Esophageal Thermal Injury after Catheter Ablation for Atrial Fibrillation with High-Power (50 Watts) Radiofrequency Energy

Background and Objectives@#Data regarding the safety of atrial fibrillation (AF) ablation using high-power (50 W) radiofrequency (RF) energy in Asian populations are limited. This study was conducted to evaluate the incidence and pattern of esophageal injury after highpower AF ablation in an Asian cohort. @*Methods@#We searched the prospective AF ablation registry to identify patients who underwent AF ablation with 50 W RF energy using the smart touch surround flow catheter (Biosense Webster, Diamond Bar, CA, USA). Visitag™ (Biosense Webster) was used for lesion annotation with predefined settings of catheter stability (3 mm for 5 seconds) and minimum contact force (50% of time >5 g). All patients underwent upper gastrointestinal endoscopy at 1 or 3 days after the ablation. @*Results@#A total of 159 patients (mean age: 63±9 years, male: 69%, paroxysmal AF: 45.3%, persistent AF: 27.7%, long-standing persistent AF: 27.0%) were analyzed. Initially, 26 patients underwent pulmonary vein isolation with 50 W for 5 seconds at each point. The remaining 133 patients underwent prolonged RF duration (anterior 10 seconds and posterior 6 seconds). The incidence rates of esophageal erythema/erosion and superficial ulceration were 1.3% for each type of the lesion. Food stasis, a suggestive finding of gastroparesis, was observed in 25 (15.7%) patients. There were no cases of cardiac tamponade, stroke, or death. @*Conclusions@#In Asian patients, AF ablations using 50 W resulted in very low rates of mild esophageal complications.

Esophageal Thermal Injury after Catheter Ablation for Atrial Fibrillation with High-Power (50 Watts) Radiofrequency Energy

Background and Objectives@#Data regarding the safety of atrial fibrillation (AF) ablation using high-power (50 W) radiofrequency (RF) energy in Asian populations are limited. This study was conducted to evaluate the incidence and pattern of esophageal injury after highpower AF ablation in an Asian cohort. @*Methods@#We searched the prospective AF ablation registry to identify patients who underwent AF ablation with 50 W RF energy using the smart touch surround flow catheter (Biosense Webster, Diamond Bar, CA, USA). Visitag™ (Biosense Webster) was used for lesion annotation with predefined settings of catheter stability (3 mm for 5 seconds) and minimum contact force (50% of time >5 g). All patients underwent upper gastrointestinal endoscopy at 1 or 3 days after the ablation. @*Results@#A total of 159 patients (mean age: 63±9 years, male: 69%, paroxysmal AF: 45.3%, persistent AF: 27.7%, long-standing persistent AF: 27.0%) were analyzed. Initially, 26 patients underwent pulmonary vein isolation with 50 W for 5 seconds at each point. The remaining 133 patients underwent prolonged RF duration (anterior 10 seconds and posterior 6 seconds). The incidence rates of esophageal erythema/erosion and superficial ulceration were 1.3% for each type of the lesion. Food stasis, a suggestive finding of gastroparesis, was observed in 25 (15.7%) patients. There were no cases of cardiac tamponade, stroke, or death. @*Conclusions@#In Asian patients, AF ablations using 50 W resulted in very low rates of mild esophageal complications.

Clinical outcomes after pulmonary vein isolation using an automated tagging module in patients with paroxysmal atrial fibrillation

Background@#An automated tagging module (VISITAG™; Biosense Webster, Irvine, CA) allows objective demonstration of energy delivery. However, the effect of VISITAG™ on clinical outcomes remains unclear. This study evaluated (1) clinical outcome after AF ablation using VISITAG™ and (2) the prevalence of gaps in the ablation line. @*Methods@#This retrospective analysis included 157 consecutive patients (mean age, 56.7 years; 73.2% men) with paroxysmal atrial fibrillation who underwent successful PVI between 2013 and 2016. Outcomes after the index procedure were compared between those using the VISITAG™ module (VISITAG group, n = 62) and those not using it (control group, n = 95). The primary outcome was recurrence of AF or atrial tachycardia after a blanking period of 3 months. @*Results@#The VISITAG group showed significantly shorter overall procedure time (172.2 ± 37.6 min vs. 286.9 ± 66.7 min, P  15 s,  60% force over time, > 6 g contact force) showed higher recurrence-free survival rate compared with those with gaps (borderline statistical significance, 91.7% vs. 66.0%, P = 0.094). @*Conclusion@#Use of the VISITAG™ module significantly reduced procedure, ablation, and fluoroscopic times with a similar AF/AT recurrence rate compared with the conventional ablation. Clinical implications of minimizing gaps along the ablation line should be evaluated further in the future prospective studies.

