Six-month Electrical Performance of the First Dual-Chamber Leadless Pacemaker.

BACKGROUND: The first dual-chamber leadless pacemaker (DC-LP) system consists of two separate atrial and ventricular devices that communicate to maintain synchronous atrioventricular pacing and sensing. The initial safety and efficacy were previously reported. OBJECTIVE: Evaluate the chronic electrical performance of the DC-LP system. METHODS: Patients meeting standard dual-chamber pacing indications were enrolled and implanted with the DC-LP system (Aveir DR, Abbott), including right atrial and ventricular helix-fixation LPs (ALP, VLP). Pacing capture threshold, sensed amplitude, and pacing impedance were collected using the device programmer at prespecified time points from 0-6 months post-implant. RESULTS: De novo devices were successfully implanted in 381 patients with complete 6M data (62% male; age 69±14 years; weight 82±20 kg; 65% sinus node dysfunction, 30% AV block). ALPs were implanted predominantly in the right atrial appendage anterior base; VLPs primarily at the mid-to-apical right ventricular septum. From implant to 1 month, pacing capture thresholds (0.4 ms pulse width) improved in both ALPs (2.4±1.5 to 0.8±0.8 V, P<0.001) and VLPs (0.8±0.6 to 0.6±0.4 V, P<0.001). Sensed amplitudes improved in both ALPs (1.8±1.3 to 3.4±1.9 mV, P<0.001) and VLPs (8.8±4.0 to 11.7±4.2 mV, P<0.001). Impedances were stable in ALPs (334±68 to 329±52 Ω, P=0.17) and reduced in VLPs (789±351 to 646±190 Ω, P<0.001). Electrical measurements remained relatively stable from 1-6 months post-implant. No differences in electrical metrics were observed among ALP or VLP implant locations. CONCLUSION: This first in-human evaluation of the new dual-chamber leadless pacemaker system demonstrated reliable electrical performance throughout the initial 6-month evaluation period.

Early real-world implant experience with a helix-fixation ventricular leadless pacemaker.

BACKGROUND: Roughly one in six patients receiving conventional transvenous pacemaker systems experience significant complications within 1 year of implant, mainly due to the transvenous lead and subcutaneous pocket. A new helix-fixation single-chamber ventricular leadless pacemaker (LP) system capable of pre-deployment exploratory electrical mapping is commercially available. Such an LP may mitigate complications while streamlining the implantation. In this study, the initial real-world implant experience of the helix-fixation LP was evaluated following its commercial release. METHODS: In patients indicated for single-chamber right ventricular pacing, helix-fixation Aveir VR LPs (Abbott, Abbott Park, IL) were implanted using the dedicated loading tool, introducer, and delivery catheter. Implant procedural characteristics, electrical parameters, and any 30-day procedure-related adverse events of consecutive implant attempts were retrospectively evaluated. RESULTS: A total of 167 patients with Class I indication for permanent pacing received implants in four North American centers (57% male, 70 years old). Pre-fixation electrical mapping of potential sites allowed repositioning to be avoided in 95.7% of patients. Median [interquartile range] LP procedure and fluoroscopy durations were 25.5 min [20.0, 35.0] and 5.7 min [4.0, 9.2], respectively. Pacing capture threshold, sensed R-wave amplitude, and impedance were 0.8 V [0.5, 1.3], 9.0 mV [6.0, 12.0], and 705 Ω [550, 910], respectively. Implantation was successful in 98.8% of patients, with 98.2% free from acute adverse events. CONCLUSIONS: The initial, real-world experience of the helix-fixation ventricular leadless pacemaker demonstrated safe and efficient implantation with minimal repositioning, viable electrical metrics, and limited acute complications.

Long-Term Outcomes of Resynchronization-Defibrillation for Heart Failure.

BACKGROUND: The Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter-defibrillators (ICDs). However, the effect of CRT on long-term survival is not known. METHODS: We randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device. RESULTS: The trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). Death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P = 0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group. CONCLUSIONS: Among patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.).

The economic burden of cardiac implantable electronic device infections in Alberta, Canada: a population-based study using validated administrative data.

