Hemodynamic response and safety of vasodilator stress cardiovascular magnetic resonance in patients with permanent pacemakers or implantable cardioverter-defibrillators.

INTRODUCTION: Vasodilator stress cardiovascular magnetic resonance (CMR) is a powerful diagnostic modality, but data toward its use in patients with permanent pacemakers (PPMs) or implantable cardioverter-defibrillators (ICDs) is limited. METHODS AND RESULTS: Patients with ICDs (>1% pacing) or PPMs who underwent regadenoson single photon emission computed tomography (SPECT) and all patients with ICDs or PPMs who underwent stress CMR were retrospectively identified. SPECT tests were analyzed for hemodynamic responses and new pacing requirements; CMR studies were examined for safety, device characteristics and programming, hemodynamic responses, and image quality. Changes from baseline were evaluated with the Related-Samples Wilcoxon Signed Rank Test. Of 67 patients (median age 65 [IQR 58-72] years, 31 [46%] female, 31 [46%] Black), 47 underwent SPECT and 20 CMR. With regadenoson SPECT, 89% of patients experienced tachycardic responses above resting heart rates (+19 [13-32] beats per minute, p < .01). During stress CMR, 10 (50%) devices were asynchronously paced approximately 10 beats per minute above resting rates, and the remaining were temporarily deactivated. Those with asynchronous pacing had no changes in heart rates, whereas patients with deactivated devices had near uniform heart rate accelerations. Image quality was diagnostic in the majority of stress CMR sequences, with nonconditional ICDs contributing 40 of 57 (70%) of nondiagnostic segments. CONCLUSION: This data supports the safety of vasodilator stress CMR with promising diagnostic quality images in patients with CMR conditional ICDs and PPMs. Despite a near uniform tachycardic response to regadenoson in the SPECT environment, high rates of asynchronous pacing during vasodilator stress CMR did not result in competitive pacing or adverse arrhythmic events. Further studies are needed to validate these findings and confirm the diagnostic and prognostic performance of stress CMR in these individuals.

Outcomes of two versus three incision techniques: Results from the subcutaneous ICD post-approval study.

BACKGROUND: Traditionally, implantation of the subcutaneous implantable cardioverter defibrillator (S-ICD) requires incisions near the lateral chest wall, the xyphoid, and the superior sternal region (three-incision technique [3IT]). A two-incision technique (2IT) avoids the superior incision and has been shown to be a viable alternative in small studies with limited follow-up. OBJECTIVES: To report on the long-term safety and efficacy of the 2IT compared to the 3IT procedure in a large patient cohort. METHODS: Patients enrolled in the S-ICD post approval study (PAS) were stratified by procedural technique (2IT vs. 3IT). Baseline demographics, comorbidities and procedural outcomes were collected. Complications and S-ICD effectiveness in treating ventricular arrhythmias through an average 3-year follow-up period were compared. RESULTS: Of 1637 patients enrolled in the S-ICD PAS, 854 pts (52.2%) were implanted using the 2IT and 782 were implanted using the 3IT (47.8%). The 2IT became more prevalent over time, increasing from 40% to 69% of implants (Q1-Q4). Mean procedure time was shorter with 2IT (69.0 vs. 86.3 min, p < .0001). No other differences in outcomes were observed between the two groups, including rates of infection, electrode migration, inappropriate shocks and first shock efficacy for treating ventricular arrhythmias. CONCLUSION: In this large cohort of patients implanted with an S-ICD and followed for 3 years the 2IT was as safe and effective as the 3IT while significantly reducing procedure time.

Safety and feasibility of left bundle branch area pacing following valvular interventions: Multicenter study.

