Incidence and predictors of late atrioventricular conduction recovery among patients requiring permanent pacemaker for complete heart block after cardiac surgery

Long-Term Safety and Efficacy of Intraoperative Leadless Pacemaker Implantation During Valve Surgery

BACKGROUND

Intraoperative implantation of leadless cardiac pacemakers (LCPs) under direct visualization during cardiac surgery is a novel strategy to provide pacing to patients with an elevated risk of postoperative conduction disorders or with a preexisting pacing indication undergoing valve surgery.

OBJECTIVES

This study sought to evaluate the long-term safety and efficacy of intraoperative LCP implantation in 100 consecutive patients.

METHODS

Retrospective single-center cohort study of consecutive patients (n = 100) who underwent intraoperative LCP implantation during valve surgery. Safety and efficacy were assessed at implantation and follow-up visits.

RESULTS

A total of 100 patients (age 68 ± 13 years, 47% female) underwent intraoperative LCP implantation. The surgery involved the tricuspid valve in 99 patients (99%), including tricuspid valve repair in 59 (59%) and tricuspid valve replacement in 40 (40%). Most of the patients (78%) underwent multivalve surgery. The indication for LCP implantation was elevated risk of postoperative atrioventricular block in 54% and preexisting bradyarrhythmias in 46%. LCP implantation was successful in all patients. During a median of 10.6 months (IQR: 2.0-22.7 months) of follow-up, no device-related complications occurred. At 12-month follow-up, the pacing thresholds were acceptable (≤2.0 V at 0.24 milliseconds) in 95% of patients.

CONCLUSIONS

Intraoperative LCP implantation under direct visualization is a safe strategy to provide permanent pacing in patients undergoing valve surgery, with a postoperative electrical performance comparable to percutaneously placed LCPs.

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.

A Dexamethasone-Loaded Polymeric Electrospun Construct as a Tubular Cardiovascular Implant

Cardiovascular tissue engineering is providing many solutions to cardiovascular diseases. The complex disease demands necessitating tissue-engineered constructs with enhanced functionality. In this study, we are presenting the production of a dexamethasone (DEX)-loaded electrospun tubular polymeric poly(l-lactide) (PLA) or poly(d,l-lactide-co-glycolide) (PLGA) construct which contains iPSC-CMs (induced pluripotent stem cell cardiomyocytes), HUVSMCs (human umbilical vein smooth muscle cells), and HUVECs (human umbilical vein endothelial cells) embedded in fibrin gel. The electrospun tube diameter was calculated, as well as the DEX release for 50 days for 2 different DEX concentrations. Furthermore, we investigated the influence of the polymer composition and concentration on the function of the fibrin gels by imaging and quantification of CD31, alpha-smooth muscle actin (αSMA), collagen I (col I), sarcomeric alpha actinin (SAA), and Connexin 43 (Cx43). We evaluated the cytotoxicity and cell proliferation of HUVECs and HUVSMCs cultivated in PLA and PLGA polymeric sheets. The immunohistochemistry results showed efficient iPSC-CM marker expression, while the HUVEC toxicity was higher than the respective HUVSMC value. In total, our study emphasizes the combination of fibrin gel and electrospinning in a functionalized construct, which includes three cell types and provides useful insights of the DEX release and cytotoxicity in a tissue engineering perspective.

Conduction system pacing: overview, definitions, and nomenclature

Pacing from the right ventricle is associated with an increased risk of development of congestive heart failure, increases in total and cardiac mortality, and a worsened quality of life. Conduction system pacing has become increasingly realized as an alternative to right ventricular apical pacing. Conduction system pacing from the His bundle and left bundle branch area has been shown to provide physiologic activation of the ventricle and may be an alternative to coronary sinus pacing. Conduction system pacing has been studied as an alternative for both bradycardia pacing and for heart failure pacing. In this review, we summarize the clinical results of conduction system pacing under a variety of different clinical settings. The anatomic targets of conduction system pacing are illustrated, and electrocardiographic correlates of pacing from different sites in the conduction system are defined. Ultimately, clinical trials comparing conduction system pacing with standard right ventricular apical pacing and cardiac resynchronization therapy pacing will help define its benefit and risks compared with existing techniques.

