Clinical analysis of temporary pacemaker implantation in 6 children with fulminant myocarditis.

BACKGROUND: There is little literature on the use of temporary pacemakers in children with fulminant myocarditis. Therefore, we summarized the use of temporary cardiac pacemakers in children with fulminant myocarditis in our hospital. METHODS: The clinical data of children with fulminant myocarditis treated with temporary pacemakers in Wuhan Children's Hospital from January 2017 to May 2022 were retrospectively analyzed. RESULTS: A total of 6 children were enrolled in the study, including 4 boys and 2 girls, with a median age of 50 months and a median weight of 15 kg. The average time from admission to pacemaker placement was 2.75 ± 0.4 h. The electrocardiogram showed that all 6 children had third-degree atrioventricular block (III°AVB). The initial pacing voltage, the sensory sensitivity of the ventricle and the pacing frequency were set to 5-10 mV, 5 V and 100-120 bpm respectively. The sinus rhythm was recovered in 5 patients within 61 h (17-134) h, and the median time of using temporary pacemaker was 132 h (63-445) h. One of the children had persistent III°AVB after the temporary pacemaker. With parental consent, the child was fitted with a permanent pacemaker on the 12th day of his illness. CONCLUSIONS: When fulminant myocarditis leads to severe bradycardia or atrioventricular block in children, temporary pacemakers have the characteristics of high safety to improve the heart function.

Atrioventricular conduction disorders in aortic valve infective endocarditis.

BACKGROUND: Aortic valve infective endocarditis may be complicated by high-degree atrioventricular block in up to 10-20% of cases. AIM: To assess high-degree atrioventricular block occurrence, contributing factors, prognosis and evolution in patients referred for aortic infective endocarditis. METHODS: Two hundred and five patients referred for aortic valve infective endocarditis between January 2018 and March 2021 were included in this study. A comprehensive assessment of clinical, electrocardiographic, biological, microbiological and imaging data was conducted, with a follow-up carried out over 1 year. RESULTS: High-degree atrioventricular block occurred in 22 (11%) patients. In univariate analysis, high-degree atrioventricular block was associated with first-degree heart block at admission (odds ratio 3.1; P=0.015), periannular complication on echocardiography (odds ratio 6.9; P<0.001) and severe biological inflammatory syndrome, notably C-reactive protein (127 vs 90mg/L; P=0.011). In-hospital mortality (12.7%) was higher in patients with high-degree atrioventricular block (odds ratio 4.0; P=0.011) in univariate analysis. Of the 16 patients implanted with a permanent pacemaker for high-degree atrioventricular block and interrogated, only four (25%) were dependent on the pacing function at 1-year follow-up. CONCLUSIONS: High-degree atrioventricular block is associated with high inflammation markers and periannular complications, especially if first-degree heart block is identified at admission. High-degree atrioventricular block is a marker of infectious severity, and tends to raise the in-hospital mortality rate. Systematic assessment of patients admitted for infective endocarditis suspicion, considering these contributing factors, could indicate intensive care unit monitoring or even temporary pacemaker implantation in those at highest risk.

Incidence, Risk Factors, and Outcomes of Left Atrial Enlargement in Patients Requiring Right Ventricular Pacing: A Retrospective Study of 461 Cases from 2012 to 2020.

BACKGROUND Long-term right ventricular (RV) pacing has been linked to left atrial enlargement (LAE). The incidence and risk factors associated with significant LAE after RV pacing remain unknown. This retrospective study included 461 patients requiring RV pacing at 2 centers between 2012 and 2020 and aimed to evaluate the incidence, risk factors, outcomes, and complications of LAE. MATERIAL AND METHODS A total of 461 patients with normal-sized pre-implant left atrial dimension and dual-chamber pacing pacemaker implantation for complete atrioventricular block were enrolled. Patients were grouped based on a ≥20% increase from their baseline left atrial dimension by echocardiography, indicating significant LAE, and initial characteristics, echocardiographic data, and outcomes were compared. RESULTS During a mean 7.0±4.9 years follow-up period, 96 patients (20.8%) developed significant LAE, whereas 365 patients did not. In multivariate logistic regression analysis, smaller pre-implant left atrial dimension (OR, 0.776; 95% CI, 0.728-0.828; P<0.001), lower post-implant left ventricular ejection fraction (OR, 0.976; 95% CI, 0.957-0.995; P=0.014), post-implant development of moderate to severe mitral regurgitation (OR, 2.357; 95% CI, 1.172-4.740; P=0.016), and RV pacing duration ≥3.3 years (OR, 1.576; 95% CI, 1.039-2.646; P=0.045) were independent predictors of significant LAE after RV-dependent pacing. There was a significant difference in the incident stroke events between patients without and with significant LAE (9.9% vs 17.7%; log-rank P=0.047). CONCLUSIONS Long-term RV pacing was linked to significant LAE in 20.8% of patients with complete atrioventricular block, with those affected experiencing a higher stroke rate during follow-up.