OBJECTIVES: To evaluate the safety and feasibility of left bundle branch area pacing (LBBAP) in patients with valvular interventions. METHODS: Eighty-four patients were included in this study. All patients underwent recent surgical or percutaneous valvular interventions. LBBAP was attempted in all patients. Implant success rates, peri- and postprocedure electrocardiogram, pacing parameters, and complications were assessed at implant, and during follow-up. RESULTS: LBBAP implantation was successful in 80/84 (95%) patients. Mean age was 74.1 ± 13.8 years and 56% patients were male. Prior valvular replacements included: percutaneous aortic (26), surgical aortic (36), combined surgical aortic plus mitral (6), MVR (10), tricuspid (1), and pulmonic (1). Average LVEF was 52.6 ± 11%. Majority of patients underwent LBBAP due to atrioventricular block (76%) and sinus node disease (13%). Total procedure duration was 74.1 ± 12.5 min and fluoroscopic duration was 9.7 ± 6.8 min. Pacing parameters were stable during follow-up period of 10.0 ± 6.3 months. Pacing QRS duration was significantly narrower than baseline QRS duration (131.5 ± 31.4 ms vs. 114.3 ± 13.7 ms, p < .001, respectively). No acute complications were observed. Mean follow-up was 10.0 ± 6.3 months (median: 8.4 months, min: 1 and max: 24 months). During follow-up, there were three device infections and two patients had loss of LBBA capture within 1 month of implant. CONCLUSIONS: LBBAP is a feasible and safe pacing modality in patients with prior interventions for valvular heart disease.

Electrocardiographic changes in loperamide toxicity: Case report and review of literature.

INTRODUCTION: Loperamide, an antidiarrheal agent, is a µ-opioid receptor agonist increasingly abused to prevent opioid withdrawal or to produce euphoric effects. At supra-therapeutic doses, loperamide can cause cardiac toxicity due to blockade of Na and IKr channels, resulting in wide QRS rhythms, severe bradycardia, prolonged QTc, polymorphic ventricular tachycardia, cardiac arrest, and death. There are limited data on the cardiotoxic effects of high dose loperamide. METHODS AND RESULTS: A case report of loperamide toxicity is presented and then added to a contemporary review of the literature. In total, the presentation and management of 36 cases of loperamide cardiotoxicity are summarized. The overall median daily dose (interquartile range) of loperamide was 200 (134-400) mg. The median QRS duration was 160 (125-170) ms. The median QTc duration was 620 (565-701) ms. Ventricular tachycardia was experienced by 24/36 (67%) of patients, 20 of which were specified to be polymorphic. Treatment was supportive, providing advanced cardiopulmonary life support and aggressive electrolyte repletion. Isoproterenol infusion or overdrive pacing was employed in 19/36 (53%) of cases. The median time to electrocardiogram normalization or hospital discharge, whichever came first, was 5 (3.5-10) days. CONCLUSION: Loperamide overdose is a toxidrome that remains underrecognized, and in patients with unexplained cardiac arrhythmias, loperamide toxicity should be suspected. Prompt recognition is critical due to the delayed recovery and high risk for life-threatening arrhythmias.

Severe tricuspid regurgitation due to interactions with right ventricular permanent pacemaker or defibrillator leads.

Although thought to be a rare event, permanent pacemakers and implantable cardioverter-defibrillators with right ventricular intracardiac leads have the potential to induce tricuspid valve dysfunction. Adverse lead-valve interactions can take place through a variety of mechanisms including damage at the time of implantation, leaflet pinning, or long-term fibrosis encapsulating the leaflet tissue. Clinical manifestations can display a wide range of severity, as well as a highly variable time span between implantation and hemodynamic deterioration. This review aims to describe the potential pathophysiologic effects of intracardiac device leads on the tricuspid valve, with a focus on ideal diagnostic strategies and treatment options once lead-induced valvular dysfunction is suspected.

Efficacy and Safety of Pulsed Field Ablation in Atrial Fibrillation: A Systematic Review.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with high morbidity and mortality. AF treatment is guided by a patient-provider risk-benefit discussion regarding drug versus ablation or combination. Thermal ablation has a high rate of adverse events compared to pulsed field ablation (PFA). In this systematic review, we aimed to determine the safety and efficacy of PFA. METHODS: The electronic search for relevant articles in English was completed in PubMed, PubMed Central, Cochrane library, Scopus, and Embase databases till July 2022. The screening was completed via the use of Covidence software. The risk of bias assessment and data extraction from the included studies was performed, and the narrative synthesis was performed accordingly. RESULTS: A total of six studies were selected for review and 1897 patients receiving PFA were involved in these studies. Our review was focused on pulmonary vein isolation success, major adverse events, and arrhythmia recurrence. Successful pulmonary vein isolation (PVI) was completed in 100% of cases except in two studies. In one of them, six out of seven patients (86%) in the epicardial cohort had successful PVI. In the MANIFEST-PF survey, the acute PVI success rate was 99.9%. The major complications were rare and included pericardial tamponade, vascular complications requiring surgery, and stroke. The atrial arrhythmia recurrence was higher in the thermal group than in the PFA group (39% vs. 11%). CONCLUSIONS: The success rate of PVI by PFA is high, and major adverse events are low. PFA is found to decrease the recurrence of atrial arrhythmia compared to thermal ablation. Substantial randomized controlled trials (RCTs) are needed to validate the efficacy and safety of PFA over conventional methods.

