Determination of optimum levels of binding antibody units (BAU) of new quantitative chemiluminescent immuno-assay (CLIA) in COVID-19 vaccinated volunteer blood donors

BACKGROUND

For assessment of COVID-19 vaccine efficacy, neutralization activity of anti-SARS-CoV-2 antibody is measured. This study was undertaken to determine optimum levels of binding antibody units (BAU/ml) in new quantitative chemiluminescent assay (CLIA) that corresponded to neutralizing potential (30% inhibition) of sVNT assay.

METHODS

Ninety-one blood samples were analyzed by CLIA and sVNT assays. Test samples (n = 75) were collected from blood donors post-2nd vaccination dose, while control samples (n = 16) were archived pre-COVID donor samples. Correlation between CLIA and sVNT was calculated and receiver operating characteristic (ROC) curve was drawn and analyzed.

RESULTS

Results indicated excellent correlation between 57.5 BAU/ml on CLIA and 30%inhibition on sVNT assay. ROC curve analysis revealed that the area under the curve (AUC) was 0.971.

DISCUSSION

The present study determined that 57.5 BAU/ml on CLIA corresponded to 30% inhibition on sVNT assay. Periodic quantitative analysis.

Worsening tricuspid regurgitation associated with permanent pacemaker and implantable cardioverter-defibrillator implantation: A systematic review and meta-analysis of more than 66,000 subjects

BACKGROUND

Worsening tricuspid regurgitation (TR) after either permanent pacemaker (PPM) or implantable cardioverter-defibrillator (ICD) implantation is an emerging clinical challenge. Early recognition of this entity is essential in guiding treatment.

OBJECTIVE

This meta-analysis was designed to identify the overall incidence and patient-specific predictors of TR post-device implantation.

METHODS

We searched electronic databases from inception to January 2023 for published studies that reported the incidence of TR worsening post-device implantation. The log odds ratio (OR) was used to summarize group differences.

RESULTS

Our analysis included 29 studies with 66,590 participants. Patients who underwent device implantation (n = 1008) were significantly more likely to develop worsening TR than controls who did not undergo device implantation (n = 58,605) (OR 3.18; P < .01). In a total of 7777 patients, the pooled incidence of at least 1-grade worsening of TR post-device implantation was 24%. Worsening TR post-device implantation significantly increases mortality (hazard ratio 1.42; P = .02). Larger right atrial area (OR 1.11; P < .01) is significantly associated with an increased risk of worsening TR post-device implantation, while male patients are less likely to develop this complication than female patients (OR 0.74; P < .01). Importantly, there is no statistically significant difference between the type of implanted device (ICD vs PPM) and post-device implantation TR. Further, right ventricular dysfunction, pulmonary artery pressure, baseline mitral regurgitation, left ventricular ejection fraction, baseline atrial fibrillation, and age have no association with worsening TR post-device implantation.

CONCLUSION

A substantial number of patients undergoing PPM or ICD implantation are at an increased risk of worsening TR. Importantly, in this largest review to date incorporating more than 66,000 subjects, worsening TR significantly increases mortality by greater than 140%, accordingly deserving more recognition and clinical attention in the current era.

Subcutaneous implantable cardioverter-defibrillator implantation position predicts successful defibrillation in obese and non-obese patients

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an alternative to transvenous ICDs for patients without a need for cardiac pacing. Obese patients have been proposed to be at higher risk for conversion failure with S-ICDs due to subcutaneous fat underneath the device. Optimal device positioning may promote equivalent outcomes between obese and non-obese patients by minimizing the effects of excess adipose tissue.

METHODS

A retrospective analysis of patients undergoing defibrillation testing at the time of S-ICD implantation was performed. The primary endpoint was the rate of successful conversion of ventricular fibrillation (VF) at the time of implant. The secondary endpoint was shock impedance.

RESULTS

A total of 184 patients were included in the study. The rate of successful conversion of VF was 90.3% for obese patients (n = 72) and 96.4% for non-obese patients (n = 112) (p = 0.086). Compared to non-obese patients, obese patients had a higher mean PRAETORIAN score (78.5 ± 58.1 vs. 48.8 ± 35.5, p < 0.001) and higher measured mean impedance (82.0 ohms ± 26.5 vs. 69.8 ohms ± 19.3, p < 0.001). Patients with a PRAETORIAN score < 90 all had successful defibrillation testing regardless of BMI.