A long-standing conundrum: an unusual case of 2:1 atrioventricular block with conflicting findings.

A 2:1 atrioventricular (AV) block can occur anywhere within the conduction system, and noninvasive measurements may not always predict the exact site of the block. Although localization of the block is critical for deciding any treatment, patients should also be carefully questioned about symptoms both at rest and during exertion. A case of 2:1 AV block that was symptomatic only during exertion, appeared infranodal by noninvasive diagnostic methods, but was found to be intranodal on electrophysiological study is reported.

Impact of New-Onset Right Bundle-Branch Block After Transcatheter Aortic Valve Replacement on Permanent Pacemaker Implantation.

BACKGROUND: A delayed and recurrent complete atrioventricular block (CAVB) is a life-threatening complication of transcatheter aortic valve replacement (TAVR). Post-TAVR evaluation may be important in predicting delayed and recurrent CAVB requiring permanent pacemaker implantation (PPI). The impact of new-onset right bundle-branch block (RBBB) after TAVR on PPI remains unknown. METHODS AND RESULTS: In total, 407 patients with aortic stenosis who underwent TAVR were included in this analysis. Intraprocedural CAVB was defined as CAVB that occurred during TAVR. A 12-lead ECG was evaluated at baseline, immediately after TAVR, on postoperative days 1 and 5, and according to the need to identify new-onset bundle-branch block (BBB) and CAVB after TAVR. Forty patients (9.8%) required PPI, 17 patients (4.2%) had persistent intraprocedural CAVB, and 23 (5.7%) had delayed or recurrent CAVB after TAVR. The rates of no new-onset BBB, new-onset left BBB, and new-onset RBBB were 65.1%, 26.8%, and 4.7%, respectively. Compared with patients without new-onset BBB and those with new-onset left BBB, the rate of PPI was higher in patients with new-onset RBBB (3.4% versus 5.6% versus 44.4%, P<0.0001). On post-TAVR evaluation in patients without persistent intraprocedural CAVB, the multivariate logistic regression analysis showed that new-onset RBBB was a statistically significant predictor of PPI compared with no new-onset BBB (odds ratio [OR], 18.0 [95% CI, 5.94-54.4]) in addition to the use of a self-expanding valve (OR, 2.97 [95% CI, 1.09-8.10]). CONCLUSIONS: Patients with new-onset RBBB after TAVR are at high risk for PPI.

The Average Age of Atrioventricular Block Onset in Middle Eastern Patients with Cardiac Rhythm Devices Adjusted for the Overall Young Population: Insights from a Multicenter International Registry.

Background: Previous registries have shown a younger average age at presentation with cardiovascular diseases in the Middle East (ME), but no study has examined atrioventricular block (AVB). Moreover, these comparisons are confounded by younger populations in the ME. We sought to describe the average age at presentation with AVB in ME and quantify the effect of being from ME, adjusted for the overall younger population. Methodology: This was a retrospective analysis of PANORAMA registries, which collected data on patients who underwent cardiac rhythm device placement worldwide. Countries with a median population age of ≤30 were considered 'young countries'. Multivariate linear regression was performed to assess the effect of being from ME, adjusted for being from a 'young country', on age at presentation with AVB. Results: The study included 5,259 AVB patients, with 640 (8.2%) from the ME. Mean age at presentation was seven years younger in ME than in other regions (62.9 ± 17.8 vs. 70 ± 14.1, P < 0.001). Being from a 'young country' was associated with 5.6 years younger age at presentation (95%CI -6.5--4.6), whereas being from ME was associated with 3.1 years younger age at presentation (95%CI -4.5--1.8), (P < 0.001 for both). Conclusion: The average age at presentation with AVB in the ME is seven years younger than in other regions. While this is mostly driven by the overall younger population, being from the ME appears to be independently associated with younger age. Determinants of the earlier presentation in ME need to be assessed, and care should be taken when applying international recommendations.