Outcome of In-Hospital Cardiac Arrest among Patients with COVID-19: A Systematic Review and Meta-Analysis.

BACKGROUND: Outcomes following in-hospital cardiac arrest (IHCA) in patients with COVID-19 have been reported by several small single-institutional studies; however, there are no large studies contrasting COVID-19 IHCA with non-COVID-19 IHCA. The objective of this study was to compare the outcomes following IHCA between COVID-19 and non-COVID-19 patients. METHODS: We searched databases using predefined search terms and appropriate Boolean operators. All the relevant articles published till August 2022 were included in the analyses. The systematic review and meta-analysis were conducted as per Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. An odds ratio with a 95% confidence interval (CI) was used to measure effects. RESULTS: Among 855 studies screened, 6 studies with 27,453 IHCA patients (63.84% male) with COVID-19 and 20,766 (59.7% male) without COVID-19 were included in the analysis. IHCA among patients with COVID-19 has lower odds of achieving return of spontaneous circulation (ROSC) (OR: 0.66, 95% CI: 0.62-0.70). Similarly, patients with COVID-19 have higher odds of 30-day mortality following IHCA (OR: 2.26, 95% CI: 2.08-2.45) and have 45% lower odds of cardiac arrest because of a shockable rhythm (OR: 0.55, 95% CI: 0.50-0.60) (9.59% vs. 16.39%). COVID-19 patients less commonly underwent targeted temperature management (TTM) or coronary angiography; however, they were more commonly intubated and on vasopressor therapy as compared to patients who did not have a COVID-19 infection. CONCLUSIONS: This meta-analysis showed that IHCA with COVID-19 has a higher mortality and lower rates of ROSC compared with non-COVID-19 IHCA. COVID-19 is an independent risk factor for poor outcomes in IHCA patients.

Catheter ablation using pulmonary vein isolation with versus without left atrial posterior wall isolation for persistent atrial fibrillation: an updated systematic review and meta-analysis.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF); however, the results are suboptimal for persistent AF. The left atrial posterior wall (LAPW) is thought to be a major additional area in initiation and perpetuation of persistent AF. Therefore, adjunctive ablation of the posterior wall may reduce AF recurrence in patients with persistent AF. OBJECTIVE: The objective of this study was to compare outcomes of catheter ablation in patients with persistent AF using PVI alone versus a combination of PVI and LAPW isolation. METHODS: Literature search was conducted in PubMed, PubMed Central, Scopus, and Embase since inception to February 2023. Screening of studies was done via Covidence software. Risk of bias assessment was done using appropriate tools. Data extraction and a narrative synthesis were carried out accordingly. RESULTS: Ten studies were included, of which five were randomized controlled trials. PVI with LAPW ablation group had significantly lower recurrence of overall atrial tachyarrhythmia (OR 0.47, CI 0.32-0.70) and AF (OR 0.39, CI 0.23-0.69). In sensitivity analysis, freedom from atrial arrhythmias was noted to be significantly higher in the PVI with LAPW ablation group (OR 2.22, CI 1.36-3.64). However, there was no significant difference in occurrence of atrial flutter (OR 1.36, CI 0.86-2.14) or with periprocedural adverse events (OR 1.10, CI 0.60-1.99). CONCLUSION: LAPW ablation, in addition to PVI, significantly improves the rates of arrhythmia freedom and reduces the recurrence of overall atrial tachyarrhythmia. There was no significant difference in atrial flutter or periprocedural adverse events.

Acute clinical evaluation of a left ventricular automatic threshold determination algorithm based on evoked response sensing.

