There were no differences in efficacy and safety outcomes between on-label rivaroxaban 20mg and off-label reduced rivaroxaban 15mg group. On-label rivaroxaban 20mg significantly reduced primary (HR 0.44, 95% CI 0.25-0.79, p = 0.006) and secondary (HR 0.51, 95% CI 0.27-0.96, p = 0.038) NCBs compared to warfarin. However, off-label reduced rivaroxaban 15mg did not reduce both primary and secondary NCBs.

Conclusion

Off-label rivaroxaban dose reduction to 15mg had no benefit compared to on-label rivaroxaban 20mg. Compared to warfarin, on-label rivaroxaban 20mg significantly improved primary and secondary NCBs, whereas off-label reduced rivaroxaban 15mg did not. Therefore, rivaroxaban 20mg is favorable as standard dose in Asian patients.

P99 Rapid ventricular stimulation induces augmented conduction delay in Brugada syndrome patients

Background

The exact mechanism for Brugada Syndrome (BrS) is still not clear. There are two main physiologic hypotheses that have been suggested: the repolarization and the depolarization disorder models. Right ventricular (RV) activation delay was verified by echocardiography, conduction time in an explanted heart or in computer simulation. Verification of prolonged longitudinal activation time in human RV of only 5 patients of type-1 BrS and 5 controls was reported in 2008.

Methods

Bidirectional longitudinal activation times were assessed between RV outflow tract (RVot) and RV-apex (RVa) by stimulating and mapping RV endocardium in BrS patients. Conduction velocity was calculated considering ventricle size and distance between catheters.

Results

The studies were performed in controls (n = 18) and BrS patients (n = 6). There was no statistical difference in RP interval and QRS duration (PR 146 ± 21.7 vs 167 ± 45.2 ms, p = 0.325; QRS 102 ± 28.2 vs 122 ± 32.2 ms, p = 0.163). There was no difference of longitudinal activation time on stimulation at 500 ms (RVa to RVot: 63 ± 14.3 versus 80 ± 34.2 ms, p = 0.290; RVot to RVa: 50 ± 12.2 versus 76 ± 35.1 ms, p = 0.122). The BrS patients had longer longitudinal activation time on stimulation at 400 ms (RVa to RVot: 61 ± 15.2 versus 87 ± 28.7 ms, p = 0.009; RVot to RVa: 52 ± 11.1 versus 76 ± 35.3 ms, p = 0.029). The difference was not significant when isoproterenol was infused.

Conclusions

BrS patients display bidirectional longitudinal conduction delay when rapid stimulation. These findings support that BrS might be partly attributable to depolarization abnormality.

P1526Pre-dialysis left atrial function assessed by two-dimensional speckle tracking echocardiography as a predictor of upcoming heart failure in hemodialysis patients

Background

Left atrial global longitudinal strain (LA GLS) by 2-dimensional speckle tracking echocardiography is a useful tool to assess LA function and left ventricular (LV) diastolic function. The authors assessed prognostic value of LA GLS, and other diastolic functional parameters in patients undergoing hemodialysis.

Methods

A total of 78 (49 male) patients undergoing hemodialysis who checked echocardiography due to heart failure (HF) symptoms were included for this analysis. Echocardiography wasperformed at the same day of, and before hemodialysis session. Besides conventional echocardiographic measurements, GLS of the LA and the LV were checked and compared. Incidence of rehospitalization due to HF symptoms during mean follow up duration of 381.4±197.5 days was investigated and echocardiographic parameters were compared between patients who experienced rehospitalization and who did not.

Results

16 (20.1%) patients experienced rehospitalization due to HF. HF rehospitalization group had significantly low baseline LV ejection fraction (55.7±7.2 vs. 61.3±7.1%, p=0.006) and LV GLS (14.7±3.4 vs. 18.2±3.9%, p=0.002), while LV geometry (LV end-diastolic volume index and LV wall thickness) did not show significant differences. In HF rehospitalization group, baseline LA function and diastolic function were significantly impaired as reflected by LA GLS (18.8±2.6 vs. 23.8±3.6%, p<0.001), E/E' ratio (20.8±3.3 vs. 15.8±4.6%, p<0.001), and right ventricular systolic pressure (61.4±9.6 vs. 53.4±12.8%, p=0.022). LA end-systolic volume index was not significantly different between the 2 groups. Among various echocardiographic parameters, receiver operation characteristic curve analysis revealed that LA GLS had the strongest power (cutoff value 20.6%, sensitivity 0.813 and specificity 0.790, area under curve 0.849) in prediction of future rehospitalization due to HF.