Left bundle branch area versus conventional pacing after transcatheter valve implant for aortic stenosis: the LATVIA study.

BACKGROUND: Atrioventricular block (AVB) is a frequent complication in patients undergoing transcatheter aortic valve implantation (TAVI). Right apex ventricular pacing (RVP) represents the standard treatment but may induce cardiomyopathy over the long term. Left bundle branch area pacing (LBBAP) is a promising alternative, minimizing the risk of desynchrony. However, available evidence with LBBAP after TAVI is still low. OBJECTIVE: To assess the feasibility and safety of LBBAP for AVB post-TAVI compared with RVP. METHODS: Consecutive patients developing AVB early after TAVI were enrolled between 1 January 2022 and 31 December 2022 at three high-volume hospitals and received LBBAP or RVP. Data on procedure and at short-term follow-up (at least 3 months) were collected. RESULTS: A total of 38 patients (61% men, mean age 83 ±â€Š6 years) were included; 20 patients (53%) received LBBAP. Procedural success was obtained in all patients according to chosen pacing strategy. Electrical pacing performance at implant and after a mean follow-up of 4.2 ±â€Š2.8 months was clinically equivalent for both pacing modalities. In the LBBAP group, procedural time was longer (70 ±â€Š17 versus 58 ±â€Š15 min in the RVP group, P  = 0.02) and paced QRS was shorter (120 ±â€Š19 versus 155 ±â€Š12 ms at implant, P  < 0.001; 119 ±â€Š18 versus 157 ±â€Š9 ms at follow-up, P  < 0.001). Complication rates did not differ between the two groups. CONCLUSION: In patients with AVB after TAVI, LBBAP is feasible and safe, resulting in a narrow QRS duration, either acutely and during the follow-up, compared with RVP. Further studies are needed to evaluate if LBBAP reduces pacing-induced cardiomyopathy in this clinical setting.

Paced QRS morphology mimicking complete left bundle branch block induced by right ventricular pacing is associated with pacing-induced cardiomyopathy.

INTRODUCTION: Right ventricular (RV) pacing sometimes causes left ventricular (LV) systolic dysfunction, also known as pacing-induced cardiomyopathy (PICM). However, the association between specifically paced QRS morphology and PICM development has not been elucidated. This study aimed to investigate the association between paced QRS mimicking a complete left bundle branch block (CLBBB) and PICM development. METHODS: We retrospectively screened 2009 patients who underwent pacemaker implantation from 2010 to 2020 in seven institutions. Patients who received pacemakers for an advanced atrioventricular block or bradycardia with atrial fibrillation, baseline LV ejection fraction (LVEF) ≥ 50%, and echocardiogram recorded at least 6 months postimplantation were included. The paced QRS recorded immediately after implantation was analyzed. A CLBBB-like paced QRS was defined as meeting the CLBBB criteria of the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society in 2009. PICM was defined as a ≥10% LVEF decrease, resulting in an LVEF of <50%. RESULTS: Among the 270 patients analyzed, PICM was observed in 38. Baseline LVEF was lower in patients with PICM, and CLBBB-like paced QRS was frequently observed in PICM. Multivariate analysis revealed that low baseline LVEF (odds ratio [OR]: 0.93 per 1% increase, 95% confidence interval [CI]: 0.89-0.98, p = 0.006) and CLBBB-like paced QRS (OR: 2.69, 95% CI: 1.25-5.76, p = 0.011) were significantly associated with PICM development. CONCLUSION: CLBBB-like paced QRS may be a novel risk factor for PICM. RV pacing, which causes CLBBB-like QRS morphology, may need to be avoided, and patients with CLBBB-like paced QRS should be followed-up carefully.