BACKGROUND: Cardiac implantable electronic devices (CIED) are being inserted with increasing frequency. Severe surgical site infections (SSI) that occur after device implantation substantially impact patient morbidity and mortality and can result in multiple hospital admissions and repeat surgeries. It is important to understand the costs associated with these infections as well as healthcare utilization. Therefore, we conducted a population-based study in the province of Alberta, Canada to understand the economic burden of these infections. METHODS: A cohort of adult patients in Alberta who had CIEDs inserted or generators replaced between January 1, 2011 and December 31, 2019 was used. A validated algorithm of International Classification of Diseases (ICD) codes to identify complex (deep/organ space) SSIs that occurred within the subsequent year was applied to the cohort. The overall mean 12-month inpatient and outpatient costs for the infection and non-infection groups were assessed. In order to control for variables that may influence costs, propensity score matching was completed and incremental costs between those with and without infection were calculated. As secondary outcomes, number of outpatient visits, hospitalizations and length of stay were assessed. RESULTS: There were 26,049 procedures performed during our study period, of which 320 (1.23%) resulted in SSIs. In both unadjusted costs and propensity score matched costs the infection group was associated with increased costs. Overall mean cost was $145,312 in the infection group versus $34,264 in the non-infection group. The incremental difference in those with infection versus those without in the propensity score match was $90,620 (Standard deviation $190,185). Approximately 70% of costs were driven by inpatient hospitalizations. Inpatients hospitalizations, length of stay and outpatient visits were all increased in the infection group. CONCLUSIONS: CIED infections are associated with increased costs and are a burden to the healthcare system. This highlights a need to recognize increasing SSI rates and implement measures to minimize infection risk. Further studies should endeavor to apply this work to full economic evaluations to better understand and identify cost-effective infection mitigation strategies.

Retrieval of Chronically Implanted Dual-chamber Leadless Pacemakers in an Ovine Model.

BACKGROUND: The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated. METHODS: Atrial and ventricular LPs were implanted in the right atrial appendage and right ventricular apex of 9 healthy ovine subjects. After ≈2 years, the LPs were retrieved using a dedicated transvenous retrieval catheter (Aveir Retrieval Catheter; Abbott) by snaring, docking, and unscrewing from the myocardium. Comprehensive necropsy/histopathology studies were conducted to evaluate device- and procedure-related outcomes. RESULTS: At a median of 1.9 years postimplant (range, 1.8-2.6), all 18 of 18 (100%) LPs were retrieved from 9 ovine subjects without complications. The median retrieval procedure duration for both LPs, from first-catheter-in to last-catheter-out, was 13.3 minutes (range, 2.5-36.4). Postretrieval, all right atrial, and right ventricular implant sites demonstrated minimal tissue disruption, with intact fibrous tissue limited to the distal device body. No significant device-related trauma, perforation, pericardial effusion, right heart or tricuspid valve injury, or chronic pulmonary thromboembolism were observed at necropsy. CONCLUSIONS: This preclinical study demonstrated the safe and effective retrieval of chronically implanted, helix-fixation, dual-chamber LP systems, paving the way for clinical studies of LP retrieval.

Successes and challenges of artificial intelligence in cardiology.

In the past decades there has been a substantial evolution in data management and data processing techniques. New data architectures made analysis of big data feasible, healthcare is orienting towards personalized medicine with digital health initiatives, and artificial intelligence (AI) is becoming of increasing importance. Despite being a trendy research topic, only very few applications reach the stage where they are implemented in clinical practice. This review provides an overview of current methodologies and identifies clinical and organizational challenges for AI in healthcare.

Complex cardiac implantable electronic device infections in Alberta, Canada: An epidemiologic cohort study of validated administrative data.