Predictor of future HF: ROC analysis

Conclusions

The present study demonstrated that functional changes of the LA as measured by LA GLS before hemodialysis session can be used as an echocardiographic parameter to predict future rehospitalization due to HF. Further studies are required to evaluate prognostic value of LA function in predicting other cardiovascular events in hemodialysis patients.

P688Cardiac dysfunction as a predictor of hepatic sinusoidal obstruction syndrome after hematopoietic cell transplantation

Background

Hepatic sinusoidal obstruction syndrome (HSOS) is a well-known fatal complication of hematopoietic cell transplantation (HCT), but the impact of cardiac abnormalities on the occurrence of HSOS has been poorly evaluated. Therefore, the authors investigated whether the structural changes or dysfunction of the heart before HCT is associated with the future occurrence of HSOS.

Methods

A total of 92 patients who underwent HCT were divided into 2 groups; HSOS group (n=11, 6 males, 53.8±15.9 years) vs no HSOS group (n=81, 51 males, 48.6±14.7 years). According to the modified Seattle criteria, HSOS was defined as otherwise unexplained occurrence of 2 or more of the following events within 20 days of HCT; serum total bilirubin >2 mg/dL, hepatomegaly or right upper quadrant pain, sudden weight gain due to fluid accumulation (>2% of baseline body weight). Echocardiography examinations were performed 1 month before HCT, and echocardiographic findings were compared between the groups.

Results

HSOS was developed in 11 patients (12.0%). HSOS group had significantly larger left ventricular end-diastolic volume index (LVEDVI) (65.2±4.9 vs 53.2±6.9 ml/m2, p<0.001) and relatively worse systolic function than no HSOS group (LV ejection fraction: 56.4±3.4 vs 65.1±5.9%, p<0.001, LV global longitudinal strain: −17.9±1.4 vs −20.1±2.0%, p=0.001). LV diastolic functional parameters were also significantly worse in HSOS group than in no HSOS group (E/E' ratio: 11.3±1.8 vs 9.1±2.0, p=0.002, left atrial global longitudinal strain: 27.7±3.3 vs 34.9±5.9%, p<0.001). However, left atrial volume index was not different between the groups (30.8±2.8 vs 29.0±3.3 ml/m2, p=0.078). By receiver operation characteristic curve analysis, among significantly different variables, LVEDVI was the most powerful predictor for HSOS, and the optimal cutoff value was 59.25 mL/m2. (81.8% sensitivity and 77.8% specificity, AUC 0.909).

Predictor of HSOS: ROC analysis

Conclusions

The present study demonstrated that structural changes or dysfunction of the heart are more prevalent in patients with HSOS after HCT and larger LVEDVI, among them, can be a useful predictor of upcoming HSOS. Routine echocardiographic study before HCT would be useful to identify high risk group for HSOS, and the development of HSOS should be carefully monitored in HCT patients with cardiac structural changes or dysfunction on echocardiography.

Impact of Anticoagulation Intensity in Korean Patients with Atrial Fibrillation: Is It Different from Western Population?

BACKGROUND AND OBJECTIVES

Although anticoagulation with warfarin is recommended as an international normalized ratio (INR) of prothrombin time between 2.0 and 3.0 and mean time in the therapeutic range (TTR) ≥70%, little has been proven that universal criteria might be suitable in Korean atrial fibrillation (AF) patients.

METHODS

We analyzed 710 patients with non-valvular AF who took warfarin. INR value and clinical outcomes were assessed during 2-year follow-up. Intensity of anticoagulation was assessed as mean INR value and TTR according to target INR range. Primary net-clinical outcome was defined as the composite of new-onset stroke and major bleeding. Secondary net-clinical outcome was defined as the composite of new-onset stroke, major bleeding and death.

