Efficacy and safety of pulsed field ablation for accessory pathways: a pilot study.

AIMS: Radiofrequency ablation is used as a first-line therapy for accessory pathways (APs). However, data regarding the effects of pulsed field ablation (PFA) on APs are limited. We sought to evaluate the acute procedural and 6-month success and safety of PFA in a cohort of patients with APs. METHODS AND RESULTS: A focal contact force-sensing PFA catheter was used for patients with APs. Pulsed field ablation generator generated a bipolar and biphasic waveform (±1000 V) with a duration of 100 ms from the tip of the PFA catheter. A 100% acute procedural success was achieved in 10 conscious patients with APs (7 left anterolateral, 2 left inferolateral, and 1 right posteroseptal APs) including 6 (60%) patients after an initial application. The average total ablation time was 6.3 ± 4.9 s for 4.7 ± 1.8 ablation sites (ASs), including 3.1 ± 2.4 s at targets and 3.2 ± 2.9 s at 3.2 ± 2 bolus ASs. The mean skin-to-skin time was 59.3 ± 15.5 min, and PFA catheter dwell time was 29.4 ± 7.8 min. One patient encountered transient sinus arrest during PFA due to parasympathetic overexcitation. Sinus rhythm was restored in all patients without any significant adverse events during the short-term follow-up. CONCLUSION: Pulsed field ablation of APs was feasible, effective, and safe. Its efficiency was remarkable for its ultrarapid termination of AP conduction. Further studies are warranted to prove whether utilization of PFA with current parameters can extend to manifold AP ablation.

Outcomes Associated With Early vs. Delayed Invasive Strategy in NSTEMI Complicated by High Degree AV Block: A Nationwide Analysis.

Background: High degree atrioventricular block (HDAVB) is an uncommon complication of non-ST-segment elevation myocardial infarction (NSTEMI) that frequently necessitates pacemaker implantation. This contemporary analysis compares need for pacemaker implantation based on the timing of intervention in acute NSTEMI complicated by HDAVB.Methods: We used 2016-2017 National Inpatient Sample database to identify admissions with NSTEMI and HDAVB. Time to coronary intervention from initial admission was used to segregate the admissions into two groups: early invasive strategy (EIS) (<24 hours) and delayed invasive strategy (DIS) (>24 hours). Multivariable linear and logistic regression analysis was performed to compare in-hospital outcomes among the two groups.Results: Out of 949,984 NSTEMI related admissions, coexistent HDAVB was present in 0.7% (n=6725) patients. Amongst those, 55.61% (n=3740) hospitalizations included invasive intervention (EIS=1320, DIS=2420). Patients treated with EIS were younger (69.95 years vs. 72.38 years, P<0.05) and had concomitant cardiogenic shock. Contrarily, prevalence of chronic kidney disease, heart failure, and pulmonary hypertension was higher in DIS group. EIS was associated with lower length of stay and total hospitalization cost. In-hospital mortality and pacemaker implantation rates were not significantly different between patients in the EIS and DIS groups.Conclusion: HDAVB is a rare complication of NSTEMI and often associated with right coronary artery disease. The timing of revascularization does not appear to influence the rate of pacemaker placement in NSTEMI complicated by HDAVB. Further studies are needed to assess if early invasive strategy can benefit all patients with NSTEMI and HDAVB.

Outcomes of Heart Block in Myocarditis: A Review of 31,760 Patients.