Atrioventricular conduction recovery immediately after the re-operation in a repaired CHD patient

This is a case of a 2.7-year-old girl with trisomy 21 and double outlet right ventricle who underwent epicardial pacemaker system placement for a surgical atrioventricular block and achieved atrioventricular conduction recovery immediately after residual ventricular septal defect closure. Although ventricular pacing ratio was 100% before re-operation, it declined to approximately 25% on the 6th post-operative day and was <1% 3 years after re-operation.

Iatrogenic Atrioventricular Block

Iatrogenic atrioventricular (AV) block can occur in the context of cardiac surgery, percutaneous transcatheter, or electrophysiologic procedures. In cardiac surgery, patients undergoing aortic and/or mitral valve surgery are at the highest risk for developing perioperative AV block requiring permanent pacemaker implantation. Similarly, patients undergoing transcatheter aortic valve replacement are also at increased risk for developing AV block. Electrophysiologic procedures, including catheter ablation of AV nodal re-entrant tachycardia, septal accessory pathways, para-Hisian atrial tachycardia, or premature ventricular complexes, are also associated with risk of AV conduction system injury. In this article, we summarize the common causes for iatrogenic AV block, predictors for AV block, and general management considerations.

Iatrogenic Atrioventricular Block

Iatrogenic atrioventricular (AV) block can occur in the context of cardiac surgery, percutaneous transcatheter, or electrophysiologic procedures. In cardiac surgery, patients undergoing aortic and/or mitral valve surgery are at the highest risk for developing perioperative AV block requiring permanent pacemaker implantation. Similarly, patients undergoing transcatheter aortic valve replacement are also at increased risk for developing AV block. Electrophysiologic procedures, including catheter ablation of AV nodal re-entrant tachycardia, septal accessory pathways, para-Hisian atrial tachycardia, or premature ventricular complexes, are also associated with risk of AV conduction system injury. In this article, we summarize the common causes for iatrogenic AV block, predictors for AV block, and general management considerations.

Clinical valuables related to resolution of complete or advanced atrioventricular block after steroid therapy in patients with cardiac sarcoidosis

BACKGROUND

Prediction of atrioventricular block (AVB) resolution after steroid therapy in patients with cardiac sarcoidosis (CS) is difficult.

METHODS

We identified 24 patients with CS and complete or advanced AVB receiving steroid therapy. AVB resolution was assessed by reviewing surface electrocardiogram and the percentage of ventricular pacing required on subsequent device interrogation reports.

RESULTS

AVB resolution was noted in eight (33%) patients 1 year after receiving steroid therapy. Univariate Cox regression analysis demonstrated that left ventricular ejection fraction (LVEF) (hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.01-1.14, P = .016), interval from recognized AVB to start of steroid therapy (HR 0.98, 95% CI 0.95-0.99, P < .001), and lysozyme (HR 1.51, 95% CI 1.12-2.19, P = .013) were significantly associated with resolution of AVB. Combination of area under the curve (AUC) of each variable that was significantly related to resolution of AVB (AUC, 0.969; 95% CI 0.921-1.000, P < .001) was tended to be higher compared with each variable alone.

CONCLUSIONS

A shorter interval from recognition of AVB to start of steroid therapy, higher LVEF, and higher lysozyme levels were significantly associated with resolution of AVB after steroid therapy in patients with CS. The combination of each variable could be able to distinguish patients with resolution of AVB from those without.

Post-operative cardiac implantable electronic devices in patients undergoing cardiac surgery: a contemporary experience

AIMS

Optimum timing of pacemaker implantation following cardiac surgery is a clinical challenge. European and American guidelines recommend observation, to assess recovery of atrioventricular block (AVB) (up to 7 days) and sinus node (5 days to weeks) after cardiac surgery. This study aims to determine rates of cardiac implantable electronic devices (CIEDs) implants post-surgery at a high-volume tertiary centre over 3 years. Implant timing, patient characteristics and outcomes at 6 months including pacemaker utilization were assessed.