RESULTS

Thromboembolism was significantly decreased when mean INR was over 1.6. Major bleeding was significantly decreased when TTR was over 70% and mean INR was less than 2.6. Mean INR 1.6-2.6 significantly reduced thromboembolism (adjusted hazard ratio [HR], 0.40; 95% confidence interval [CI], 0.19-0.85), major bleeding (HR, 0.43; 95% CI, 0.23-0.81), primary (HR, 0.50; 95% CI, 0.29-0.84) and secondary (HR, 0.45; 95% CI, 0.28-0.74) net-clinical outcomes, whereas mean INR 2.0-3.0 did not. Simultaneous satisfaction of mean INR 1.6-2.6 and TTR ≥70% was associated with significant risk reduction of major bleeding, primary and secondary net-clinical outcomes.

CONCLUSIONS

Mean INR 1.6-2.6 was better than mean INR 2.0-3.0 for the prevention of thromboembolism and major bleeding. However, INR 1.6-2.6 and TTR ≥70% had similar clinical outcomes to INR 2.0-3.0 and TTR ≥70% in Korean patients with non-valvular AF.

Experimental verification of the value of the Tpeak -Tend interval in ventricular arrhythmia inducibility in an early repolarization syndrome model

INTRODUCTION

In patients with early repolarization patterns on ECG, many researchers have studied to find predictors of fatal arrhythmia. However, there are no satisfying clinical predictors. We evaluated the value of the T_peak -T_end interval on pseudo-ECG in canine myocardial wedge preparation models of early repolarization syndrome.

METHODS AND RESULTS

Transmural pseudo-ECG and endocardial/epicardial action potentials were recorded from coronary-perfused canine left ventricular wedge preparations (n = 34). The I_to agonist NS5806 (8-10 µM), the calcium channel blocker verapamil (3 µM) and acetylcholine (2-3 µM) were used to mimic the disease model. A ventricular arrhythmia induction test was performed. QT_peak , QT_end , T_peak -T_end , and T_peak -T_end /QT_end were measured at 15 to 20 minutes after the provocative agent infusion. Polymorphic ventricular tachycardias (pVT) developed in 23 of the 34 preparations (67%). The maximal values of T_peak -T_end and T_peak -T_end /QT_end were recorded just before pVT induction. At baseline, without the provocative agents, T_peak -T_end and T_peak -T_end /QT_end were not different between pVT-induced and pVT-noninduced preparations. The T_peak -T_end of the pVT-induced preparations was longer than that of non-induced preparations (58 ± 26.8 msec vs 33 ± 6.8 msec, P < .001). The T_peak -T_end /QT_end of pVT- induced preparations was larger than that of noninduced preparations (0.220 ± 0.1017 vs 0.128 ± 0.0312, P < .001). The transmural and epicardial dispersion of repolarization of pVT-induced preparations were larger than those of pVT-noninduced preparations. The transmural dispersion of repolarization showed a positive correlation with T_peak -T_end .

CONCLUSION

T_peak -T_end predicted malignant ventricular arrhythmias in early repolarization syndrome models. T_peak -T_end reflects the repolarization heterogeneity of ventricular myocardium.

Real World Comparison of Rivaroxaban and Warfarin in Korean Patients with Atrial Fibrillation: Propensity Matching Cohort Analysis