BACKGROUND: Various electrocardiographic abnormalities, including atrioventricular conduction block, have been reported in patients with myocarditis. We performed an observation study to describe the characteristics and outcomes of inpatients diagnosed with myocarditis complicated by heart block (HB) in a large national cohort. METHODS: We identified patients with primary ICD-9 codes for myocarditis HB from the Nationwide Inpatient Sample (NIS) Database from 1998 to 2013. We compared the baseline characteristics and compared clinical outcomes between patients with and without HB, and in patients with/without high degree atrioventricular block (HDAVB). RESULTS: From the NIS database, 31,760 patients had a principal diagnosis of myocarditis and HB was reported in 1.7% of these patients (n=540). Female gender and Asian race were independently associated with HB. Out of 540 patients, 363 patients had HDAVB (67.2%) and 177 patients had not advanced HB (32.8%). Not advanced HB was not associated with an increased mortality rate compared to patients without HB (0% vs. 2.7%, p=0.315). On the other hand, the incidence of cardiogenic shock, respiratory failure and renal failure were higher in patients with HDAVB (26.2% vs. 5.0%, 33.9% vs. 5.9% and 29.2% vs. 5.5%, p<0.001 respectively). Patients with HDAVB required more procedural support (incidence of intra-aortic balloon pump 17.8% vs. 3.3%). They also had significantly longer lengths of hospital stay (9.4±9.4 vs. 4.3±8.4, p<0.001) and higher mortality (15.5% vs. 2.7%, p<0.001). Compared to myocarditis patients without HB, the odds for mortality in myocarditis patients with HDAVB 1.58 (95% CI=1.03-2.49, p=0.039). CONCLUSIONS: The incidence of HB and HDAVB among patients with acute myocarditis was 1.7% and 1.1% respectively. Female gender and Asian race were both independently associated with significant odds for the occurrence of HB and HDAVB. High degree atrioventricular block was independently associated with increased morbidity and mortality.

Case Report: Bradycardia in neonatal lupus: differential diagnosis between atrioventricular block and premature atrial contractions with block.

Neonatal lupus may be associated with severe cardiac conduction problems, including high-degree or complete atrioventricular (AV) block, necessitating immediate pacemaker implantation during the neonatal period. However, cardiac manifestations of neonatal lupus may extend beyond AV block. Our case was a full-term female neonate, who presented with fetal arrhythmia and bradycardia with a heart rate of approximately 70-75 beats per minute after birth. Neonatal lupus was diagnosed later due to positive maternal and neonatal anti-SSA/Ro antibody. High-degree AV block was considered initially but bigeminy premature atrial contractions (PACs) with block was confirmed through a detailed evaluation of an electrocardiogram, which demonstrated unfixed PP intervals and fixed RR intervals. Atrial tachycardia (AT) developed when the neonate was 23 days old. The key point that differentiates high-degree AV block from PACs with block is the PP interval. The PP interval is fixed in high-degree AV block and unfixed in PACs with block. Careful differential diagnosis is required in neonates with bradycardia because it may lead to very different management. Our case presents a good illustration of why these arrhythmias need to be differentiated. Furthermore, our case may be the first of neonatal lupus with AT.

Permanent pacemaker reduction using temporary-permanent pacemaker as a 1-month bridge after transcatheter aortic valve replacement: a prospective, multicentre, single-arm, observational study.

Background: The permanent pacemaker (PPM) implantation and pacemaker dependency rates after transcatheter aortic valve replacement (TAVR) are highly variable as some of the conduction disturbances are reversible. It remains poorly investigated how to optimise temporary pacing in these patients. This study aimed to explore the potential reduction in the PPM implantation rate using temporary-permanent pacemaker (TPPM) as a 1-month bridge. Methods: This is a prospective, multicentre, single-arm, observational study. Consecutive patients undergoing TAVR from March 1, 2022 to March 1, 2023 in 13 tertiary hospitals in China were screened. Patients who developed high-degree atrioventricular block, complete heart block, or first-degree atrioventricular block plus new onset left bundle branch block during the TAVR procedure or within 1 month after TAVR were included to receive TPPM. Patients with pre-existing PPM implantation or indications for PPM implantation before the TAVR procedure were excluded. Patients with TPPM were monitored to determine whether the conduction disturbances persisted or recovered. The primary endpoint was the rate of freedom from indications for PPM implantation 1 month after TAVR. This study is registered with ChiCTR, ChiCTR2200057931. Findings: Of 688 patients who have undergone TAVR, 71 developed conduction disturbance and met the inclusion criteria, 1 patient withdrew due to noncompliance, 70 patients received TPPM and completed follow-up. There were 41 (58.6%) men and 29 (41.4%) women in the study, with a mean age of 74.3 ± 7.3 years. At 1 month follow-up, 75.7% (53/70) of the patients with TPPM did not require PPM implantation. For 688 patients who have undergone TAVR, the rate of PPM implantation at 1 month was 2.47% (17/688, 95% CI 1.55%-3.92%), representing a significant reduction in self-comparison with the rate at 48 h after TPPM (2.47% vs. 8.28% [95% CI 6.45%-10.58%], P < 0.0001). Similar results were obtained in the subgroup analysis of patients with HAVB/CHB. Multivariate analysis revealed the baseline PR interval, difference between the membranous septum length and implantation depth, and timing of postprocedural conduction disturbance occurrence were independent predictors of freedom from indications for PPM implantation at 1 month after TAVR. Interpretation: Using TPPM as a 1-month bridge allows for a buffer period to distinguish whether conduction disturbances are reversible or persistent, resulting in a significant reduction in the PPM implantation rate after TAVR when compared with the current strategy. However, this is an observational study, the results need to be confirmed in a randomized trial. Funding: Beijing Science and Technology Plan 2022 from Beijing Municipal Science & Technology Commission.

