Initial experience of left bundle branch pacing using the Abbott Agilis HisPro Catheter with stylet-driven leads.

AIMS: Conduction system pacing has gained steady interest over recent years. While the majority of tools and delivery techniques were developed for His bundle pacing (HBP), the feasibility and reproducibility of using these similar tools for left bundle branch pacing (LBBP) has yet to be determined. We describe our technique for performing LBBP using the Abbott Agilis HisPro™ Steerable Catheter. METHODS AND RESULTS: A series of 22 patients with a mean age of 71.7 years (16 males, 72.7%), underwent LBBP procedure with this catheter between May and October 2021. Nineteen patients (86%) had successful LBBP lead implantation. There were no major complications or mortality. CONCLUSION: The Agilis HisPro™ catheter along with the stylet driven Tendril STS Model 2088TC lead is a safe and feasible delivery system for LBBP.

Physiological optimization of robotic endoscopic epicardial CRT-D implantation using multielectrode electroanatomic mapping.

Multielectrode epicardial mapping during robotic implantation of cardiac resynchronization-defibrillator system. Robotically assisted endoscopic implantation of cardiac implantable devices is well documented to be both feasible and safe, and this technique provides particular benefit in patients with limited vascular access. In a patient meeting Class I indication for cardiac resynchronization therapy with defibrillator and inaccessible vascular access, we describe in this case an optimization strategy for intraoperative left ventricular lead placement utilizing robotic epicardial electroanatomic mapping as well as the feasibility of implanting a totally epicardial biventricular cardioverter-defibrillator system.

Simultaneous leadless pacemaker and subcutaneous implantable cardioverter-defibrillator implantation-When vascular options have run out.

An end-stage renal failure patient who was planned for a left brachioaxillary arteriovenous graft required an implantable cardioverter-defibrillator for secondary prevention of ventricular tachycardia and a pacemaker for complete heart block but was found to have a right subclavian venous occlusion. Due to the lack of vascular access, we performed a successful subcutaneous implantable cardioverter-defibrillator (S-ICD) and leadless pacemaker implantation. There was no interaction between the devices at the time of implantation, during defibrillation testing and following an appropriate defibrillation therapy.

An implantable cardioverter defibrillator in a patient with triple mechanical valves.

A patient with permanent atrial fibrillation, triple mechanical prosthetic valve replacements, and nonischemic cardiomyopathy presented with symptomatic high-grade atrioventricular block. A transvenous implantable cardioverter-defibrillator system was achieved with the defibrillator lead and bipolar pace-sense lead in separate anterolateral branches of the coronary sinus with successful defibrillation testing.

Early Diagnosis of Defibrillation Lead Dislodgement.

OBJECTIVES: This study sought to develop and evaluate an algorithm for early diagnosis of dislodged implantable cardioverter-defibrillator (ICD) leads. BACKGROUND: Dislodged defibrillation leads may sense atrial and ventricular electrograms (EGMs), triggering shocks in the vulnerable period that induce ventricular fibrillation (VF). METHODS: We developed a 2-step algorithm by using experimental lead dislodgements (LDs) at ICD implantation and a control dataset of newly implanted, in situ leads. Step 1 consisted of an alert triggered by abrupt decrease in R-wave amplitude and increase in pacing threshold. Step 2 withheld therapy based on ventricular EGM evidence of LD identified from experimental LD behavior. We estimated the algorithm's performance using a registry dataset of 3,624 new implantations and an atrial dislodgement dataset of 14 LDs at the atrium. RESULTS: In the registry dataset, the algorithm identified 20 of 21 radiographic LDs (95%) at a median of 11 days before clinical diagnosis. Step 1 had positive predictive values of 57% for radiographic LD and 77% for surgical revision. The false positive rate was 0.4% after step 1 and ≤0.2% after step 2. In the atrial dislodgement dataset, step 1 identified all 14 LDs; step 2 would have prevented inappropriate therapy in all 7 patients with stored EGMs at LD, including 2 patients with fatal, shock-induced VF. CONCLUSIONS: An ICD algorithm can facilitate early diagnosis of defibrillation LD. Additional data are needed to determine the safety of withholding shocks based on EGM evidence of LD.

High-resolution mapping of the triangle of Koch: Spatial heterogeneity of fast pathway atrionodal connections.

