Different responses to exercise between Andersen-Tawil syndrome and catecholaminergic polymorphic ventricular tachycardia.

Aims: Andersen-Tawil Syndrome (ATS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are both inherited arrhythmic disorders characterized by bidirectional ventricular tachycardia (VT). The aim of this study was to evaluate the diagnostic value of exercise stress tests for differentiating between ATS and CPVT. Methods and results: We included 26 ATS patients with KCNJ2 mutations from 22 families and 25 CPVT patients with RyR2 mutations from 22 families. We compared the clinical and electrocardiographic (ECG) characteristics, responses of ventricular arrhythmias (VAs) to exercise testing, and the morphology of VAs between ATS and CPVT patients. Ventricular arrhythmias were more frequently observed at baseline in ATS patients compared with CPVT patients [the ratio of ventricular premature beats (VPBs)/sinus: 0.83 ± 1.87 vs. 0.06 ± 0.30, P = 0.01]. At peak exercise, VAs were suppressed in ATS patients, whereas they were increased in CPVT patients (0.14 ± 0.40 vs. 1.94 ± 2.71, P < 0.001). Twelve-lead ECG showed that all 25 VPBs and 15 (94%) of 16 bidirectional VTs were right bundle branch block (RBBB) morphology in ATS patients, whereas 19 (86%) of 22 VPBs had left bundle branch block (LBBB), and 12 (71%) of 17 bidirectional VT had LBBB and RBBB morphologies in CPVT patients. Conclusion: In patients with ATS, VAs with RBBB morphology were frequently observed at baseline and suppressed at peak exercise. In contrast, exercise provoked VAs with mainly LBBB morphology in patients with CPVT. In adjunct to clinical and baseline ECG assessments, exercise testing might be useful for making the diagnosis of ATS vs. CPVT, both characterized by bidirectional VT.

Persistent tachycardia within isolated pulmonary veins during atrial fibrillation ablation.

During circumferential pulmonary vein (PV) isolation for ongoing atrial fibrillation (AF), distinguishing passive conduction to the pulmonary vein (PV) from rapid PV arrhythmia in the isolated PV is difficult. Hence, the purpose of this study is to investigate both the feasibility of distinguishing the PV tachycardia after circumferential PV isolation and the electrophysiological characteristics of these tachycardia. Among 178 consecutive patients who underwent circumferential PV isolation during ongoing AF, fibrillatory PV converted to a regular cycle length PV tachycardia independent of the atrial rhythm (=independent PV tachycardia) in 13 PVs among 12 (7%) patients. We classified independent PV tachycardia according to 3 different atrial rhythms: sinus rhythm (type 1, n = 2), atrial tachycardia (type 2, n = 4), and AF (type 3, n = 6). independent PV tachycardia was observed in 3 right PV and 10 left PV (P = 0.0864). There were 10 mappable independent PV tachycardia, in which 8 were focal and 2 were macroreentrant tachycardia. i-PVT can be diagnosed in a small number of patients who underwent circumferential PV isolation during AF. The main mechanism or independent PV tachycardia was focal tachycardia mainly in the left PV.

The Occurrence of Implantable Cardioverter Defibrillator Therapies After Generator Replacement in Patients Who No Longer Meet Primary Prevention Indications.