Clinical impact of applying strategic programming in patients with implantable cardioverter‑defibrillators beyond reducing inappropriate shocks

Background@#The incidence of inappropriate shocks remains high at 30% in patients with implantable cardioverter-defibrillators (ICDs). This retrospective study sought to examine the efficacy of strategic programming (ICD programming with a long detection interval and high-rate cutoff) in reducing electrical storm, inappropriate shocks, and unexpected hospital visits in patients with ICDs with/without cardiac resynchronization therapy with defibrillator (CRT-Ds). @*Methods@#This was a single tertiary center retrospective study, evaluating the clinical outcomes, especially regarding inappropriate therapies in patients with ICDs or CRT-Ds. Enrolled patients underwent ICD or CRT-D implantations from January 2008 to May 2016. Clinical information was attained by a thorough chart review. @*Results@#We analyzed 155 defibrillator patients from January 2008 to May 2016 (124 patients had ICDs and 31 had CRT-Ds). Since we adopted this strategic programming as a default programming from 2015 implanted ICDs and CRT-Ds, we divided the patients into two groups: devices implanted before 2015 (group A, n = 94) versus implanted after 2015 (group B, n = 61). During a median of 1289 days of follow-up, electrical storms occurred in three patients (eight events) in group B versus 11 (28 events) in group A (P = 0.18); appropriate therapies were delivered in 27 patients (56 events) in group A versus 7 (15 events) in group B (P = 0.72); inappropriate therapies were delivered in 15 patients (21 events) in group A versus 1 with 1 episode in group B (P = 0.03); and 5 unexpected hospitalizations occurred in four patients in group B versus 36 in 24 patients in group A (P = 0.02). @*Conclusion@#The clinical application of strategic programming reduced inappropriate shocks and unexpected hospitalizations in ICD and CRT-D patients.

Long-term Clinical Outcomes of Radiofrequency Catheter Ablation versus Permanent Pacemaker Implantation in Patients with Tachycardia-Bradycardia Syndrome

Background and Objectives@#Pacemaker (PM) implantation is a well-accepted treatment option for patients with paroxysmal atrial fibrillation (AF) and related tachycardiabradycardia syndrome (TBS). Data on the long-term clinical outcomes after radiofrequency catheter ablation (RFCA) or PM implantation are sparse. @*Methods@#The medical records of 217 patients with TBS were retrospectively assessed.Outcomes in patients who underwent RFCA (n=108, 49.8%) were compared to those with PM implantation (n=109, 50.2%). The clinical outcomes were sinus rhythm maintenance, conversion to persistent AF, additional procedure or crossover, and the composite of cardiovascular hospitalization and death. @*Results@#During the follow-up period (mean 3.5±2.0 years), the RFCA group, compared to the PM group, showed better sinus rhythm maintenance (adjusted hazard ratio [aHR], 0.27;95% confidence interval [CI], 0.15–0.46; p=0.002) and less progression to persistent AF (aHR, 0.20; 95% CI, 0.06–0.63; p=0.006). Additional procedure or crossover did not differ significantly between the groups (aHR, 2.07; 95% CI, 0.71–6.06; p=0.185 and aHR, 0.69; 95% CI, 10.8–2.67; p=0.590, respectively). Most RFCA patients (92.6%) did not require pacemaker implantation during long term follow-up period (>3.5 years). The composite endpoint of cardiovascular rehospitalization and death was not significantly different between the groups (aHR, 0.92; 95% CI, 0.50–1.66; p=0.769).Background and Objectives: Pacemaker (PM) implantation is a well-accepted treatment option for patients with paroxysmal atrial fibrillation (AF) and related tachycardiabradycardia syndrome (TBS). Data on the long-term clinical outcomes after radiofrequency catheter ablation (RFCA) or PM implantation are sparse. @*Methods@#The medical records of 217 patients with TBS were retrospectively assessed.Outcomes in patients who underwent RFCA (n=108, 49.8%) were compared to those with PM implantation (n=109, 50.2%). The clinical outcomes were sinus rhythm maintenance, conversion to persistent AF, additional procedure or crossover, and the composite of cardiovascular hospitalization and death. @*Results@#During the follow-up period (mean 3.5±2.0 years), the RFCA group, compared to the PM group, showed better sinus rhythm maintenance (adjusted hazard ratio [aHR], 0.27;95% confidence interval [CI], 0.15–0.46; p=0.002) and less progression to persistent AF (aHR, 0.20; 95% CI, 0.06–0.63; p=0.006). Additional procedure or crossover did not differ significantly between the groups (aHR, 2.07; 95% CI, 0.71–6.06; p=0.185 and aHR, 0.69; 95% CI, 10.8–2.67; p=0.590, respectively). Most RFCA patients (92.6%) did not require pacemaker implantation during long term follow-up period (>3.5 years). The composite endpoint of cardiovascular rehospitalization and death was not significantly different between the groups (aHR, 0.92; 95% CI, 0.50–1.66; p=0.769). @*Conclusions@#RFCA is an effective alternative to PM implantation in patients with TBS.In these patients, successful RF ablation of AF is related to a higher rate of sinus rhythm maintenance compared to PM implantation, and the composite outcome of cardiovascular rehospitalization and death is similar.

