Transvenous lead extraction versus surgical lead extraction or conservative treatment for cardiac implantable electronic device infections: Propensity score-weighted analyses of a nationwide claim-based database.

INTRODUCTION: Infection is one of the most important complications associated with cardiac implantable electronic device (CIED) therapy. The number of reports comparing the outcomes of transvenous lead extraction (TLE), surgical lead extraction, and conservative treatment for CIED infections using a real-world database is limited. This study investigated the association between the treatment strategies for CIED infections and their outcomes. METHODS: We performed a retrospective analysis of 3605 patients with CIED infections admitted to 681 hospitals using a nationwide claim-based database collected between April 2012 and March 2018. RESULTS: We divided the 3605 patients into TLE (n = 938 [26%]), surgical lead extraction (n = 182 [5.0%]), and conservative treatment (n = 2485 [69%]) groups. TLE was performed more frequently in younger patients and at larger hospitals (p for trend < .001 for both). The rate of TLE increased during the study period, whereas that of surgical lead extraction decreased (p for trend < .001 for both). TLE was associated with lower in-hospital mortality (vs. surgical lead extraction: odds ratio [OR], 0.20; 95% CI, 0.06-0.70; vs. conservative treatment: OR, 0.45; 95% CI: 0.22-0.94) and lower 30-day readmission rates (vs. surgical lead extraction: OR, 0.18; 95% CI: 0.06-0.56; vs. conservative treatment: OR, 0.06; 95% CI, 0.03-0.13) in propensity score-weighted analyses. CONCLUSIONS: Only 26% of patients hospitalized for CIED infections received TLE. TLE was associated with significantly lower in-hospital mortality and 30-day recurrence rates than surgical lead extraction and conservative treatment, suggesting that TLE should be more widely recommended as a first-line treatment for CIED infections.

Clinical Predictors of Pacing Device Implantation in Implantable Cardiac Monitor Recipients for Unexplained Syncope.

Background: Implantable cardiac monitors (ICMs) help investigate the cause of unexplained syncope, but the probability and predictors of needing a pacing device thereafter remain unclear. Methods: We retrospectively analyzed the data of patients who received ICM insertion for unexplained syncope with suspected arrhythmic etiology. The data were obtained from a nationwide database obtained between April 1, 2012 and March 31, 2020. Multivariable mixed-effects survival analysis was performed to identify predictors of pacing device implantation (PDI), and a risk score model was developed accordingly. Results: In total, 2905 patients (age: 72 years [range: 60-78]) implanted with ICMs to investigate the cause of syncope were analyzed. During the median follow-up period of 128 days (range: 68-209) days, 473 patients (16%) underwent PDI. Older age, history of atrial fibrillation, bundle branch block (BBB), and diabetes were independent predictors of PDI in multivariable analysis. A risk score model was developed with scores ranging from 0 to 32 points. When patients with the lowest quartile score (0-13 points) were used as a reference, those with higher quartiles had a higher risk of PDI (second quartile: 14-15 points, hazard ratio [HR]: 3.86, 95% confidence interval [CI]: 2.62-5.68; third quartile: 16-18 points, HR: 4.67, 95% CI: 3.14-6.94; fourth quartile: 19-32 points, HR: 6.59, 95% CI: 4.47-9.71). Conclusions: The 4 identified predictors are easily assessed during the initial evaluation of patients with syncope. They may help identify patients with a higher risk of requiring permanent PDI.