INTRODUCTION: At the time of generator replacement, after ICD implantation for primary prevention, many patients may no longer meet implantation criteria. We investigated the occurrence of ICD therapy after generator replacement in patients initially implanted ICD for primary prevention. METHODS: Patients from 3 hospitals undergoing ICD generator replacement, who were initially implanted for primary prevention, were retrospectively evaluated for occurrence of appropriate ICD therapy after generator replacement. Patients were categorized as to whether or not they had appropriate ICD therapy during their first battery life, and by their left ventricular ejection fraction (LVEF) before generator replacement. RESULTS: Data from 168 patients were analyzed, with average follow-up after generator replacement of 41.2 ± 26.5 months. Seventy-six (45.2%) patients had ventricular arrhythmia episodes (>180 beats per minutes) and 63 (37.5%) received appropriate ICD therapy during the first battery life. Among 105 patients without ICD therapy before generator replacement, those with an LVEF ≤35% before ICD replacement had higher occurrence of ICD therapy after generator replacement than patients with an LVEF ≥36%. Patients who no longer met primary prevention ICD indications (no ICD therapy and LVEF ≥36% before generator replacement) showed a lower risk for ICD therapy after generator replacement (11.6% over 5-year follow-up). CONCLUSIONS: In patients without ICD therapy before generator replacement, low LVEF (≤35%) contributed to future ICD therapy. In patients initially undergoing ICD implantation for primary prevention, history of ICD therapy during the first battery life and LVEF should be utilized for risk stratification at the time of generator replacement.

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) Associated With Ryanodine Receptor (RyR2) Gene Mutations　- Long-Term Prognosis After Initiation of Medical Treatment.

BACKGROUND: The long-term prognosis of cardiac ryanodine receptor (RyR2) positive catecholaminergic polymorphic ventricular tachycardia (CPVT) patients after initiation of medical therapy has not been well investigated. This study aimed to assess the recurrence of fatal cardiac event after initiation of medical therapy inRyR2-positive CPVT patients. METHODS AND RESULTS: Thirty-fourRyR2-positive CPVT patients with a history of cardiac events were enrolled. All patients had medical treatment initiated after the first symptom or diagnosis. Exercise stress tests (ESTs) were performed to evaluate the efficacy of the medical therapy. Even after the initiation of medical therapy, high-risk ventricular arrhythmias (VAs), including premature ventricular contraction couplets, bigeminy, and ventricular tachycardia, were still induced in the majority of patients (80.6%). During 7.4 years of follow-up after the diagnosis, 7 of the 34 (20.6%) patients developed fatal cardiac events. Among those 7 patients, 6 (85.7%) were not compliant with either exercise restriction or medication therapy at the time of the events. CONCLUSIONS: Even after initiation of medical treatment, high-risk VAs were induced during EST in mostRyR2-positive CPVT patients. Most fatal recurrent cardiac events occurred in patients who were noncompliant with exercise restriction and/or medical therapy. Medical management including strict exercise restriction should be emphasized to prevent recurrent cardiac event in mostRyR2-positive CPVT patients. (Circ J 2016; 80: 1907-1915).

Pocket infections of cardiac implantable electronic devices treated by negative pressure wound therapy.

AIMS: Managing an infection of the pocket of a cardiac implantable electronic device (CIED) is frequently challenging. The wound is often treated with a drain or wet-to-dry dressings that allow healing by secondary intention. Such treatment can prolong the hospital stay and can frequently result in a disfiguring scar. Negative pressure wound therapy (NPWT) has been frequently used to promote the healing of chronic or infected surgical wounds. Here we describe the first series of 28 patients in which NPWT was successfully used to treat CIED pocket infections. METHODS AND RESULTS: After removal of the CIED and debridement of the pocket, a negative pressure of 125 mmHg continuously applied to the wound through an occlusive dressing. Negative pressure wound therapy was continued for a median of 5 days (range 2-15 days) and drained an average of 260 mL sero-sanguineous fluid (range 35-970 mL). At the conclusion of NPWT, delayed primary closure of the pocket was performed with 1-0 prolene mattress sutures. The median length of stay after CIED extraction was 11.0 days (range 2-43 days). Virtually all infected pockets healed without complications and without evidence of recurrent infection over a median follow-up of 49 days (range 10-752 days). One patient developed a recurrent infection when NPWT was discontinued prematurely and a new device was implanted at the infected site. CONCLUSION: We conclude that NPWT is a safe and effective means to promote healing of infected pockets with a low incidence of recurrent infection and a satisfactory cosmetic result.

Utility and safety of temporary pacing using active fixation leads and externalized re-usable permanent pacemakers after lead extraction.

