Upper turnaround point in a reentry circuit of the idiopathic left posterior fascicular ventricular tachycardia.

BACKGROUND: The anatomic extent of the reentry circuit in idiopathic left posterior fascicular ventricular tachycardia (LPF-VT) is yet to be fully elucidated. We hypothesized that entrainment mapping could be used to delineate the reentry circuit of an LPF-VT, especially including the upper turnaround point. METHODS: Twenty-three consecutive LPF-VT patients (mean age, 29 ± 9 years, 18 males) were included. We performed overdrive pacing with entrainment attempts at the left bundle branch (LBB) and the left His bundle (HB) region. RESULTS: Overdrive pacing from the LBB region showed concealed fusion in all 23 patients (post-pacing interval [PPI], 322.1 ± 64.3 ms; tachycardia cycle length [TCL], 319.0 ± 61.6 ms; PPI-TCL, 3.1 ± 4.6 ms) with a long stimulus-to-QRS interval (287.9 ± 58.0 ms, approximately 90% of the TCL). Pacing from the same LBB region at a slightly faster pacing rate showed manifest fusion with antidromic conduction to the LBB and minimal in-and-out time to the LBB potential (PPI-TCL, 21.3 ± 13.7 ms). Overdrive pacing from the left HB region showed manifest fusion with a long PPI-TCL (53.9 ± 22.5 ms). CONCLUSIONS: Our pacing study results suggest that the upper turnaround point in a reentry circuit of the LPF-VT may extend to the proximal His-Purkinje conduction system near the LBB region but below the left HB region. The LPF may constitute the retrograde limb of the reentry circuit.

Usefulness of cardiac magnetic resonance images for prediction of sudden cardiac arrest in patients with mitral valve prolapse: a multicenter retrospective cohort study.

BACKGROUND: An association has been identified between mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), and ventricular arrhythmias (VA). This study aimed to elucidate predictive factors for SCA or VA in MVP patients. METHODS: MVP patients who underwent cardiac magnetic resonance (CMR) were retrospectively included. Patients with other structural heart disease or causes of aborted SCA were excluded. Clinical characteristics (sex, age, body mass index, histories of diabetes, hypertension, and dyslipidemia) and electrocardiographic (PR interval, QRS duration, corrected QT interval, inverted T wave in the inferior leads, bundle branch block, and atrial fibrillation), echocardiographic [mitral regurgitation grade, prolapsing mitral leaflet, and right ventricular systolic pressure (RVSP)], and CMR [left atrial volume index, both ventricular ejection fractions, both ventricular end-diastolic and systolic volume indexes, prolapse distance, mitral annular disjunction, systolic curling motion, presence of late gadolinium enhancement (LGE), LGE volume and proportion] parameters were analyzed. RESULTS: Of the 85 patients [age, 54.0 (41.0-65.0) years; 46 men], seven experienced SCA or VA. Younger age and wide QRS complex were observed more often in the SCA/VA group than in the no-SCA/VA group. The SCA/VA group exhibited lower RVSP, more systolic curling motion and LGE, greater LGE volume, and higher LGE proportion. The presence of LGE [hazard ratio (HR), 19.8; 95% confidence interval (CI) 2.65-148.15; P = 0.004], LGE volume (HR 1.08; 95% CI 1.02-1.14; P = 0.006) and LGE proportion (HR 1.32; 95% CI 1.08-1.60; P = 0.006) were independently associated with higher risk of SCA or VA in MVP patients together with systolic curling motion in each model. CONCLUSIONS: The presence of systolic curling motion, high LGE volume and proportion, and the presence of LGE on CMR were independent predictive factors for SCA or VA in MVP patients.

Clinical Implications of Ventricular Repolarization Parameters on Long-Term Risk of Atrial Fibrillation　- Longitudinal Follow-up Data From a General Ambulatory Korean Population.

