Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial.

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure.

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure.

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Predictors of permanent pacemaker requirement after cardiac surgery for infective endocarditis.

BACKGROUND: Infectious endocarditis is often complicated by conduction abnormalities at the time of presentation. Cardiac surgery is the treatment of choice for many infectious endocarditis patients, but carries an additional risk of persistent postoperative conduction abnormality. We sought to define the incidence and clinical predictors of significant postoperative conduction abnormalities necessitating permanent pacemaker implantation after cardiac surgery for infectious endocarditis. METHODS: All consecutive patients with infectious endocarditis who were surgically treated at Cleveland Clinic from 2007 to 2013 were identified using the Cleveland Clinic Infective Endocarditis Registry and the Cardiovascular Information Registry. Patients with a pre-existing cardiac implantable electronic device were excluded. The primary outcome was the need for permanent pacemaker placement postoperatively for atrioventricular block. Regression analysis was performed to identify risk factors for permanent pacemaker requirement. RESULTS: Among 444 infectious endocarditis patients who underwent cardiac surgery for infectious endocarditis, 57 (13%) required postoperative permanent pacemaker for atrioventricular block. Multivariable analysis identified that prolongation in preoperative PR and QRS intervals, Staphylococcus aureus as the infectious endocarditis organism, the presence of intracardiac abscess, tricuspid valve involvement, and prior valvular surgery independently predicted postoperative permanent pacemaker placement. The developed model exhibited excellent predictive ability (c-statistic 0.88) and calibration. CONCLUSION: Infectious endocarditis cardiac surgery patients often require a postoperative permanent pacemaker. Preoperative conduction abnormality, S. aureus infection, abscess, tricuspid valve involvement, and prior valvular surgery are strong predictors of postoperative permanent pacemaker placement.

Predictors of long-term outcomes greater than 10 years after cardiac resynchronization therapy implantation.

BACKGROUND: Cardiac resynchronization therapy (CRT) is indicated in patients with medically refractory heart failure and wide QRS duration. While much is known about predictors of left ventricular (LV) remodeling after CRT implantation and short-term mortality, limited data exist on long-term outcomes after CRT placement. METHODS: We retrospectively reviewed all patients undergoing CRT implantation at our center between 2003 and 2008 and examined mortality using institutional electronic records, social security death index, and online obituary search. We included only patients with preimplant echoes with LV ejection fraction (LVEF) 35% or below. Variable selection was performed using stepwise regression and models were compared using goodness-of-fit criteria. A final model was validated with the bootstrap regression method. RESULTS: Out of the 877 CRT patients undergoing implantation during this time, 287 (32.7%) survived longer than 10 years. Significant (P < .05) predictors of survival in our multivariate model were age, left ventricular diastolic diameter, sex, presence of nonischemic vs ischemic cardiomyopathy, QRS duration, atrial fibrillation, BNP levels, and creatinine levels at the time of CRT implantation. A model using the odds ratios from these variables had a receiver operating curve with an area under the curve score of 0.816 (standard error, 0.019) at predicting survival or freedom from LVAD or heart transplant for longer than 10 years after CRT implantation. The specificity for factors 3 or above and 5 or above was 68% and 77%, respectively. CONCLUSION: A large proportion of patients are still alive 10 years after CRT implantation. Variables at the time of CRT implant can help provide prognostic information to patients and electrophysiologists to determine the long-term benefit and survival of patients after CRT implantation.

Effect of Left Ventricular Conduction Delay on All-Cause and Cardiovascular Mortality (from the PRECISION Trial).