Is electrophysiological study a novel predictor for permanent pacemaker implantation after transcatheter aortic valve implantation?

Background/aim: Despite advancements in valve technology and increased clinical experience, complications related to conduction defects after transcatheter aortic valve implantation (TAVR) have not improved as rapidly as expected. In this study, we aimed to predict the development of complete atrioventricular (AV) block and bundle branch block during and after the TAVR procedure and to investigate any changes in the cardiac conduction system before and after the procedure using electrophysiological study. Materials and methods: A total of 30 patients who were scheduled for TAVR at our cardiovascular council were planned to be included in the study. TAVR was performed on patients at Erciyes University Medical Faculty Hospital as a single center between May 2019 and August 2020 Diagnostic electrophysiological study was performed before the TAVR procedure and after its completion. Changes in the cardiac conduction system during the preprocedure, intra-procedure, and postprocedure periods were recorded. Results: Significant increases in baseline cycle length, atrial-His (AH) interval, his-ventricular (HV) interval and atrioventricular (AV) distance were observed before and after the TAVR procedure (p = 0.039, p < 0.001, p = 0.018, p < 0.001, respectively). During the TAVR procedure, the preprocedural HV interval was longer in patients who developed AV block and bundle branch block compared to those who did not and this difference was statistically significant (p = 0.024). ROC curve analysis revealed that a TAVR preprocedure HV value >59.5 ms had 86% specificity and 75% sensitivity in detecting AV block and bundle branch block (AUC = 0.83, 95% CI: 0.664-0.996, p = 0.013). The preprocedure HV distance was 98 ± 10.55ms in the group with permanent pacemaker implantation and the mean value in the group without permanent pacemaker implantation was 66.27 ± 15.55 ms, showing a borderline significant difference (p = 0.049). Conclusion: The prolongation of HV interval in patients with AV block and bundle branch block suggests that the block predominantly occurs at the infra-hisian level. Patients with longer preprocedural HV intervals should be closely monitored for the need for permanent pacemaker implantation after the TAVR procedure.

Rotors anchored by refractory islands drive torsades de pointes in an experimental model of electrical storm.

BACKGROUND: Electrical storm (ES) is a life-threatening emergency in patients at high risk of ventricular tachycardia/ventricular fibrillation (VF), but the pathophysiology and molecular basis are poorly understood. OBJECTIVE: The purpose of this study was to explore the electrophysiological substrate for experimental ES. METHODS: A model was created by inducing chronic complete atrioventricular block in defibrillator-implanted rabbits, which recapitulates QT prolongation, torsades des pointes (TdP), and VF episodes. RESULTS: Optical mapping revealed island-like regions with action potential duration (APD) prolongation in the left ventricle, leading to increased spatial APD dispersion, in rabbits with ES (defined as ≥3 VF episodes/24 h). The maximum APD and its dispersion correlated with the total number of VF episodes in vivo. TdP was initiated by an ectopic beat that failed to enter the island and formed a reentrant wave and perpetuated by rotors whose centers swirled in the periphery of the island. Epinephrine exacerbated the island by prolonging APD and enhancing APD dispersion, which was less evident after late Na+ current blockade with 10 µM ranolazine. Nonsustained ventricular tachycardia in a non-ES rabbit heart with homogeneous APD prolongation resulted from multiple foci with an electrocardiographic morphology different from TdP driven by drifting rotors in ES rabbit hearts. The neuronal Na+-channel subunit NaV1.8 was upregulated in ES rabbit left ventricular tissues and expressed within the myocardium corresponding to the island location in optically mapped ES rabbit hearts. The NaV1.8 blocker A-803467 (10 mg/kg, intravenously) attenuated QT prolongation and suppressed epinephrine-evoked TdP. CONCLUSION: A tissue island with enhanced refractoriness contributes to the generation of drifting rotors that underlies ES in this model. NaV1.8-mediated late Na+ current merits further investigation as a contributor to the substrate for ES.

Permanent His-bundle pacing using distal His-bundle electrogram-guided approach in patients with atrioventricular block.