Contexte: Les moniteurs cardiaques implantables (MCI) aident à déterminer la cause d'une syncope inexpliquée, mais la probabilité et les facteurs prédictifs du besoin d'un dispositif de stimulation cardiaque par la suite demeurent incertains. Méthodologie: Nous avons analysé de façon rétrospective les données de patients s'étant fait implanter un MCI après une syncope inexpliquée et chez lesquels une étiologie d'arythmie était soupçonnée. Les données proviennent d'une base de données nationale et s'étendent du 1er avril 2012 au 31 mars 2020. Une analyse de survie multivariable à effets mixtes a été effectuée pour cibler les facteurs prédictifs de l'implantation d'un dispositif de stimulation cardiaque (IDSC), et un modèle de score de risque a été conçu en conséquence. Résultats: Au total, les cas de 2905 patients (âge : 72 ans [écart interquartile (ÉI) : 60-78]) ayant reçu un MCI pour déterminer la cause de la syncope ont été analysés. Durant la période de suivi médiane de 128 jours (ÉI : 68-209), 473 patients (16 %) ont subi une IDSC. L'âge avancé, les antécédents de fibrillation auriculaire, le bloc de branche et le diabète étaient des facteurs prédictifs indépendants de l'IDSC dans l'analyse multivariable. Un modèle de score de risque a été conçu, les scores allant de 0 à 32 points. Lorsque les patients ayant un score dans le quartile inférieur (0 à 13 points) étaient utilisés à titre de référence, ceux ayant un score dans les quartiles supérieurs avaient un risque plus élevé d'IDSC (deuxième quartile : 14-15 points, rapport des risques instantanés [RRI] : 3,86, intervalle de confiance [IC] à 95 % de 2,62 à 5,68; troisième quartile : 16-18 points, RRI : 4,67, IC à 95 % de 3,14 à 6,94; quatrième quartile : 19-32 points, RRI : 6,59, IC à 95 % de 4,47 à 9,71). Conclusions: Les quatre facteurs prédictifs ciblés sont faciles à évaluer durant l'évaluation initiale des patients ayant subi une syncope. Ils peuvent aider à repérer les patients présentant un risque plus élevé d'avoir besoin d'un dispositif de stimulation cardiaque permanent.

Differences in patient characteristics, clinical practice and outcomes of cardiac implantable electric device therapy between Japan and the USA: a cross-sectional study using data from nationally representative administrative databases.

OBJECTIVES: To identify differences in patient characteristics, clinical practice and outcomes of cardiac implantable electronic device (CIED) therapy between Japan and the USA. DESIGN: A cross-sectional study. SETTING: Nationally representative administrative databases from Japan and the USA containing hospitalisations with first-time implantations of pacemakers, implantable cardioverter-defibrillators (ICD) and cardiac-resynchronisation therapy with or without defibrillators (CRTP/CRTD). PARTICIPANTS: Patients hospitalised with first-time implantations of CIEDs. OUTCOME MEASURES: In-hospital mortality, in-hospital complication and 30-day readmission rates. RESULTS: Overall, 107 339 (median age 78 (71-84), 48 415 women) and 295 584 (age 76 (67-83), 127 349 women) records with CIED implantations were included from Japan and the USA, respectively. Proportion of women in defibrillator recipients was lower in Japan than in the USA (ICD, 21% vs 28%, p<0.001; CRTD, 24% vs 29%, p<0.001). Length of stay after CIED implantation was longer in Japan than in the USA for all device types (conventional pacemaker, 8(7-11) vs 1 (1-3) days, p<0.001; leadless pacemaker, 5 (3-9) vs 2 (1-5) days, p<0.001; ICD, 8 (7-11) vs 1 (1-3) days, p<0.001, CRTP, 9 (7-13) vs 2 (1-4) days, p<0.001; CRTD, 9 (8-14) vs 2 (1-4) days, p<0.001). In-hospital mortality after CIED implantation was similar between Japan and the USA ((OR) (95% CI), conventional pacemaker 0.58 (0.83 to 1.004); ICD 0.77 (0.57 to 1.03); CRTP 0.85 (0.51 to 1.44); CRTD 1.11 (0.81 to 1.51)), except that after leadless pacemaker implantation in Japan was lower than that in the USA (0.32 (0.23 to 0.43)). 30-day readmission rates were lower in Japan than in the USA for all device types (conventional pacemaker 0.55 (0.53 to 0.57); leadless pacemaker 0.50 (0.43 to 0.58); ICD 0.54 (0.49 to 0.58); CRTP 0.51 (0.42 to 0.62); CRTD 0.57 (0.51 to 0.64)). CONCLUSIONS: International variations in patient characteristics, practice and outcomes were observed. In-hospital mortality after CIED implantation was similar between Japan and the USA, except in cases of leadless pacemaker recipients.