CONCLUSIONS

In this study, a PRAETORIAN score < 90 was associated with a 100% success rate of defibrillation testing following S-ICD implantation regardless of patient body mass index (BMI). Thus, the impact of obesity on impedance and the risk of failed shocks may be minimized with close attention to implantation technique to achieve a low PRAETORIAN score.

Wide area circumferential ablation for pulmonary vein isolation using radiofrequency versus laser balloon ablation

Background

Persistent atrial fibrillation (AF) is associated with high recurrence rates of AF and atypical atrial flutters or tachycardia (AFT) postablation. Laser balloon (LB) ablation of the pulmonary vein (PV) ostia has similar efficacy as radiofrequency wide area circumferential ablation (RF‐WACA); however, an approach of LB wide area circumferential ablation (LB‐WACA) may further improve success rates.

Objective

To evaluate freedom from atrial tachyarrhythmia (AFT/AF) recurrence postablation using RF‐WACA versus LB‐WACA in persistent AF patients.

Methods

This was a retrospective multicenter study. Patients were followed for up to 24 months via office visits, Holter, and/or device monitoring. The primary endpoint was freedom from AFT/AF after a single ablation procedure. Secondary endpoints included freedom from AF, freedom from AFT, first‐pass isolation of all PVs, and procedural complications.

Results

Two hundred and four patients were studied (LB‐WACA: n = 103; RF‐WACA: n = 101). Patients’ baseline characteristics were similar except patients in the RF‐WACA group were older (64 vs. 68, p = .03). First‐pass isolation was achieved more often during LBA (LB‐WACA: 88% vs. RF‐WACA 75%; p = .04). Procedure (p = .36), LA dwell (p = .41), and fluoroscopy (p = .44) time were similar. The mean follow‐up was 506 ± 279 days. Sixty‐six patients had arrhythmic events including 24 AFT and 59 AF recurrences. LB‐WACA group had higher arrhythmia‐free survival (p = .009) after single ablation procedures. In the multivariate Cox regression model, RF‐WACA was associated with a higher recurrence of AFT compared with LB‐WACA (Adjusted HR 3.16 [95% CI: 1.13–8.83]; p = .03).

Conclusions

LB‐WACA was associated with higher freedom from atrial arrhythmias mostly driven by the lower occurrence of AFT compared with RF‐WACA.

Mortality benefit of catheter ablation versus medical therapy in atrial fibrillation: An RCT only meta-analysis

INTRODUCTION

Catheter ablation for atrial fibrillation (AF) in comparison to medical therapy alone is known to improve freedom from arrhythmia and quality of life, but the benefit regarding mortality is unclear. The publication of several recent large randomized controlled trials (RCT) comparing ablation with medical therapy has warranted an updated meta-analysis.

METHODS

We sought to compare the effectiveness of catheter ablation versus medical therapy only in patients with AF. MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched from inception until 04/30/2021. Relevant RCTs comparing catheter ablation versus medical therapy in patients with AF were selected.

RESULTS

A total of 24 RCTs involving 5730 adult patients were included (2992 in catheter ablation and 2738 in medical therapy). There was a reduction in all-cause mortality with catheter ablation compared with medical therapy only (risk ratio (RR) 0.70 [95% confidence interval (CI) 0.55-0.89]; p = .003). Catheter ablation also demonstrated a reduction in hospitalizations (RR 0.50 [95% CI 0.36-0.70]; p < .001), improvement in left ventricular ejection fraction (LVEF) (mean difference [MD] + 5.94% [95% CI 0.40-11.48] p = .04), greater freedom from atrial arrhythmia (RR 2.23 [95% CI 1.79-2.76]; p < .001), and AF (RR 1.95 [95% CI 1.44-2.66]; p < .001). In subgroup analysis, catheter ablation demonstrated a significant reduction in mortality and hospitalizations among patients with reduced LVEF, and when ablation was compared with antiarrhythmic drug use.

CONCLUSIONS

In comparison to medical therapy only, catheter ablation for atrial fibrillation reduces mortality, hospitalizations, and increases freedom from arrhythmia.