BACKGROUND: Permanent His-bundle pacing (HBP) is effective and safe; however, the success rate of HBP is low, especially in patients with infranodal block. This study aimed to assess the efficacy and feasibility of HBP implantation using an electrophysiological guided approach targeting a distal His-bundle electrogram (HBE) in patients with atrioventricular block (AVB). METHODS: Thirty-four consecutive patients with AVB (infranodal block in 28 patients) who underwent HBP were enrolled. During implantation, we attempted to target the distal part of the HBE (distal HBE) beyond the block site based on unipolar mapping. The His-capture threshold was evaluated for 1 year after implantation. RESULTS: HBP was achieved in 26 patients and in 21 patients (75%) with infranodal block. Detection of distal HBE was significantly higher in the successful HBP group than in the HBP failure group (65.4% vs. 0%, p = .001). Among 15 patients with intra-Hisian block, 14 patients (93%) successfully achieved HBP with distal HBE detection. During the 1-year follow-up period, an increase in His-capture threshold by ≥1.0 V at 1.0 ms occurred in five (19.2%) of 26 patients. The increased His-capture threshold group exhibited significantly less detection of distal HBE (20% vs. 76.2%; odds ratio 0.078, 95% confidence interval 0.07-0.87, p = .038) and a higher His-capture threshold at implantation (2.0 ± 1.1 V vs. 1.1 ± 0.9 V; odds ratio 1.702, 95% confidence interval 1.025-2.825, p = 0.04) than the non-increased His-capture threshold group. CONCLUSION: HBP implantation guided by distal HBE approach may be feasible with subsequent stable pacing in patients with intra-Hisian and atrioventricular nodal block.

Hemodynamics-driven mathematical model of first and second heart sound generation.

NEW & NOTEWORTHY: To the best of our knowledge, this is the first hemodynamic-based heart sound generation model embedded in a complete real-time computational model of the cardiovascular system. Simulated heart sounds are similar to experimental and clinical measurements, both quantitatively and qualitatively. Our model can be used to investigate the relationships between heart sound acoustic features and hemodynamic factors/anatomical parameters.

Cardioneuroablation for Treatment of Atrioventricular Block.

[Figure: see text].

Time Course and Risk Factors of New-Onset Complete Atrioventricular Block After Transcatheter Aortic Valve Implantation.

In this study, we aimed to investigate the time course of new-onset complete atrioventricular block (CAVB) and its reversibility after transcatheter aortic valve implantation (TAVI). We analyzed 206 consecutive patients without baseline CAVB who underwent successful TAVI. The incidence of new-onset CAVB was determined to be 12.6% (26/206). Among these patients, 14 recovered from CAVB within 2 weeks (6.8%, 14/206), while the remaining 12 (5.8%, 12/206) underwent permanent pacemaker (PPM) insertion. Among the 12 patients who received the PPM, 4 were able to recover from CAVB within 4 months. Thus, only 8 among 206 patients (3.8%) showed persistent CAVB. Early-onset CAVB on the day of the procedure was the strongest predictor of PPM implantation (OR = 127). The electrocardiographic changes that occurred after TAVI were mostly recovered after 1 month. The most critical procedural factor that predicts CAVB and PPM insertion is the deep implantation (>4 mm) of a big valve (oversizing index >5.9%). In conclusion, the incidence of CAVB after TAVI was estimated to be at 12.6%. Two-thirds of these patients recovered from CAVB within 3 days, resulting in a final rate of persistent CAVB of 4%. To prevent CAVB, we have to implant an appropriate valve type with an optimal size and depth.

Bedside Electrophysiological Study Using a Temporary Pacemaker May Predict Recurrence of Atrioventricular Block After Transcatheter Aortic Valve Replacement.