INTRODUCTION: Automatic pacing threshold (AT) testing may simplify device follow-up and improve device longevity. This study's objective was to evaluate the performance of a left ventricular (LV) evoked response sensing-based AT algorithm, for cardiac resynchronization therapy (CRT) devices. METHODS: Patients scheduled for CRT-D/P implant were enrolled. A manual step-down threshold test and a Left Ventricular Automatic Threshold (LVAT) test in each of four pacing vectors-LVTip→Can, LVTip→right ventricle (RV), = LVRing→Can, and LVRing→RV-were conducted. Patients were randomized to either 0.4-ms or 1.0-ms pacing pulse width and in the manual and LVAT test order. A blinded core lab electrophysiologist (EP) determined the threshold using the surface electrocardiogram (gold standard). RESULTS: Data from 70 patients were analyzed. Bipolar LV leads from three major manufacturers were used. A total of 273 AT tests were performed; 12 AT tests did not result in a threshold due to improper testing conditions. Of 261 eligible tests, 234 AT tests (89.6%) returned a threshold measurement. Of the 234 tests, in 233 tests (99.5%) the algorithm-determined threshold matched the EP-determined threshold for that test. A total of 16,689 capture and 526 noncapture beats were collected and the accuracy for detecting capture and noncapture were 98.5% and 99.7% with a two-sided 95% confidence level of (98.4%, 98.7%) and (99.4%, 100%), respectively. No AT threshold measurement was lower than the EP-determined threshold. CONCLUSION: In this study, the results suggest that the LVAT algorithm is accurate at determining pacing thresholds in multiple pacing configurations and a wide range of LV leads in CRT-D/P patients.

Atrioventricular junction ablation in patients with conduction system pacing leads: A comparison of His-bundle vs left bundle branch area pacing leads.

BACKGROUND: Single-center studies have shown feasibility of conduction system pacing (CSP) via His-bundle pacing (HBP) or left bundle branch area pacing (LBBAP) in atrial fibrillation (AF) patients undergoing atrioventricular junction ablation (AVJA). OBJECTIVE: The purpose of this study was to compare outcomes in patients with HBP and LBBAP leads undergoing AVJA. METHODS: Consecutive patients with CSP leads referred for AVJA between October 2014 and May 2021 were included. Pacing lead characteristics, procedural characteristics, complications, and long-term outcomes were assessed. RESULTS: One hundred five AVJA procedures (55 HBP, 50 LBBAP) were performed in 98 patients (48 HBP, 50 LBBAP). The acute success rate of the AVJA procedure was 94% vs 100% (P = .11) in HBP vs LBBAP groups. Seven (14%) redo AVJA procedures were required in the HBP group. Mean procedural time (44 ± 24 min vs 34 ± 16 min; P = .02) and mean fluoroscopy time (16 ± 18 min vs 7 ± 6 min; P <.001) were significantly longer in the HBP vs LBBAP group. An acute rise in threshold was noted in 8 cases (14.5%), and 4 (8%) developed exit block after AVJA in HBP patients. Chronic HBP threshold ≥2.5 V was seen in 23 patients (48%), and 4 (8%) HBP leads were deactivated. CSP preserved ejection fraction (EF) in the overall cohort (N = 70; 53% ± 10% vs 55% ± 10%; P = .09) and significantly improved in those with reduced EF <50% at baseline (N = 16; 37% ± 7.6% vs 46% ± 13%; P = .02). CONCLUSION: AVJA in the presence of an LBBAP lead is associated with a higher success rate and fewer acute and chronic lead-related complications. CSP with either HBP or LBBAP preserves left ventricular systolic function in patients with refractory atrial fibrillation post AVJA.

Left bundle branch area pacing in patients with atrioventricular conduction disease: A prospective multicenter study.

BACKGROUND: The reported success rate of His-bundle pacing (HBP) in patients with infranodal atrioventricular (AV) conduction disease is only 52%-76%. The success rate of left bundle branch area pacing (LBBAP) in this cohort is not well studied. OBJECTIVE: The purpose of this study was to evaluate the feasibility, safety, and electrophysiological characteristics of LBBAP in patients with AV conduction disease. METHODS: Patients with AV conduction disease referred for pacemaker implantation at 2 centers between February 2019 and June 2021 were considered for LBBAP. Baseline demographic characteristics, procedural success rates, electrophysiological parameters, and complications were assessed. RESULTS: LBBAP was successful in 340 of 364 patients (93%). Mean age was 72 ± 13 years, and mean follow-up was 331 ± 244 days. Pacing indications were Mobitz I in 27 patients (7%), Mobitz II or 2:1 AV block or high-grade AV block in 94 patients (26%), complete heart block in 199 patients (55%), and sick sinus syndrome with isolated bundle branch block in 44 patients (12%). Left bundle branch block and right bundle branch block were present in 57 patients (16%) and 140 patients (38%), respectively. Procedural success rates did not differ between indications (92.6%, 93.6%, 92.9%, and 95%, respectively) or between patients with narrow (<120 ms) vs wide QRS (≥120 ms). Mean LBBAP threshold was 0.77 ± 0.34 V at 0.4 ms at implant and remained stable during follow-up. There were 4 (1.2%) acute LBBAP lead dislodgments. CONCLUSION: LBBAP is safe and feasible with high success rates for patients with AV conduction disease. In contrast to HBP, LBBAP success rates remain high over the entire spectrum of AV conduction disease, and lead parameters remain stable during follow-up.