Current clinical practice of subcutaneous implantable cardioverter-defibrillator: Analysis using the JROAD-DPC database.

BACKGROUND: Current evidence describing the characteristics of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy, its trend, and perioperative outcomes compared with transvenous implantable cardioverter-defibrillator (TV-ICD) based on a real-world, large-scale database is scarce. OBJECTIVE: The purpose of this study was to identify the characteristics of current S-ICD therapy using a nationwide database. METHODS: A retrospective analysis of ICD implantation was performed using a nationwide database obtained between 2016 and 2020. A total of 8690 patients implanted with ICD (median age 65 [52-72] year; 6902 men; 2021 S-ICD recipients) were analyzed. RESULTS: Younger patients were more prone to have S-ICD (P <.001). A history of ventricular fibrillation (VF) (odds ratio [OR] 2.45; 95% confidence interval [CI] 2.04-2.93), nonsustained ventricular tachycardia (VT) (OR 1.73; 95% CI 1.36-2.21), Brugada syndrome (BrS) (OR 3.14; 95% CI 2.48-4.00), and dialysis treatment (OR 2.02; 95% CI 1.44-2.82) were independent predictors of S-ICD selection on mixed-model logistic analysis. The proportion of S-ICD implantations has been increasing (P <.001), especially in patients with BrS (P <.001) and dialysis (P = .04). The proportion of combined complications after S-ICD implantation was low (1.3%) in the unmatched cohort and was comparable to TV-ICD in the 1:1 propensity-matched cohort of 3354 patients (1.5% vs 2.3%; OR 0.65; 95% CI 0.38-1.10). CONCLUSION: S-ICD was more likely to be implanted in younger patients and those with a history of VF, nonsustained VT, BrS, and dialysis treatment. The proportion of S-ICD implantation increased, especially in patients with BrS. The incidence of in-hospital complications was low in S-ICD recipients.

Long term prognosis in patients with pulmonary hypertension undergoing catheter ablation for supraventricular tachycardia.

Various forms of supraventricular tachycardia (SVT) occur in patients with severe pulmonary hypertension (PH). Despite the high efficacy of radiofrequency catheter ablation (RFCA) for SVT, insufficient data exist regarding patients with PH. Thirty SVTs in 23 PH patients (age 47 [35-60] years; mean pulmonary artery pressure 44 [32-50] mmHg) were analyzed. Procedural success rate, short- and long-term clinical outcomes, were evaluated during a median follow-up of 5.1 years. Single-procedure success rate was 83%; 94% (17/18) in typical atrial flutter, 73% (8/11) in atrial tachycardia (AT), and 100% (1/1) in atrioventricular nodal reentrant tachycardia. Antiarrhythmic drugs, serum brain natriuretic peptide levels and number of hospitalizations significantly decreased after RFCA than that before (p = 0.002, 0.04, and 0.002, respectively). Four patients had several procedures. After last RFCA, 12 patients had SVT and 8 patients died. Kaplan-Meier curves showed that patients with SVT after the last RFCA had a lower survival rate compared to those without (p = 0.0297). Multivariate analysis identified any SVT after the last RFCA as significant risk factor of mortality (hazard ratio: 9.31; p = 0.016). RFCA for SVT in patients with PH is feasible and effective in the short-term, but SVT is common during long-term follow-up and associated with lower survival.

Clinical Differences in Japanese Patients Between Brugada Syndrome and Arrhythmogenic Right Ventricular Cardiomyopathy With Long-Term Follow-Up.