Clinical Implications of Preoperative Nonvalvular Atrial Fibrillation with Respect to Postoperative Cardiovascular Outcomes in Patients Undergoing Non-Cardiac Surgery

BACKGROUND AND OBJECTIVES@#Atrial fibrillation (AF) is associated with a higher long-term risk of major cardiovascular events. However, its clinical implications with respect to peri-operative cardiovascular outcomes in patients undergoing non-cardiac surgery is unclear. We tried to examine the association between pre-operative AF and peri-operative cardiovascular outcomes.@*METHODS@#We retrospectively analyzed data from 26,501 consecutive patients who underwent comprehensive preoperative cardiac evaluations for risk stratification prior to receiving non-cardiac surgery at our center. Preoperative AF was diagnosed in 1,098 patients (4.1%), and their cardiovascular outcomes were compared with those of patients without AF. The primary outcome was the rate of major adverse cardiac and cerebrovascular events (MACCE) during immediate post-surgery period (<30 days).@*RESULTS@#Patients with AF were older and had higher proportion of male sex, higher rate of extra-cardiac comorbidities, higher CHA₂DS₂-VASc score, and higher revised cardiac risk index (RCRI) compared with those without AF. The rate of MACCE was significantly higher in AF patients compared to non-AF patients (4.6% vs. 1.2%, p<0.001). Preoperative AF was associated with higher risk of MACCE, even after multivariable adjustment (odds ratio, 2.97; 95% confidence interval, 2.13–4.07, p<0.001). The relative contribution of AF to MACCE was larger in patients with lower RCRI (p for interaction=0.010). The discriminating performance of RCRI was significantly enhanced by addition of AF.@*CONCLUSIONS@#In patients undergoing non-cardiac surgery, preoperative AF was associated with a higher risk of peri-operative cardiovascular outcomes.

Clinical Implications of Preoperative Nonvalvular Atrial Fibrillation with Respect to Postoperative Cardiovascular Outcomes in Patients Undergoing Non-Cardiac Surgery

BACKGROUND AND OBJECTIVES: Atrial fibrillation (AF) is associated with a higher long-term risk of major cardiovascular events. However, its clinical implications with respect to peri-operative cardiovascular outcomes in patients undergoing non-cardiac surgery is unclear. We tried to examine the association between pre-operative AF and peri-operative cardiovascular outcomes.METHODS: We retrospectively analyzed data from 26,501 consecutive patients who underwent comprehensive preoperative cardiac evaluations for risk stratification prior to receiving non-cardiac surgery at our center. Preoperative AF was diagnosed in 1,098 patients (4.1%), and their cardiovascular outcomes were compared with those of patients without AF. The primary outcome was the rate of major adverse cardiac and cerebrovascular events (MACCE) during immediate post-surgery period (<30 days).RESULTS: Patients with AF were older and had higher proportion of male sex, higher rate of extra-cardiac comorbidities, higher CHA₂DS₂-VASc score, and higher revised cardiac risk index (RCRI) compared with those without AF. The rate of MACCE was significantly higher in AF patients compared to non-AF patients (4.6% vs. 1.2%, p<0.001). Preoperative AF was associated with higher risk of MACCE, even after multivariable adjustment (odds ratio, 2.97; 95% confidence interval, 2.13–4.07, p<0.001). The relative contribution of AF to MACCE was larger in patients with lower RCRI (p for interaction=0.010). The discriminating performance of RCRI was significantly enhanced by addition of AF.CONCLUSIONS: In patients undergoing non-cardiac surgery, preoperative AF was associated with a higher risk of peri-operative cardiovascular outcomes.