BACKGROUND: Dedicated mapping studies of the triangle of Koch to characterize retrograde fast pathway activation have not been previously performed using high-resolution, 3-dimensional, multielectrode mapping technology. OBJECTIVE: To delineate the activation pattern and spatial distribution of the retrograde fast pathway within the triangle of Koch during typical atrioventricular nodal reentrant tachycardia (AVNRT) and right ventricular pacing in a consecutive series of patients using the Rhythmia mapping system (Boston Scientific, Natick, MA). METHODS: A total of 18 patients with symptomatic typical AVNRT referred for ablation underwent ultra high-density mapping of atrial activation with minielectrode basket configuration during tachycardia. The earliest atrial activation was mapped using automated annotation, with manual overreading by 2 independent observers. The triangle of Koch was classified into 3 anatomic regions: anteroseptal (His), midseptal, and posteroseptal (coronary sinus roof). Thirteen patients underwent mapping of atrial activation during ventricular pacing. RESULTS: A median of 422 mapping points (interquartile range 258-896 points) was acquired within the triangle of Koch during tachycardia. The most common site of earliest atrial activation within the triangle of Koch was anterior in 67% of patients (n = 12). Midseptal early atrial activation was seen in 17% (n = 3), and posteroseptal activation was observed in 11% (n = 2). One patient exhibited broad simultaneous activation of the entire triangle of Koch. Slow pathway potentials were not identified. CONCLUSIONS: With high-resolution multielectrode mapping, atrial activation during typical AVNRT exhibited anatomic variability and spatially heterogeneous activation within the triangle of Koch. These findings highlight the limitations of an anatomically based classification of atrioventricular nodal retrograde pathways.

Outcomes of primary percutaneous coronary intervention in acute myocardial infarction due to unprotected left main thrombosis: The Asia-Pacific Left Main ST-Elevation Registry (ASTER).

INTRODUCTION: Prior studies of ULM STEMI have been confined to small cohorts. Recent registry data with larger patient cohorts have shown contrasting results. We aim to study the outcomes of patients with unprotected left main (ULM) ST-elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). METHODS: The Asia-pacific left main ST-Elevation Registry (ASTER) is a multicenter retrospective registry involving 4 sites in Singapore, South Korea, and the United States. The registry included patients presenting with STEMI due to an ULM coronary artery culprit lesion who underwent emergency PCI. The primary outcome was in-hospital mortality. Secondary outcomes included major adverse cardiovascular events. RESULTS: A total of 67 patients (mean age 64.2 ± 12.8 years, 53 [79.1%] males) were included. The distal left main bifurcation was most commonly involved (85%, n = 57). Fifty one (76%) patients had TIMI 3 flow post-PCI. The in-hospital mortality rate was 47.8% (n = 32); 61% (n = 41) had cardiac failure, 4% (n = 3) had emergency coronary artery bypass grafting, 1% (n = 1) had a re-infarction, 3% (n = 2) had stroke and 55% (n = 37) had malignant ventricular arrhythmias. On multivariate analysis, predictors of in-hospital mortality included older age (odds ratio (OR) 1.085 (95% confidence interval (CI) 1.002-1.175), P = 0.044), diabetes mellitus (OR 10.882 (95%CI 11.074-110.287), P = 0.043) and absence of post-PCI TIMI 3 flow (OR 71.429 (95%CI 2.985-1000), P = 0.008). CONCLUSIONS: STEMI from culprit unprotected left main coronary artery stenosis is associated with significant mortality and morbidity. Emergency PCI provides an important treatment option in this high-risk group, but in-hospital mortality remains high.

Tpeak-to-Tend interval corrected for heart rate: A more precise measure of increased sudden death risk?

BACKGROUND: The Tpeak to Tend (Tpe) interval on the 12-lead electrocardiogram predicts an increased risk of sudden cardiac arrest (SCA). There is controversy over whether Tpe would be more useful if corrected for heart rate (Tpec). OBJECTIVES: We evaluated whether the predictive value of Tpe for SCA improves with heart rate correction and sought to determine an optimal cutoff value for Tpec in the context of SCA risk. METHODS: Cases of SCA (n = 628; mean age 66.4 ± 14.5 years; n = 416, 66.2% men) from the Oregon Sudden Unexpected Death Study with an archived electrocardiogram available prior and unrelated to the SCA event were analyzed. Comparisons were made with control subjects (n = 819; mean age 66.7 ± 11.5 years; n = 559, 68.2% men). The Tpe interval was corrected for heart rate using Bazett (TpecBa) and Fridericia (TpecFd) formulas, and the predictive value of Tpec for SCA was evaluated using logistic regression models. RESULTS: The area under the curve for Tpec predicting SCA improved with both correction formulas. TpecBa and TpecFd were shown to have an area under the curve of 0.695 and 0.672, respectively, as compared with a baseline of 0.601 with an uncorrected Tpe. A TpecBa value of >90 ms was predictive of SCA, independent of age, sex, comorbidities, QRS duration, corrected QT interval, and severely reduced left ventricular ejection fraction (≤35%; odds ratio 2.8; 95% confidence interval 1.92-4.17; P < .0001). CONCLUSION: Correcting Tpe for heart rate, using either the Bazett or the Fridericia formula, improved the independent predictive value of this marker for the assessment of SCA risk. Prolongation of TpecBa beyond 90 ms was associated with a nearly 3-fold increased risk of SCA.