The prognosis associated with prolonged intraventricular conduction on electrocardiogram (ECG) remains uncertain. We aimed to compare clinical outcomes of narrow versus prolonged intraventricular conduction on ECG stratified by QRS morphology and cardiovascular disease (CVD) status. A post-hoc analysis was performed of the randomized-control PRECISION trial. Patients with centrally adjudicated, nonpaced baseline ECGs were included. QRS duration was classified narrow (≤100 ms) versus prolonged (>100 ms) with additional categorization into left (LBBB) or right (RBBB) bundle branch block or nonspecific intraventricular conduction delay (IVCD). IVCD was subclassified if left ventricular conduction delay (LVCD) was present (L-IVCD) or absent (O-IVCD). The primary outcome was adjudicated all-cause and cardiovascular (CV) mortality. Of 24,081 patients randomized, 22,067 (92%) were included with follow-up 34 ± 13 months. Study patients were 63 ± 9 years, 64% female, 75% Caucasian, 23% with established CVD. The prevalence of QRS prolongation was 5.6% (1,240): 760 right bundle branch block (3.4%), 313 LBBB (1.4%), and 161 IVCD (0.7%), 95 subclassified L-IVCD (0.4%). After adjustment, LBBB and L-IVCD were similarly associated with increased all-cause (LBBB: 2.3 [1.4 to 3.8], p = 0.001; L-IVCD: 4.0 [2.1 to 7.9], p <0.001) and CV (LBBB: 3.6 [2.0 to 6.5], p <0.001; L-IVCD 3.6 [1.3 to 9.7], p = 0.001) mortality. The presence of LVCD (LBBB or L-IVCD) was associated with all-cause (2.8 [1.8 to 4.2], p <0.001) and CV (3.6 [2.2 to 6.1], p <0.001) mortality exceeding the observed risks of coronary artery disease, left ventricular hypertrophy, or diabetes. The LVCD hazard persisted across QRS durations (100 to 120 vs >120 ms) and CVD status. In conclusion, LVCD, whether LBBB or L-IVCD, was strongly associated with increased mortality in patients with and at-risk for CVD.

Atrial Tachyarrhythmias Among Patients With Left Ventricular Assist Devices: Prevalence, Clinical Outcomes, and Impact of Rhythm Control Strategies.

OBJECTIVES: This study sought to describe the burden of atrial fibrillation (AF)/atrial flutter (AFL) in patients with left ventricular assist devices (LVAD) and to evaluate the impact of rhythm control strategies. BACKGROUND: AF and AFL among patients with LVADs are poorly characterized. METHODS: Retrospective multivariable survival analysis of all LVAD recipients at the Cleveland Clinic from January 1, 2004 to June 30, 2016 examining the association of death, thromboembolism, and major bleeding with AF/AFL and exposure to rhythm control measures. RESULTS: Among 418 patients (median age: 58 [interquartile range: 50 to 67] years, 80% male) with median follow-up of 445 (interquartile range: 165 to 936) days, AF (n = 287 of 418, 69%) and AFL (n = 61 of 418, 15%) were highly prevalent. Patients with AF/AFL (n = 302 of 418, 72%) and without AF/AFL (n = 116 of 418, 28%) had similar mortality (39% vs. 38%; p = 0.88) and major bleeding (46% vs. 49%; p = 0.53); AF/AFL patients had fewer thromboembolic events (13% vs. 23%; p < 0.01). Paroxysmal or persistent AF/AFL was present in 238 patients (57%), and rhythm control exposure (n = 166, 70%) was not associated with decreased mortality (39% vs. 43%; p = 0.57), thromboembolism (13% vs. 17%; p = 0.41), or bleeding (49% vs. 39%; p = 0.16). In the multivariable survival analysis only prior valve surgery (hazard ratio: 2.0; 95% confidence interval: 1.3 to 3.0; p = 0.002) was associated with increased hazard; AF/AFL had no association with risk of death, thromboembolism, or bleeding. CONCLUSIONS: Though highly prevalent among LVAD patients, AF/AFL was not associated with increased mortality, thromboembolism, or bleeding, and among paroxysmal/persistent AF patients, rhythm control measures were not associated with improved outcomes.

Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis.