Assessing Accuracy of Wrist-Worn Wearable Devices in Measurement of Paroxysmal Supraventricular Tachycardia Heart Rate

BACKGROUND AND OBJECTIVES: Wrist-worn wearable devices provide heart rate (HR) monitoring function via photoplethysmography technology. Recently, these devices have been used by patients to measure the HR when palpitation occurs, but few validation studies of these instruments have been conducted. We assessed the accuracy of these devices for measuring a HR. METHODS: This study enrolled 51 consecutive patients with a history of paroxysmal supraventricular tachyarrhythmia (SVT) or paroxysmal palpitations who were scheduled to undergo an electrophysiological study (EPS). Three devices were assessed: Apple Watch Series 2 (Apple), Samsung Galaxy Gear S3 (Galaxy), and Fitbit Charge 2 (Fitbit). Patients were randomly assigned to wear 2 different devices. The HR at baseline and induced SVT were measured during the EPS. After successful ablation of SVT, HR measurements was also done during atrial and ventricular pacing study. RESULTS: The mean patient age was 44.4±16.6 years and 27 patients were male (53%). The accuracy (within ±5 beats per minute [bpm] of an electrocardiogram [ECG] measurement) of the baseline HR measurements was 100%, 100%, and 94%, for Apple, Galaxy, and Fitbit, respectively. The HR during induced SVT ranged from 108 bpm to 228 bpm and the accuracy (within ±10 bpm of an ECG) was 100%, 90%, and 87% for the Apple, Galaxy, and Fitbit, respectively. During pacing study, accuracy of these devices was also acceptable but tended to decrease as the HR increased, and showed differences between the devices. CONCLUSIONS: Wrist-worn wearable devices accurately measure baseline and induced SVT HR. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0002282

Assessing Accuracy of Wrist-Worn Wearable Devices in Measurement of Paroxysmal Supraventricular Tachycardia Heart Rate

BACKGROUND AND OBJECTIVES@#Wrist-worn wearable devices provide heart rate (HR) monitoring function via photoplethysmography technology. Recently, these devices have been used by patients to measure the HR when palpitation occurs, but few validation studies of these instruments have been conducted. We assessed the accuracy of these devices for measuring a HR.@*METHODS@#This study enrolled 51 consecutive patients with a history of paroxysmal supraventricular tachyarrhythmia (SVT) or paroxysmal palpitations who were scheduled to undergo an electrophysiological study (EPS). Three devices were assessed: Apple Watch Series 2 (Apple), Samsung Galaxy Gear S3 (Galaxy), and Fitbit Charge 2 (Fitbit). Patients were randomly assigned to wear 2 different devices. The HR at baseline and induced SVT were measured during the EPS. After successful ablation of SVT, HR measurements was also done during atrial and ventricular pacing study.@*RESULTS@#The mean patient age was 44.4±16.6 years and 27 patients were male (53%). The accuracy (within ±5 beats per minute [bpm] of an electrocardiogram [ECG] measurement) of the baseline HR measurements was 100%, 100%, and 94%, for Apple, Galaxy, and Fitbit, respectively. The HR during induced SVT ranged from 108 bpm to 228 bpm and the accuracy (within ±10 bpm of an ECG) was 100%, 90%, and 87% for the Apple, Galaxy, and Fitbit, respectively. During pacing study, accuracy of these devices was also acceptable but tended to decrease as the HR increased, and showed differences between the devices.@*CONCLUSIONS@#Wrist-worn wearable devices accurately measure baseline and induced SVT HR.TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0002282

Tachyarrhythmia Cycle Length in Appropriate versus Inappropriate Defibrillator Shocks in Brugada Syndrome, Early Repolarization Syndrome, or Idiopathic Ventricular Fibrillation