METHODS AND RESULTS

All cardiac operations (n = 5950) were screened for CIED implantation following surgery, during the same admission, from 2015 to 2018. Data collection included patient, operative, and device characteristics; pacing utilization and complications at 6 months. A total of 250 (4.2%) implants occurred; 232 (3.9%) for bradycardia. Advanced age, infective endocarditis, left ventricle systolic impairment, and valve surgery were independent predictors for CIED implants (P < 0.0001). Relative risk (RR) of CIED implants and proportion of AVB increased with valve numbers operated (single-triple) vs. non-valve surgery: RR 5.4 (95% CI 3.9-7.6)-21.0 (11.4-38.9) CIEDs. Follow-up pacing utilization data were available in 91%. Significant utilization occurred in 82% and underutilization (<1% A and V paced) in 18%. There were no significant differences comparing utilization rates in early (≤day 5 post-operatively) vs. late implants (P = 0.55).

CONCLUSION

Multi-valve surgery has a particularly high incidence of CIED implants (14.9% double, 25.6% triple valve). Age, left ventricle systolic impairment, endocarditis, and valve surgery were independent predictors of CIED implants. Device underutilization was infrequent and uninfluenced by implant timing. Early implantation (≤5 days) should be considered in AVB post-multi-valve surgery.

Impact of early (<7 days) pacemaker implantation after cardiac surgery on long-term pacemaker dependency

OBJECTIVE

We aimed to investigate pacemaker dependency after at least 1 year in patients with early (<7 days) implantation, compared to those who received a pacemaker ≥7 days after cardiac surgery. Secondary endpoints were length of hospital stay and in-hospital complications.

METHODS

Retrospective analysis of 108 consecutive patients who received a pacemaker after cardiac surgery between 06/2012 and 06/2018. Characteristics and outcomes were compared between patients with early (<7 days) and late (≥7 days) implantation. Patients were followed up with evaluation of pacemaker dependency between April and June 2019. We identified predictors of dependency by logistic regression.

RESULTS

In total, 63.9% were men, average age 71.9 ± 11.8 years; 32 (29.6%) had early implantation, and 76 (70.4%) late implantation. After a median 3.2 years [IQR 1.9, 4.5] of follow-up, 30 patients (27.8%) had died, and there was no difference in pacemaker dependency among survivors (66.7% vs. 46.5%, early vs. late respectively, p = .15). Patients in the early group had a shorter length of stay (11.5 [9.0, 14.0] vs. 15.0 [11.5, 20] days, p = .002) and less often had new-onset atrial fibrillation (AF) post-surgery (22.7% vs. 47.8%, p = .05). The only significant predictor of dependency was aortic valve replacement surgery (OR = 4.70, 95% CI [1.36 to 16.24]).

CONCLUSION

Early implantation of a permanent pacemaker (<7 days after cardiac surgery) does not impact on the proportion of patients with long-term (>12 months) pacemaker dependency, but is associated with shorter length of stay and less frequent new-onset AF. These findings warrant prospective confirmation in randomized trials.

Whole-Exome Sequencing Identifies a Novel TRPM4 Mutation in a Chinese Family with Atrioventricular Block

Atrioventricular block (AVB) is a leading cause of sudden cardiac death, and most of AVB cases are presented as autosomal dominant. The electrocardiogram of AVB patients presents an abnormal progressive cardiac conduction disorder between atria and ventricles. Transient receptor potential melastatin 4 (TRPM4) is a nonselective Ca²⁺-activated cation channel gene defined as a novel disease-causing gene of AVB. So far, 47 mutations of TRPM4 have been recorded in Human Gene Mutation Database. The aim of this study was to explore the relationship between TRPM4 mutation and pathogenesis of AVB. We investigated a Chinese family with AVB by whole-exome sequencing. An arrhythmia-related gene filtering strategy was used to analyze the disease-causing mutations. Three different bioinformatics programs were used to predict the effects of the mutation result. A novel mutation of TRPM4 was identified (c.2455C>T/p.R819C) and cosegregated in the affected family members. The three bioinformatics programs predicted that the novel mutation may lead to damage. Our study will contribute to expand the spectrum of TRPM4 mutations and supply accurate genetic testing information for further research and the clinical therapy of AVB.