AIMS: After extraction of an infected cardiac implantable electronic device (CIED) in a pacemaker-dependent patient, a temporary pacemaker wire may be required for long periods during antibiotic treatment. Loss of capture and under sensing are commonly observed over time with temporary pacemaker wires, and patient mobility is restricted. The use of an externalized permanent active-fixation pacemaker lead connected to a permanent pacemaker generator for temporary pacing may be beneficial because of improved lead stability, and greater patient mobility and comfort. The aim of this study was to investigate the efficacy and safety of a temporary permanent pacemaker (TPPM) system in patients undergoing transvenous lead extraction due to CIED infection. METHODS AND RESULTS: Of 47 patients who underwent lead extraction due to CIED infection over a 2-year period at our centre, 23 were pacemaker dependent and underwent TPPM implantation. A permanent pacemaker lead was implanted in the right ventricle via the internal jugular vein and connected to a TPPM generator, which was secured externally at the base of the neck. The TPPM was used for a mean of 19.4 ± 11.9 days (median 18 days, range 3-45 days), without loss of capture or sensing failure in any patient. Twelve of 23 patients were discharged home or to a nursing facility with the TPPM until completion of antibiotic treatment and re-implantation of a new permanent pacemaker. CONCLUSION: External TPPMs are safe and effective in patients requiring long-term pacing after infected CIED removal.

Gender difference in coronary sinus anatomy and left ventricular lead pacing parameters in patients with cardiac resynchronization therapy.

BACKGROUND: Recent studies have suggested better outcomes from cardiac resynchronization therapy (CRT) in women. Gender differences in coronary sinus (CS) anatomy and left ventricular (LV) lead parameters in patients undergoing CRT, however, have not been well studied. METHODS AND RESULTS: Two hundred and twenty-three consecutive patients, undergoing CRT at the University of California in San Diego Medical Center from 2003 to 2011 were included in this study. The location of the LV lead was assessed on coronary venography and chest X-ray recorded at the time of device implantation. Optimal LV lead position was defined as either mid-lateral or posterolateral LV wall. The relationship between LV lead position (optimal or non-optimal position) and LV lead parameters at completion of implant were compared between genders. No statistically significant gender differences were noted in baseline characteristics. LV lead implantation was successful in 217 patients (97.3%). Lateral or posterolateral CS branches were unavailable in more women than men (26.3% vs. 10.8%, P=0.011). Women had a higher LV lead pacing threshold than men (P=0.003) and gender was an independent risk factor of high LV lead pacing threshold (P=0.008). CONCLUSIONS: Women had an anatomical disadvantage for LV lead placement and had higher LV lead pacing threshold compared to men. Implanting physicians should be aware of gender differences during LV lead placement in order to maximize CRT benefits.

Successful slow pathway ablation in a patient with a rare unroofed type coronary sinus.

We report a case of atrioventricular nodal reentrant tachycardia coexistent with a coronary sinus (CS) anomaly. During a standard electrophysiological study, the CS could not be cannulated despite several attempts. A persistent left superior vena cava angiogram through the left brachial vein confirmed an unroofed type CS. Successful slow pathway ablation from the right posterior paraseptum lesion was achieved using an anatomical approach.

Abrupt heart rate fallings in a patient with biventricular pacing: latent risk for exacerbation of heart failure.

This case report describes abrupt heart rate fallings below the lower pacing rate limit in a patient with cardiac resynchronization therapy (CRT). Interrogated information including stored episodes or data regarding the lead did not show any device problems and only simultaneous intracardiac electrogram revealed the cause, T-wave oversensing during biventricular pacing. At this moment, CRT has become an established modality for patients with severe heart failure. However, bradycardia below the lower rate limit during biventricular pacing due to T-wave oversensing would exacerbate heart failure in patients with CRT. We should notice this latent risk and correct the malfunction immediately.

Clinical effect of implantable cardioverter defibrillator replacements: when should you resume driving after an implantable cardioverter defibrillator replacement?