Rivaroxaban has emerged as a potential alternative to warfarin for the prevention of thromboembolism in patients with atrial fibrillation (AF). However, there has been concern for the risk of major bleeding, especially in Asian patients. We investigated the efficacy and safety of rivaroxaban compared to warfarin in Korean real world practice. A total of 2,208 consecutive non-valvular AF patients were divided into the Warfarin group (n=990) and the Rivaroxaban group (n=1218). Propensity matched 1-year clinical outcomes were compared (Warfarin, n=804; Rivaroxaban, n=804). The efficacy outcome was defined as stroke/systemic embolism (SE). The safety outcome was major bleeding. The primary net clinical benefit (NCB) was defined as the composite of stroke/SE, major bleeding, and all-cause mortality. Secondary, NCB was defined as the composite of stroke, SE, and major bleeding. Rivaroxaban had the similar efficacy in terms of thromboembolic event prevention [hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.37-1.32, p=0.266] compared to warfarin. Rivaroxaban significantly lowered the risk of major bleeding [HR 0.41, 95% CI 0.22-0.76, p=0.004]. Primary NCB was significantly low in the rivaroxaban group [HR 0.54, 95% CI 0.36-0.81, p=0.003]. Secondary NCB was also low in the rivaroxaban group [HR 0.62, 95% CI 0.40-0.99, p=0.041]. Both rivaroxaban 15 mg and 20 mg groups had similar efficacy and significantly lower risks of major bleeding as well as primary and secondary NCB compared to the warfarin group. In patients with non-valvular AF, rivaroxaban had a similar efficacy to warfarin in Korean real world practice. However, rivaroxaban had better safety and net clinical outcomes compared to warfarin.

Predictors of Clinical Outcome in Patients with Angiographically Intermediate Lesions with Minimum Lumen Area Less than 4 mm2 Using Intravascular Ultrasound in Non-Proximal Epicardial Coronary Artery

We investigated predictors of major adverse cardiac events (MACE) with two years after medical treatment for lesions with angiographically intermediate lesions with intravascular ultrasound (IVUS) minimum lumen area (MLA) <4 mm² in non-proximal epicardial coronary artery. We retrospectively enrolled 104 patients (57 males, 62±10 years) with angiographically intermediate lesions (diameter stenosis 30–70%) with IVUS MLA <4 mm² in the non-proximal epicardial coronary artery with a reference lumen diameter between 2.25 and 3.0 mm. We evaluated the incidences of major adverse cardiovascular events (MACE including death, myocardial infarction, target lesion and target vessel revascularizations, and cerebrovascular accident) two years after medical therapy. During the two-year follow-up, 15 MACEs (14.4%) (including 1 death, 2 myocardial infarctions, 10 target vessel revascularizations, and 2 cerebrovascular accidents) occurred. Diabetes mellitus was more prevalent (46.7% vs. 18.0%, p=0.013) and statins were used less frequently in patients with MACE compared with those without MACE (40.0% vs. 71.9%, p=0.015). Independent predictors of MACEs with two years included diabetes mellitus (odds ratio [OR]=3.41; 95% CI=1.43–8.39, p=0.020) and non-statin therapy (OR=3.11; 95% CI=1.14–6.50, p=0.027). Long-term event rates are relatively low with only medical therapy without any intervention, so the cut-off of IVUS MLA 4 mm² might be too large to be applied for defining significant stenosis. The predictors of long-term MACE were diabetes mellitus and statin therapy in patients with angiographically intermediate lesions in non-proximal epicardial coronary artery.

Role of Red Cell Distribution Width in the Relationship between Clinical Outcomes and Anticoagulation Response in Patients with Atrial Fibrillation

Little is known as to why elevated red cell distribution width (RDW) is associated with adverse clinical outcomes in patients with atrial fibrillation (AF). We hypothesized that RDW value might predict the intensity of anticoagulation, resulting in higher adverse events in patients with AF taking warfarin. We analyzed 657 patients with non-valuvular AF who took warfarin. The intensity of anticoagulation was assessed as mean time in the therapeutic range (TTR) and defined TTR ≥60% as an optimal intensity. The primary end-point was the composite of stroke/systemic embolism and major bleeding. The secondary end-point was the composite of stroke/systemic embolism, major bleeding and death. The relationship between the baseline RDW with TTR and clinical outcomes was assessed using categorical variables as quartiles or dichotomous variables. The mean value of TTR decreased as an increment of the RDW (45.2% vs. 44.7% vs. 40.8% vs. 35.2%, p<0.001). Primary and secondary end-points were significantly increased when TTR was less than 60% and RDW was more than 13.6%. Ratio of patients achieving optimal anticoagulation were significantly decreased as an increment of RDW. A RDW of ≥13.6% was a significant predictor for poor anticoagulation control (adjusted Odds ratio [OR] 0.43, 95% confidence interval [CI] 0.23–0.82), stroke (adjusted hazard ratio [HR] 3.86, 95% CI 1.11–13.40), primary (adjusted HR 1.88, 95% CI 1.12–3.16) and secondary end-point (adjusted HR 2.46, 95% CI 1.26–4.81). RDW was negatively associated with TTR in patients with AF. Therefore, RDW might be a useful marker for the prediction of anticoagulation response and clinical outcomes in patients with AF.