Clinical outcomes of left bundle branch area pacing compared to right ventricular pacing: Results from the Geisinger-Rush Conduction System Pacing Registry

BACKGROUND

Left bundle branch area pacing (LBBAP) has been shown to be a feasible option for patients requiring ventricular pacing.

OBJECTIVE

The purpose of this study was to compare clinical outcomes between LBBAP and RVP among patients undergoing pacemaker implantation METHODS: This observational registry included patients who underwent pacemaker implantations with LBBAP or RVP for bradycardia indications between April 2018 and October 2020. The primary composite outcome included all-cause mortality, heart failure hospitalization (HFH), or upgrade to biventricular pacing. Secondary outcomes included the composite endpoint among patients with a prespecified burden of ventricular pacing and individual outcomes.

RESULTS

A total of 703 patients met inclusion criteria (321 LBBAP and 382 RVP). QRS duration during LBBAP was similar to baseline (121 ± 23 ms vs 117 ± 30 ms; P = .302) and was narrower compared to RVP (121 ± 23 ms vs 156 ± 27 ms; P <.001). The primary composite outcome was significantly lower with LBBAP (10.0%) compared to RVP (23.3%) (hazard ratio [HR] 0.46; 95%T confidence interval [CI] 0.306-0.695; P <.001). Among patients with ventricular pacing burden >20%, LBBAP was associated with significant reduction in the primary outcome compared to RVP (8.4% vs 26.1%; HR 0.32; 95% CI 0.187-0.540; P <.001). LBBAP was also associated with significant reduction in mortality (7.8% vs 15%; HR 0.59; P = .03) and HFH (3.7% vs 10.5%; HR 0.38; P = .004).

CONCLUSION

LBBAP resulted in improved clinical outcomes compared to RVP. Higher burden of ventricular pacing (>20%) was the primary driver of these outcome differences.

High-power short duration vs. conventional radiofrequency ablation of atrial fibrillation: a systematic review and meta-analysis

AIMS

We sought to compare the effectiveness and safety of high-power short-duration (HPSD) radiofrequency ablation (RFA) with conventional RFA in patients with atrial fibrillation (AF).

METHODS AND RESULTS

MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched until 15 May 2020 for relevant studies comparing HPSD vs. conventional RFA in patients undergoing initial catheter ablation for AF. A total of 15 studies involving 3718 adult patients were included in our meta-analysis (2357 in HPSD RFA and 1361 in conventional RFA). Freedom from atrial arrhythmia was higher in HPSD RFA when compared with conventional RFA [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.10-1.90; P = 0.009]. Acute PV reconnection was lower (OR 0.56, P = 0.005) and first-pass isolation was higher (OR 3.58, P < 0.001) with HPSD RFA. There was no difference in total complications between the two groups (P = 0.19). Total procedure duration [mean difference (MD) -37.35 min, P < 0.001], fluoroscopy duration (MD -5.23 min, P = 0.001), and RF ablation time (MD -16.26 min, P < 0.001) were all significantly lower in HPSD RFA. High-power short-duration RFA also demonstrated higher freedom from atrial arrhythmia in the subgroup analysis of patients with paroxysmal AF (OR 1.80, 95% CI 1.29-2.50; P < 0.001), studies with ≥50 W protocol in the HPSD RFA group (OR 1.53, 95% CI 1.08-2.18; P = 0.02] and studies with contact force sensing catheter use (OR 1.65, 95% CI 1.21-2.25; P = 0.002).

CONCLUSION

High-power short-duration RFA was associated with better procedural effectiveness when compared with conventional RFA with comparable safety and shorter procedural duration.

Use of infrared thermography to delineate temperature gradients and critical isotherms during catheter ablation with normal and half normal saline: Implications for safety and efficacy

BACKGROUND

Radiofrequency (RF) ablation with half-normal saline (HNS) has shown promise as a bail-out strategy following failed ventricular tachycardia ablation using standard approaches.

OBJECTIVE

To use a novel infrared thermal imaging (ITI) model to evaluate biophysical and lesion characteristics during RF ablation using normal saline (NS) and HNS irrigation.