BACKGROUND: Lower pH after out-of-hospital cardiac arrest (OHCA) has been associated with worsening neurologic outcome, with <7.2 identified as an "unfavorable resuscitation feature" in consensus treatment algorithms despite conflicting data. This study aimed to describe the relationship between decremental post-resuscitation pH and neurologic outcomes after OHCA. METHODS: Consecutive OHCA patients treated with targeted temperature management (TTM) at multiple US centers from 2008 to 2017 were evaluated. Poor neurologic outcome at hospital discharge was defined as cerebral performance category ≥3. The exposure was initial arterial pH after return of spontaneous circulation (ROSC) analyzed in decremental 0.05 thresholds. Potential confounders (demographics, history, resuscitation characteristics, initial studies) were defined a priori and controlled for via ATT-weighting on the inverse propensity score plus direct adjustment for the linear propensity score. RESULTS: Of 723 patients, 589 (80%) experienced poor neurologic outcome at hospital discharge. After propensity-adjustment with excellent covariate balance, the adjusted odds ratios for poor neurologic outcome by pH threshold were: ≤7.3: 2.0 (1.0-4.0); ≤7.25: 1.9 (1.2-3.1); ≤7.2: 2.1 (1.3-3.3); ≤7.15: 1.9 (1.2-3.1); ≤7.1: 2.4 (1.4-4.1); ≤7.05: 3.1 (1.5-6.3); ≤7.0: 4.5 (1.8-12). CONCLUSIONS: No increased hazard of progressively poor neurologic outcomes was observed in resuscitated OHCA patients treated with TTM until the initial post-ROSC arterial pH was at least ≤7.1. This threshold is more acidic than in current guidelines, suggesting the possibility that post-arrest pH may be utilized presently as an inappropriately-pessimistic prognosticator.

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

BACKGROUND: New-onset complete heart block (CHB) commonly complicates cardiac surgery, for which some patients require a permanent pacemaker (PPM). Little is known regarding late atrioventricular (AV) conduction recovery. OBJECTIVE: The purpose of this study was to characterize the incidence and predictors of late AV conduction recovery among patients requiring PPM after cardiac surgery. METHODS: Consecutive patients receiving PPM for CHB after cardiac surgery at a high-volume U.S. center from 2000 to 2014 were evaluated. The primary outcome was late AV conduction recovery, defined as a reduction in ventricular pacing requirement to <10% beyond 1 month postimplant. Regression analysis was performed to evaluate predictors of AV recovery. RESULTS: Among 301 patients evaluated over 4 ± 4 years of follow-up, the incidence of late AV conduction recovery was 12% (n = 37), for whom the median ventricular pacing requirement decreased from 96% at implant to <1% at 6 months and persisted throughout study follow-up. AV recovery was less common when preoperative conduction abnormalities were present, including no recovery among patients with preoperative PR >200 ms and QRS >120 ms (n = 42). Multivariable analysis identified only female sex and transient AV conduction postoperatively as independent predictors of recovery (odds ratio 3.5; P <.01 for each). Neither cardiac surgery subtype nor PPM implant timing postoperatively was significantly associated with recovery. CONCLUSION: Late AV conduction recovery is not uncommon after cardiac surgery, occurring in 1 of 8 patients within 6 months postoperatively. Preoperative AV conduction abnormalities were associated with decreased recovery, whereas female sex and transient postoperative AV conduction were associated with increased recovery.

C-GRApH: A Validated Scoring System for Early Stratification of Neurologic Outcome After Out-of-Hospital Cardiac Arrest Treated With Targeted Temperature Management.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) results in significant morbidity and mortality, primarily from neurologic injury. Predicting neurologic outcome early post-OHCA remains difficult in patients receiving targeted temperature management. METHODS AND RESULTS: Retrospective analysis was performed on consecutive OHCA patients receiving targeted temperature management (32-34°C) for 24 hours at a tertiary-care center from 2008 to 2012 (development cohort, n=122). The primary outcome was favorable neurologic outcome at hospital discharge, defined as cerebral performance category 1 to 2 (poor 3-5). Patient demographics, pre-OHCA diagnoses, and initial laboratory studies post-resuscitation were compared between favorable and poor neurologic outcomes with multivariable logistic regression used to develop a simple scoring system (C-GRApH). The C-GRApH score ranges 0 to 5 using equally weighted variables: (C): coronary artery disease, known pre-OHCA; (G): glucose ≥200 mg/dL; (R): rhythm of arrest not ventricular tachycardia/fibrillation; (A): age >45; (pH): arterial pH ≤7.0. A validation cohort (n=344) included subsequent patients from the initial site (n=72) and an external quaternary-care health system (n=272) from 2012 to 2014. The c-statistic for predicting neurologic outcome was 0.82 (0.74-0.90, P<0.001) in the development cohort and 0.81 (0.76-0.87, P<0.001) in the validation cohort. When subdivided by C-GRApH score, similar rates of favorable neurologic outcome were seen in both cohorts, 70% each for low (0-1, n=60), 22% versus 19% for medium (2-3, n=307), and 0% versus 2% for high (4-5, n=99) C-GRApH scores in the development and validation cohorts, respectively. CONCLUSIONS: C-GRApH stratifies neurologic outcomes following OHCA in patients receiving targeted temperature management (32-34°C) using objective data available at hospital presentation, identifying patient subsets with disproportionally favorable (C-GRApH ≤1) and poor (C-GRApH ≥4) prognoses.