BACKGROUND: The intervals of the driving restrictions after an implantable cardioverter defibrillator (ICD) replacement vary across the different countries around the world. However, little is known regarding the appropriate duration for driving restrictions after an ICD replacement. The aim of this study was to investigate the clinical effect of ICD replacements and to elucidate when to resume driving an automobile after an ICD replacement. METHODS AND RESULTS: The study reviewed 139 consecutive patients with an ICD replacement in order to evaluate the incidence of ICD therapies before and after ICD replacements, and to assess the time-dependence of the ICD therapies after the ICD replacement. There was no significant difference in the incidence of ICD therapies delivered during durations of 3 months and 6 months before and after the ICD replacement (P=0.28, and 1.0, respectively). ICD therapies after the replacements were observed in 8.6% of the patients who were legally eligible to drive according to the Japanese guidelines at 1 year, and that was associated with a relatively low annual risk of death or injury to others. CONCLUSIONS: Implantable cardioverter defibrillator replacements did not affect the future ICD therapies under similar algorithms. The appropriate interval for driving restrictions after an ICD replacement is recommended to be a week or so, with a system integrity check performed before resumption of driving.

Occurrence, mortality and predictors of complicated cardiac perforation in patients with CRT-D: Based on the National Inpatient Sample registry.

BACKGROUND: Cardiac Resynchronization Therapy Defibrillator (CRT-D) has been one of the most important therapies for patients with cardiomyopathy over the last decades. Cardiac perforation occurs infrequently but can be fatal. The occurrence of cardiac perforation after CRT-D implantation has not been studied well. The aim of study is to investigate the occurrence, mortality and predictors of cardiac perforation in patients receiving CRT-D during the index hospitalization. METHODS: Data were obtained from the National Inpatient Sample, the largest all-player inpatient dataset in the United States. Patients who received CRT-D from 2002 to 2012 were identified using ICD-9 codes. Multivariate analyses were used to identify predictors of cardiac perforation. Complications including in-hospital death and cardiac perforation were identified using ICD-9 codes. RESULTS: A total of 77,827 patients with CRT-D implantation were included into our analysis. After the CRT-D implantation, the in-hospital and rate of cardiac perforation was between 0.24 and 0.48% and had increased significantly (p = 0.02). Although occurrence of cardiac perforation is rare (0.32%), the mortality was 10.6% among those patients with cardiac perforation. In Multivariate analysis identified female as independent risk factors for cardiac perforation (OR: 2.628, 95% CI 1.926-3.585, p < 0.0001). CONCLUSION: Despite rapid progress of the tools and skills for CRT-D implantation, the occurrence of cardiac perforation has not improved. While cardiac perforation is rare, it carries the highest rate of mortality, especially in female patients. Implanting physicians should be familiar with the comorbidities and patient demographics that put them at a higher risk for complications.

Cardiac Resynchronization Defibrillator Therapy for Nonspecific Intraventricular Conduction Delay Versus Right Bundle Branch Block.

BACKGROUND: The benefits of cardiac resynchronization therapy (CRT) in patients with non-left bundle branch block (LBBB) conduction abnormality have not been fully explored. OBJECTIVES: This study sought to evaluate clinical outcomes among Medicare-aged patients with nonspecific intraventricular conduction delay (NICD) versus right bundle branch block (RBBB) in patients eligible for implantation with a CRT with defibrillator (CRT-D). METHODS: Using the National Cardiovascular Data Registry implantable cardioverter-defibrillator (ICD) registry data between 2010 and 2013, the authors compared outcomes in CRT-eligible patients implanted with CRT-D versus ICD-only therapy among patients with NICD and RBBB. Also, among all CRT-D-implanted patients, the authors compared outcomes in those with NICD versus RBBB. Survival curves and multivariable adjusted hazard ratios (HRs) were used to assess outcomes including hospitalization and death. RESULTS: In 11,505 non-LBBB CRT-eligible patients, after multivariable adjustment, among patients with RBBB, CRT-D was not associated with better outcomes, compared with ICD alone, regardless of QRS duration. Among patients with NICD and a QRS ≥150 ms, CRT-D was associated with decreased mortality at 3 years compared with ICD alone (HR: 0.602; 95% confidence interval [CI]: 0.416 to 0.871; p = 0.0071). Among 5,954 CRT-D-implanted patients, after multivariable adjustment NICD compared with RBBB was associated with lower mortality at 3 years in those with a QRS duration of ≥150 ms (HR: 0.757; 95% CI: 0.625 to 0.917; p = 0.0044). CONCLUSIONS: Among non-LBBB CRT-D-eligible patients, CRT-D implantation was associated with better outcomes compared with ICD alone specifically in NICD patients with a QRS duration of ≥150 ms. Careful patient selection should be considered for CRT-D implantation in patients with non-LBBB conduction.