BACKGROUND AND OBJECTIVES: Implantable cardioverter–defibrillators (ICDs) are indicated in patients with Brugada syndrome (BS), early repolarization syndrome (ERS), or idiopathic ventricular fibrillation (IVF) who are at high risk for sudden cardiac death. The optimal ICD programming for reducing inappropriate shocks in these patients remains to be determined. We investigated the difference in the mean cycle length of tachyarrhythmias that activated either appropriate or inappropriate ICD shocks in these three patient groups to determine the optimal ventricular fibrillation (VF) zone for minimizing inappropriate ICD shocks. SUBJECTS AND METHODS: We selected 41 patients (35 men) (mean age±standard deviation=42.6±13.0 year) who received ICD shocks between April 1996 and April 2014 to treat BS (n=24), ERS (n=9), or IVF (n=8). Clinical and ICD interrogation data were retrospectively collected and analyzed for all events with ICD shocks. RESULTS: Of the 244 episodes, 180 (73.8%) shocks were appropriate and 64 (26.2%) were inappropriate. The mean cycle lengths of the tachyarrhythmias that activated appropriate and inappropriate shocks were 178.9±28.7 ms and 284.8±24.4 ms, respectively (p<0.001). The cutoff value with the highest sensitivity and specificity for discriminating between appropriate and inappropriate shocks was 235 ms (sensitivity, 98.4%; specificity, 95.6%). When we programmed a single VF zone of ≤270 ms, inappropriate ICD shocks were reduced by 70.5% and appropriate shocks were missed in 1.7% of these patients. CONCLUSION: Programming of a single VF zone of ≤270 ms in patients with BS, ERS, or IVF could reduce inappropriate ICD shocks, with a low risk of missing appropriate shocks.

Transvenous Lead Extraction via the Inferior Approach Using a Gooseneck Snare versus Simple Manual Traction

BACKGROUND AND OBJECTIVES: The number of patients with cardiac implantable electronic devices needing lead extraction is increasing for various reasons, including infections, vascular obstruction, and lead failure. We report our experience with transvenous extraction of pacemaker and defibrillator leads via the inferior approach of using a gooseneck snare as a first-line therapy and compare extraction using a gooseneck snare with extraction using simple manual traction. SUBJECTS AND METHODS: The study included 23 consecutive patients (43 leads) who underwent transvenous lead extraction using a gooseneck snare (group A) and 10 consecutive patients (17 leads) who underwent lead extraction using simple manual traction (group B). Patient characteristics, indications, and outcomes were analyzed and compared between the groups. RESULTS: The dwelling time of the leads was longer in group A (median, 121) than in group B (median, 56; p=0.000). No differences were noted in the overall procedural success rate (69.6% vs. 70%), clinical procedural success rate (82.6% vs. 90%), and lead clinical success rate (86% vs. 94.1%) between the groups. The procedural success rates according to lead type were 89.2% and 100% for pacing leads and 66.7% and 83.3% for defibrillator leads in groups A and B, respectively. Major complications were noted in 3 (mortality in 1) patients in group A and 2 patients in group B. CONCLUSION: Transvenous extraction of pacemaker leads via an inferior approach using a gooseneck snare was both safe and effective. However, stand-alone transvenous extraction of defibrillator leads using the inferior approach was suboptimal.

Cardiac Implantable Electronic Device Safety during Magnetic Resonance Imaging

BACKGROUND AND OBJECTIVES: Although magnetic resonance imaging (MRI) conditional cardiac implantable electronic devices (CIEDs) have become recently available, non-MRI conditional devices and the presence of epicardial and abandoned leads remain a contraindication for MRIs. SUBJECTS AND METHODS: This was a single center retrospective study, evaluating the clinical outcomes and device parameter changes in patients with CIEDs who underwent an MRI from June 1992 to March 2015. Clinical and device related information was acquired by a thorough chart review. RESULTS: A total of 40 patients, 38 with a pacemaker (including epicardially located pacemaker leads) and 2 with implantable cardioverter defibrillators, underwent 50 MRI examinations. Among the patients, 11 had MRI conditional CIEDs, while the remaining had non-MRI conditional devices. Among these patients, 23 patients had traditional contraindications for an MRI: (1) nonfunctional leads (n=1, 2.5%), (2) epicardially located leads (n=9, 22.5%), (3) scanning area in proximity to a device (n=9, 22.5%), (4) devices implanted within 6 weeks (n=2, 5%), and (5) MRI field strength at 3.0 Tesla (n=6, 15%). All patients underwent a satisfactory MRI examination with no adverse events during or after the procedure. There were no significant changes in parameters or malfunctioning devices in any patients with CIEDs. CONCLUSION: Under careful monitoring, MRI is safe to perform on patients with non-MRI conditional CIEDs, remnant leads, and epicardially located leads, as well as MRI-conditional devices.

