Prognostic benefits of His-Purkinje capture in physiological pacemakers for bradycardia

INTRODUCTION

Clinical outcomes of long-term ventricular septal pacing (VSP) without His-Purkinje capture remain unknown. This study evaluated the differences in clinical outcomes between conduction system pacing (CSP), VSP, and right ventricular pacing (RVP).

METHODS

Consecutive patients with bradycardia indicated for pacing from 2016 to 2022 were prospectively followed for the clinical endpoints of heart failure (HF)-hospitalizations and all-cause mortality at 2 years. VSP was defined as septal pacing due to unsuccessful CSP implant or successful CSP followed by loss of His-Purkinje capture within 90 days.

RESULTS

Among 1016 patients (age 73.9 ± 11.2 years, 47% female, 48% atrioventricular block), 612 received RVP, 335 received CSP and 69 received VSP. Paced QRS duration was similar between VSP and RVP, but both significantly longer than CSP (p < .05). HF-hospitalizations occurred in 130 (13%) patients (CSP 7% vs. RVP 16% vs. VSP 13%, p = .001), and all-cause mortality in 143 (14%) patients (CSP 7% vs. RVP 19% vs. VSP 9%, p < .001). The association of pacing modality with clinical events was limited to those with ventricular pacing (Vp) > 20% (pinteraction < .05). Adjusting for clinical risk factors among patients with Vp > 20%, VSP (adjusted hazard ratio [AHR]: 4.74, 95% confidence interval [CI]: 1.57-14.36) and RVP (AHR: 3.08, 95% CI: 1.44-6.60) were associated with increased hazard of HF-hospitalizations, and RVP (2.52, 95% CI: 1.19-5.35) with increased mortality, compared to CSP. Clinical endpoints did not differ between VSP and RVP with Vp > 20%, or amongst groups with Vp < 20%.

CONCLUSION

Conduction system capture is associated with improved clinical outcomes. CSP should be preferred over VSP or RVP during pacing for bradycardia.

Comparison of Pacing Performance and Clinical Outcomes Between Left Bundle Branch and His Bundle Pacing

BACKGROUND

Left bundle branch (LBBP) and His-bundle pacing (HBP) provide physiological ventricular activation.

OBJECTIVES

This study investigated differences in feasibility, device performance, and clinical outcomes between LBBP and HBP.

METHODS

Consecutive patients with LBBP and HBP from 2018 to 2021 in 2 centers were prospectively studied. The primary endpoint was optimal device performance during follow-up, defined as the presence of pacing thresholds <2.5 V, R-wave amplitude ≥5 V, and absence of conduction system pacing (CSP)-related complications. The secondary endpoint was the composite of heart failure hospitalizations or all-cause mortality.

RESULTS

Among 338 patients, 282 underwent successful CSP (119 HBP, 163 LBBP). Success rates, CSP-related complications, and need for reoperations did not differ between LBBP and HBP (P > 0.05). Pacing thresholds were lower, whereas R-wave amplitudes and lead impedance were higher in LBBP (P < 0.05). The primary endpoint was more frequent in LBBP than HBP (79% vs 34%; P < 0.001), with LBBP independently associated with 9-fold increased odds of optimal device performance (adjusted OR: 9.31; 95% CI: 5.14-16.86). LBBP was less likely to have increased pacing thresholds by >1 V (1% vs 19% HBP, P < 0.001). The secondary outcome was less frequent in LBBP than HBP (9% vs 24%, P = 0.001), with LBBP trending towards higher event-free survival (HR: 0.62; 95% CI: 0.31-1.23). The secondary outcome was independent of pacing burden or pacing indication.

CONCLUSIONS

Despite similar feasibility and safety profiles, LBBP confers additional benefits in pacing performance and reliability, shows trends towards improved survival compared to HBP, and should be the preferred first-line CSP modality of choice.

Stroke Recurrence in Embolic Stroke of Undetermined Source Without Atrial Fibrillation on Invasive Cardiac Monitoring

BACKGROUND

More than half of patients with embolic stroke of undetermined source (ESUS) suffer from recurrent ischaemic stroke, despite the absence of atrial fibrillation (AF) on invasive cardiac monitoring (ICM). This study investigated the predictors and prognosis of recurrent stroke in ESUS without AF on ICM.