Early Versus Delayed Pacemaker for Heart Block After Valve Surgery: A Cost-Effectiveness Analysis

BACKGROUND

A significant percentage of patients who acutely develop high-grade atrioventricular block after valve surgery will ultimately recover, yet the ability to predict recovery is limited. The purpose of this analysis was to evaluate the cost-effectiveness of two different management strategies for the timing of permanent pacemaker implantation for new heart block after valve surgery.

METHODS

A cost-effectiveness model was developed using costs and probabilities of short- and long-term complications of pacemaker placement, short-term atrioventricular node recovery, intensive care unit stays, and long-term follow-up. We aggregated the total expected cost and utility of each option over a 20-y period. Quality-adjusted survival with a pacemaker was estimated from the literature and institutional patient-reported outcomes. Primary decision analysis was based on an expected recovery rate of 36.7% at 12 d with timing of pacemaker implantation: early placement (5 d) versus watchful waiting for 12 d.

RESULTS

A strategy of watchful waiting was more costly ($171,798 ± $45,695 versus $165,436 ± $52,923; P < 0.0001) but had a higher utility (9.05 ± 1.36 versus 8.55 ± 1.33 quality-adjusted life years; P < 0.0001) than an early pacemaker implantation strategy. The incremental cost-effectiveness ratio of watchful waiting was $12,724 per quality-adjusted life year. The results are sensitive to differences in quality-adjusted survival and rates of recovery of atrioventricular node function.

CONCLUSIONS

Watchful waiting for pacemaker insertion is a cost-effective management strategy compared with early placement for acute atrioventricular block after valve surgery. Although this is cost-effective from a population perspective, clinical risk scores predicting recovery will aid in personalized decision-making.

Atrioventricular Block after Tricuspid Valve Surgery

Tricuspid valve (TV) surgery is associated with a high risk of postoperative pacemaker requirement. We set out to identify the incidence of atrioventricular block (AVB) after TV surgery and determine whether atrioventricular conduction recovers within time.We investigated pre/intra- and postoperative predictors of AVB in patients who underwent tricuspid valve surgery (not only isolated TV surgery) at our institution between 2004 and 2017. Patients who had pacemakers prior to surgery were excluded.One year after surgery, 5.8% of the surviving cohort had received a pacemaker due to AVB. In the complete follow-up time, 33 out of 505 patients required pacemaker implantation because of AVB. Of the 37 patients who presented to the intensive care unit postoperatively with AVB III, 14 (38%) underwent pacemaker implantation for AVB, and 20 (54%) did not require a pacemaker. AVB III at ICU admission was identified as a predictor of pacemaker implantation (OR: 9.7, CI: 3.8-24.5, P < 0.001). TV endocarditis was also identified as a predictor (OR: 12.4, CI: 3.3-46.3, P < 0.001). Eleven out of 32 patients (34%) with tricuspid endocarditis required a pacemaker for AVB. The mean ventricular pacing burden within the first 5 years after pacemaker implantation was 79%.The issue of AVB after TV surgery is significant. Both the initial rhythm after surgery and etiology of the tricuspid disease can help predict pacemaker requirement. Within the first 5 years after surgery, the ventricular pacing burden remains high without relevant rhythm recovery.

Novel missense variant in TTN cosegregating with familial atrioventricular block

BACKGROUND

Cardiovascular diseases are the most common cause of death globally. In which atrioventricular block (AVB) is a common disorder with genetic causes, but the responsible genes have not been fully identified yet. To determine the underlying causative genes involved in cardiac AVB, here we report a three-generation Chinese family with severe autosomal dominant cardiac AVB that has been ruled out as being caused by known genes mutations.

METHODS

Whole-exome sequencing was performed in five affected family members across three generations, and co-segregation analysis was validated on other members of this family.

