Worldwide survey on implantation of and outcomes for conduction system pacing with His bundle and left bundle branch area pacing leads.

BACKGROUND: Adoption and outcomes for conduction system pacing (CSP), which includes His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), in real-world settings are incompletely understood. We sought to describe real-world adoption of CSP lead implantation and subsequent outcomes. METHODS: We performed an online cross-sectional survey on the implantation and outcomes associated with CSP, between November 15, 2020, and February 15, 2021. We described survey responses and reported HBP and LBBAP outcomes for bradycardia pacing and cardiac resynchronization CRT indications, separately. RESULTS: The analysis cohort included 140 institutions, located on 5 continents, who contributed data to the worldwide survey on CSP. Of these, 127 institutions (90.7%) reported experience implanting CSP leads. CSP and overall device implantation volumes were reported by 84 institutions. In 2019, the median proportion of device implants with CSP, HBP, and/or LBBAP leads attempted were 4.4% (interquartile range [IQR], 1.9-12.5%; range, 0.4-100%), 3.3% (IQR, 1.3-7.1%; range, 0.2-87.0%), and 2.5% (IQR, 0.5-24.0%; range, 0.1-55.6%), respectively. For bradycardia pacing indications, HBP leads, as compared to LBBAP leads, had higher reported implant threshold (median [IQR]: 1.5 V [1.3-2.0 V] vs 0.8 V [0.6-1.0 V], p = 0.0008) and lower ventricular sensing (median [IQR]: 4.0 mV [3.0-5.0 mV] vs. 10.0 mV [7.0-12.0 mV], p < 0.0001). CONCLUSION: In conclusion, CSP lead implantation has been broadly adopted but has yet to become the default approach at most surveyed institutions. As the indications and data for CSP continue to evolve, strategies to educate and promote CSP lead implantation at institutions without CSP lead implantation experience would be necessary.

Long-term prognosis of asymptomatic individuals with spontaneous or drug-induced type 1 electrocardiographic phenotype of Brugada syndrome.

BACKGROUND: Risk stratification of asymptomatic individuals with type 1 electrocardiogram (ECG) phenotype of Brugada syndrome (BS) still remains controversial. This study investigated the long-term prognosis of asymptomatic subjects with spontaneous or drug-induced type 1 ECG pattern of BS. METHODS AND RESULTS: Data from 33 apparently healthy individuals (30 males; age, 43.6 ± 13.4 years) with spontaneous (n = 12) or drug-induced (n = 21) type 1 ECG pattern of BS were retrospectively analyzed. Thirteen subjects (39.4%) displayed a positive family history of BS and/or sudden cardiac death. Electrophysiologic study was performed in 16 subjects, and programed right ventricular stimulation induced polymorphic ventricular tachycardia in 9 (56.3%) of them. A cardioverter defibrillator was implanted in 6 cases. During a mean follow-up period of 5.3 ± 2.8 years, all subjects remained asymptomatic. None of them had syncope or cardioverter defibrillator discharges due to ventricular arrhythmias. CONCLUSIONS: Asymptomatic individuals with spontaneous or drug-induced type 1 ECG phenotype of BS display a benign clinical course during long-term follow-up.

Tpeak-Tend interval and Tpeak-Tend/QT ratio as markers of ventricular tachycardia inducibility in subjects with Brugada ECG phenotype.

AIMS: The present study investigated whether several ECG markers of ventricular repolarization are associated with ventricular tachycardia/fibrillation (VT/VF) inducibility in subjects with type 1 ECG pattern of Brugada syndrome (BS). METHODS AND RESULTS: The clinical data of 23 individuals (19 males, age 42.69 +/- 14.63) with spontaneous (n = 10) or drug-induced (n = 13) type 1 ECG pattern of BS who underwent programmed ventricular stimulation were analysed. Sustained VT/VF was induced in 17 subjects (74%) and was significantly associated with the presence of spontaneous type 1 ECG of BS (P = 0.012). Among the studied ECG repolarization markers, subjects with inducible VT/VF displayed an increased T(peak)-T(end) interval in leads V(2) (88.82 +/- 15.70 vs. 78.33 +/- 4.08 ms, P = 0.02) and V(6) (76.33 +/- 10.08 vs. 66.66 +/- 5.16 ms, P = 0.04) and a greater T(peak)-T(end)/QT ratio in lead V(6) (0.214 +/- 0.028 vs. 0.180 +/- 0.014, P = 0.009) compared with those without arrhythmias. Ventricular tachycardia/fibrillation inducibility was not associated with arrhythmic events during a mean follow-up period of 4.61 +/- 2.14 years (P = 0.739). CONCLUSION: The T(peak)-T(end) interval and T(peak)-T(end)/QT ratio were associated with VT/VF inducibility in BS. The utility of T(peak)-T(end)/QT ratio as a new marker of arrhythmogenesis in BS requires further studies, including a large number of patients.