OBJECTIVE: To establish the epidemiology of cardiac implantable electronic device (CIED) infections in Alberta, Canada, using validated administrative data. DESIGN: Retrospective, population-based cohort study. SETTING: Alberta Health Services is a province-wide health system that services all of Alberta, Canada. PARTICIPANTS: Adult patients who underwent first-time CIED implantation or generator replacement in Alberta, Canada, between January 1, 2011, and December 31, 2019. METHODS: CIED implant patients were identified from the Paceart database. Patients who developed an infection within 1 year of the index procedure were identified through validated administrative data (International Classification of Diseases, Tenth Revision in Canada). Demographic characteristics of patients were summarized. Logistic regression models were used to analyze device type, comorbidities, and demographics associated with infection rates and mortality. RESULTS: Among 27,830 CIED implants, there were 205 infections (0.74%). Having 2 or more comorbidities was associated with higher infection risk. Generator replacement procedures (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.34-0.84; P = .008), age increase of every 10 years (OR, 0.73; 95% CI, 0.66-0.82; P ≤ .001), and index procedure after 2014 were associated with decreased risk. Comparing the infected to uninfected groups, the hospitalization rates were 2.63 compared to 0.69, and the mortality rates were 10.73% compared to 3.49%, respectively (P < .001). CONCLUSIONS: There is a slightly lower overall rate of CIED infections Alberta, Canada compared to previously described epidemiology. Implants after 2014, and generator replacements showed a decreased burden of infection. Patients with younger age, and 2 or more comorbidities are at greatest risk of CIED infection. The burden of hospitalization and mortality is substantially higher in infected patients.

A Dual-Chamber Leadless Pacemaker.

BACKGROUND: Single-chamber ventricular leadless pacemakers do not support atrial pacing or consistent atrioventricular synchrony. A dual-chamber leadless pacemaker system consisting of two devices implanted percutaneously, one in the right atrium and one in the right ventricle, would make leadless pacemaker therapy a treatment option for a wider range of indications. METHODS: We conducted a prospective, multicenter, single-group study to evaluate the safety and performance of a dual-chamber leadless pacemaker system. Patients with a conventional indication for dual-chamber pacing were eligible for participation. The primary safety end point was freedom from complications (i.e., device- or procedure-related serious adverse events) at 90 days. The first primary performance end point was a combination of adequate atrial capture threshold and sensing amplitude at 3 months. The second primary performance end point was at least 70% atrioventricular synchrony at 3 months while the patient was sitting. RESULTS: Among the 300 patients enrolled, 190 (63.3%) had sinus-node dysfunction and 100 (33.3%) had atrioventricular block as the primary pacing indication. The implantation procedure was successful (i.e., two functioning leadless pacemakers were implanted and had established implant-to-implant communication) in 295 patients (98.3%). A total of 35 device- or procedure-related serious adverse events occurred in 29 patients. The primary safety end point was met in 271 patients (90.3%; 95% confidence interval [CI], 87.0 to 93.7), which exceeded the performance goal of 78% (P<0.001). The first primary performance end point was met in 90.2% of the patients (95% CI, 86.8 to 93.6), which exceeded the performance goal of 82.5% (P<0.001). The mean (±SD) atrial capture threshold was 0.82±0.70 V, and the mean P-wave amplitude was 3.58±1.88 mV. Of the 21 patients (7%) with a P-wave amplitude of less than 1.0 mV, none required device revision for inadequate sensing. At least 70% atrioventricular synchrony was achieved in 97.3% of the patients (95% CI, 95.4 to 99.3), which exceeded the performance goal of 83% (P<0.001). CONCLUSIONS: The dual-chamber leadless pacemaker system met the primary safety end point and provided atrial pacing and reliable atrioventricular synchrony for 3 months after implantation. (Funded by Abbott Medical; Aveir DR i2i ClinicalTrials.gov number, NCT05252702.).

Dual-chamber leadless pacing: Atrioventricular synchrony in preclinical models of normal or blocked atrioventricular conduction.

BACKGROUND: Dual-chamber leadless pacemakers (LPs) require robust communication between distinct right atrial (RA) and right ventricular (RV) LPs to achieve atrioventricular (AV) synchrony. OBJECTIVE: The purpose of this preclinical study was to evaluate a novel, continuous implant-to-implant (i2i™) communication methodology for maintaining AV-synchronous, dual-chamber DDD(R) pacing by the 2 LPs. METHODS: RA and RV LPs were implanted and paired in 7 ovine subjects (4 with induced complete heart block). AV synchrony (% AV intervals <300 ms) and i2i communication success (% successful i2i transmissions between LPs) were evaluated acutely and chronically. During acute testing, 12-lead electrocardiographic and LP diagnostic data were collected from 5-minute recordings, in 4 postures and 2 rhythms (AP-VP and AS-VP, or AP-VS and AS-VS) per subject. Chronic i2i performance was evaluated through 23 weeks postimplant (final i2i evaluation period: week 16-23). RESULTS: Acute AV synchrony and i2i communication success across multiple postures and rhythms were median [interquartile range] 100.0% [100.0%-100.0%] and 99.9% [99.9%-99.9%], respectively. AV synchrony and i2i success rates did not differ across postures (P = .59, P = .11) or rhythms (P = 1, P = .82). During the final i2i evaluation period, the overall i2i success was 98.9% [98.1%-99.0%]. CONCLUSION: Successful AV-synchronous, dual-chamber DDD(R) leadless pacing using a novel, continuous, wireless communication modality was demonstrated across variations in posture and rhythm in a preclinical model.