METHOD

This prospective study included patients with ESUS at two tertiary hospitals from 2015 to 2021 who underwent comprehensive neurological imaging, transthoracic echocardiography, and inpatient continuous electrographic monitoring for ≥48 hours prior to ICM for definitive exclusion of AF. Recurrent ischaemic stroke, all-cause mortality, and functional outcome by the modified Rankin scale (mRS) at 3 months were evaluated in patients without AF.

RESULTS

Of 185 consecutive patients with ESUS, AF was not detected in 163 (88%) patients (age 62±12 years, 76% men, 25% prior stroke, median time to ICM insertion 26 [7, 123] days), and stroke recurred in 24 (15%) patients. Stroke recurrences were predominantly ESUS (88%), within the first 2 years (75%), and involved a different vascular territory from qualifying ESUS (58%). Pre-existing cancer was the only independent predictor of recurrent stroke (adjusted hazard ratio [AHR] 5.43, 95% CI 1.43-20.64), recurrent ESUS (AHR 5.67, 95% CI 1.15-21.21), and higher mRS score at 3 months (ß 1.27, 95% CI 0.23-2.42). All-cause mortality occurred in 17 (10%) patients. Adjusting for age, cancer, and mRS category (≥3 vs <3), recurrent ESUS was independently associated with more than four times greater hazard of death (AHR 4.66, 95% CI 1.76-12.34).

CONCLUSIONS

Patients with recurrent ESUS are a high-risk subgroup. Studies elucidating optimal diagnostic and treatment strategies in non-AF-related ESUS are urgently required.

Conduction system versus biventricular pacing in heart failure with non-left bundle branch block

INTRODUCTION

The benefits of cardiac resynchronization therapy (CRT) with biventricular pacing (BiV) is significantly lower when applied to heart failure (HF) patients with non-left bundle branch block (LBBB) conduction delay. We investigated clinical outcomes of conduction system pacing (CSP) for CRT in non-LBBB HF.

METHODS

Consecutive HF patients with non-LBBB conduction delay undergoing CSP were propensity matched for age, sex, HF-etiology, and atrial fibrillation (AF) in a 1:1 ratio to BiV from a prospective registry of CRT recipients. Echocardiographic response was defined as an increase in left ventricular ejection fraction (LVEF) by ≥10%. The primary outcome was the composite of HF-hospitalizations or all-cause mortality.

RESULTS

A total of 96 patients were recruited (mean age 70 ± 11years, 22% female, 68% ischemic HF and 49% AF). Significant reductions in QRS duration and LV dimensions were seen only after CSP, while LVEF improved significantly in both groups (p < 0.05). Echocardiographic response occurred more frequently in CSP than BiV (51% vs. 21%, p < 0.01), with CSP independently associated with four-fold increased odds (adjusted odds ratio 4.08, 95% confidence interval [CI] 1.34-12.41). The primary outcome occurred more frequently in BiV than CSP (69% vs. 27%, p < 0.001), with CSP independently associated with 58% risk reduction (adjusted hazard ratio [AHR] 0.42, 95% CI 0.21-0.84, p = 0.01), driven by reduced all-cause mortality (AHR 0.22, 95% CI 0.07-0.68, p < 0.01), and a trend toward reduced HF-hospitalization (AHR 0.51, 95% CI 0.21-1.21, p = 0.12).

CONCLUSIONS

CSP provided greater electrical synchrony, reverse remodeling, improved cardiac function and survival compared to BiV in non-LBBB, and may be the preferred CRT strategy for non-LBBB HF.

Clinical Outcomes in Conduction System Pacing Compared to Right Ventricular Pacing in Bradycardia

BACKGROUND

Conduction system pacing (CSP) provides more physiological ventricular activation than right ventricular pacing (RVP).

OBJECTIVES

This study evaluated the differences in clinical outcomes in patients receiving CSP and RVP.