BACKGROUND: This study investigated 12-lead electrocardiogram (ECG) predictors associated with atrial fibrillation (AF) or flutter (AFL), specifically whether ventricular repolarization abnormalities in surface ECG (i.e., non-specific ST-T abnormalities [NSSTTA], QT prolongation, early repolarization [ER]) were associated with the development of AF or AFL.Methods and Results:This study included 16,793 ambulatory Koreans (mean age 48.2 years, 62.3% male) who underwent medical check-ups at Asan Medical Center in 2002 (NSSTTA, n=1,037 [6.2%]; ER, n=1,493 [8.9%]). The primary outcome was the incidence of ECG-documented AF or AFL. During follow-up, new-onset AF or AFL was documented in 334 subjects (2.0%). The incidence of AF or AFL at the 10-year follow-up was higher in patients with than without NSSTTA (3.5% vs. 1.6%; hazard ratio [HR] 1.79, 95% confidence interval [CI] 1.28-2.50). The QT interval was associated with a higher risk of AF or AFL (HR 1.12 [95% CI 1.07-1.17] per 10 ms), and the risk was even higher in patients with multiple-region NSSTTA (HR 2.30; 95% CI 1.64-3.21) and NSSTTA with QT prolongation (HR 4.06; 95% CI 2.14-7.69). ER was not associated with a higher risk of AF or AFL (HR 1.02; 95% CI 0.71-1.46). CONCLUSIONS: NSSTTA and QT prolongation, but not ER, were associated with a higher risk of future AF or AFL in a general ambulatory population after adjusting for parameters of atrial depolarization.

Association of pericardial effusion after pulmonary vein isolation and outcomes in patients with paroxysmal atrial fibrillation.

BACKGROUND: The clinical implications of pericardial effusion (PE) after catheter ablation for atrial fibrillation (AF) are not well understood. We evaluated the association between newly developed PE after pulmonary vein isolation (PVI) for paroxysmal AF and arrhythmic recurrence. METHODS: From a prospective AF ablation registry, 184 patients (mean age 59 ± 10 years, 65% male) who underwent first-time PV isolation using a smart touch surround flow catheter (Biosense Webster, Diamond Bar, CA) were analyzed. Postablation transthoracic echocardiography (TTE) was performed within 1-3 days after ablation, and the occurrence of PE was assessed. RESULTS: PE developed in 91 patients (49.5%), and most were of minimal severity (minimal, 93.4%; mild, 6.6%). Patients with PE had significantly lower body mass index and underwent cavotricuspid isthmus ablation more frequently. Early arrhythmic recurrence (EAR) (within 3 months) was observed in 28.8% of patients and was not different according to the PE development (PE [+]: 29.7% vs PE [-]: 28.0%; P = .80). During a median follow-up of 696 days, the cumulative rate of the late arrhythmic recurrence (LAR) (after 3 months) was 36.4%, and there was no difference between groups (PE [+]: 36.7% vs PE [-]: 35.1%; P = .988). The only predictor of LAR was EAR, and no echocardiographic parameters showed a significant correlation with LAR. CONCLUSIONS: Minimal or mild PE after PVI for paroxysmal AF is a frequent echocardiographic finding, and it had no significant association with AF recurrence. Routine TTE after AF ablation has no clinical implication.

Incidence and predictors of moderate to severe tricuspid regurgitation after dual-chamber pacemaker implantation.

INTRODUCTION: The incidence and predictors of tricuspid regurgitation (TR) after permanent pacemaker (PM) implantations have not been well evaluated. We attempted to determine TR's natural course and predictors, especially focusing on the influence of atrial fibrillation (AF). METHODS: Data from 530 patients with dual-chamber PMs were evaluated. The main study outcomes were moderate to severe TR and isolated TR (moderate to severe TR without other structural heart diseases [SHDs]) in follow-up echocardiography. RESULTS: Over a median follow-up period of 7.6 years, moderate to severe TR developed in 14.5% patients. Of those, concomitant SHD was observed in 51.9% of patients, and 48.1% presented with isolated TR. A multivariable analysis identified the independent predictors of moderate to severe TR (diabetes mellitus [DM], chronic lung disease, preexisting mild TR, peripheral artery disease, moderate to severe aortic regurgitation, and persistent AF [PeAF]) and isolated TR (DM, preexisting mild TR, and PeAF). PeAF (n = 67, 12.6%) was an independent predictor of both moderate to severe TR (hazard ratio [HR] 2.59, 95% confidence interval [CI]: 1.22-5.51) and isolated TR (HR 4.54, 95% CI: 1.60-12.90). The patients with PeAF exhibited a higher incidence of moderate to severe TR (21.8% vs 12.9% vs 11.6% PeAF, paroxysmal AF, and without AF, respectively) and isolated TR (18.6% vs 6.6% vs 4.2%, respectively) during the follow-up. CONCLUSION: Moderate to severe TR after PM implantations developed with or without the influence of concomitant SHD. Patients with PeAF exhibited a higher risk of moderate to severe TR after PM implantations.