Prognostic significance of early repolarization in inferolateral leads in Brugada patients with documented ventricular fibrillation: a novel risk factor for Brugada syndrome with ventricular fibrillation.

BACKGROUND: Little is known about the clinical and prognostic impact of early repolarization (ER) on patients with Brugada syndrome (BrS), especially those with documented ventricular fibrillation (VF). OBJECTIVE: To investigate the prevalence and prognostic significance of ER in inferolateral leads in patients with BrS and documented VF. METHODS: We investigated 10 different 12-lead electrocardiograms (ECGs) recorded on different days to identify the presence of ER, which was defined as J-point elevation ≥0.1 mV in inferior (II, III, aVF) or lateral leads (I, aVL, V4-V6), in 49 individuals (46 men; age 46 ± 13 years) with a type 1 ECG of BrS and previous history of VF. RESULTS: ER was observed persistently (in all ECGs) in 15 patients (31%; P group), intermittently (in at least one but not in all ECGs) in 16 patients (33%; I group), and not observed in 18 patients (37%; N group), yielding an overall ER incidence of 63% (31/49). During the follow-up period (7.7 years), recurrence of VF was documented in all 15 patients (100%) in the P group, and less in 12 patients (75%) in the I group and in 8 patients (44%) in the N group. The P group showed a worse prognosis than N group (P = .0001) by Kaplan-Meier analysis. Either persistent or intermittent ER in an inferolateral lead was an independent predictor of fatal arrhythmic events (hazard ratio 4.88, 95% confidence interval 2.02-12.7, P = .0004; and hazard ratio 2.50, 95% confidence interval 1.03-6.43, P = .043, respectively). CONCLUSION: The prevalence of ER in inferolateral leads was high and an especially persistent form of ER was associated with a worse outcome in BrS patients with documented VF.

Significance of non-type 1 anterior early repolarization in patients with inferolateral early repolarization syndrome.

OBJECTIVES: The aim of this study was to investigate the significance of non-type 1 anterior early repolarization (NT1-AER) combined with inferolateral early repolarization syndrome (ERS). BACKGROUND: Inferolateral ERS might be a heterogeneous entity, although it excludes type 1 Brugada syndrome (BS). METHODS: Of 84 patients with spontaneous ventricular fibrillation, 31 ERS patients were divided into 2 groups. The ERS(A)-group consisted of inferolateral ER and NT1-AER--that is, notching or slurring with J-wave ≥ 1 mm at the end of QRS to early ST segment in any of V1 to V3 leads, in which the ST-T segment did not change to a coved pattern in the standard and high costal (second and third) electrocardiographic recordings even after drug provocation tests (n = 12). The other, ERS(B)-group, showed only inferolateral ER (n = 19). Clinical characteristics and outcomes were compared between the ERS groups, 40 patients with type-1 BS (BS-group), and 13 patients with idiopathic ventricular fibrillation lacking J-wave (IVF-group). RESULTS: Ventricular fibrillation occurred during sleep or near sleep in 10 of 12 patients in ERS(A)-group and in 22 of 40 patients in BS-group but in 2 of 19 patients in ERS(B)-group and in 1 of 13 patients in IVF-group (ERS[A] vs. ERS[B], p < 0.0001). Ventricular fibrillation recurrence was significantly higher in ERS(A)-group (58%), particularly in patients with J waves in the high lateral lead, and BS-group (55%), compared with ERS(B)-group (11%) and IVF-group (15%) (ERS[A] vs. ERS[B], p = 0.012). CONCLUSIONS: Inferolateral ERS comprises heterogeneous ER subtypes with and without NT1-AER. Coexistence of NT1-AER was a key predictor of poor outcome in patients with ERS.