Some Brugada syndrome (BrS) patients have been suspected of being in the initial state of arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aimed to clarify the electrocardiographic (ECG) and clinical differences between BrS and ARVC in long-term follow-up (mean 11.9 ± 6.3 years). A total of 50 BrS and 65 ARVC patients with fatal ventricular tachyarrhythmia (VTA) were evaluated according to the revised Task Force Criteria for ARVC. Based on the current diagnostic criteria concerning electrocardiographic, repolarization abnormality was positive in 2.0% and 2.6% of BrS patients at baseline and follow-up, and depolarization abnormality was positive in 6.0% and 12.8% of BrS patients at baseline and follow-up, respectively. At baseline, none of the BrS patients were definitively diagnosed with ARVC. Considering patients' lives since birth, Kaplan-Meier analysis revealed that age at first VTA attack showed the same tendency between the groups (BrS: mean 42.2 ± 12.5 years old vs ARVC: mean 44.8 ± 13.7 years old, log-rank p = 0.123). Moreover, the incidence of VTA recurrence was similar between the groups during follow-up (log-rank p = 0.906). Incidence of sustained monomorphic ventricular tachycardia was significantly higher in ARVC than in BrS whereas the opposite was true for ventricular fibrillation (log-rank p <0.001 and p <0.001, respectively). None of the diagnoses of BrS patients were changed to ARVC during follow-up. During long-term follow-up, although age at first VTA attack and VTA recurrence were similar, BrS consistently exhibited features that differed from those of ARVC.

Clinical and Electrocardiographic Differences in Brugada Syndrome With Spontaneous or Drug-Induced Type 1 Electrocardiogram.

BACKGROUND: Spontaneous type 1 electrocardiogram (ECG) in the right precordial lead is a dominant predictor of ventricular fibrillation (VF) in Brugada syndrome (BrS). In some BrS patients with VF, however, spontaneous type 1 ECG is undetectable, even in repeated ECG and immediately after VF. This study investigated differences between BrS patients with spontaneous or drug-induced type 1 ECG. Methods and Results: We evaluated 15 BrS patients with drug-induced (D-BrS) and 29 with spontaneous type 1 ECG (SP-BrS). All patients had had a previous VF episode. In each D-BrS patient, ECG was recorded more than 15 times (mean, 46±34) during 7.2±5.1 years of follow-up. Age and family history were comparable between groups. Inferolateral early repolarization (ER) was observed in 13 D-BrS (87%) at least once but in only 3 SP-BrS (10%, P<0.01). Immediately after VF, inferolateral ER was accentuated in 9 of 10 D-BrS, while type 1 ECG was accentuated in 12 of 16 SP-BrS. Fragmented QRS in the right precordial lead and aVR sign were absent in D-BrS but present in 20 (69%, P<0.01) and 11 (38%, P<0.01) SP-BrS, respectively. There was no prognostic difference between groups. CONCLUSIONS: Although having similar clinical profiles, there are obvious ECG differences between VF-positive BrS patients with spontaneous or drug-induced type 1 ECG. The inferolateral lead rather than the right precordial lead on ECG may be particularly crucial in some BrS patients.

Multicenter Study of the Validity of Additional Freeze Cycles for Cryoballoon Ablation in Patients With Paroxysmal Atrial Fibrillation: The AD-Balloon Study.