High-degree atrioventricular block (HAVB) or complete heart block (CHB) is a common complication associated with transcatheter aortic valve replacement (TAVR). However, some patients with HAVB/CHB recover with time. The results of electrophysiological studies (EPSs) using permanent pacemaker implantation (PPI) in patients with suspicious HAVB/CHB are considered controversial.This study aimed to evaluate whether HAVB/CHB induction at the bedside using a temporary pacemaker can predict recurrence in patients who had recovered from HAVB/CHB after TAVR.We enrolled a total of 11 patients who had recovered from HAVB/CHB and evaluated their electrophysiology using right ventricular pacing and/or procainamide administration.HAVB/CHB induction was positive. Three patients tested positive for HAVB/CHB, whereas 8 tested negative. The ejection fraction and the interval between HAVB/CHB onset and EPS were found to be significant. HAVB/CHB positive patients underwent PPI. A patient with a balloon-expandable valve tested positive just before recovery of CHB, but tested negative 5 days later and was included in the negative group. The 4 patients who tested negative received a cardiovascular implantable electric device (CIED). We observed HAVB/CHB in 2 patients who had previously tested positive after 3 months. Among those who tested negative, those with CIED had no HAVB/CHB, and others showed neither HAVB/CHB on electrocardiogram nor experienced syncope or sudden death.Our EPS revealed that HAVB/CHB induction may predict HAVB/CHB recurrence after TAVR. Valve type and EPS timing may affect the results.

Interplay between temporal and spatial dispersion of repolarization in the initiation and perpetuation of torsades de pointes in the chronic atrioventricular block dog.

Ventricular arrhythmias, consisting of single ectopic beats (sEB), multiple EB (mEB), and torsades de pointes (TdP, defined as ≥5 beats with QRS vector twisting around isoelectric line) can be induced in the anesthetized chronic atrioventricular block (CAVB) dog by dofetilide (IKr blocker). The interplay between temporal dispersion of repolarization, quantified as short-term variability (STV), and spatial dispersion of repolarization (SDR) in the initiation and perpetuation of these arrhythmias remains unclear. Five inducible (≥3 TdPs/10 min) CAVB dogs underwent one mapping experiment and were observed for 10 min from the start of dofetilide infusion (0.025 mg/kg, 5 min). An intracardiac decapolar electrogram (EGM) catheter and 30 intramural cardiac needles in the left ventricle (LV) were introduced. STVARI was derived from 31 consecutive activation recovery intervals (ARIs) on the intracardiac EGM, using the formula: [Formula: see text]. The mean SDR3D in the LV was determined as the three-dimensional repolarization time differences between the intramural cardiac needles. Moments of measurement included baseline (BL) and after dofetilide infusion before first 1) sEB (occurrence at 100 ± 35 s), 2) mEB (224 ± 96 s), and 3) non-self-terminating TdP (454 ± 298 s). STVARI increased from 2.15 ± 0.32 ms at BL to 3.73 ± 0.99 ms* before the first sEB and remained increased without further significant progression to mEB (4.41 ± 0.45 ms*) and TdP (5.07 ± 0.84 ms*) (*P < 0.05 compared with BL). SDR3D did not change from 31 ± 11 ms at BL to 43 ± 13 ms before sEB but increased significantly before mEB (68 ± 7 ms*) and to TdP (86 ± 9 ms*+) (+P < 0.05 compared with sEB). An increase in STV contributes to the initiation of sEB, whereas an increase in SDR is important for the perpetuation of non-self-terminating TdPs.NEW & NOTEWORTHY This study compared two well-established electrophysiological parameters, being temporal and spatial dispersion of repolarization, and provided new insights into their interplay in the arrhythmogenesis of torsades de pointes arrhythmias. Although it confirmed that an increase in temporal dispersion of repolarization contributes to the initiation of single ectopic beats, it showed that an increase in spatial dispersion of repolarization is important for the perpetuation of non-self-terminating torsades de pointes arrhythmias.

Micra-AV leadless pacemaker and atrioventricular (dys)synchrony: A stepwise process.

Leadless pacemakers have become a major breakthrough in the management of bradyarrhythmia as an attractive alternative to the standard transvenous pacemakers, but safety and long-term outcomes of the new Micra-AV, which is capable guarantee atrioventricular (AV) synchrony, have been poorly described. Hence, we describe how we managed a 57-year-old patient who developed pacemaker syndrome due to significant Micra-AV dyssynchrony. This case emphasizes how leadless pacemaker AV synchrony could be overestimated, thereby requiring a stepwise process leading to adequate device reprogramming. Holter-ECG monitoring and exercise test resulted to be valuable tools for an early detection of inadequate AV synchrony, integrating and completing device reports.