Effect of sodium-channel blockade on early repolarization in inferior/lateral leads in patients with idiopathic ventricular fibrillation and Brugada syndrome.

BACKGROUND: A high incidence of early repolarization (ER) pattern in the inferolateral leads has been reported in patients with idiopathic ventricular fibrillation (IVF). Brugada syndrome (BS) is characterized by J-point or ST-segment elevation in the right precordial leads and ventricular fibrillation, and some patients with BS also have ER in the inferolateral leads. OBJECTIVE: To compare the clinical characteristics and effects of sodium-channel blockade on ER between IVF patients with ER (early repolarization syndrome [ERS]) and BS patients with or without ER. METHODS: Fourteen patients with ERS and 21 patients with BS were included in this study. ER was defined as an elevation of at least 0.1 mV from baseline in the QRS-T junction in the inferorolateral leads. Provocative tests with sodium-channel blockers were conducted in all patients with ERS to distinguish ERS from BS. RESULTS: In the ERS group, all patients were male and most patients experienced ventricular fibrillation during sleep or low activity (79%). ER was attenuated by sodium-channel blockers in most patients with ERS (13/14, 93%) and BS (5/5, 100%), whereas ST-segment elevation was augmented in the right precordial leads in the BS group. The rates of positive late potentials were significantly higher in the BS group (60%) than in the ERS group (7%) (P <.01). CONCLUSIONS: Some similarities were observed between ERS and BS, including gender, arrhythmia triggers, and response of ER to sodium-channel blockers. Unlike the ST segment in the right precordial leads in BS, ER was attenuated in patients with both ERS and BS, suggesting a differential mechanism between ER in the inferolateral leads and ST elevation in the right precordial leads.

Clinical impact of the number of extrastimuli in programmed electrical stimulation in patients with Brugada type 1 electrocardiogram.

BACKGROUND: Use of programmed electrical stimulation (PES) for risk stratification of Brugada syndrome (BrS) is controversial. OBJECTIVE: To elucidate the role of the number of extrastimuli during PES in patients with BrS. METHODS: Consecutive 108 patients with type 1 electrocardiogram (104 men, mean age 46 ± 12 years; 26 with ventricular fibrillation [VF], 40 with syncope, and 42 asymptomatic) underwent PES with a maximum of 3 extrastimuli from the right ventricular apex and the right ventricular outflow tract. Ventricular arrhythmia (VA) was defined as VF or nonsustained polymorphic ventricular tachycardia >15 beats. Patients with VA induced by a single extrastimulus or double extrastimuli were assigned to group SD (Single/Double), by triple extrastimuli to group T (Triple), and the remaining patients to group N. RESULTS: VA was induced in 81 patients (VF in 71 and polymorphic ventricular tachycardia in 10), in 4 by a single extrastimulus, in 41 by double extrastimuli, and in 36 by triple extrastimuli. During 79 ± 48 months of follow-up, 24 patients had VF events. Although the overall inducibility of VA was not associated with an increased risk of VF (log-rank P = .78), group SD had worse prognosis than did group T (P = .004). Kaplan-Meier analysis in patients without prior VF also showed that group SD had poorer outcome than did group T and group N (P = .001). Positive and negative predictive values of VA induction with up to 2 extrastimuli were, respectively, 36% and 87%, better than those with up to 3 (23% and 81%, respectively). CONCLUSIONS: The number of extrastimuli that induced VA served as a prognostic indicator for patients with Brugada type 1 electrocardiogram. Single extrastimulus or double extrastimuli were adequate for PES of patients with BrS.