METHODS

Left ventricular strips of myocardium were excised from fresh porcine hearts. RF ablation was performed using an open-irrigated ablation catheter (Thermocool ST/SF) with NS (n = 75) and HNS (n = 75) irrigation using different power settings (40/50 W), RF durations (30/60 s), contact force of 10-15 g, and flow rate of 15 ml/min. RF lesions were recorded using an infrared thermal camera and border zone, lethal, 100° isotherms were matched with necrotic borders after 2% triphenyltetrazolium chloride staining. Lesion dimensions and isotherms (mm² ) were measured.

RESULTS

In total, 150 lesions were delivered. HNS lesions were deeper (6.4 ± 1.1 vs. 5.7 ±0.8 mm; p = .03), and larger in volume (633 ± 153 vs. 468 ± 107 mm³ ; p = .007) than NS lesions. Steam pops (SPs) occurred during 19/75 lesions (25%) in the NS group and 32/75 lesions (43%) in the HNS group (p = .34). Lethal (57.8 ± 6.5 vs. 36.0 ± 3.9 mm² ; p = .001) and 100°C isotherm areas (16.9 ± 6.9 vs. 3.8 ± 4.2 mm² ; p = .003) areas were larger and were reached earlier in the HNS group.

CONCLUSIONS

RFA using HNS created larger lesions than NS irrigation but led to more frequent SPs. The presence of earlier lethal isotherms and temperature rises above 100°C on ITI suggest a potentially narrower therapeutic-safety window with HNS.

Development of New-Onset or Progressive Atrial Fibrillation in Patients With Permanent HIS Bundle Pacing Versus Right Ventricular Pacing: Results From the RUSH HBP Registry

Background

Conventional right ventricular pacing (RVP) has been associated with an increased incidence of atrial fibrillation (AF). We sought to compare the occurrence of new‐onset AF and assessed AF disease progression during long‐term follow‐up between His bundle pacing (HBP) and RVP.

Methods and Results

We included patients undergoing initial dual‐chamber pacemaker implants at Rush University Medical Center between January 1, 2016, and June 30, 2019. A total of 360 patients were evaluated, and 225 patients (HBP, n=105; RVP, n=120) were included in the study. Among the 148 patients (HBP, n=72; RVP, n=76) with no history of AF, HBP demonstrated a lower risk of new‐onset AF (adjusted hazard ratio [HR], 0.53; 95% CI, 0.28–0.99; P=0.046) compared with traditional RVP. This benefit was observed with His or RVP burden exceeding 20% (HR, 0.29; 95% CI, 0.13–0.64; P=0.002), ≥40% (HR, 0.31; P=0.007), ≥60% (HR, 0.35; P=0.015), and ≥80% (HR, 0.40; P=0.038). There was no difference with His or RV pacing burden <20% (HR, 0.613; 95% CI, 0.213–1.864; P=0.404). In patients with a prior history of AF, there was no difference in AF progression (P=0.715); however, in a subgroup of patients with a pacing burden ≥40%, HBP demonstrated a trend toward a lower risk of AF progression (HR, 0.19; 95% CI, 0.03–1.16; P=0.072).

Conclusions

HBP demonstrated a lower risk of new‐onset AF compared with RVP, which was primarily observed at a higher pacing burden.

Cryoballoon Ablation and Bipolar Voltage Mapping in Patients With Left Atrial Appendage Occlusion Devices

Left atrial appendage occlusion is utilized as a second line therapy to long-term oral anticoagulation in appropriately selected patients with atrial fibrillation (AF). We examined the feasibility of cryoballoon (CB) pulmonary vein isolation (PVI) subsequent to Watchman device implantation. The study prospectively identified patients with Watchman devices (>90 days old) who underwent CB-PVI ablation between 2018 and 2019. Twelve consecutive patients (male 50%; mean age 71 ± 9 years; CHA₂DS₂-VASc score 3.4 ± 1.1) underwent CB-PVI procedures after Watchman device implantation (mean 182 ± 82 days). Acute PVI was achieved in 100% of patients. All patients had evidence of complete (n = 9) or partial (n = 3) endothelialization of the surface of the Watchman device with conductive tissue properties demonstrated during electrophysiologic testing. There were no major procedure-related complications including death, stroke, pericardial effusion, device dislodgment, device thrombus, or new or increasing peri-device leak. Mean peri-device leak size (45-day postimplant: 0.06 ± 0.09 mm vs Post-PVI: 0.04 ± 0.06 mm; p = 0.61) remained unchanged. Two patients had recurrence of AF after the 90-day blanking period (13.2 ± 6.6 months). One patient underwent a redo ablation procedure for recurrent AF. This pilot study suggests the potential feasibility of CB-PVI ablation in patients with chronic Watchman left atrial appendage occlusion devices. Larger prospective studies are needed to confirm the clinical efficacy and safety of this approach.