Intermediate-term performance and safety of His-bundle pacing leads: A single-center experience.

BACKGROUND: The short-term safety, feasibility, and performance of His-bundle pacing (HBP) leads have been reported; however, their longer-term performance beyond 1 year remains unclear. OBJECTIVE: The purpose of this study was to examine the intermediate-term performance and safety of HBP. METHODS: All HBP lead implants at Virginia Commonwealth University between January 2014 and January 2019 were analyzed. HBP was performed using a Medtronic SelectSecure 3830-69 cm pacing lead. RESULTS: Of 295 attempts, successful HBP implantation (selective or nonselective) was seen in 274 cases (93%). Mean follow-up duration was 22.8 ± 19.5 months (median 19.5; interquartile range 11-33). Mean age was 69 ± 15 years; 58% were males; and ejection fraction <50% was noted in 30%. Indications for pacemaker included sick sinus syndrome in 41%, atrioventricular block in 36%, cardiac resynchronization therapy in 7%, and refractory atrial fibrillation in 15%. Selective HBP was achieved in 33%. Mean HBP capture threshold at implant was 1.1 ± 0.9 V at 0.8 ± 0.2 ms, which significantly increased at chronic follow-up to 1.7 ± 1.1 V at 0.8 ± 0.3 ms (P <.001). Threshold was ≥2.5 V in 24% of patients, and 28% had an increase in HBP threshold ≥1 V. Loss of His-bundle capture at follow-up (septal right ventricular pacing) was seen in 17%. There was a total of 31 (11%) lead revisions, primarily for unacceptably high thresholds. CONCLUSION: Although HBP can prevent or improve pacing-induced cardiomyopathy, the elevated capture thresholds, loss of His-bundle capture, and lead revision rates at intermediate follow-up are of concern. Longer-term follow-up data from multiple centers are needed.

Imaging-Based Localization of His Bundle Pacing Electrodes: Results From the Prospective IMAGE-HBP Study.

OBJECTIVES: This study sought to evaluate the correlation between His bundle (HB) pacing (HBP) implantation characteristics, lead-tip location, and association of intraprocedural His recordings with approximated HB anatomic landmarks using computed tomography (CT) imaging. BACKGROUND: HBP continues to grow in clinical practice due to offering true physiological pacing. However, a clear understanding of HB anatomy and the lead-tip location's influence on pacing characteristics is lacking. METHODS: The IMAGE-HBP study (Imaging Study of Lead Implant for His Bundle Pacing) was a prospective, multicenter study designed to assess implantation characteristics of the SelectSecure Model 3830 lead placed at the HB, evaluate protocol-specified HBP success (His recording present on electrogram and HBP threshold ≤2.5 V at 1 ms), and correlation between lead-tip location by CT imaging and HBP characteristics as well as lead-related complications through 12 months. RESULTS: Sixty-nine patients underwent a lead implantation attempt at the HB. Of these, 61 patients (88%) had a lead successfully implanted at the HB, and 52 patients (75%) met the pre-specified definition of successful HBP. In 51 patients with CT imaging, 11 leads (22%) were placed in the atrial aspect of the HB region (36% selective HBP), and 40 leads (78%) were placed in the ventricular aspect (28% selective HBP). Four of the 51 patients had P-wave oversensing, all with leads in the atrium. Freedom from lead-related complication at 12 months was 93%. CONCLUSIONS: Successful HBP could be achieved at lead-tip locations in the atrium or ventricle but is preferable in the ventricle to eliminate risk of oversensing. The IMAGE-HBP study offers better insight into approximated HB anatomic landmarks, lead-tip location, and correlation with pacing characteristics. (Imaging Study of Lead Implant for His Bundle Pacing [IMAGE-HBP]; NCT03294317).

An unusual source of electromagnetic interference: a device-device interaction.