Impact of fasciculoventricular bypass tracts on the diagnosis and treatment of concomitant arrhythmias and cardiac diseases.

BACKGROUND: Fasciculoventricular (FV) bypass tracts (BTs) are the rarest form of ventricular preexcitation. Although they are not involved in clinically significant reentrant tachycardia, they may cause diagnostic and therapeutic confusion if not properly understood. This study aimed to assess the impact of FV BTs on the diagnosis and treatment of concomitant arrhythmias and cardiac diseases. METHODS: Twenty-two patients with FV BTs who underwent electrophysiologic (EP) study were evaluated. The prevalence of concomitant arrhythmias and cardiac diseases in FV BTs was evaluated. The mechanisms of concomitant arrhythmias were determined by EP study and cardiac diseases were diagnosed by echocardiography. RESULTS: One patient had FV BT with complete infra-Hisian atrioventricular (AV) block that mimicked a slow ventricular escape rhythm. Two patients had FV BT with atrial fibrillation or atrial flutter, which was misinterpreted as AV BT requiring emergency DC cardioversion. Eight patients had accompanying AV BTs. In 2 patients with AV BTs, unnecessary RF application was delivered after successful ablation of AV BT because conduction through a FV BT was mistaken for conduction through a residual AV BT. Five patients had no concomitant arrhythmia; however, two of them had hypertrophic cardiomyopathy with symptoms requiring beta-blocker. Patients had not been prescribed beta-blockers to avoid a proarrhythmic response before the EP study because the FV BTs mimicked AV BTs. CONCLUSION: FV BTs were frequently accompanied by AV BTs or other arrhythmias and cardiac diseases. They may cause misdiagnosis and inappropriate therapy and even unnecessary RF delivery when misinterpreted as AV BTs.

Metabolic Syndrome and the Risk of New-Onset Atrial Fibrillation in Middle-Aged East Asian Men.

BACKGROUND: Although the prevalence of both atrial fibrillation (AF) and metabolic syndrome (MetS) has been increasing in East Asia, the association between them is uncertain.Methods and Results:A total of 24,741 middle-aged Korean men without baseline AF were enrolled in a health screening program from January 2003 to December 2008. Among them, 21,981 subjects were evaluated to determine the risk of AF based on baseline MetS status through December 2016. At every visit, the subjects were evaluated for AF using ECG. MetS was defined using the criteria of the International Diabetes Federation and was present in 2,529 subjects (11.5%). Mean (±standard deviation) age was 45.9±5.3 years. During a mean follow-up of 8.7 years, 168 subjects (0.8%) were diagnosed with AF. The age-adjusted and multivariate-adjusted hazard ratios (HR) for MetS with AF were 1.62 (P=0.02) and 1.57 (P=0.03), respectively. Among the components of MetS, central obesity (age-adjusted HR 1.62, P<0.01) and raised blood pressure (age-adjusted HR 1.43, P=0.02) were associated with an increased risk of AF. CONCLUSIONS: MetS is associated with an increased risk of AF in middle-aged East Asian men. Of the components of MetS, central obesity is the most potent risk factor for the development of AF in this population.

Radiofrequency Catheter Ablation Targeting the Vein of Marshall in Difficult Mitral Isthmus Ablation or Pulmonary Vein Isolation.