Sensors for rate-adaptive pacing: How they work, strengths, and limitations

Chronotropic incompetence is the inability of the sinus node to increase heart rate commensurate with increased metabolic demand. Cardiac pacing alone may be insufficient to address exercise intolerance, fatigue, dyspnea on exertion, and other symptoms of chronotropic incompetence. Rate-responsive (adaptive) pacing employs sensors to detect physical or physiological indices and mimic the response of the normal sinus node. This review describes the development, strengths, and limitations of a variety of sensors that have been employed to address chronotropic incompetence. A mini-tutorial on programming rate-adaptive parameters is included along with emphasis that patients' lifestyles and underlying medical conditions require careful consideration. In addition, special sensor applications used to respond prophylactically to physiologic signals are detailed and an in-depth discussion of sensors as a potential aid in heart failure management is provided.

A systematic review and meta-analysis comparing second-generation cryoballoon and contact force radiofrequency ablation for initial ablation of paroxysmal and persistent atrial fibrillation

INTRODUCTION

Cryoballoon ablation (CBA) and radiofrequency ablation (RFA) are the preferred modalities for catheter ablation of atrial fibrillation (AF). Technological advances have improved procedural outcomes, warranting an updated comparison. We sought to evaluate the efficacy and safety of CBA-2nd generation (CBA-2G) in comparison to RFA-contact force (RFA-CF) in patients with AF.

METHODS

MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched until 03/01/2020 for relevant studies comparing CBA-2G versus RFA-CF in patients undergoing initial catheter ablation for AF.

RESULTS

A total of 17 studies, involving 11 793 patients were included. There was no difference between the two groups in the outcomes of freedom from atrial arrhythmia (p = .67) and total procedural complications (p = .65). There was a higher incidence of phrenic nerve palsy in CBA-2G (odds ratio: 10.7; 95% confidence interval [CI]: 5.85 to 19.55; p < .001). Procedure duration was shorter (mean difference: -31.32 min; 95% CI: -40.73 to -21.92; p < .001) and fluoroscopy duration was longer (+3.21 min; 95% CI: 1.09 to 5.33; p = .003) in CBA-2G compared to RFA-CF. In the subgroup analyses of patients with persistent AF and >1 freeze lesion delivered per vein, there was no difference in freedom from atrial arrhythmia.

CONCLUSIONS

In AF patients undergoing initial ablation, CBA-2G and RFA-CF were equally efficacious. The procedure duration was shorter, but with a higher incidence of phrenic nerve palsy in CBA-2G. In patients with persistent AF, there was no difference in the efficacy between CBA-2G or RFA-CF techniques.

Supplemental Radiofrequency Ablation After Acutely Unsuccessful Cryoballoon Pulmonary Vein Isolation is Associated With Increased Risk of Recurrent Atrial Fibrillation

Background

Cryoballoon (CB) ablation is widely performed for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Anatomic variations in patient pulmonary vein (PV) anatomy are believed to impact short‐ and long‐term procedural success of CB PVI.

Methods and Results

We hypothesized that failure of initial PV isolation with a standard technique (ie, requiring >2 freeze cycles per PV and/or radiofrequency ablation [RFA] to achieve PV isolation) during index CB PVI procedures would be associated with decreased freedom from AF. We examined a cohort of 177 consecutive patients with drug‐refractory AF who underwent CB PVI with a 28‐mm balloon second‐generation CB device. Mean follow‐up time was 19±9 months. Forty‐three patients had AF recurrence after the 90‐day blanking period after ablation. In 40 patients, acute isolation of one or more PVs could not be achieved by CB ablation with the standard technique (single freeze with or without bonus freeze). To obtain complete acute PVI, 15 patients received extra freeze applications, 20 required supplemental RFA, and 5 received both extra freeze applications and supplemental RFA. Multivariate regression analysis revealed supplemental RFA use during index CB PVI procedures was independently associated with a threefold increased risk of AF recurrence (adjusted hazard ratio, 3.01; 1.45–10.87; P=0.003).