Association of the Timing and Extent of Cardiac Implantable Electronic Device Infections With Mortality.

Importance: Cardiac implantable electronic device (CIED) infection is a potentially devastating complication with an estimated 12-month mortality of 15% to 30%. The association of the extent (localized or systemic) and timing of infection with all-cause mortality has not been established. Objective: To evaluate the association of the extent and timing of CIED infection with all-cause mortality. Design, Setting, and Participants: This prospective observational cohort study was conducted between December 1, 2012, and September 30, 2016, in 28 centers across Canada and the Netherlands. The study included 19 559 patients undergoing CIED procedures, 177 of whom developed an infection. Data were analyzed from April 5, 2021, to January 14, 2023. Exposures: Prospectively identified CIED infections. Main Outcomes and Measures: Time-dependent analysis of the timing (early [≤3 months] or delayed [3-12 months]) and extent (localized or systemic) of infection was performed to determine the risk of all-cause mortality associated with CIED infections. Results: Of 19 559 patients undergoing CIED procedures, 177 developed a CIED infection. The mean (SD) age was 68.7 (12.7) years, and 132 patients were male (74.6%). The cumulative incidence of infection was 0.6%, 0.7%, and 0.9% within 3, 6, and 12 months, respectively. Infection rates were highest in the first 3 months (0.21% per month), reducing significantly thereafter. Compared with patients who did not develop CIED infection, those with early localized infections were not at higher risk for all-cause mortality (no deaths at 30 days [0 of 74 patients]: adjusted hazard ratio [aHR], 0.64 [95% CI, 0.20-1.98]; P = .43). However, patients with early systemic and delayed localized infections had an approximately 3-fold increase in mortality (8.9% 30-day mortality [4 of 45 patients]: aHR, 2.88 [95% CI, 1.48-5.61]; P = .002; 8.8% 30-day mortality [3 of 34 patients]: aHR, 3.57 [95% CI, 1.33-9.57]; P = .01), increasing to a 9.3-fold risk of death for those with delayed systemic infections (21.7% 30-day mortality [5 of 23 patients]: aHR, 9.30 [95% CI, 3.82-22.65]; P < .001). Conclusions and Relevance: Findings suggest that CIED infections are most common within 3 months after the procedure. Early systemic infections and delayed localized infections are associated with increased mortality, with the highest risk for patients with delayed systemic infections. Early detection and treatment of CIED infections may be important in reducing mortality associated with this complication.

Self-Management Support Using Advertising Principles for Older Adults With Low Income at High Cardiovascular Risk: A Randomized Controlled Trial.

BACKGROUND: Self-management education and support (SMES) interventions have modest effects on intermediate outcomes for those at risk of cardiovascular disease, but few studies have measured or demonstrated an effect on clinical end points. Advertising for commercial products is known to influence behavior, but advertising principles are not typically incorporated into SMES design. METHODS: This randomized trial studied the effect of a novel tailored SMES program designed by an advertising firm among a population of older adults with low income at high cardiovascular risk in Alberta, Canada. The intervention included health promotion messaging from a fictitious "peer" and facilitated relay of clinical information to patients' primary care provider and pharmacist. The primary outcome was the composite of death, myocardial infarction, stroke, coronary revascularization, and hospitalizations for cardiovascular-related ambulatory care-sensitive conditions. Rates of the primary outcome and its components were compared using negative binomial regression. Secondary outcomes included quality of life (EQ-5D [EuroQoL 5-dimension] index score), medication adherence, and overall health care costs. RESULTS: We randomized 4761 individuals, with a mean age of 74.4 years, of whom 46.8% were female. There was no evidence of statistical interaction (P=0.99) or of a synergistic effect between the 2 interventions in the factorial trial with respect to the primary outcome, which allowed us to evaluate the effect of each intervention separately. Over a median follow-up time of 36 months, the rate of the primary outcome was lower in the group that received SMES compared with the control group (incidence rate ratio, 0.78 [95% CI, 0.61 to 1.00]; P=0.047). No significant between-group changes in quality of life over time were observed (mean difference, 0.0001 [95% CI, -0.018 to 0.018]; P=0.99). The proportion of participants who were adherent to medications was not different between the 2 groups (P=0.199 for statins and P=0.754 for angiotensin-converting enzyme inhibitors/angiotensin receptor blockers). Overall adjusted health care costs did not differ between those receiving SMES and the control group ($2015 [95% CI, -$1953 to $5985]; P=0.320). CONCLUSIONS: For older adults with low income, a tailored SMES program using advertising principles reduced the rate of clinical outcomes compared with usual care. The mechanisms of improvement are unclear and further studies are required. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02579655.