INTRODUCTION: Implantable cardioverter-defibrillators (ICDs) are susceptible to oversensing of extracardiac signals, also known as electromagnetic interference (EMI). We report a case of an unusual source of electrical interference of only the high voltage (HV) impedance measurement in the Teligen ICD (Boston Scientific, St. Paul, MN, USA) caused by electrical interference from an electrosurgical generator with an electrocautery patch located in close proximity to the ICD pulse generator. METHOD AND RESULTS: A patient underwent an uneventful implant of a Boston Scientific Teligen 100 ICD. Once the device was inserted in a pocket, interrogation of the device repeatedly demonstrated HV electrode impedance measurements between <20 and 40 Omega and noise only on the HV electrode. A new lead and generator were implanted without a change in the interrogation results. The erroneous measurements of HV impedance were caused by a combination of the close proximity of the electrocautery patch to the ICD generator. The continuous low-amplitude current emitted by the contact quality monitoring system of the electrosurgical cautery generator interfered with an equally weak current delivered through the lead by the device to measurement HV impedance. The Medtronic Virtuoso (Medtronic Inc., Minneapolis, MN, USA) ICD and the St. Jude Medical Current DR (St. Jude Medical, St. Paul, MN, USA) ICD were not affected by the patch due to greater magnitude of current delivered by the device to measure HV electrode impedance. CONCLUSION: It is important that the operator must be aware of any potential source of EMI, as it may affect the device and require immediate troubleshooting. Failure to recognize this interaction may result in inappropriate and unnecessary pulse generator replacement.

Initial Experience, Safety, and Feasibility of Left Bundle Branch Area Pacing: A Multicenter Prospective Study.

OBJECTIVES: This study sought to evaluate the safety and feasibility of conduction system pacing by performing left bundle branch area pacing (LBBAP). BACKGROUND: There are limited data from single centers showing that LBBAP may circumvent the technical and electrophysiological challenges encountered with His bundle pacing. METHODS: Patients referred for pacemaker implantation at 2 centers between February 1, 2019, and March 31, 2020, were considered for LBBAP. LBBAP was performed by implanting a lumen-less, exposed helix lead approximately 2 cm distal to the His bundle and deep into the septum using a specialized delivery sheath. Implant success rates, complications, and electrophysiological parameters were assessed. RESULTS: LBBAP was successful in 305 of 341 patients (89%). Mean age was 72 ± 12 years; 45% were women; and 39% had QRS duration (QRSd) >130 ms, 22% right bundle branch block, 11% left bundle branch block, and 6% intraventricular conduction defect. Pacing indications were sinus node dysfunction in 28.7%, atrioventricular block in 52.5%, cardiac resynchronization therapy in 8.8%, and refractory atrial fibrillation in 10% of patients. Procedural duration was 74.7 ± 34 min and fluoroscopic time was 10.4 ± 8.1 min. The mean baseline QRSd and paced QRSd in the overall cohort was 114 ± 29.8 ms versus 112 ± 11.7 ms (p < 0.001) and in patients with infra-Hisian disease was 144.5 ± 19 ms versus 115 ± 12 ms (p < 0.001), respectively. Mean left ventricular activation time was 71.7 ± 11 ms at high output and 74.7 ± 11 ms at low output. LBB potentials were noted in 41% patients. Pacing threshold and R waves were 0.74 ± 0.3 V at 0.4 ms and 10.7 ± 4.9 mV at time of implantation and were stable at 1-, 3-, 6-, and 12-month follow-ups. The only major complications were 3 LBBAP lead dislodgements, 2 within 24 h and 1 at 2 weeks. CONCLUSIONS: LBBA pacing is safe, feasible, and a reliable alternative to His bundle pacing for providing physiological pacing. Randomized controlled studies are needed to confirm the safety, feasibility, and clinical outcomes of LBBAP.

Antiarrhythmic Drugs: Risks and Benefits.

The narrow therapeutic window of antiarrhythmic drugs makes their use clinically challenging. A solid understanding of the mechanisms of arrhythmias and how antiarrhythmics affect these mechanisms is only a preliminary step in their appropriate selection. Clinical factors, side-effect profiles, and proarrhythmic risks are more important than the cellular mechanisms of actions in drug selection and monitoring. This article provides a simplified approach to understanding cellular mechanisms and provides a practical approach to the selection and use of this important class of medications.

Novel Method for Assessment of His Bundle Pacing Morphology Using Near Field and Far Field Device Electrograms.