Conclusions

Use of supplemental RFA during CB PVI procedures to assist with isolation of one or more PVs was independently associated with increased risk of AF recurrence. Use of additional freezes to achieve PVI did not increase the risk for recurrent AF.

Comparison between minimal fluoroscopy and conventional approaches for visually guided laser balloon pulmonary vein isolation ablation

INTRODUCTION

Although balloon-based techniques, such as the laser balloon (LB) ablation have simplified pulmonary vein isolation (PVI), procedural fluoroscopy usage remains higher in comparison to radiofrequency PVI approaches due to limited 3-dimensional mapping system integration.

METHODS

In this prospective study, 50 consecutive patients were randomly assigned in alternating fashion to a low fluoroscopy group (LFG; n = 25) or conventional fluoroscopy group (CFG; n = 25) and underwent de novo PVI procedures using visually guided LB technique.

RESULTS

There was no statistical difference in baseline characteristics or cross-overs between treatment groups. Acute PVI was accomplished in all patients. Mean follow up was 318 ± 69 days. Clinical recurrence of atrial fibrillation after PVI was similar between groups (CFG: 19% vs LFG: 15%; P = .72). Total fluoroscopy time was significantly lower in the LFG than the CFG (1.7 ± 1.4  vs 16.9 ± 5.9 minutes; P < .001) despite similar total procedure duration (143 ± 22 vs 148 ± 22 minutes; P = .42) and mean LA dwell time (63 ± 15 vs 59 ± 10 minutes; P = .28). Mean dose area product was significantly lower in the LFG (181 ± 125 vs 1980 ± 750 μGym² ; P < .001). Fluoroscopy usage after transseptal access was substantially lower in the LFG (0.63 ± 0.43 vs 11.70 ± 4.32 minutes; P < .001). Complications rates were similar between both groups (4% vs 2%; P = .57).

CONCLUSIONS

This study demonstrates that LB PVI can be safely achieved using a novel low fluoroscopy protocol while also substantially reducing fluoroscopy usage and radiation exposure in comparison to conventional approaches for LB ablation.

Derivation of whole blood biomonitoring equivalents for titanium for the interpretation of biomonitoring data

Biomonitoring equivalents (BEs) have been increasingly applied for biomonitoring purposes by regulatory bodies worldwide. The present report describes the development of a BE for titanium based on a 4-step process: (i) identification of a critical study/point of departure (PoD) supporting an established oral exposure guidance value (OEGV);, (ii) review the available oral PK data and application of a pharmacokinetic model for titanium; (iii) selection of the most appropriate biomarker of exposure in a specific tissue and calculation of steady-state tissue levels corresponding to the PoD in the critical study; and (iv) derivation of BE value adjusting for the uncertainties considered in the original OEGV assessment. Using the above 4-step approach, a blood BE value of 32.5 μg titanium/L was derived. Key components of the analysis included a pharmacokinetic model developed by investigators at the Netherlands National Institute of Public Health (RIVM) and a two-year rodent bioassay of titanium conducted by the US National Cancer Institute. The most sensitive pharmacokinetic parameter involved in the current BE derivation is the oral absorption factor of 0.02%. The provisional BE proposed in this article may be updated as new information on the pharmacokinetics of titanium becomes available.

Near-zero Fluoroscopic Approach for Laser Balloon Pulmonary Vein Isolation Ablation: A Case Study

Fluoroscopy remains a cornerstone imaging modality for catheter placement and positioning in electrophysiology device and ablation procedures. However, efforts are being made to reduce the cumulative exposure to radiation in the patient and physician alike. We present the case of a 59-year-old male patient with hypertension, chronic kidney disease, and paroxysmal atrial fibrillation who underwent successful near-fluoroless laser balloon (LB) pulmonary vein isolation (PVI) ablation. Though this case demonstrates the usage of a novel protocol for near-fluoroless LB ablation that resulted in successful, uncomplicated acute PVI, the feasibility and safety of this technique should be validated in a larger series or prospective comparative study.