BACKGROUND: Pulmonary vein isolation (PVI) is a cornerstone of catheter ablation in patients with paroxysmal atrial fibrillation, and balloon-based ablation has been recently performed worldwide. The second-generation cryoballoon (CB2) ablation has proven to be highly effective in achieving freedom from paroxysmal atrial fibrillation. However, there are some debatable questions, including the ideal number of freeze cycles. METHODS: The AD-Balloon study (Multicenter Study of the Validity of Additional Freeze Cycles for Cryoballoon Ablation) was designed as a prospective, multicenter, and randomized clinical trial for investigation of the optimal strategy of freeze cycles for the CB2 ablation. One hundred and ten consecutive patients (aged 64±11 years) were randomly assigned to 2 groups after achieving a PVI by the CB2 ablation: 3-minute freeze cycles were added to each pulmonary vein (AD group: n=55) or not (non-AD group: n=55). Delayed-enhancement magnetic resonance imaging was also performed 1 to 2 months after the PVI to assess the ablation lesions. RESULTS: The patient characteristics did not differ between the 2 groups. A complete PVI was achieved in all patients. The total number of freeze cycles and durations for all pulmonary veins were significantly shorter in the non-AD group than in the AD group (5.7±1.6 versus 9.1±1.6 cycles, P<0.0001, and 932±244 versus 1483±252 seconds, P<0.0001). The cumulative freedom from any atrial tachyarrhythmia at 1 year was 87.3% in the AD group and 89.1% in the non-AD group (log-rank test P=0.78). There was no significant difference in the frequency of gaps on the PVI lines in the delayed-enhancement magnetic resonance imaging (46% in the AD group versus 36% in the non-AD group; P=0.38). CONCLUSIONS: No benefit was found in the patients receiving additional 3-minute freeze cycles after the complete PVI with the CB2 ablation, suggesting that an insurance freeze after achieving a PVI with the CB2 may be unnecessary and time consuming.

Low-Voltage Type 1 ECG Is Associated With Fatal Ventricular Tachyarrhythmia in Brugada Syndrome.

Background Epicardial mapping can reveal low-voltage areas on the right ventricular outflow tract in patients with Brugada syndrome with several ventricular fibrillation ( VF ) episodes. A type 1 ECG is associated with an abnormal electrogram on right ventricular outflow tract epicardium. This study investigated the clinical significance of the amplitude of type 1 ECGs in patients with Brugada syndrome. Methods and Results In 209 patients with Brugada syndrome with a spontaneous type 1 ECG (26 resuscitated from VF , 54 with syncope, and 129 asymptomatic), the amplitude of the ECG in leads exhibiting type 1 was measured among V1 to V3 leads positioned in the standard and upper 1 and 2 intercostal spaces. The number of ECG leads exhibiting type 1 did not differ among groups. The averaged amplitude of type 1 ECG was, however, significantly smaller in the group resuscitated from VF than in the asymptomatic group ( P<0.05). Moreover, the minimum amplitude of type 1 ECG was significantly smaller in the group resuscitated from VF than in the group with syncope and the asymptomatic group ( P<0.05 and P<0.01, respectively). During follow-up (56±48 months), VF occurred in 29 patients. Kaplan-Meier analysis revealed that patients with the minimum amplitude of type 1 ECG lower than or at the median value had a higher incidence of VF (log-rank test, P<0.01). In multivariate analysis, syncope, past VF episode, and minimum amplitude of type 1 ECG ≤0.8 mV were independent predictors of VF events during follow-up. Conclusions Low-voltage type 1 ECG is highly and independently related to fatal ventricular tachyarrhythmia in patients with Brugada syndrome.

Relation of Electrocardiographic Left Atrial Abnormalities to Risk of Stroke in Patients with Atrial Fibrillation.

The P-wave terminal force in lead V1 (PTFV1) on the 12-lead electrocardiogram (ECG) quantifies left atrial (LA) structural and electrophysiologic abnormalities. We aimed to evaluate the association between PTFV1 and cerebrovascular accident (CVA) as well as LA structure and function in patients with atrial fibrillation (AF). We conducted a cross-sectional study of 229 patients with AF (60 ± 10years, 72% men) with (n = 21) and without (n = 208) a history of CVA, who underwent preablation ECG and cardiac magnetic resonance in sinus rhythm. PTFV1 was defined as the duration (in milliseconds) of the downward deflection of the P wave in lead V1 multiplied by the absolute value of its amplitude (in microvolts) on ECG. PTFV1 is associated with LA minimum volume (Vmin) and left ventricular ejection fraction but not associated with the extent of LA fibrosis quantified by cardiac magnetic resonance late gadolinium enhancement. In addition, PTFV1 is associated with CVA independent of the CHA2DS2-VASc score and LA Vmin (odds ratio 1.23; 95% confidence interval 1.08 to 1.40; p = 0.002). Furthermore, PTFV1 has an incremental value over the CHA2DS2-VASc score as a marker of CVA (p <0.001). In conclusion, ECG-defined PTFV1 is independent marker of stroke in patients with AF and reflects the underlying LA remodeling. Our findings suggest that evaluation of PTFV1 can improve the current risk stratification of stroke.