INTRODUCTION: The ligament of Marshall may hinder the creation of mitral isthmus (MI) block or pulmonary vein (PV) isolation (PVI) in radiofrequency (RF) catheter ablation of atrial fibrillation (AF). We aimed to assess the benefit of RF ablation targeting the vein of Marshall (VOM) in failed cases of MI block or PVI. METHODS AND RESULTS: We reviewed the medical records of patients who underwent RF ablation targeting the VOM after failed MI ablation or left PVI using the conventional method, which included circumferential point-by-point ablation around the PV antrum and carina for PVI, and endocardial MI and epicardial distal coronary sinus (CS) ablation for MI block. The VOM was identified by using selective VOM venography with an external irrigation RF ablation catheter. RF ablation targeting the VOM was performed with RF application at the ostium of the VOM inside the CS or at the endocardial region facing the VOM course. During the set period, CS venography was performed in 42 patients after failure of left PVI (n = 5) or MI block (n = 37). Under CS venography, the VOM was visualized in 22 of 42 patients (MI = 19 and PVI = 3). During selective venography of the VOM, no procedure-related complication was observed. RF application targeting the VOM successfully achieved MI block in 13 patients (68.4%) and PVI in 2 patients (66.7%). CONCLUSION: Selective VOM venography using an irrigated ablation catheter is feasible and safe. RF ablation targeting the VOM may provide additional benefit in failed cases of MI block or PVI.

Variants of Brugada Syndrome and Early Repolarization Syndrome: An Expanded Concept of J-Wave Syndrome.

BACKGROUND: The role of J-waves in the pathogenesis of ventricular fibrillation (VF) occurring in structurally normal hearts is important. METHODS: We evaluated 127 patients who received an implantable cardioverter-defibrillator (ICD) for Brugada syndrome (BS, n = 53), early repolarization syndrome (ERS, n = 24), and patients with unknown or deferred diagnosis (n = 50). Electrocardiography (ECG), clinical characteristics, and ICD data were analyzed. RESULTS: J-waves were found in 27/50 patients with VF of unknown/deferred diagnosis. The J-waves were reminiscent of those seen in BS or ERS, and this subgroup of patients was termed variants of ERS and BS (VEB). In 12 VEB patients, the J/ST/T-wave morphology was coved, although amplitudes were <0.2 mV. In 15 patients, noncoved-type J/ST/T-waves were present in the right precordial leads. In the remaining 23 patients, no J-waves were identified. VEB patients exhibited clinical characteristics similar to those of BS and ERS patients. Phenotypic transition and overlap were observed among patients with BS, ERS, and VEB. Twelve patients with BS had background inferolateral ER, while five ERS patients showed prominent right precordial J-waves. Patients with this transient phenotype overlap showed a significantly lower shock-free survival than the rest of the study patients. CONCLUSIONS: VEB patients demonstrate ECG phenotype similar to but distinct from those of BS and ERS. The spectral nature of J-wave morphology/distribution and phenotypic transition/overlap suggest a common pathophysiologic background in patients with VEB, BS, and ERS. Prognostic implication of these ECG variations requires further investigation.

Incidence of Atrial Tachyarrhythmias in Patients With Early Repolarization Syndrome.

Atrial tachyarrhythmias (ATAs) occur in a significant proportion of Brugada syndrome (BrS) patients and are often an important cause of inappropriate shocks. The aim of this retrospective study was to evaluate the incidence of ATAs and ATA-induced inappropriate shocks in early repolarization syndrome (ERS) patients as compared to BrS patients.We analyzed data from 20 consecutive patients who were diagnosed with ERS and compared them with patients diagnosed with BrS (n = 31). Clinical and ICD interrogation data were collected and analyzed for all events with ICD shocks.Three patients had a history of atrial fibrillation (AF) prior to ICD implantation. One patient had AV reentrant tachycardia and was successfully ablated before ICD implantation. ATAs were newly diagnosed in 4 patients with no prior history of AF. There were no significant differences in gender, age, or left atrial diameter between ATA development. Four (20%) of 20 consecutive patients received inappropriate ICD shocks for ATAs. One suffered from repeat inappropriate shocks triggered by paroxysmal AF and received catheter ablation for AF.ATAs were not infrequent in patients with ERS and seemed to be related to inappropriate ICD therapy. Careful ICD programming is required to reduce ATA-related inappropriate ICD shock in patients with ERS.