Meta-analysis of pulmonary vein isolation ablation for atrial fibrillation conventional vs low- and zero-fluoroscopy approaches

INTRODUCTION

Radiation exposure during catheter ablation procedures is a significant hazard for both patients and operators. Atrial fibrillation (AF) ablation procedures have been historically associated with higher fluoroscopy usage than other electrophysiology procedures. Recent efforts have been made to reduce dependence on fluoroscopy during pulmonary vein isolation (PVI) ablation procedures using alternative techniques.

METHODS

We performed a meta-analysis of studies comparing zero or low fluoroscopy (LF) vs conventional fluoroscopy (CF) approaches for AF ablation. Outcomes of interest included acute and 12-month procedural efficacy, safety, procedure duration, fluoroscopy time, and dose area product. Aggregated data were analyzed with random-effects models, using a Bayesian hierarchical approach.

RESULTS

A total of 2228 participants (LF, n = 1190 vs CF, n = 1038) from 15 studies were included in the meta-analysis. Risk of AF recurrence in 12 months (odds ratio [OR], 95% confidence interval [95% CI] = 1.343 [0.771-2.340]; P = .297), redo-ablation procedures (OR [95% CI] = 0.521 [0.198-1.323]; P = .186), and procedural complications (OR [95% CI] = 0.99 [0.485-2.204]; P = .979) were similar between LF- and CF-ablation groups. In comparison to CF ablation, LF ablation led to shorter procedure duration (weighted mean differences [WMDs] [95% CI] = -14.6 minutes [-22.5 to -6.8]; P < .001), fluoroscopy time (WMD [95% CI] = -8.8 minutes [-11.9 to -5.9]; P < .001), and dose area product (WMD [95% CI] = -1946 mGy/cm² [-2685 to 1207]; P < .001).

CONCLUSION

LF approaches have similar clinical efficacy and safety as CF approaches for PVI. LF approaches are associated with shorter procedure time, fluoroscopy usage, and dose area product during PVI.

Derivation of whole blood biomonitoring equivalents for lithium for the interpretation of biomonitoring data

INTRODUCTION

Lithium salts have numerous industrial uses and are also used in the treatment of bipolar disorders. The main source of lithium exposure to the general population is drinking water and foods. Lithium is nephrotoxic at higher doses. Thus, oral exposure guidelines for lithium have been derived, including ICH's permitted daily exposure (PDE = 0.008 mg lithium/kg-bw/day) adopted by Health Canada and the United States Environmental Protection Agency's (U.S. EPA) provisional peer reviewed toxicity value (PPRTV = 0.002 mg lithium/kg-bw/day), both based on human data.

OBJECTIVE

To derive whole blood biomonitoring equivalents (BEs) associated with PDE and PPRTV to interpret population-level biomonitoring data in health risk context.

METHOD

A simple kinetic relationship based on plasma clearance value (0.5 L/kg-bw/day) and the oral absorption fraction (100%) was used to derive blood BEs for PDE and PPRTV.

RESULTS

This analysis resulted in BE values in plasma and whole blood of 16 and 10 μg/L, respectively, based on the PDE values developed by the Health Canada and of 4.2 and 2.7 μg/L, respectively, based on the PPRTV developed by U.S. EPA.

CONCLUSION

The derived BE values can be used to interpret population-level biomonitoring data.

Heparin reversal with protamine sulfate is not required in atrial fibrillation ablation with suture hemostasis

BACKGROUND

The utility of protamine sulfate for heparin reversal in catheter-based atrial fibrillation (AF) ablation is unclear when using the suture closure technique for vascular hemostasis.

OBJECTIVE

This study sought to address if protamine sulfate use for heparin reversal reduces vascular access complications in AF catheter ablation when suture techniques are used for postprocedural vascular hemostasis.

METHODS

This is a retrospective multicenter observational study of 294 consecutive patients who underwent catheter ablation for AF with subsequent vascular access hemostasis by means of a figure-of-eight suture or stopcock technique. A total of 156 patients received protamine for heparin reversal before sheath removal while 138 patients did not receive protamine. The two groups were compared for procedural activated clotting time (ACT), access site complications, and duration of hospital stay.

RESULTS

Baseline demographic characteristics were comparable in both groups. Despite higher ACT before venous sheath removal in patients not receiving protamine (288.0 ± 44.3 vs 153.9 ± 32.0 seconds; P < .001), there was no significant difference in groin complications, postoperative thromboembolic events, or duration of hospital stay between the two groups. Suture failure requiring manual compression was rarely observed in this cohort (0.34%).