Leadless cardiac pacing: What primary care providers and non-EP cardiologists should know.

Over the last 50 years, the use of transvenous pacemakers has been constrained by long-term complications that affect more than 1 in 10 patients, largely attributable to the endovascular leads and surgical pocket. Leadless cardiac pacing involves a self-contained pacemaker deployed directly into the heart without a lead or incisional access. The procedure has shown promise, eliminating pocket-related complications. Other advantages include postprocedural shoulder mobility and the ability to drive, shower, and bathe. Current devices are limited to single-chamber ventricular pacing. Future advances may allow atrial and dual-chamber pacing and combination with a subcutaneous defibrillator to deliver antitachycardia pacing and provide bradycardia backup.

Incidence and predictors of right ventricular pacing-induced cardiomyopathy in patients with complete atrioventricular block and preserved left ventricular systolic function.

BACKGROUND: Right ventricular (RV) pacing may worsen left ventricular cardiomyopathy in patients with reduced left ventricular ejection fraction (LVEF) and advanced atrioventricular block. OBJECTIVE: The objectives of this study were to calculate incidence and identify predictors of RV pacing-induced cardiomyopathy (PICM) in complete heart block (CHB) with preserved LVEF and to describe outcomes of subsequent cardiac resynchronization therapy (CRT) upgrade. METHODS: An analysis of consecutive patients receiving permanent pacemaker (PPM) from 2000 to 2014 for CHB with LVEF >50% was performed. PICM was defined as CRT upgrade or post-PPM LVEF ≤40%. PICM association was determined via multivariable regression analysis. CRT response was defined by LVEF increase ≥10% or left ventricular end-systolic volume decrease ≥15%. RESULTS: Of the 823 study patients, 101 (12.3%) developed PICM over the mean follow-up of 4.3 ± 3.9 years, with post-PPM LVEF being 33.7% ± 7.4% in patients with PICM vs 57.6% ± 6.1% in patients without PICM (P < .001). In multivariable analysis, lower pre-PPM LVEF (hazard ratio [HR] 1.047 per 1% LVEF decrease; 95% confidence interval [CI] 1.002-1.087; P = .042) and RV pacing % both as a continuous (HR 1.011 per 1% RV pacing; 95% CI 1.002-1.02; P = .021) and as a categorical (<20% or ≥20% RV pacing) (HR 6.76; 95% CI 2.08-22.0; P = .002) variable were independently associated with PICM. Only 29 patients with PICM (28.7%) received CRT upgrade despite an 84% responder rate (LVEF increase 18.5% ± 8.1% and left ventricular end-systolic volume decrease 45.1% ± 15.0% in responders). CRT upgrade was associated with greater post-PPM LVEF decrease, lower post-PPM LVEF, and post-PPM LVEF ≤35% (P = .006, P = .004, and P = .004, respectively). CONCLUSION: PICM is not uncommon in patients receiving PPM for CHB with preserved LVEF and is strongly associated with RV pacing burden >20%. CRT response rate is high in PICM, but is perhaps underutilized.

Implantable Cardioverter-Defibrillator Use in Patients With Left Ventricular Assist Devices: A Systematic Review and Meta-Analysis.