Impact of Improved Left Ventricular Systolic Function on the Recurrence of Ventricular Arrhythmia in Heart Failure Patients With an Implantable Cardioverter-Defibrillator.

INTRODUCTION: Data are lacking on the relationship between improved left ventricular ejection fraction (LVEF) and the incidence of ventricular arrhythmia in patients with an implantable cardioverter-defibrillator (ICD) for secondary prevention. The aim of this study was to evaluate the incidence and predictors of improvement in left ventricular (LV) function and determine the impact of improved LVEF on the occurrence of appropriate ICD therapy in patients with reduced LVEF and ICD for secondary prevention. METHODS: In this study, 93 patients who received ICDs for secondary prevention, had an LVEF of < 45%, and underwent echocardiographic follow-up assessment after receiving an ICD were enrolled. RESULTS: The mean patient age was 56.9 ± 13.1 years, the median time of repeat LVEF assessment was 19.7 (10.4-29.7) months, and the mean LVEF was 30.6 ± 8.5%. Of the patients, 58 (62.4%) had nonischemic cardiomyopathy. LV function improved after ICD implantation in 24 (25.8%) of 93 patients. Multivariable logistic regression revealed a short duration from the time of diagnosis of heart failure to ICD implantation and the presence of ventricular fibrillation as significant predictors of improved LV function. The incidence of appropriate ICD therapy was lower in the patients with than in those without LV function improvement. The composite endpoint of all-cause mortality or heart transplant was lower in the patients with than in those without LV function improvement. CONCLUSION: Overall survival was better and the recurrence of ventricular arrhythmia was lower in the patients with improved LV function.

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.

Prospective randomized study to assess the efficacy of site and rate of atrial pacing on long-term progression of atrial fibrillation in sick sinus syndrome: Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) Study.

BACKGROUND: Atrial-based pacing is associated with lower risk of atrial fibrillation (AF) in sick sinus syndrome compared with ventricular pacing; nevertheless, the impact of site and rate of atrial pacing on progression of AF remains unclear. We evaluated whether long-term atrial pacing at the right atrial (RA) appendage versus the low RA septum with (ON) or without (OFF) a continuous atrial overdrive pacing algorithm can prevent the development of persistent AF. METHODS AND RESULTS: We randomized 385 patients with paroxysmal AF and sick sinus syndrome in whom a pacemaker was indicated to pacing at RA appendage ON (n=98), RA appendage OFF (n=99), RA septum ON (n=92), or RA septum OFF (n=96). The primary outcome was the occurrence of persistent AF (AF documented at least 7 days apart or need for cardioversion). Demographic data were homogeneous across both pacing site (RA appendage/RA septum) and atrial overdrive pacing (ON/OFF). After a mean follow-up of 3.1 years, persistent AF occurred in 99 patients (25.8%; annual rate of persistent AF, 8.3%). Alternative site pacing at the RA septum versus conventional RA appendage (hazard ratio=1.18; 95% confidence interval, 0.79-1.75; P=0.65) or continuous atrial overdrive pacing ON versus OFF (hazard ratio=1.17; 95% confidence interval, 0.79-1.74; P=0.69) did not prevent the development of persistent AF. CONCLUSIONS: In patients with paroxysmal AF and sick sinus syndrome requiring pacemaker implantation, an alternative atrial pacing site at the RA septum or continuous atrial overdrive pacing did not prevent the development of persistent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT00419640.

Comparison of the axillary venous approach and subclavian venous approach for efficacy of permanent pacemaker implantation. 8-Year follow-up results.