RESULTS

Whole-exome sequencing and subsequent co-segregation validation identified a novel germline heterozygous point missense mutation, c.49287C > A (p.N16429K), in the titin (TTN, NM_001267550.2) gene in all 5 affected family members but not in the unaffected family members, neither in the large population according to the Genome Aggregation Database (https://gnomad.broadinstitute.org/). The point mutation is predicted to be functionally deleterious by in-silico software tools. Our finding was further supported by the conservative analysis across species.

CONCLUSION

Based on this study, TTN was identified as a potential novel candidate gene for autosomal dominant AVB; this study expands the mutational spectrum of TTN gene and is the first to implicate TTN mutations as AVB disease causing in a Chinese pedigree.

Predictors of permanent pacemaker requirement after cardiac surgery for infective endocarditis

BACKGROUND

Infectious endocarditis is often complicated by conduction abnormalities at the time of presentation. Cardiac surgery is the treatment of choice for many infectious endocarditis patients, but carries an additional risk of persistent postoperative conduction abnormality. We sought to define the incidence and clinical predictors of significant postoperative conduction abnormalities necessitating permanent pacemaker implantation after cardiac surgery for infectious endocarditis.

METHODS

All consecutive patients with infectious endocarditis who were surgically treated at Cleveland Clinic from 2007 to 2013 were identified using the Cleveland Clinic Infective Endocarditis Registry and the Cardiovascular Information Registry. Patients with a pre-existing cardiac implantable electronic device were excluded. The primary outcome was the need for permanent pacemaker placement postoperatively for atrioventricular block. Regression analysis was performed to identify risk factors for permanent pacemaker requirement.

RESULTS

Among 444 infectious endocarditis patients who underwent cardiac surgery for infectious endocarditis, 57 (13%) required postoperative permanent pacemaker for atrioventricular block. Multivariable analysis identified that prolongation in preoperative PR and QRS intervals, Staphylococcus aureus as the infectious endocarditis organism, the presence of intracardiac abscess, tricuspid valve involvement, and prior valvular surgery independently predicted postoperative permanent pacemaker placement. The developed model exhibited excellent predictive ability (c-statistic 0.88) and calibration.

CONCLUSION

Infectious endocarditis cardiac surgery patients often require a postoperative permanent pacemaker. Preoperative conduction abnormality, S. aureus infection, abscess, tricuspid valve involvement, and prior valvular surgery are strong predictors of postoperative permanent pacemaker placement.

Permanent pacing and conduction recovery in patients undergoing cardiac surgery for active infective endocarditis in an Australian Tertiary Center

BACKGROUND

Postoperative heart block is common among patients undergoing surgery for infective endocarditis (IE). Limited data exists allowing cardiologists to predict who will require permanent pacemaker (PPM) implantation postoperatively. We aimed to determine the rate of postoperative PPM insertion, predictors for postoperative PPM, and describe PPM utilization and rates of device-related infection during follow-up.

MATERIALS AND METHODS

A retrospective analysis was performed of 191 consecutive patients from a single institution who underwent cardiac surgery for IE between 2001 and 2017. Preoperative and operative predictors for postoperative PPM were evaluated using univariate and multivariate logistic regression.

RESULTS

The rate of postoperative PPM implantation was 11% (17/154). The PPM group had more preoperative prolonged PR interval alone (33% vs 12%; P = .03), coexistent prolonged PR and QRS durations (13% vs 2%; P = .01), infection beyond the valve leaflets (82% vs 41%; P = .001), aortic root debridement (65% vs 23%; P = <.001), patch repair (47% vs 20%; P = .01), postoperative prolonged PR interval (50% vs 24%; P = .01), and prolonged QRS duration (47% vs 15%; P = .001). On multivariate analysis, infection beyond the valve leaflets emerged as an independent predictor for postoperative PPM (odds ratio, 1.94, 95% confidence interval, 1.14-3.28; P = .014). A reduction in PPM utilization was observed in five patients while eight patients continued to show significant ventricular pacing with no underlying rhythm at 12 months. There were no device-related infections.

CONCLUSION

Postoperative PPM was required in 11% of patients undergoing surgery for IE over a 16-year period. Infection beyond the valve leaflet was an independent predictor for postoperative PPM insertion.