Eliminating Medication Copayments for Low-Income Older Adults at High Cardiovascular Risk: A Randomized Controlled Trial.

BACKGROUND: One in eight people with heart disease has poor medication adherence that, in part, is related to copayment costs. This study tested whether eliminating copayments for high-value medications among low-income older adults at high cardiovascular risk would improve clinical outcomes. METHODS: This randomized 2×2 factorial trial studied 2 distinct interventions in Alberta, Canada: eliminating copayments for high-value preventive medications and a self-management education and support program (reported separately). The findings for the first intervention, which waived the usual 30% copayment on 15 medication classes commonly used to reduce cardiovascular events, compared with usual copayment, is reported here. The primary outcome was the composite of death, myocardial infarction, stroke, coronary revascularization, and cardiovascular-related hospitalizations over a 3-year follow-up. Rates of the primary outcome and its components were compared using negative binomial regression. Secondary outcomes included quality of life (Euroqol 5-dimension index score), medication adherence, and overall health care costs. RESULTS: A total of 4761 individuals were randomized and followed for a median of 36 months. There was no evidence of statistical interaction (P=0.99) or of a synergistic effect between the 2 interventions in the factorial trial with respect to the primary outcome, which allowed us to evaluate the effect of each intervention separately. The rate of the primary outcome was not reduced by copayment elimination, (521 versus 533 events, incidence rate ratio 0.84 [95% CI, 0.66-1.07], P=0.162). The incidence rate ratio for nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death (0.97 [95% CI, 0.67-1.39]), death (0.94 [95% CI, 0.80 to 1.11]), and cardiovascular-related hospitalizations (0.78 [95% CI, 0.57 to 1.06]) did not differ between groups. No significant between-group changes in quality of life over time were observed (mean difference, 0.012 [95% CI, -0.006 to 0.030], P=0.19). The proportion of participants who were adherent to statins was 0.72 versus 0.69 for the copayment elimination versus usual copayment groups, respectively (mean difference, 0.03 [95% CI, 0.006-0.06], P=0.016). Overall adjusted health care costs did not differ ($3575 [95% CI, -605 to 7168], P=0.098). CONCLUSIONS: In low-income adults at high cardiovascular risk, eliminating copayments (average, $35/mo) did not improve clinical outcomes or reduce health care costs, despite a modest improvement in adherence to medications. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02579655.