Complete Heart Block Induced Torsades de Pointes.

High-degree atrioventricular node block is a known cause of bradycardia. Heart rate and QT interval have an inverse relation. Therefore, bradycardia can lead to prolonged QT interval, which can predispose patients to Torsades de Pointes, a life-threatening arrhythmia. Correcting the underlying etiology can often reverse the arrhythmia and prevent recurrence. For this reason, recognizing the etiology of this arrhythmia plays an essential role in management.

A challenging EP tracing.

A 69-year-old male patient with prolonged PR interval presented with narrow QRS complex tachycardia for electrophysiological study. A discussion on different possibilities is made During tachycardia, diagnosis was made as atrioventricular nodal reentrant tachycardia, trial to ablate the slow pathway was not successful to cure the tachycardia along with a high degree atrioventricular block occurs made it more challenging for diagnosis, by studying the sequence of atrial, His and ventricular potentials diagnosis was supposed to be an accessory pathway connecting the atria with ventricle.

Prognostic Implications of High-Degree Atrio-Ventricular Block in Patients with Acute Myocardial Infarction in the Contemporary Era.

BACKGROUND: High-degree atrioventricular block (HAVB) is a known complication of ST-segment elevation myocardial infarction (STEMI). We aimed to determine the prevalence and prognostic impact of HAVB in a contemporary cohort of STEMI. METHODS: Data were collected from the DIAMANTE registry that included STEMI patients admitted to our cardiac intensive care unit treated with urgent reperfusion. We studied the clinical characteristics and evolution in patients with and without HAVB at admission. RESULTS: From 1109 consecutive patients, HAVB was documented in 95 (8.6%). The right coronary artery was the culprit vessel in 84 patients with HAVB (88.4%). The independent predictors of HAVB were: male sex (OR 1.9, 95% CI 1.2-2.9), age (OR 1.03, 95% CI 1.01-1.05), involvement of right coronary artery (OR 12.4, 95% CI 7.6-20.2), and creatinine value (OR 1.5, 95% CI 1.1-2.0). A transient percutaneous pacemaker was used in 37 patients with HAVB (38.9%). Patients with HAVB had higher mortality that patients without HAVB (15.8% vs. 4.1%, p < 0.001); however, in multivariate analysis, HAVB was not an independent predictor of in-hospital mortality. CONCLUSIONS: HAVB was seen in 9% of STEMI patients and was particularly frequent in elderly males with renal failure. Patients with HAVB had a poor prognosis during hospitalization, but HAVB was not an independent predictor of in-hospital mortality.

Transient central hypoxemia due to intermittent high-degree atrioventricular block in a heart-transplanted patient diagnosed during routine electroencephalography: a case report.