BACKGROUND: Long-term data on lead complication rates are limited for both the axillary and subclavian venous approaches for permanent pacemaker implantation. METHODS AND RESULTS: We conducted a single-center, retrospective, nonrandomized comparison. We reviewed the patients who had consented to receiving a permanent pacemaker implant. A superficial landmark or radiographic contrast guiding was used for the axillary venous approach, whereas conventional landmarks were used for the subclavian venous approach. From January 1992 to December 2005, we analyzed 1,161 permanent pacemaker leads in 655 patients [subclavian venous approach (group I: 338 patients, 542 leads) and axillary venous approach (group II: 317 patients, 619 leads)]. Baseline characteristics of the patients did not differ. However, DDD-pacemakers and atrial leads were used more often in group II than in group I (94% vs. 62% and 49% vs. 40%, P<0.01). During the 8-year follow-up, lead complication rates were lower in group II (17 leads, 3%) than in group I (31 leads, 6%) (P=0.03), and group II had a better complication-free survival curve than group I with a 49% relative risk reduction in lead complication rates (hazard ratio =0.51; 95% confidence interval, 0.27-0.94; P=0.03). CONCLUSIONS: The axillary venous approach for permanent pacemaker implantation has better long-term efficacy and lower lead complication rates than the subclavian venous approach.

Coronary sinus activation pattern in the differential diagnosis of regular atrial tachyarrhythmias during catheter ablation of atrial fibrillation.

BACKGROUND: Prompt diagnosis and management of atrial tachyarrhythmias (ATAs) during catheter ablation of atrial fibrillation (AF) is still challenging. METHODS AND RESULTS: In 88 patients undergoing catheter ablation of AF, 128 regular ATAs were induced or converted from AF. The coronary sinus activation time (CSAT) around the mitral annulus (MA) was measured as the difference in activation time between the most proximal and distal poles of the coronary sinus (CS) electrodes. Entrainment pacing was performed around the MA, roof area, or cavotricuspid isthmus (CTI) depending on the CSAT result. Mechanisms of tachycardias included macro-reentry around the MA (perimitral atrial flutter [PM-AFL], n=63), roof-dependent AFL (Roof-AFL, n=14), CTI-dependent AFL (CTI-AFL, n=25), and atrial tachycardia (AT, n=26). When the CSAT was ≥ 45 ms, the MA activation sequence was sequential, either proximal to distal or distal to proximal. When the CSAT was <45 ms, the MA activation sequence was mainly non-sequential with converging or diverging patterns. CSAT <45 ms was highly sensitive in ruling out PM-AFL from other left ATAs. When combined with PPI data from the MA, roof area or CTI, PM-, Roof-, CTI-AFL and AT was successfully differentiated with a high predictive accuracy. CONCLUSIONS: A diagnostic algorithm combining CSAT and entrainment pacing is helpful to assess the mechanism of ATAs during catheter ablation of AF.

Long-term comparison of apical versus asymmetric hypertrophic cardiomyopathy.

Although apical hypertrophic cardiomyopathy (HCM) has been considered to be more benign than asymmetric HCM, few studies have directly compared their clinical features. We compared the electrocardiographic data and longterm outcomes between patients with apical HCM versus asymmetric HCM. This retrospective study enrolled 796 patients (243 apical HCM and 553 asymmetric HCM). We assessed long-term all-cause and cardiac mortalities using an inverse probability of treatment weighted (IPTW) method and propensity score matched (PSM) analysis. In patients with asymmetric HCM, QT prolongation, QRS widening, PR prolongation, and pathologic Q wave were significantly more frequent. The incidences of early repolarization were similar (11% in apical and 12% in asymmetric HCM, P = 0.19). The median follow-up duration was 6.5 years. There was a borderline significant difference in overall survival rates between the apical and asymmetric HCM groups (73% versus 69%, log rank P = 0.38, IPTW: P = 0.05, PSM: P = 0.05). Regarding cardiac death, asymmetric HCM was more hazardous than apical HCM (89% versus 77%, log rank P = 0.04, IPTW: P = 0.03, PSM: P = 0.03). There was no electrocardiographic predictor for the long-term outcomes, although beta-blocker use was significantly associated with lower overall death (HR = 0.58, 95% CI = 0.41-0.81) and slightly lower cardiac death (HR = 0.86, 95% CI = 0.55-1.33). The overall survival rate of apical HCM was as high as that of asymmetric HCM, but the cardiac survival rate was significantly lower in patients with asymmetric HCM. Beta-blocker use was associated with better long-term outcomes.

Ablation catheter entrapment by chordae tendineae in the mitral valve during ventricular tachycardia ablation.