Hypoparathyroidism and subclinical hypothyroidism with secondary hemochromatosis

Hemochromatosis is an inherited genetic disorder of iron metabolism which can also occur as a secondary result of iron-overload. It leads to organ damage such as cardiomyopathy, liver cirrhosis, hypogonadism, and diabetes. This paper discusses a case of secondary hemochromatosis associated with repeated transfusions, presenting as asymptomatic hypoparathyroidism and subclinical hypothyroidism with multiple organ involvement. The 29-year-old female, who had severe aplastic anemia, received multiple transfusions totaling approximately 1,400 units of red blood cells over 15 years. During her routine laboratory examination, hypocalcemia was detected with decreased intact parathyroid hormone and increased thyroid stimulating hormone. Serum ferritin, iron, and total iron binding capacity had increased to 27,583.03 ng/mL, 291 µg/dL, and 389 µg/dL, respectively. She had unusually bronze skin and computed tomography revealed iron deposition in the thyroid, liver, and heart. Multiorgan involvement as seen in this case is rare in hemochromatosis associated with secondary transfusions. To the best of the author's knowledge, this is the first case report in Korea of hypoparathyroidism and subclinical hypothyroidism due to iron deposition in the parathyroid and thyroid gland.

Structure determination of new analogues of vardenafil and sildenafil in dietary supplements

New analogues of vardenafil and sildenafil illegally added to dietary supplements were detected by high-performance liquid chromatography (HPLC) analysis with a photodiode array detector (PDA). These compounds were isolated and their structures elucidated by mass spectrometry (MS), infrared (IR) spectroscopy, one- and two-dimensional nuclear magnetic resonance (NMR). One of the new analogues given the trivial name pseudovardenafil (compound 1) was structurally elucidated and shown to be 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-piperidine. It was a vardenafil analogue isolated from a dietary supplement capsule. Compared with vardenafil, the piperidine ring was substituted for the ethylpiperazine group. The second new analogue, trivially named hydroxyhongdenafil (compound 2), was separated from bulk powder used as a raw material for a dietary supplement. The piperazine and phenyl groups were connected through an acetyl group instead of a sulfonyl group, and hydroxyethylpiperazine was substituted for the methylpiperazine of sildenafil. It was structurally elucidated as 5-[2-ethoxy-5-[[4-(2-hydroxyethyl)-1-piperazinyl]acetyl]phenyl]-1,4-dihydro-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one.

Comparison of radioactivity measurements with radionuclide calibrators in the Republic of Korea

Recognizing the importance of comparisons of radionuclide calibrators in nuclear medicine and the need to provide access to activity standards that are traceable to the international measurement system, the Korea Food & Drug Administration (KFDA) as a national secondary standard dosimetry laboratory (SSDL), started a comparison program in 2002. The first two comparisons were conducted with (131)I (71 participants) and (99m)Tc (72 participants). The results indicated that only 61% of reported activities for (131)I and 65% for (99m)Tc were within +/-5% of the correct value. These numbers increased to 84% for (131)I and 83% for (99m)Tc when a +/-10% limit was applied. Follow-up action on those calibrators with results outside the +/-10% limits only produced a small improvement. There was also a marked difference in performance between the various calibrator types used. The results have shown that such comparisons are necessary to improve the quality of the measurements and to identify those radionuclide calibrators that are not functioning correctly.