METHODS

Consecutive patients with pacemakers implanted for bradycardia from 2016 to 2021 in 2 centers were prospectively followed for the primary composite outcome of heart failure (HF) hospitalizations, upgrade to biventricular pacing, or all-cause mortality, stratified by ventricular pacing burden (Vp) .

RESULTS

Among 860 patients (mean age 74 ± 11 years, 48% female, 48% atrioventricular block), 628 received RVP and 231 received CSP (95 His-bundle pacing, 136 left bundle branch pacing). The primary outcome occurred in 217 (25%) patients, more commonly in patients with RVP than CSP (30% vs 13%, P < 0.001). In multivariable analyses, CSP was independently associated with 47% reduction of the primary outcome (adjusted hazard ratio [AHR]: 0.53; 95% CI: 0.29-0.97; P = 0.04) and HF hospitalization alone (AHR: 0.40; 95% CI: 0.17-0.95; P = 0.04), among only patients with Vp >20%. The incidence of the primary outcome was highest among RVP with Vp >20% and lowest in CSP with Vp >20% (35% vs 10%, P < 0.001). Compared with RVP with Vp >20%, both CSP with Vp >20% (AHR: 0.51; 95% CI: 0.28-0.91; P = 0.02) and all patients with Vp ≤20% (AHR: 0.73; 95% CI: 0.54-0.99; P = 0.04) were independently associated with reduced primary outcome, driven primarily by reductions in HF hospitalizations (P < 0.05). Event-free survival was similar between CSP with Vp >20% and those needing ≤20% Vp.

CONCLUSIONS

CSP significantly reduced adverse clinical outcomes for bradycardic patients requiring ventricular pacing and should be the preferred pacing modality of choice.

Use of extendable helix leads for conduction system pacing: differences in lead handling and performance: Conclusion

INTRODUCTION

Pacing leads with extendable-retractable helix (EHL) are alternatives to fixed-helix leads (FHL) for conduction system pacing (CSP), but data on handling characteristics are limited. This study evaluated a dual-center experience of lead handling and performance during CSP.

METHODS AND RESULTS

Consecutive patients with His-bundle pacing (HBP) or left bundle branch pacing (LBBP) were evaluated for the primary outcome of lead failure, defined as structural damage to the lead necessitating lead replacement. Differences in pacing characteristics were compared. Among 280 patients (mean age 74±11 years, 44% male, 50% LBBP), 246 (88%) received FHL and 34 (12%) received EHL. Of 299 leads used, lead failure occurred more frequently among patients with EHL than FHL (29% vs 2%, p<0.001), regardless of CSP modality. Majority of damaged leads (89%) in the form of helix deformation were successfully removed, with failure occurring in only 2 patients, both EHL, leading to helix fracture and retention within the septal myocardium. EHL, compared to FHL, was associated with 25-fold increased odds of lead failure (odds ratio 25.21, 95% confidence interval 7.35-86.51), and persisted after adjustment in turn for age, pacing modality and indication. CSP implant success rates did not differ by lead design (FHL 80% vs EHL 71%, p=0.18), with similar pacing thresholds at implant and follow-up. This article is protected by copyright. All rights reserved.

Acute procedural outcomes of his bundle pacing with or without electrophysiology mapping system: a multicenter study

Funding Acknowledgements

Type of funding sources: None.

Introduction

His bundle pacing (HBP) is associated with improved clinical outcomes compared to right ventricular apical pacing. However, it can be technically challenging and may result in prolonged fluoroscopy and procedural time.

Purpose

We sought to compare the feasibility of performing HBP with or without electrophysiology mapping (EP) system, focusing on evaluating acute procedural success, complication rates and short-term outcomes.

Methods

HBP patients at 3 hospitals were recruited between August 2018 to December 2020. HBP was performed with EP mapping system in 1 center, and without EP mapping in the other 2 centers. Acute procedural success was defined as either selective or non-selective His bundle capture with a threshold of less than or equal to 1.5V at 1ms at the end of procedure implantation.