Perioperative Safety and Early Patient and Device Outcomes Among Subcutaneous Versus Transvenous Implantable Cardioverter Defibrillator Implantations : A Randomized, Multicenter Trial.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) improve survival in patients at risk for cardiac arrest, but are associated with intravascular lead-related complications. The subcutaneous ICD (S-ICD), with no intravascular components, was developed to minimize lead-related complications. OBJECTIVE: To assess key ICD performance measures related to delivery of ICD therapy, including inappropriate ICD shocks (delivered in absence of life-threatening arrhythmia) and failed ICD shocks (which did not terminate ventricular arrhythmia). DESIGN: Randomized, multicenter trial. (ClinicalTrials.gov: NCT02881255). SETTING: The ATLAS trial. PATIENTS: 544 eligible patients (141 female) with a primary or secondary prevention indication for an ICD who were younger than age 60 years, had a cardiogenetic phenotype, or had prespecified risk factors for lead complications were electrocardiographically screened and 503 randomly assigned to S-ICD (251 patients) or transvenous ICD (TV-ICD) (252 patients). Mean follow-up was 2.5 years (SD, 1.1). Mean age was 49.0 years (SD, 11.5). MEASUREMENTS: The primary outcome was perioperative major lead-related complications. RESULTS: There was a statistically significant reduction in perioperative, lead-related complications, which occurred in 1 patient (0.4%) with an S-ICD and in 12 patients (4.8%) with TV-ICD (-4.4%; 95% CI, -6.9 to -1.9; P = 0.001). There was a trend for more inappropriate shocks with the S-ICD (hazard ratio [HR], 2.37; 95% CI, 0.98 to 5.77), but no increase in failed appropriate ICD shocks (HR, 0.61 (0.15 to 2.57). Patients in the S-ICD group had more ICD site pain, measured on a 10-point numeric rating scale, on the day of implant (4.2 ± 2.8 vs. 2.9 ± 2.2; P < 0.001) and 1 month later (1.3 ± 1.8 vs. 0.9 ± 1.5; P = 0.035). LIMITATION: At present, the ATLAS trial is underpowered to detect differences in clinical shock outcomes; however, extended follow-up is ongoing. CONCLUSION: The S-ICD reduces perioperative, lead-related complications without significantly compromising the effectiveness of ICD shocks, but with more early postoperative pain and a trend for more inappropriate shocks. PRIMARY FUNDING SOURCE: Boston Scientific.

Machine learning prediction of atrial fibrillation in cardiovascular patients using cardiac magnetic resonance and electronic health information.

Background: Atrial fibrillation (AF) is a commonly encountered cardiac arrhythmia associated with morbidity and substantial healthcare costs. While patients with cardiovascular disease experience the greatest risk of new-onset AF, no risk model has been developed to predict AF occurrence in this population. We hypothesized that a patient-specific model could be delivered using cardiovascular magnetic resonance (CMR) disease phenotyping, contextual patient health information, and machine learning. Methods: Nine thousand four hundred forty-eight patients referred for CMR imaging were enrolled and followed over a 5-year period. Seven thousand, six hundred thirty-nine had no prior history of AF and were eligible to train and validate machine learning algorithms. Random survival forests (RSFs) were used to predict new-onset AF and compared to Cox proportional-hazard (CPH) models. The best performing features were identified from 115 variables sourced from three data domains: (i) CMR-based disease phenotype, (ii) patient health questionnaire, and (iii) electronic health records. We evaluated discriminative performance of optimized models using C-index and time-dependent AUC (tAUC). Results: A RSF-based model of 20 variables (CIROC-AF-20) delivered an overall C-index of 0.78 for the prediction of new-onset AF with respective tAUCs of 0.80, 0.79, and 0.78 at 1-, 2- and 3-years. This outperformed a novel CPH-based model and historic AF risk scores. At 1-year of follow-up, validation cohort patients classified as high-risk of future AF by CIROC-AF-20 went on to experience a 17.3% incidence of new-onset AF, being 24.7-fold higher risk than low risk patients. Conclusions: Using phenotypic data available at time of CMR imaging we developed and validated the first described risk model for the prediction of new-onset AF in patients with cardiovascular disease. Complementary value was provided by variables from patient-reported measures of health and the electronic health record, illustrating the value of multi-domain phenotypic data for the prediction of AF.

Geographic and temporal variation in the treatment and outcomes of atrial fibrillation: a population-based analysis of national quality indicators.