Mechanical dyssynchrony of the left atrium during sinus rhythm is associated with history of stroke in patients with atrial fibrillation.

Aims: We sought to evaluate the relationship between left atrial (LA) mechanical dyssynchrony and history of stroke or transient ischaemic attack (TIA) in patients with atrial fibrillation (AF). We hypothesized that mechanical dyssynchrony of the LA is associated with history of stroke/TIA independent of LA function and Cardiac failure, Hypertension, Age, Diabetes, Stroke/transient ischaemic attack (TIA), VAscular disease, and Sex category (CHA2DS2-VASc) score in patients with AF. Methods and results: We conducted a cross-sectional study of 246 patients with a history of AF (59 ± 10 years, 29% female, 26% non-paroxysmal AF) referred for catheter ablation to treat drug-refractory AF who underwent preablation cardiac magnetic resonance (CMR) in sinus rhythm. Using tissue-tracking CMR, we measured the LA longitudinal strain and strain rate in each of 12 equal-length segments in two- and four-chamber views. We defined indices of LA mechanical dyssynchrony, including the standard deviation of the time to the peak longitudinal strain (SD-TPS). Patients with a prior history of stroke or TIA (n = 23) had significantly higher SD-TPS than those without (n = 223) (39.9 vs. 23.4 ms, P < 0.001). Multivariable analysis showed that SD-TPS was associated with stroke/TIA after adjusting for the CHA2DS2-VASc score, LA minimum index volume, and the peak LA longitudinal strain (P < 0.001). The receiver-operating characteristics curve showed that SD-TPS identified patients with stroke/TIA more accurately than CHA2DS2-VASc score alone (c-statistics: 0.82 vs. 0.75, P < 0.001). Conclusion: Higher mechanical dyssynchrony of the LA during sinus rhythm is associated with a history of stroke/TIA in patients with AF.

Significance of Coronary Artery Spasm Diagnosis in Patients With Early Repolarization Syndrome.

BACKGROUND: Previously described patients with early repolarization syndrome (ERS) may have experienced silent coronary artery spasm (CAS) because the diagnosis of CAS was mainly based on symptoms or coronary angiography findings, without performing a spasm provocation test. This study investigated the significance of CAS diagnosis and evaluated the incidence of silent CAS in patients with possible ERS (ie, idiopathic ventricular fibrillation [VF] and inferolateral J wave). METHODS AND RESULTS: The study included 34 patients with idiopathic VF and inferolateral J wave. Thirteen patients (38%) were diagnosed as having CAS on the basis of coronary angiography with spasm provocation test (n=8) and documentation of spontaneous ST elevation (n=5). Of the 13 patients with CAS, 5 (38%) did not experience chest symptoms before and during VF, and were diagnosed as having silent CAS. The remaining 21 patients (62%), with a negative provocation test result and absence of chest symptoms, were considered to have ERS. During the 92 months of follow-up, patients with CAS receiving appropriate medical treatment with antianginal drugs showed a favorable outcome. In contrast, 4 of 21 patients with ERS (19%) had VF recurrences. The use of monotherapy or combination therapy, consisting of quinidine, cilostazol, and bepridil, in the 4 patients with ERS, was effective in suppressing VF. CONCLUSIONS: Approximately 40% of patients with CAS with documented VF and inferolateral J wave did not experience chest symptoms at the first VF, and could have been misdiagnosed as having ERS. The use of the spasm provocation test is considered essential to differentiate patients for optimal medical treatment.

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.

Feasibility evaluation of long-term use of beta-blockers and calcium antagonists in patients with Brugada syndrome.