Results

A total of 233 patients were recruited, of which HBP was performed with EP mapping in 77 patients (33.0%) and without EP mapping in 156 patients (67.0%). Both groups were similar in age (73.2 ± 11.0 years vs 75.3 ± 9.5 years, p = 0.125) and male sex (58.4% vs 48.1%, p = 0.136). There were more patients with ischemic heart disease (45.5% vs 22.4%, p &lt; 0.01) and reduced left ventricular ejection fraction ≤ 40% (28.6% vs 10.9%, p &lt; 0.01) in the group with EP mapping. The indications for HBP was for high-grade atrioventricular block (55.8%), sick sinus syndrome (35.6%) and cardiac resynchronization therapy (CRT) (8.6%). There were more patients who required CRT in the center with EP mapping (18.2% vs 3.8%, p &lt; 0.01). HBP was successful in 39 patients (50.6%) with EP mapping and 93 patients (59.6%) without EP mapping (p= 0.382). The median R wave at implant was similar in both groups [4.0 (2.9 – 6.2) mV vs 4.3 (4.3 – 7.0) mV, p = 0.808]. Impedance at implant (607 ± 195 ohms vs 547 ± 166 ohms, p &lt; 0.01) and selective His bundle bipolar threshold at implant [1.25 (0.75-1.75) V vs 0.7 (0.5 – 1.25) V, p = 0.01] was higher in patients with EP mapping while non-selective His bundle bipolar threshold at implant [1.75 (1.0 – 3.0) V vs 1.5 (0.9 – 2.2) V, p = 0.133] and paced QRS duration (116.4 ± 25.4 ms vs 114.4 ± 24.2 ms, p =0.655) were similar. There were no differences in procedural or fluoroscopy time between groups (111 ± 36.9 min vs 107 ± 40.7 min, p = 0.479; and 10.3 ± 8.9 min vs 12.1± 14.0 min, p = 0.328 respectively). There was a similar rate of acute procedural complications (5.2% vs 1.3%, p = 0.076) and patients requiring wound or lead revision (6.8% vs 1.9%, p = 0.115) after a median follow up duration of 205 days (67-397). The prevalence of new onset paroxysmal atrial fibrillation  (11.7% vs 4.2%, p = 0.037) and all cause mortality (12.3% vs 3.2%, p = 0.029) was increased in patients who underwent HBP with EP mapping.

Conclusion

HBP in centers with or without EP mapping showed similar acute procedure success and complication rates. The use of EP mapping system was not shown to affect procedural or fluoroscopy duration.

Submammary placement of implantable cardioverter defibrillators: a Singapore plastic surgeon experience

The use of implantable cardioverter defibrillators (ICDs) in young women has been increasing in recent years owing to greater awareness about inherited cardiac conditions that increase the risk of sudden death. Traditional placement of ICDs in the infraclavicular region among young women often leads to visible scars, a constant prominence that causes irritation from purse or bra straps and can result in body image concerns and device-related emotional distress. In this case series, two women with long QT syndrome required placement of ICDs for prevention of sudden cardiac death. Submammary placement of ICDs was performed in collaboration with electrophysiologists. We describe our local experience and technique in submammary placement of ICDs as well as the challenges faced.

Adopting permanent His bundle pacing: learning curves and medium-term outcomes

AIMS

This study aims to determine procedural characteristics, acute success rates, and medium-term outcomes of consecutive patients undergoing His bundle pacing (HBP); and learning curves of experienced electrophysiologists adopting HBP.

METHODS AND RESULTS

Consecutive HBP patients at three hospitals were recruited. Clinical characteristics, acute procedural details, and medium-term outcomes were extracted from electronic medical records. Two hundred and thirty-three patients [mean age 74.6 ± 10.1 years, 48% female, 68% narrow QRS, 71% normal left ventricular ejection fraction (LVEF), 55.8% atrioventricular block] underwent HBP. Acute procedural success was 81.1% (mean procedural and fluoroscopic times of 105.5 ± 36.5 and 13.8 ± 9.3 min). Broad QRS was associated with lower HBP success (odds ratio 0.39, P = 0.02). Fluoroscopic and procedural times decreased and plateaued after 30-40 cases per operator. Implant HBP threshold was 1.3 ± 0.7 V at 1.0 ± 0.2 ms and R wave was 5.0 ± 3.9 mV. During follow-up, loss of HBP occurred in a further 12.4% and 11.3% of patients experienced a ≥1 V increase in HBP threshold. Five (2.6%) patients required HBP revision for pacing difficulties. About 8.6% of patients had a >50% decrease in R wave but lead revision for sensing issues was not necessary. On an intention to treat basis, 56.7% of patients in whom HBP was attempted had persisting HBP capture and thresholds of <2 V.