Complications of Cardiac Perforation and Lead Dislodgement with an MRI-Conditional Pacing Lead: a Korean Multi-Center Experience

Medtronic CapSureFix MRI 5086 pacing lead (5086; Medtronic, Inc., Minneapolis, MN, USA) has been reported to be associated with increased cardiac perforation and lead dislodgement. This study aimed to compare the incidence of cardiac perforation and lead dislodgement within 30 days after pacemaker implantation between 5086 MRI lead and previous Medtronic CapSureFix Novus 5076 non-MRI pacing lead. This was a nationwide, multicenter retrospective study in which we compared the incidence of adverse events between 277 patients implanted with 5086 lead and 205 patients implanted with 5076 lead between March 2009 and September 2014. Cardiac perforation within 30 days of pacemaker implantation occurred in 4 patients (1.4%) with the 5086 lead and in no patient with the 5076 lead (P = 0.084). Lead dislodgement occurred in 8 patients (2.9%) with the 5086 lead and in 5 patients (2.4%) with the 5076 lead (P = 0.764). On multivariate logistic regression analysis, age was significantly associated with cardiac perforation. Congestive heart failure and implantation of right atrial (RA) lead at RA free wall or septum were significant factors for the incidence of lead dislodgement and lead revision. The incidence of cardiac perforation and lead dislodgement were not statistically different between the patients with 5086 lead and the patients with 5076 lead. However, careful attention for cardiac perforation may be needed when using the 5086 MRI lead, especially in elderly patients.

Impact of Impaired Renal Function on the Incidence of Atrial Fibrillation following Radiofrequency Ablation of Cavotricuspid Isthmus-Dependent Atrial Flutter

BACKGROUND AND OBJECTIVES: Atrial fibrillation (AF) occurs frequently after successful radiofrequency ablation (RFA) of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL). Renal impairment has been implicated in the development of AF. The purpose of this study is to clarify the impact of impaired renal function on the incidence of AF after RFA of CTI-AFL. SUBJECTS AND METHODS: Between January 2001 and December 2013, 240 non-dialysis patients with no prior history of AF {mean age 55.9+/-15.2 years old; male, 192 (80.0%)} who had undergone successful CTI-AFL ablation were included in the present study. The baseline estimated glomerular filtration rate was calculated, and patients were divided into those with impaired renal function ( or = 60 mL/min/1.73 m2). The incidence of AF was retrospectively analyzed. RESULTS: 69 (28.8%) patients experienced new onset AF during a median follow-up duration of 26 months (inter-quartile, 7-53). The incidence of AF was significantly higher in patients with impaired renal function than in those with preserved renal function {13/25 (52.0%) versus 56/215 (26.0%), log rank p=0.019}. Age, CHADS2 score, impaired renal function, and left atrial diameter were significantly associated with the incidence of AF in univariate Cox regression analysis. Multivariate analysis showed that age was the only significant predictor of AF incidence (hazard ratio, 1.024; 95% confidence interval, 1.004-1.044, p=0.020). CONCLUSION: Patients with impaired renal function may require careful attention for the incidence of new onset AF following successful RFA of CTI-AFL.

Morphological and Electrical Characteristics in Patient with Hypertrophic Cardiomyopathy: Quantitative Analysis of 864 Korean Cohort