OBJECTIVES: This study evaluated the impact of implantable cardioverter-defibrillators (ICDs) on mortality in patients with left ventricular assist devices (LVADs) by conducting a systematic review and meta-analysis of published studies. BACKGROUND: The burden of ventricular arrhythmias in patients with LVADs is high. Prior studies assessing the impact of ICD on survival of patients with LVADs have yielded conflicting results. METHODS: Relevant studies from January 2000 through October 2015 were identified in the databases PubMed and OVID. Weighted relative risks were estimated using random effects meta-analysis techniques. RESULTS: Six observational studies (n = 937) were included. Patients were 53 ± 12 years of age, and 80% were male. Bridge-to-transplantation was the indication for LVAD use in 93% of the patients. A continuous-flow (CF) LVAD was present in 39% of patients. Mean left ventricular ejection fraction was 16 ± 6%. An ICD was present in 355 patients (38%). During a mean follow-up of 7 months, 241 patients (26%) died (16% in the ICD group vs. 32% in the no-ICD group). Presence of an ICD was associated with a 39% relative risk reduction in all-cause mortality (RR: 0.61; 95% confidence interval [CI]: 0.46 to 0.82; p < 0.01). Among subgroup of patients with CF-LVAD (n = 361), ICD use was associated with a statistically nonsignificant trend toward improved survival (RR: 0.76; 95% CI: 0.51 to 1.12; p = 0.17). CONCLUSIONS: ICD use was associated with a significant reduction in mortality in LVAD patients, however, this effect was not significant in patients with CF-LVADs. Although these data support the use of ICDs, larger randomized trial data are strongly warranted to evaluate ICD effectiveness in patients with current generation LVADs.

Feasibility of small animal cranial irradiation with the microRT system.

PURPOSE: To develop and validate methods for small-animal CNS radiotherapy using the microRT system. MATERIALS AND METHODS: A custom head immobilizer was designed and built to integrate with a pre-existing microRT animal couch. The Delrin couch-immobilizer assembly, compatible with multiple imaging modalities (CT, microCT, microMR, microPET, microSPECT, optical), was first imaged via CT in order to verify the safety and reproducibility of the immobilization method. Once verified, the subject animals were CT-scanned while positioned within the couch-immobilizer assembly for treatment planning purposes. The resultant images were then imported into CERR, an in-house-developed research treatment planning system, and registered to the microRTP treatment planning space using rigid registration. The targeted brain was then contoured and conformal radiotherapy plans were constructed for two separate studies: (1) a whole-brain irradiation comprised of two lateral beams at the 90 degree and 270 degree microRT treatment positions and (2) a hemispheric (left-brain) irradiation comprised of a single A-P vertex beam at the 0 degree microRT treatment position. During treatment, subject animals (n=48) were positioned to the CERR-generated treatment coordinates using the three-axis microRT motor positioning system and were irradiated using a clinical Ir-192 high-dose-rate remote after-loading system. The radiation treatment course consisted of 5 Gy fractions, 3 days per week. 90% of the subjects received a total dose of 30 Gy and 10% received a dose of 60 Gy. RESULTS: Image analysis verified the safety and reproducibility of the immobilizer. CT scans generated from repeated reloading and repositioning of the same subject animal in the couch-immobilizer assembly were fused to a baseline CT. The resultant analysis revealed a 0.09 mm average, center-of-mass translocation and negligible volumetric error in the contoured, murine brain. The experimental use of the head immobilizer added 0.1 mm to microRT spatial uncertainty along each axis. Overall, the total spatial uncertainty for the prescribed treatments was +/-0.3 mm in all three axes, a 0.2 mm functional improvement over the original version of microRT. Subject tolerance was good, with minimal observed side effects and a low procedure-induced mortality rate. Throughput was high, with average treatment times of 7.72 and 3.13 min/animal for the whole-brain and hemispheric plans, respectively (dependent on source strength). CONCLUSIONS: The method described exhibits conformality more in line with the size differential between human and animal patients than provided by previous prevalent approaches. Using pretreatment imaging and microRT-specific treatment planning, our method can deliver an accurate, conformal dose distribution to the targeted murine brain (or a subregion of the brain) while minimizing excess dose to the surrounding tissue. Thus, preclinical animal studies assessing the radiotherapeutic response of both normal and malignant CNS tissue to complex dose distributions, which closer resemble human-type radiotherapy, are better enabled. The procedural and mechanistic framework for this method logically provides for future adaptation into other murine target organs or regions.