BACKGROUND: Bradycardia frequently occurs in heart-transplanted patients, mainly as a temporally restricted manifestation early after transplantation and often without symptoms. A high-degree atrioventricular block is mostly symptomatic through cerebral hypoxia induced through cerebral hypoperfusion. Only a few published cases show this specific electroencephalography result in this context. The purpose of this case is to bring attention to atypical manifestations of typical cardiac complications after heart transplantation and the importance of perseverance in the diagnostic. CASE PRESENTATION: A Central European man in his 50s with history of heart transplantation 31 years previously was admitted to the internal medicine ward for short-lived recurrent episodes of generalized weakness with multiple falls but without loss of consciousness. During routine electroencephalography, the patient perceived this recurrent sensation. This episode coincided with a transient third-degree atrioventricular block followed 8-10 seconds later by a generalized slowing of the electroencephalography, reflecting cerebral hypoxia due to cerebral hypoperfusion. Holter monitoring confirmed the diagnosis. A pacemaker was implanted, consequently resolving the episodes. CONCLUSION: This case report illustrates the pathophysiological central hypoxemic origin of episodes of generalized weakness caused by a high-degree atrioventricular block in a patient surviving 29 years after heart transplant. It highlights the benefit of electroencephalography as a diagnostic tool in well-selected patients.

Conductive disturbances in the transcatheter aortic valve implantation setting: An appraisal of current knowledge and unmet needs.

New-onset conduction disturbances, including left bundle branch block and permanent pacemaker implantation, remain a major issue after transcatheter aortic valve implantation. Preprocedural risk assessment in current practice is most often limited to evaluation of the baseline electrocardiogram, whereas it may benefit from a multimodal approach, including ambulatory electrocardiogram monitoring and multidetector computed tomography. Physicians may encounter equivocal situations during the hospital phase, and the management of follow-up is not fully defined, despite the publication of several expert consensuses and the inclusion of recommendations regarding the role of electrophysiology studies and postprocedural monitoring in recent guidelines. This review provides an overview of current knowledge and future perspectives regarding the management of new-onset conduction disturbances in the setting of transcatheter aortic valve implantation, from the preprocedural phase to long-term follow-up.

Evaluation of the 2021 European Society of Cardiology guidelines in pre-existing right bundle branch block patients undergoing transcatheter aortic valve implantation with a balloon-expandable valve.

Aims: The 2021 European Society of Cardiology guidelines recommend early pacemaker implantation in pre-existing right bundle branch block (RBBB) patients who develop PR prolongation or QRS axis change after transcatheter aortic valve implantation (TAVI). We aimed to evaluate this recommendation in TAVI recipients with a balloon-expandable valve (BEV). Methods and results: We retrospectively reviewed 188 pre-existing RBBB patients without pre-existing permanent pacemaker (PPM) who underwent TAVI with a BEV at our institution in 2015-19. Patients who developed high-degree atrioventricular block (HAVB) during TAVI or within 24 h post-TAVI were excluded. Eligible patients were divided according to the guideline-directed criteria (ΔPR interval ≥20 ms and/or QRS axis change). Patients who met the criteria (n = 102, 54.3%), compared with those who did not (n = 86), had a higher prevalence of baseline right axis deviation and were more likely to have received a larger valve with greater oversizing. The 30-day delayed HAVB rate did not differ significantly between the groups (3.9% vs. 4.7%, P = 1.00; odds ratio = 0.84, 95% confidence interval = 0.20-3.45). There was also no significant difference in terms of death (5.0% vs. 8.4% at 1 year; overall log-rank P = 0.94) or a composite of death or PPM implantation (14.8% vs. 16.6% at 1 year; overall log-rank P = 0.94) during follow-up post-TAVI. The majority of PR prolongations (79.4%) and QRS axis changes (52.0%) regressed within the following 24 h. Conclusion: The present data did not demonstrate an association of significant changes in PR interval or QRS axis with heightened delayed HAVB risk in BEV recipients with pre-existing RBBB. Prospective studies are warranted to confirm these findings.

Cardiac Magnetic Resonance Imaging-Based Screening for Cardiac Sarcoidosis in Patients With Atrioventricular Block Requiring Temporary Pacing.