CONCLUSION

Physicians adopting HBP should be cognizant of the learning curve and preferentially select non-dependent patients with normal QRS and LVEF, to minimize risk of lead revision. Further rises in HBP threshold may increase battery drain and need for reoperations, important considerations when choosing HBP for cardiac resynchronization therapy.

Coronary venoplasty during cardiac resynchronization therapy device implantations: Acute results and clinical outcomes

BACKGROUND

Optimal left ventricular (LV) lead placement improves response to cardiac resynchronization therapy (CRT) but can be hindered by unfavorable venous anatomy. Interventional procedures in the coronary veins have been described with promising short-term outcomes.

OBJECTIVE

The purpose of this study was to establish the safety and efficacy of percutaneous coronary venoplasty (PCV) during CRT implantation and assess medium-term lead performances and clinical outcomes against matched controls not requiring PCV.

METHODS

Each consecutive PCV case was matched according to age, gender, and bundle branch morphology to 2 controls from a large prospective registry of CRT recipients. Demographics, procedural success, lead performance, and response to CRT were tracked using a comprehensive electronic medical records system.

RESULTS

Of 422 consecutive CRT recipients treated between 2012 to 2018, 29 patients (6.9%; mean age 65.7 ± 10.7 years; 7 female; 17 ischemic cardiomyopathy; 22 left bundle branch block) required PCV, which was successful in 21 cases (72%). Target veins measuring 1.1 ± 0.6 mm were dilated by noncompliant balloons with mean diameter 2.8 ± 0.5 mm. No complications occurred. Fluoroscopic and procedural durations were longer in the PCV group (P <.01) Over mean follow-up of 33.0 ± 25.0 months, no differences in lead performance, CRT response, or 2-year survival were observed compared to the control group.

CONCLUSION

PCV during CRT device implant is typically successful, safe and associated with long-term clinical outcomes comparable to patients who did not need PCV. This is an important technique to optimize LV lead placement and maximize CRT response.

Optimal Strategies for Mitigating Sudden Cardiac Death Risk in At-risk Patients with Structural Heart Disease

This article reviews the strategies used to mitigate sudden death risks in at-risk patients with structural heart disease. The roles of implantable and non-implantable technologies to prevent arrhythmic death are discussed.

Electrocardiographic findings in pulmonary embolism

Pulmonary embolism (PE) poses a challenge to physicians, as it can be difficult to diagnose but results in significant mortality and morbidity in patients. Diagnosing PE requires an integrated approach using clinical findings, electrocardiography (ECG), blood investigations and imaging modalities. Abnormalities in ECG are common among patients with massive acute PE and can serve as a prognostic indicator. In this article, we describe the ECG presentations of two patients diagnosed with PE, and review the literature on the various types of ECG presentations and their role in predicting the prognosis of PE.

Mapping clinical journeys of Asian patients presenting to the Emergency Department with syncope: Strict adoption of international guidelines does not reduce hospitalisations

BACKGROUND

Limited data exists about management of syncope in Asia. The American College of Emergency Physicians (ACEP) and European Society of Cardiology (ESC) guidelines have defined the high-risk syncope patient. This study aims to determine the effectiveness of managing syncope in an Asian healthcare system and whether strict adherence of international guidelines would reduce hospitalizations.

METHODS

Patients attending the Emergency Department of a Singaporean tertiary hospital with syncope were identified. Clinical journeys of all patients were meticulously mapped by interrogation of a comprehensive electronic medical record system and linkages with national datasets. Primary endpoint was hospitalization. Secondary endpoints were recurrent syncope within 1year and all-cause mortality. Expected admission rates based on application of ACEP/ESC guidelines were calculated.