Aims: Beta-blockers (BBs) and calcium antagonists (CAs) are reported to aggravate ST-segment elevation in some patients with Brugada syndrome (BrS). The feasibility of their long-term use in BrS still remains unknown. We investigated the safety of long-term use of BB and CA in BrS patients. Methods and results: Of the 360 consecutive BrS patients, 29 [5: a history of ventricular fibrillation (VF), 17: syncope, 7: asymptomatic] took BB and/or CA (BB: 22, CA: 8) for more than 1 year for the treatment of co-morbidities such as atrial tachyarrhythmia, vasospastic angina, and neurally mediated syncope. The electrocardiographic changes and clinical outcome after the treatment were evaluated. Eleven patients showed type 1 electrocardiogram (ECG) at baseline. BBs and CAs were used within normal dosage range in all patients. After starting a BB and/or CA, type 1 ECG was still observed in 9 patients. There were no significant differences in the ECG parameters such as the amplitude of J-point, QRS duration, and corrected QT intervals before and after starting BB and/or CA. During follow-up of 89 ± 65 months after initiation of the drugs, 1 patient experienced a VF recurrence without significant changes of ECG parameters 2 years after BB therapy was started. Conclusion: Long-term intake of BB or CA within normal dosage range was not associated with the aggravation of ECG parameters and clinical outcome in patients with BrS. The use of BBs and CAs is acceptable under careful observation.

Isolated Late Activation Detected by Magnetocardiography Predicts Future Lethal Ventricular Arrhythmic Events in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND: Risk stratification of ventricular arrhythmias is vital to the optimal management in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). We hypothesized that 64-channel magnetocardiography (MCG) would be useful to detect isolated late activation (ILA) by overcoming the limitations of conventional noninvasive predictors of ventricular tachyarrhythmias, including epsilon waves, late potential (LP), and right ventricular ejection fraction (RVEF), in ARVC patients.Methods and Results:We evaluated ILA on MCG, defined as discrete activations re-emerging after the decay of main RV activation (%magnitude >5%), and conventional noninvasive predictors of ventricular tachyarrhythmias (epsilon waves, LP, and RVEF) in 40 patients with ARVC. ILA was noted in 24 (60%) patients. Most ILAs were found in RV lateral or inferior areas (17/24, 71%). We defined "delayed ILA" as ILA in which the conduction delay exceeded its median (50 ms). During a median follow-up of 42.5 months, major arrhythmic events (MAEs: 1 sudden cardiac death, 3 sustained ventricular tachycardias, and 4 appropriate implantable cardioverter defibrillator discharges) occurred more frequently in patients with delayed ILA (6/12) than in those without (2/28; log-rank: P=0.004). Cox regression analysis identified delayed ILA as the only independent predictor of MAEs (hazard ratio 7.63, 95% confidence interval 1.72-52.6, P=0.007), and other noninvasive parameters were not significant predictors. CONCLUSIONS: MCG is useful to identify ARVC patients at high risk of future lethal ventricular arrhythmias.

Electrocardiographic Strain Pattern Is Associated With Left Ventricular Concentric Remodeling, Scar, and Mortality Over 10 Years: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Both ECG strain pattern and QRS measured left ventricular (LV) hypertrophy criteria are associated with LV hypertrophy and have been used for risk stratification. However, the independent predictive value of ECG strain in apparently healthy individuals in predicting mortality and adverse cardiovascular events is unclear. METHODS AND RESULTS: MESA (Multi-Ethnic Study of Atherosclerosis) is a multicenter, prospective cohort of 6441 participants (mean age, 62 years; 54% women). In 2847 of these participants, cardiac magnetic resonance imaging was repeated ≈10 years later (Year-10). At Year-10, 1759 participants underwent cardiac magnetic resonance imaging with gadolinium to detect myocardial scar. During a median follow-up of 11.7 years, ECG strain (n=168, 2.6%) was significantly associated with all-cause death (adjusted hazard ratio, 1.33; 95% confidence interval, 1.01-1.77; P=0.045), heart failure (2.62; 1.73-3.97; P<0.001), myocardial infarction (1.86; 1.09-3.18; P=0.024), and incident cardiovascular disease (1.45; 1.06-2.00; P=0.022). ECG strain was also associated with an increase in LV mass (ß=9.29 g; P<0.001) and LV mass-to-volume ratio (ß=0.07 g/mL; P=0.007) and a decline in LV ejection fraction (ß=-3.30%; P<0.001). Moreover, ECG strain either at baseline and Year-10 was associated with LV scar (odds ratio, 4.93 and 5.22; P=0.002 and <0.001, respectively), whereas these associations were not observed in ECG LV hypertrophy. CONCLUSIONS: ECG strain is independently associated with all-cause mortality, adverse cardiovascular events, development of LV concentric remodeling and systolic dysfunction, and myocardial scar over 10 years in multiethnic participants without past cardiovascular disease. ECG strain may be an early marker of LV structural remodeling that contributes to development of adverse cardiovascular events. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00005487.