PURPOSE: Although several studies have reported the morphological and electrical characteristics in patients with hypertrophic cardiomyopathy (HCM), comparison between asymmetric and apical HCM has not been investigated in a reasonably sized cohort. MATERIALS AND METHODS: Echocardiography and electrocardiography were quantitatively analyzed in patients with HCM in a Korean tertiary referral center. RESULTS: Of 864 patients (mean age 55.4+/-14.2 years, 68.9% men), 255 (29.5%) patients had apical HCM, 553 (64.0%) patients asymmetric HCM, and 56 (6.4%) patients mixed type HCM. In echocardiographic evaluations, about three quarters of patients (75.8%) had left atrial enlargement. Left ventricular (LV) dilatations and systolic dysfunction were observed in 6.1% and 2.4%, respectively. QRS widening, PR prolongation, and pathologic Q wave are frequent in patients with asymmetric HCM, while LV strain is frequent in patient with apical HCM. The prevalence of J-point elevations (9.4% in inferior, 2.2% in lateral leads) were substantially higher than that in general population. Giant negative T wave was observed in 15.0% of total patients (32.2% in apical, 6.2% in asymmetric, 25% in mixed type). There was no significant correlation between the thickness of the apical wall and the amplitude of T wave inversion (r=-0.005, p=0.71). CONCLUSION: In a large cohort of HCM including apical type, repolarization abnormalities, including early repolarization and QT prolongation as well as LV strain, were significantly observed. T wave inversion was not appropriate for screening of HCM and not correlated with apical wall thickness.

Safety and Efficacy of Switching Anticoagulation to Aspirin Three Months after Successful Radiofrequency Catheter Ablation of Atrial Fibrillation

PURPOSE: Although current guidelines recommend continuing the same antithrombotic strategy regardless of rhythm control after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), anticoagulation has a risk of major bleeding. We evaluated the safety of switching warfarin to aspirin in patients with successful AF ablation. MATERIALS AND METHODS: Among 721 patients who underwent RFCA of AF, 608 patients (age, 57.3+/-10.9 years; 77.0% male, 75.5% paroxysmal AF) who had no evidence of AF recurrence at 3 months post-RFCA were included. We compared the thromboembolic and hemorrhagic events in patients for whom warfarin was switched to aspirin (ASA group; n=296) and patients who were kept on warfarin therapy (W group; n=312). RESULTS: There were no significant differences in CHA2DS2-VASc or HAS-BLED scores between the groups. In 30 patients in the ASA group and 37 patients in W group, AF recurred and warfarin was restarted or maintained during the 18.0+/-12.2 months of follow-up. There were no significant differences in thromboembolic (0.3% vs. 1.0%, p=0.342) and major bleeding incidences (0.7% vs. 0.6%, p=0.958) between ASA and W groups during the follow-up period. In the 259 patients with a CHA2DS2-VASc score > or =2, there were no significant differences in thromboembolism (0.8% and 2.2%, p=0.380) or major bleeding incidences (0.8% and 1.4%, p=0.640) between ASA and W groups. CONCLUSION: Switching warfarin to aspirin 3 months after successful RFCA of AF could be as safe and efficacious as long-term anticoagulation even in patients with CHA2DS2-VASc score > or =2. However, strict rhythm monitoring cannot be overemphasized.

Prognosis after Implantation of Cardioverter-Defibrillators in Korean Patients with Brugada Syndrome

PURPOSE: Our study aims to analyze prognosis after implantable cardioverter-defibrillator (ICD) implantation in Korean patients with Brugada syndrome (BrS). MATERIALS AND METHODS: This was a retrospective study of BrS patients implanted with an ICD at one of four centers in Korea between January 1998 and April 2012. Sixty-nine patients (68 males, 1 female) were implanted with an ICD based on aborted cardiac arrest (n=38, 55%), history of syncope (n=17, 25%), or induced ven tricular tachyarrhythmia on electrophysiologic study in asymptomatic patients (n=14, 20%). A family history of sudden cardiac death and a spontaneous type 1 electrocardiography (ECG) were noted in 13 patients (19%) and 44 patients (64%), respectively. RESULTS: During a mean follow-up of 59+/-46 months, 4.6+/-5.5 appropri ate shocks were delivered in 19 patients (28%). Fourteen patients (20%) experienced 5.2+/-8.0 inappropriate shocks caused by supraventricular arrhythmia, lead failure, or abnormal sensing. Six patients were admitted for cardiac causes during follow-up, but no cardiac deaths occurred. An episode of aborted cardiac arrest was a significant predictor of appropriate shock, and the composite of cardiac events in the Cox pro portional hazard model [hazard ratio (95% confidence interval) was 11.34 (1.31-97.94) and 4.78 (1.41-16.22), respectively]. However, a spontaneous type 1 ECG was not a predictor of cardiac events. CONCLUSION: Appropriate shock (28%) and inappropriate shock (20%) were noted during a mean follow-up of 59+/-46 months in Korean BrS patients implanted with an ICD. An episode of aborted cardiac ar rest was the most powerful predictor of cardiac events.