Remote monitoring of patients with cardiac implantable electronic devices: a Southeast Asian, single-centre pilot study.

INTRODUCTION: Remote monitoring of cardiac implantable electronic devices (CIED) has been shown to improve patient safety and reduce in-office visits. We report our experience with remote monitoring via the Medtronic CareLink(®) network. METHODS: Patients were followed up for six months with scheduled monthly remote monitoring transmissions in addition to routine in-office checks. The efficacy of remote monitoring was evaluated by recording compliance to transmissions, number of device alerts requiring intervention and time from transmission to review. Questionnaires were administered to evaluate the experiences of patients, physicians and medical technicians. RESULTS: A total of 57 patients were enrolled; 16 (28.1%) had permanent pacemakers, 34 (59.6%) had implantable cardioverter defibrillators and 7 (12.3%) had cardiac resynchronisation therapy defibrillators. Overall, of 334 remote transmissions scheduled, 73.7% were on time, 14.5% were overdue and 11.8% were missed. 84.6% of wireless transmissions were on time, compared to 53.8% of non-wireless transmissions. Among all transmissions, 4.4% contained alerts for which physicians were informed and only 1.8% required intervention. 98.6% of remote transmissions were reviewed by the second working day. 73.2% of patients preferred remote monitoring. Physicians agreed that remote transmissions provided information equivalent to in-office checks 97.1% of the time. 77.8% of medical technicians felt that remote monitoring would help the hospital improve patient management. No adverse events were reported. CONCLUSION: Remote monitoring of CIED is safe and feasible. It has possible benefits to patient safety through earlier detection of arrhythmias or device malfunction, permitting earlier intervention. Wireless remote monitoring, in particular, may improve compliance to device monitoring. Patients may prefer remote monitoring due to possible improvements in quality of life.

Wide QRS-T Angle on the 12-Lead ECG as a Predictor of Sudden Death Beyond the LV Ejection Fraction.

INTRODUCTION: Improvements in risk stratification for sudden cardiac arrest (SCA) will require discovery of markers that extend beyond the LV ejection fraction (LVEF). The frontal QRS-T angle has been shown to predict risk of SCA but the value of this marker independent of the LVEF has not been investigated. METHODS AND RESULTS: Cases of adult SCA with an archived electrocardiogram (12-lead ECG) available before the event, with a computable frontal QRS-T angle, were identified from the Oregon Sudden Unexpected Death Study (Oregon SUDS) ongoing in the Portland, Oregon metro area. A total of 666 SCA cases (mean age 67.2 years; 95% CI, 52.3-82.1 years; 68.6% males) were compared to 863 controls (mean age 66.6 years, 55.2-78.0 years; 68.1% males; 75.0% had CAD) from the same geographical region. The mean frontal QRS-T angle was wider in cases (74(o) ; 95% CI, 17(o) -131(o) ) compared to controls (51(o) ; 95% CI, 5(o) -97(o;) P< 0.0001). A frontal QRS-T angle of more than 90(o) remained associated with increased risk of SCD after adjusting for age, gender, heart rate, prolonged intraventricular conduction, electrocardiographic left ventricular hypertrophy (ECG LVH), baseline comorbidities, and left ventricular ejection fraction (LVEF) (OR 2.2; 95% CI, 1.60-3.09; P< 0.0001). CONCLUSION: A wide QRS-T angle greater than 90(o) is associated with an increased risk of SCA independent of the left ventricular ejection fraction.

An automated high-content screening image analysis pipeline for the identification of selective autophagic inducers in human cancer cell lines.

Automated image processing is a critical and often rate-limiting step in high-content screening (HCS) workflows. The authors describe an open-source imaging-statistical framework with emphasis on segmentation to identify novel selective pharmacological inducers of autophagy. They screened a human alveolar cancer cell line and evaluated images by both local adaptive and global segmentation. At an individual cell level, region-growing segmentation was compared with histogram-derived segmentation. The histogram approach allowed segmentation of a sporadic-pattern foreground and hence the attainment of pixel-level precision. Single-cell phenotypic features were measured and reduced after assessing assay quality control. Hit compounds selected by machine learning corresponded well to the subjective threshold-based hits determined by expert analysis. Histogram-derived segmentation displayed robustness against image noise, a factor adversely affecting region growing segmentation.