We report on the entrapment of an ablation catheter by chordae tendineae in the mitral valve during radiofrequency (RF) ablation of ventricular tachycardia. The entrapped tip had to be removed via open surgery. Great care must be taken when performing radiofrequency ablation around the mitral valve apparatus.

Circadian and seasonal variations of ventricular tachyarrhythmias in patients with early repolarization syndrome and Brugada syndrome: analysis of patients with implantable cardioverter defibrillator.

INTRODUCTION: The circadian and seasonal patterns of ventricular tachyarrhythmia (VTA) in patients with early repolarization syndrome (ERS) have not been determined. We compared the timing of VTAs in patients with ERS and Brugada syndrome (BS). METHODS AND RESULTS: We enrolled patients with ERS (n = 14) and BS (n = 53) who underwent implantable cardioverter defibrillator (ICD) implantation. The timing of VTAs, including cardiac arrest and appropriate shocks, was determined. During follow up of 6.4 ± 3.6 years in the ERS group and 5.0 ± 3.3 years in the BS group, 5 of 14 (36%) ERS and 10 of 53 (19%) BS patients experienced appropriate shocks (P = 0.37). Cardiac arrest showed a trend of nocturnal distribution peaking from midnight to early morning (P = 0.14 in ERS, P = 0.16 in BS). Circadian distribution of appropriate shocks showed a significant nocturnal peak in patients with ERS (P < 0.0001) but a trend toward a nocturnal peak in patients with BS (P = 0.08). There were no seasonal differences in cardiac arrest in patients with ERS and BS. However, patients with ERS showed a seasonal peak in appropriate shocks from spring to summer (P < 0.0001). There was no significant seasonal peak in patients with BS. The timing of VTAs (cardiac arrest plus appropriate shock) showed significant nocturnal distributions in patients with ERS and BS (P < 0.01, respectively). A significant clustering of VTAs was noted from spring to summer (P < 0.01) in patients with ERS, but not in patients with BS (P = 0.42). CONCLUSIONS: Incidence of VTAs showed marked circadian variations with night-time peaks in patients with ERS and BS.

Effects of slow pathway ablation on fast pathway function in patients with atrioventricular nodal reentrant tachycardia: cryo- vs. radiofrequency ablation.

BACKGROUND: In typical atrioventricular nodal reentrant tachycardia, radiofrequency (RF) ablation of the slow pathway (SP) is known to change the effective refractory period of the fast pathway (ERP(FP)) after successful RF ablation of the SP. The purpose of this study was to ascertain the mechanism of the ERP(FP) changes after SP ablation by comparing the results of both cryo- and RF ablation. METHODS AND RESULTS: A total of 112 patients were enrolled prospectively and their electrophysiological properties analyzed before and after successful SP ablation. Patients were grouped into cryoablation (n=54) and RF ablation (n=58) groups and each group was subdivided into complete ablation (CG) and modification (MG) based on the presence of the SP after successful ablation. CG was performed in 64 patients: 30 by cryoablation and 34 by RF ablation. In patients who underwent complete SP ablation, the ERP(FP) was shortened significantly after cryoablation (375 ± 74 vs. 281 ± 39 ms, P<0.01), without significant change in the atrio-His (AH) or sinus cycle length (SCL) interval. Similarly, the ERP(FP) was shortened significantly (358 ± 106 vs. 289 ± 84 ms, P=0.01) also after RF ablation without change in AH or SCL interval. CONCLUSIONS: ERP(FP) shortening was observed after complete SP ablation with both cryo- and RF ablation without significant changes in indices of autonomic activity.

Using the surface electrocardiogram to localize the origin of idiopathic ventricular tachycardia.

The surface electrocardiogram (ECG) is a useful tool to help identify the sites of origin of ventricular tachycardia (VT). Despite such limitations as chest wall deformity and metabolic and drug effects, the analysis of the QRS morphologic patterns and vectors can discern the site of activation of myocardium. There have been described numerous reports about ECG features of idiopathic left- and right-ventricular VT. In this review, we summarized typical ECG characteristics according to the VT sites of origin based on previous reports, with anatomical considerations of the left and right ventricles, including the outflow tracts and epicardium.