Long-term Prognosis of Left Ventricular Lead

Transvenous left ventricular (LV) lead implantation is on the increase due to cardiac resynchronization therapy (CRT). However, there has been paucity of data on the prognosis of LV lead. Consecutive 32 patients with LV lead for CRT (n=22) or pacemaker (n=10) were subjected. Serial changes in pacing threshold and impedance along with lead-related complications were evaluated. Over 2 yr follow-up, there was no significant change in relative threshold voltage to the initial value (100%, 110%, 89.6%, and 79.6% at baseline, 1, 6, and 24 months respectively, P=0.62) as well as lead impedance (816+/-272, 650+/-178, 647+/-191, and 590+/-185 ohm at baseline, 1, 6, and 24 months respectively, P=0.80). The threshold change was not affected by lead position, lead polarity, and indication of lead implantation. The cumulative rates of lead revision were 6.3% (n=2) and 9.4% (n=3) in 6 month and 2 yr follow-up, respectively. One case of phrenic nerve capture at left lateral decubitus position was detected 1 month after the implantation. However, there were no serious complications over 2 yr period. In conclusion, transvenous LV lead implantation showed favorable long-term prognosis. Pacing parameters remained stable without significant changes over 2 yr follow-up.

Prevalence and Positive Predictive Value of Poor R-Wave Progression and Impact of the Cardiothoracic Ratio

BACKGROUND AND OBJECTIVES: Poor R-wave progression (PRWP) is a common electrocardiographic diagnosis. However, the diagnostic usefulness of PRWP for coronary artery disease (CAD) and the plausible explanation for subjects with normal heart function are unclear. SUBJECTS AND METHODS: We included 20,739 subjects who had routine medical examinations and applied the commonly used criteria (R-waves in V3 or V4 < or =2 mm) and the Marquette criteria in the current study. Subjects with PRWP by the Marquette criteria, but with no evidence of specific causes, were identified. Healthy age- and gender-matched controls were selected randomly for comparing cardiothoracic ratios. RESULTS: The commonly used criteria in practice were met by 372 of the 20,739 subjects (1.8%). The Marquette criteria were met by 96 subjects (0.5%), and 82 of who agreed to medical evaluation. Five subjects had known CAD and only one subject was shown to have a silent myocardial infarction by additional testing. Therefore, the positive predictive value of PRWP for CAD was 7.3% (6/82) based on the Marquette criteria. As compared with the control group, the subjects with PRWP had a significantly low cardiothoracic ratio (0.425 vs. 0.445, p<0.05), especially among the male group (0.454 vs. 0.407, p=0.02). CONCLUSION: The positive predictive value of PRWP for CAD in the general population is so low that additional tests for diagnosis may be unreasonable. In addition, a low cardiothoracic ratio could be a plausible explanation of PRWP in subjects without any identifiable cause.

Simple Method of Counterclockwise Isthmus Conduction Block by Comparing Double Potentials and Flutter Cycle Length

BACKGROUND AND OBJECTIVES: Local wide split double potentials are used as a parameter to determine complete conduction block during cavotricuspid isthmus ablation in patients with isthmus dependent atrial flutter. However, delayed slow conduction in that region can sometimes be very difficult to differentiate from complete block. Flutter cycle length (FCL) can be used to confirm isthmus conduction block, because FCL is a measure of conduction time around the tricuspid annulus (TA). This study was designed to determine which degree of splitting of the local electrograms is adequate to confirm complete isthmus block, using FCL as a reference. SUBJECTS AND METHODS: Cavotricuspid isthmus (CTI) ablation was performed in fifty consecutive patients. The interval between the pacing stimulus on the lateral side of the CTI and the first component of the double potentials on the block line (SD1) corresponded to the counterclockwise conduction time. The interval between the pacing stimulus and second component (SD2) represented the clockwise conduction time to the contralateral side of the ablation line. SD1 and SD2 were measured before and after complete isthmus block. RESULTS: An SD1+SD2 reaching 90% of the FCL identified the counterclockwise isthmus conduction block with 94% sensitivity and 100% specificity. CONCLUSION: If the sum of SD1 and SD2 following isthmus ablation was close to the FCL, complete conduction block was predicted with high diagnostic accuracy and positive predictive value for at least counterclockwise conduction.