Background Some myocardial diseases, such as cardiac sarcoidosis, predispose to complete atrioventricular block. The European Society of Cardiology Guidelines on cardiac pacing in 2021 recommend myocardial disease screening in patients with conduction disorder requiring pacemaker with multimodality imaging, including cardiac magnetic resonance (CMR) imaging. The ability of CMR imaging to detect myocardial disease in patients with a temporary pacing wire is not well documented. Methods and Results Our myocardial disease screening protocol is based on using an active fixation pacing lead connected to a reusable extracorporeal pacing generator (temporary permanent pacemaker) as a bridge to a permanent pacemaker. From 2011 to 2019, we identified 17 patients from our CMR database who underwent CMR imaging with a temporary permanent pacemaker for atrioventricular block. We analyzed their clinical presentations, CMR data, and pacemaker therapy. All CMRs were performed without adverse events. Pacing leads induced minor artifacts to the septal myocardial segments. The extent of late gadolinium enhancement in CMR imaging was used to screen patients for the presence of myocardial disease. Patients with evidence of late gadolinium enhancement underwent endomyocardial biopsy. If considered clinically indicated, also 18-F-fluorodeoxyglucose positron emission tomography and extracardiac tissue biopsy were performed if sarcoidosis was suspected. Eventually, 8 of 17 patients (47.1%) were diagnosed with histologically confirmed granulomatous inflammatory cardiac disease. Importantly, only 1 had a previously diagnosed extracardiac sarcoidosis at the time of presentation with high-degree atrioventricular block. Conclusions CMR imaging with temporary permanent pacemaker protocol is an effective and safe early screening tool for myocardial disease in patients presenting with atrioventricular block requiring immediate, continuous pacing for bradycardia.

Unmet Needs in TAVR: Conduction Disturbances and Management of Coronary Artery Disease.

Over the past two decades, transcatheter aortic valve replacement (TAVR) swiftly evolved from a disrupting technology towards mainstream therapy in the field of severe symptomatic aortic stenosis. A series of randomized evaluations established its role in treating severe aortic stenosis patients across all surgical risk categories, paving the way for an extension of its indications to younger low-risk patients with a longer life expectancy. Therefore, managing comorbidities and limiting procedural complications, which may affect long-term outcomes, is of paramount importance. Among those, new-onset conduction disturbances and concomitant coronary artery disease remain two of the most debated issues. In the present review, we will discuss the incidence, prognostic impact, and unmet needs of patients with post-TAVR new-onset conduction disturbances and the ongoing challenges posed by the management of concomitant coronary artery disease.

Septal versus apical pacing sites in permanent right ventricular pacing: The multicentre prospective SEPTAL-PM study.

BACKGROUND: The optimal right ventricular pacing site for patients requiring pacemaker implantation for permanent atrioventricular block is a matter of debate. Long-term right ventricular apical pacing has been associated with left ventricular ejection fraction impairment and heart failure. Right ventricular septal pacing has been proposed as an alternative. AIM: The aim of this randomized prospective multicentre trial was to compare left ventricular remodelling and outcomes between right ventricular apical and septal pacing after mid-term follow-up. METHODS: Patients requiring pacemaker implantation for high-degree atrioventricular block were enrolled and randomized in a 1:1 fashion to receive a right ventricular apical or septal lead. RESULTS: A total of 141 patients were included, 69 in the septal group and 72 in the apical group. Both groups exhibited similar left ventricular ejection fractions after 18 months of follow-up (septal 57.1±11.9% vs. apical 57.4±13.4%), and left ventricular ejection fraction variation was similar in the two groups at the end of follow-up (septal -1.5±13.2% vs. apical 0.3±13.3%). Additionally, left ventricular volume, quality of life and 6-minute walk distance were similar in the two groups. However, patients in the septal group were more likely to be asymptomatic, with a significantly lower concentration of N-terminal prohormone of brain natriuretic peptide. Lastly, lead position did not impact 18-month survival. CONCLUSION: Pacing from the right ventricular apex does not have any detrimental effect on left ventricular systolic function compared with septal pacing over an 18-month period.