Evaluation of a new ultralow-dose radiation protocol for electrophysiological device implantation: A near-zero fluoroscopy approach for device implantation.

BACKGROUND: Radiation is one of the main hazards of electrophysiological device implantation, and insertion of cardiac resynchronization therapy (CRT) devices in particular is associated with high radiation doses. OBJECTIVE: The purpose of this study was to evaluate the impact of a new ultralow-dose radiation protocol on radiation doses, success rate, and safety of electrophysiological device implantations. METHODS: In 2018, we established a new ultralow-dose radiation protocol (reduced pulse width, increased thickness of minimum copper filters, reduced detector entrance dose, reduced pulse rate, optimized image postprocessing settings) for de novo device implantation at our hospital. A total of 1173 patients (11% single-chamber devices, 69% dual-chamber devices, 20% CRT devices) were analyzed. Five hundred twelve patients (44%) in the ultralow-dose group were compared to 661 patients (66%) treated during 2017 with a conventional low-dose protocol. RESULTS: With the ultralow-dose radiation protocol, effective doses could be reduced by 59% (median 0.25 [interquartile range: 0.11-0.63] vs median 0.10 [interquartile range: 0.03-0.28] mSv; P <.0001) per procedure without a significant change in procedure time (P = .5). This dose reduction could be achieved without decreasing procedure success (P = 1) or increasing complication rate (P = .8). Male gender, higher body mass index, increased procedure and fluoroscopy times, and use of the conventional radiation protocol were independent predictors of higher radiation doses in multivariate regression analysis. CONCLUSION: By establishing a new ultralow-dose radiation protocol, we could significantly decrease radiation exposure, reaching the lowest radiation doses for electrophysiological device implantation reported to date.

Predictors of atrial tachyarrhythmias in subjects with type 1 ECG pattern of Brugada syndrome.

BACKGROUND: Previous studies have demonstrated a high incidence of atrial tachyarrhythmias (ATs) in patients with Brugada syndrome (BS). The present study aimed to investigate whether various 12-lead electrocardiogram (ECG) and electrophysiological parameters may help to differentiate subjects with a high probability to develop ATs. METHODS AND RESULTS: The clinical records of 38 individuals (31 males, age 44.4 +/- 13.9) with spontaneous (n = 15) or ajmaline-induced (n = 23) type 1 ECG pattern of BS were analyzed. During a mean follow-up period of 4.6 +/- 2.2 years, nine subjects suffered ATs (24%). Six subjects displayed paroxysmal atrial fibrillation and three typical atrial flutter. Among the studied 12-lead ECG parameters, subjects with ATs exhibited increased values of P-wave duration in lead II, P-wave dispersion, PR interval in leads II, QRS duration in leads II and V(2), Tpeak-end interval in lead II, and Tpeak-end dispersion of the 12 leads in relation to those without ATs (P < 0.05). Among the assessed electrophysiological parameters, atrial-His (AH) and His-ventricular (HV) intervals were significantly prolonged in subjects with ATs (P < 0.05). Multiple Cox proportional hazards analysis revealed that P-wave duration in lead II, P-wave dispersion, Tpeak-end in lead II, Tpeak-end dispersion of the 12 leads, as well as AH and HV intervals are independent predictors of ATs in subjects with BS (P < 0.05). Cut-off point analysis showed that an HV interval>or=56 ms displayed the highest predictive ability (P < 0.01). CONCLUSION: Our findings demonstrate that simple 12-lead ECG and electrophysiological parameters may easily be applied to identify high-risk subjects with BS ECG phenotype to develop ATs.