RESULTS

638 patients (43.8±22.4years, 49.0% male) presented with syncope. 48.9% were hospitalized for 2.9±3.2days. Yields of common investigations ranged from 0 to 11.5% and no diagnosis was reached in 51.5% of patients. Diuretics use (HR 5.1, p=0.01) and prior hospitalization for syncope (HR 6.9, p<0.01) predicted recurrent syncope. Over 2.8 SD 0.3years of follow-up, 40 deaths occurred. 24 patients who died within 12months of presentation were admitted or had a firm diagnosis upon discharge. Application of guidelines did not significantly reduce hospitalisations, with limited agreement which patients warrant admission. (Actual 376, ACEP 354, ESC 391 admissions, p=NS).

CONCLUSIONS

Unstructured management of syncope results in nearly half of patients being admitted and substantial healthcare expenditures, yet with limited diagnostic yield. Strict adoption of ACEP or ESC guidelines does not reduce admissions.

Visit-to-visit variability in LDL- and HDL-cholesterol is associated with adverse events after ST-segment elevation myocardial infarction: A 5-year follow-up study

INTRODUCTION

We evaluated the relationship between visit-to-visit low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) variability and 5-year clinical outcomes in patients who presented with ST-segment elevation myocardial infarction (STEMI).

METHODS

130 patients presenting with STEMI and surviving to discharge were analyzed. Visit-to-visit LDL-C and HDL-C variability was evaluated from 2 months after discharge on the basis of corrected variation independent of mean (cVIM, primary measure), coefficient of variation and standard deviation. Major adverse cardiac event (MACE) included death, myocardial infarction, stroke, unplanned revascularization, and heart failure admission.

RESULTS

After an average of 62.4 ± 30.5 months follow-up, 41 patients (31.5%) had experienced MACE. Compared with the non-MACE group, the MACE group had a higher visit-to-visit LDL-C variability (cVIM: 0.23 ± 0.11 vs. 0.19 ± 0.08; p = 0.049; coefficient of variation: 0.24 ± 0.12 vs. 0.19 ± 0.00; p = 0.019; standard deviation: 24.1 ± 14.5 vs. 17.6 ± 10.0; p = 0.006), mean follow-up LDL-C (p = 0.033) and a higher prevalence of diabetes mellitus (p = 0.012). After adjusting for mean follow-up cholesterol levels and diabetes mellitus, each 0.01 cVIM increase in LDL-C and HDL-C variability increased the risk of MACE by 3.4% (HR: 1.034; 95% CI: 1.004 to 1.065; p = 0.025) and 6.8% (HR: 1.068; 95% CI: 1.003 to 1.137; p = 0.04), respectively. Results derived from coefficient of variation and standard deviation as measures of cholesterol variability were similar.

CONCLUSION

This is the first report to show an independent association between visit-to-visit LDL-C and HDL-C variability and long-term MACE in patients presenting with STEMI.

Assessment of the nutritional status of urban homeless adults

Homeless people eat foods at municipal and charity run shelters, fast-food restaurants, delicatessens, and from garbage bins. Data on the adequacy of the diets and the nutritional status of homeless persons are sparse. Therefore, nutritional indicators of 55 urban homeless subjects were assessed, and a high prevalence of risk factors was identified. Although 93 percent of subjects reported that they obtained enough to eat, a low dietary adequacy score of 10.1 (norm = 16) indicated that the quality of the diet was inadequate. Diet records showed a high intake of sodium, saturated fat, and cholesterol. Serum cholesterol levels above the desirable limit of 200 mg per dl were prevalent. Anthropometric measurements were significantly different from percentile distributions of the U.S. population (P less than .001). Triceps skinfold measurement was above the 95th percentile in 25 percent of subjects. Upper arm muscle area, which reflects lean body mass, was below the 5th percentile in 23.3 percent of women and 44 percent of the men. These decreased levels of lean body mass and increased levels of body fat, together with the elevated serum cholesterol levels and the shortages of essential nutrients in the diet, may place the homeless at risk of developing nutrition-related disorders.