An unusual cause of a complete heart block in a young healthy man! (a case report).

Acute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. It is rare to see heart block as the first-and-only presentation of infectious myocarditis. We report the case of a young healthy patient who presented with syncope secondary to a complete heart block. It was caused by acute presumed viral myocarditis. The diagnosis was confirmed with cardiac magnetic resonance imaging. With close monitoring, the EKG abnormalities resolved over the following 5 days. In this case report, we present the importance of several imaging tools to diagnose a rare and reversible cause of conduction disturbances. In at-risk individuals, clinicians should rule out a treatable cause of heart block before proceeding with permanent pacemaker implantation due to enormous clinical and cost implications involved.

Contemporary practice pattern of permanent pacing for conduction disorders in inferior ST-elevation myocardial infarction.

BACKGROUND: Currently, there is no clear consensus regarding the optimal waiting period before permanent pacemaker implantation in patients with conduction disorders following an inferior myocardial infarction. HYPOTHESIS: We aimed to elucidate the contemporary practice pattern of pacing, especially the timing of pacemaker implantation, for sinoatrial node and atrioventricular (AV) conduction disorders following an inferior ST-elevation myocardial infarction (STEMI). METHODS: Using the National Inpatient Sample database from 2010 to 2014, we identified patients with a primary diagnosis of inferior STEMI. Primary conduction disorders were classified into: (a) high-degree AV block (HDAVB) consisting of complete AV block or Mobitz-type II second-degree AV block, (b) sinoatrial node dysfunction (SND), and (c) no major conduction disorders. RESULTS: Among 66 961 patients, 2706 patients (4.0%) had HDAVB, which mostly consisted of complete AV block (2594 patients). SND was observed in 393 patients (0.6%). Among the 2706 patients with HDAVB, 267 patients (9.9%) underwent permanent pacemaker. In patients with HDAVB, more than one-third (34.9%) of permanent pacemakers were placed within 72 hours after admission. The median interval from admission to permanent pacemaker implantation was 3 days (interquartile range; 2-5 days) for HDAVB vs 4 days (3-6 days) for SND (P < .001). HDAVB was associated with increased in-hospital mortality, whereas SND was not. CONCLUSIONS: In patients who developed HDAVB following an inferior STEMI, only one in 10 patients underwent permanent pacemaker implantation. Despite its highly reversible nature, permanent pacemakers were implanted relatively early.

Suspicious index in Lyme carditis: Systematic review and proposed new risk score.

BACKGROUND: Lyme carditis (LC), an early manifestation of Lyme disease that most commonly presents as high-degree atrioventricular block (AVB), usually resolves with antibiotic treatment. When LC is not identified as the cause of AVB, a permanent pacemaker may be inappropriately implanted in a reversible cardiac conduction disorder. HYPOTHESIS: The likelihood that a patient's high-degree AVB is caused by LC can be evaluated by clinical characteristics incorporated into a risk stratification tool. METHODS: A systematic review of all published cases of LC with high-degree AVB, and five cases from the authors' experience, was conducted. The results informed the development of a new risk stratification tool, the Suspicious Index in LC (SILC) score. The SILC score was then applied to each case included in the review. RESULTS: Of the 88 cases included, 51 (58%) were high-risk, 31 (35.2%) intermediate-risk, and 6 (6.8%) low-risk for LC according to the SILC score (sensitivity 93.2%). For the subset of 32 cases that reported on all SILC variables, 24 (75%) cases were classified as high-risk, 8 (25%) intermediate-risk, and 0 low-risk (sensitivity 100%). Specificity could not be assessed (no control group). Notably, 6 of the 11 patients who received permanent pacemakers had reversal of AVB with antibiotic treatment. CONCLUSION: The SILC risk score and COSTAR mnemonic (constitutional symptoms; outdoor activity; sex = male; tick bite; age < 50; rash = erythema migrans) may help to identify LC in patients presenting with high-degree AVB, and ultimately, minimize the implantation of unnecessary permanent pacemakers.