BACKGROUND: The 12-lead ECG is considered the gold standard to differentiate between selective (S), nonselective (NS) His bundle pacing (HBP), and right ventricular septal capture in routine clinical practice. We sought to assess the utility of device EGM recordings as a tool to identify the type of HBP morphology. METHODS: One hundred forty-eight consecutive patients underwent HBP with a 3830 Select Secure lead (Medtronic, Inc) at 3 centers between October 2016 and October 2017. The near field V-EGM morphology (NF EGM), near field V-EGM time to peak (NFTime to peak), and far-field EGM QRS duration (QRSd) were recorded while pacing the His lead with simultaneous 12-lead ECG rhythm strips. RESULTS: Indications for HBP were sinus node dysfunction, atrioventricular conduction disease, and cardiac resynchronization therapy in 68 (46%), 56 (38%), and 24 (16%) patients, respectively. Baseline QRSd was 108±38 ms with QRSd >120 ms in 57 (39%) patients (27 right bundle branch block, 18 left bundle branch block, and 12 intraventricular conduction delay). S-HBP was noted in 54 (36%) patients. A positive NFEGM and NFTime to peak >40 ms were highly sensitive (94% and 93%, respectively) and specific (90% and 94%) for S-HBP irrespective of baseline QRSd. All 3 parameters (+NFEGM, NFTime to peak >40 ms, and far-field EGM QRSd <120 ms) had high negative predictive value (97%, 95%, and 92%). A novel device-based algorithm for S-HBP was proposed. EGM transitions correlated with ECG transitions during threshold testing and can help accurately differentiate between S-HBP, NS-HBP, and right ventricular septal pacing with a cumulative positive predictive value of 91% (positive predictive value =100% in patients with baseline QRSd <120 ms). CONCLUSIONS: We propose a novel and simple criteria for accurate differentiation between S-HBP, NS-HBP, and right ventricular septal capture morphologies by careful analysis of device EGMs alone. This study paves the way for future studies to assess autocapture algorithms for devices with HBP.

Benefit of primary prevention implantable cardioverter-defibrillators in the setting of chronic kidney disease: a decision model analysis.

INTRODUCTION: Primary prevention ICD trials have excluded patients with CKD. Comorbidities and lower life expectancy in patients with CKD make the benefit of primary prevention ICD implantation uncertain. METHODS: A decision analysis model was devised to evaluate the risks and benefits of implantable cardioverter-defibrillators (ICD) implantation in patients with chronic kidney disease (CKD) who meet current criteria for a primary prevention ICD. Published data capturing event rates, infection risks, and overall survival in CKD patients with and without ICDs were utilized. Variables included patient's age, GFR and stage of CKD, probability of sudden cardiac death (SCD), and device implantation mortality. RESULTS: The benefit of an ICD for primary prevention of SCD in patients with CKD depends primarily on the patient's age and stage of kidney disease. With stages 1 and 2 CKD, ICD implantation reduces mortality. However, in patients with more advanced stages of CKD, the benefit is less significant and age-dependent. This is attributed to patients with advanced CKD having a higher procedural risk and decreased life expectancy. With average procedural mortality, ICD implantation is favored at ages <80 for stage 3, ages <75 for stage 4, and ages <65 for stage 5. As procedural mortality rates increase, age thresholds for ICD implantation decrease. CONCLUSIONS: Our model shows that benefit from primary prevention ICD implantation is determined by the patient's age and stage of kidney disease. While there is limited impact with lower stages of CKD, careful consideration of ICD implantation is suggested for older patients with more advanced stages of kidney disease.

Sensing failure associated with the Medtronic Sprint Fidelis defibrillator lead.

INTRODUCTION: The diameter of implantable cardioverter-defibrillator (ICD) leads has become progressively smaller over time. However, the long-term performance characteristics of these smaller ICD leads are unknown. METHODS: We retrospectively evaluated 357 patients who underwent implantation of a Medtronic Sprint Fidelis defibrillating lead at two separate centers between September 2004 and October 2006. Lead characteristics were measured at implant, at early follow-up (1-4 days post implant), and every 3-6 months thereafter. RESULTS: During the study period, 357 patients underwent implantation of the Medtronic Sprint Fidelis lead. The mean R-wave measured at implant through the device was not different (P = NS) when compared with that measured at first follow-up (10.5 +/- 5.0 mV vs 10.7 +/- 5.1 mV). Forty-one patients (13%) had an R-wave amplitude