Impact of electrocardiogram screening during drug challenge test for the prediction of T-wave oversensing by a subcutaneous implantable cardioverter defibrillator in patients with Brugada syndrome.

Screening tests conducted at rest may be inadequate for the prediction of the T-wave oversensing (TWOS) in subcutaneous implantable cardioverter defibrillator (S-ICD) candidates with Brugada syndrome (BrS) because of the dynamic nature of electrocardiogram (ECG) morphology. We evaluated the utility of ECG screening during drug challenge (DC) for prediction of TWOS in BrS patients implanted with an S-ICD. The study enrolled 6 consecutive BrS patients implanted with an S-ICD. In addition to baseline ECG screening, pre-implant screening during DC using a sodium channel blocker was performed in all patients. All patients underwent appropriate morphological analysis on baseline ECG screening; however, 2 BrS patients (33%) showed inappropriate sensing during DC. During 243 days of follow-up after S-ICD implantation, no patient experienced an appropriate shock. TWOS was confirmed during exercise testing in one of 2 patients who showed inappropriate sensing during DC. However, one patient with appropriate sensing during DC experienced recurrent episodes of inappropriate shocks due to TWOS during exercise. The present initial experience indicates that further studies are needed to detect the risk for TWOS from an S-ICD in BrS patients.

Electrocardiographic Impact of Myocardial Diffuse Fibrosis and Scar: MESA (Multi-Ethnic Study of Atherosclerosis).

Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging. In individuals without a late gadolinium enhancement-defined myocardial scar (n = 1131), T1 mapping was used to assess left ventricular (LV) interstitial diffuse fibrosis. The associations of LV diffuse fibrosis or myocardial scar with ECG parameters (QRS voltage, QRS duration, and corrected QT interval [QTc]) were evaluated by using multivariable regression analyses adjusted for demographic data, risk factors for scar, LV end-diastolic volume, and LV mass. Results The mean age of the 1669 participants was 67.4 years ± 8.7 (standard deviation); 49.8% were women. Lower postcontrast T1 time at 12 minutes was significantly associated with lower QRS Sokolow-Lyon voltage (ß = 15.1 µV/10 msec, P = .004), lower QRS Cornell voltage (ß = 9.2 µV/10 msec, P = .031), and shorter QRS duration (ß = 0.16 msec/10 msec, P = .049). Greater extracellular volume (ECV) fraction was also significantly associated with lower QRS Sokolow-Lyon voltage (ß = -35.2 µV/1% ECV increase, P < .001) and Cornell voltage (ß = -23.7 µV/1% ECV increase, P < .001), independent of LV structural indexes. In contrast, the presence of LV scar (n = 106) was associated with longer QTc (ß = 4.3 msec, P = .031). Conclusion In older adults without prior coronary heart disease, underlying greater LV diffuse fibrosis is associated with lower QRS voltage and shorter QRS duration at surface ECG, whereas clinically unrecognized myocardial scar is associated with a longer QT interval. © RSNA, 2016 Online supplemental material is available for this article.