CONCLUSION

With modern vascular access and sheath management techniques, for patients undergoing catheter ablation for AF, simple suture closure techniques can obviate the need for protamine administration to safely achieve hemostasis after removal of vascular sheaths.

Left atrial appendage occlusion using a Watchman device in a transplanted heart with biatrial anastomosis

A percutaneous left atrial appendage (LAA) occlusion using a Watchman device was performed in a patient with prior biatrial anastomosis orthotopic heart transplant (OHT). Due to the anatomical changes following biatrial anastomosis, transesophageal echocardiography (TEE) imaging and transseptal puncture become technically challenging. We describe how the standard LAA views on TEE were obtained for device sizing, and how the transseptal puncture was modified to cross the scarred septum. This case demonstrates that LAA occlusion using a Watchman device in biatrial anastomosis OHT is safe and can successfully be done.

A Review of Magnetic Particle Imaging and Perspectives on Neuroimaging

Magnetic particle imaging is an emerging tomographic technique with the potential for simultaneous high-resolution, high-sensitivity, and real-time imaging. Magnetic particle imaging is based on the unique behavior of superparamagnetic iron oxide nanoparticles modeled by the Langevin theory, with the ability to track and quantify nanoparticle concentrations without tissue background noise. It is a promising new imaging technique for multiple applications, including vascular and perfusion imaging, oncology imaging, cell tracking, inflammation imaging, and trauma imaging. In particular, many neuroimaging applications may be enabled and enhanced with magnetic particle imaging. In this review, we will provide an overview of magnetic particle imaging principles and implementation, current applications, promising neuroimaging applications, and practical considerations.

Left Atrium and Left Atrial Appendage Screening Prior to Atrial Fibrillation Ablation: A Comprehensive Review of the Literature

In the past decade, certain patient groups have been observed to have a presumptive lower incidence of left atrial (LA)/LA appendage (LAA) thrombus, particularly those who have no or minimal comorbidities. This has led to the question of whether a preprocedural evaluation of the LA/LAA is necessary in every patient, or if it can be avoided in certain patient populations. The answer to this is further complicated by the possibility of newer anticoagulation approaches affecting the incidence of intracardiac thrombus, including uninterrupted warfarin therapy and uninterrupted novel oral anticoagulant (NOAC) therapy, both of which are becoming more common. In this study, we conducted a comprehensive review of the literature addressing these questions in an attempt to summarize current approaches to evaluating the LA/LAA prior to ablation in order to elucidate the strategies that are currently being employed, to determine which strategies are becoming more favorable for use, and to identify what topics can or should be targeted for future study. In addition, this paper seeks to address the following specific questions: is ruling out LA/LAA thrombus necessary in all patients prior to atrial fibrillation (AF) ablation? Are there any identifiable patient populations at reliably lower risk who could potentially avoid LA/LAA thrombus screening prior to AF ablation? What are the current strategies being employed by electrophysiologists in the published literature? What is the opinion of the current literature on warfarin and NOAC drugs as they pertain to the incidence of LA/LAA thrombus prior to AF ablation, and how does each fit into the current treatment strategies for the prevention of procedural thromboembolism? Finally, what is the future of preprocedural intracardiac thrombus evaluation prior to AF ablation, and what steps can be taken to ensure that the risk to the patient is minimized while improving laboratory efficiency and avoiding unnecessary costs?

Cybersecurity for Cardiac Implantable Electronic Devices: What Should You Know?

Medical devices have been targets of hacking for over a decade, and this cybersecurity issue has affected many types of medical devices. Lately, the potential for hacking of cardiac devices (pacemakers and defibrillators) claimed the attention of the media, patients, and health care providers. This is a burgeoning problem that our newly electronically connected world faces. In this paper from the Electrophysiology Section Council, we briefly discuss various aspects of this relatively new threat in light of recent incidents involving the potential for hacking of cardiac devices. We explore the possible risks for the patients and the effect of device reconfiguration in an attempt to thwart cybersecurity threats. We provide an outline of what can be done to improve cybersecurity from the standpoint of the manufacturer, government, professional societies, physician, and patient.