The cerebrovascular response to traditional acupuncture after stroke

Acupuncture is useful in treating the nausea and vomiting related to chemotherapy, adult postoperative surgery pain and postoperative dental pain. We obtained single-photon emission computed tomography (SPECT) brain perfusion images of six patients with middle cerebral artery occlusion obtained before and after acupuncture and compared the changes in regional cerebral blood flow (rCBF) to those in normal control. Images were obtained before and after acupuncture at six traditional acupoints (LI 4, 10, 11, 15 and 16 and TE5) in the affected arm. The baseline image was subtracted from the postacupuncture image, to produce a subtraction image displaying only voxels with values >2 SD from the mean and those voxels were coregistered to the baseline SPECT or T2-weighted MRI. Similar images were obtained before and after acupuncture of eight normal volunteers. Statistical parametric mapping with a threshold of P =0.001 and a corrected P of 0.05 was performed for group comparison between postacupuncture and baseline SPECT. Focally increased CBF was seen in all patients especially in the hypoperfused zone surrounding the ischaemic lesion, the ipsilateral or contralateral sensorimotor area, or both. Normal subjects showed increased rCBF mainly in the parahippocampal gyrus, premotor area, frontal and temporal areas bilaterally and ipsilateral globus pallidus. Acupuncture stimulation after stroke patients appears to activate perilesional or use-dependent reorganised sites and might be a way of looking at brain reorganisation.

Immunological characterization of 130 kDa phospholipase C-beta 4 isozyme in rat cerebellar Purkinje cells

We have developed a monoclonal antibody, beta4-22-9 that recognizes an epitope on pleckstrin homology (PH) domain (1-136 amino acids) located at the amino terminus of rat 130 kDa phospholipase C-beta4 (PLC-beta4). Tissue distribution of 130 kDa PLC-beta4 was determined with this monoclonal antibody. One hundred and thirty kiloDalton PLC-beta4 was exclusively expressed in the nervous tissues including cerebellum and cerebrum, especially at very high levels in cerebellum. The expression of 130 kDa PLC-beta4 in cerebellum was gradually increased from 5 days after birth to adulthood. In the adult cerebellum, especially high level of 130 kDa PLC-beta4 was localized on the periphery of Purkinje cells in the patch-like pattern. These data implies that 130 kDa PLC-beta4 may a role in cerebellar Purkinje cells.

Intrinsic mutagenicity and electrophilicity of 1-sulfooxy-3-methylcholanthrene: implications for metabolic activation of the carcinogen 3-methylcholanthrene

Hydroxylation of a meso-anthracenic carbon atom with subsequent formation of a reactive ester bearing a good leaving group (e.g., sulfate) has been proposed as a possible biochemical mechanism responsible for DNA binding, mutagenicity and tumorigenicity of 3-methylcholanthrene, one of the most potent carcinogenic polycyclic aromatic hydrocarbons in experimental animals. In support of this supposition, the chemically synthesized sulfuric acid ester, 1-sulfooxy-3-methylcholanthrene (1-SMC) was directly mutagenic in bacteria and covalently bound to DNA without metabolic activation. The intrinsic mutagenicity of this reactive ester was significantly potentiated by addition of extra acetate or chloride anions to the media. Reduced glutathione and ascorbic acid protected against 1-SMC-induced mutagenesis. These findings suggest 1-SMC as a potential ultimate electrophilic and tumorigenic metabolite of 3-methylcholanthrene.

Bioactivation of 5-hydroxymethyl-2-furaldehyde to an electrophilic and mutagenic allylic sulfuric acid ester

5-Hydroxymethyl-2-furaldehyde (HMF), a ubiquitous food contaminant, has been proposed to be metabolically activated through sulfonation of its allylic hydroxyl functional group. In support of this idea, we have found the strong direct mutagenicity of chemically synthesized sulfuric acid ester, 5-sulfooxymethylfurfural (SMF), in Salmonella typhimurium TA104. The intrinsic mutagenicity of this reactive ester was significantly inhibited by glutathione and glutathione S-transferase activity in dialyzed rat liver cytosol. The metabolic formation of SMF was elucidated by enhanced mutagenicity of HMF in the presence of rat hepatic cytosol enriched with the sulfo-group donor, 3'-phosphoadenosine-5'-phosphosulfate (PAPS). The PAPS- and cytosol-dependent mutagenicity of HMF was markedly lessened by sulfotransferase inhibitors such as 2,6-dichloro-4-nitrophenol and dehydroepiandrosterone. These results suggest that HMF can be metabolically activated to an allylic sulfuric acid ester which may play a role as an ultimate electrophilic metabolite in toxification of the parent compound in vivo.