BACKGROUND: Assessment of potential geographic variation in quality indicators of atrial fibrillation care may identify opportunities for improvement in the quality of atrial fibrillation care. The objective of this study was to assess for potential geographic variation in the quality of atrial fibrillation care in Alberta, Canada. METHODS: In a population-based cohort of adults (age ≥ 18 yr) with incident nonvalvular atrial fibrillation (NVAF) diagnosed between Apr. 1, 2008, and Mar. 31, 2016, in Alberta, we investigated the variation in national quality indicators of atrial fibrillation care developed by the Canadian Cardiovascular Society. Specifically, we assessed the geographic and temporal variation in the proportion of patients with initiation of oral anticoagulant therapy, persistence with therapy, ischemic stroke and major bleeding outcomes 1 year after atrial fibrillation diagnosis using linked administrative data sets. We defined stroke risk using the CHADS2 score. We assessed geographic variation using small-area variation statistics and geospatial data analysis. RESULTS: Of the 64 093 patients in the study cohort (35 019 men [54.6%] and 29 074 women [45.4%] with a mean age of 69 [standard deviation 15.9] yr), 36 199 were at high risk for stroke and 14 411 were at moderate risk. Within 1 year of NVAF diagnosis, 20 180 patients (55.7%) in the high-risk group and 6448 patients (44.7%) in the moderate-risk group were prescribed anticoagulation. A total of 2187 patients (3.4%) had an ischemic stroke, and 2996 patients (4.7%) experienced a major bleed. There was substantial regional variation observed in initiation of oral anticoagulant therapy but not in the proportion of patients with ischemic stroke or major bleeding. Among the 64 Health Status Areas in Alberta, therapy initiation rates ranged from 22.6% to 71.2% among patients at high stroke risk and from 22.7% to 55.8% among those at moderate stroke risk, with clustering of lower therapy initiation rates in rural northern regions. INTERPRETATION: The rate of initiation of oral anticoagulant therapy among adults with incident atrial fibrillation was less than 60% in patients in whom oral anticoagulant therapy would be considered guideline-appropriate care. The large geographic variation in oral anticoagulant prescribing warrants additional study into patient, provider and health care system factors that contribute to variation and drive disparities in high-quality, equitable atrial fibrillation care.

Lower body muscle preactivation and tensing mitigate symptoms of initial orthostatic hypotension in young females.

BACKGROUND: Initial orthostatic hypotension (IOH) is a form of orthostatic intolerance defined by a transient decrease in blood pressure upon standing. Current clinical recommendations for managing IOH includes standing up slowly or lower body muscle tensing (TENSE) after standing. Considering that IOH is likely due to a large muscle activation response resulting in excessive vasodilation with a refractory period (<2 minutes), we hypothesized that preactivating lower body muscles (PREACT) before standing would reduce the drop in mean arterial pressure (MAP) upon standing and improve presyncope symptoms. OBJECTIVE: The purpose of this study was to provide IOH patients with effective symptom management techniques. METHODS: Study participants completed 3 sit-to-stand maneuvers, including a stand with no intervention (Control), PREACT, and TENSE. Continuous heart rate and beat-to-beat blood pressure were measured. Stroke volume and cardiac output were then estimated from these waveforms. RESULTS: A total of 24 female IOH participants (mean ± SD: 32 ± 8 years) completed the study. The drops in MAP following PREACT (-21 ± 8 mm Hg; P <.001) and TENSE (-18 ± 10 mm Hg; P <.001) were significantly reduced compared to Control (-28 ± 10 mm Hg). The increase in cardiac output was significantly larger following PREACT (2.6 ± 1 L/min; P <.001) but not TENSE (1.9 ± 1 L/min; P = .2) compared to Control (1.4 ± 1 L/min). The Vanderbilt Orthostatic Symptom Score following PREACT (9 ± 8 au; P = .033) and TENSE (8 ± 8 au; P = .046) both were significantly reduced compared to Control (14 ± 9 au). CONCLUSION: Both the drop in MAP and symptoms upon standing improved with either PREACT or TENSE. These maneuvers provide novel symptom management techniques for patients with IOH.

Diagnosis-to-ablation time predicts recurrent atrial fibrillation and rehospitalization following catheter ablation.

BACKGROUND: Wait times for catheter ablation in patients with symptomatic atrial fibrillation (AF) may influence clinical outcomes. OBJECTIVE: This study examined the relationship between the duration from AF diagnosis to ablation, or diagnosis-to-ablation time (DAT), on the clinical response to catheter ablation in a large nationwide cohort of patients. METHODS: We identified patients with new AF who underwent catheter ablation between January 2014 and December 2017 using the IBM MarketScan databases. Cox proportional hazard models were used to estimate the strength of the association between DAT and the outcomes of AF recurrence and hospitalization at 1 year postablation. RESULTS: Among 11,143 AF patients who underwent ablation, the median age was 59 years, 31% were female, and the median CHA2DS2-VASc score was 2. Median DAT was 5.5 (2.6, 13.1) months. At 1 year postablation, 10.0% (n = 1116) developed recurrent AF. For each year increase in DAT, the risk of AF recurrence increased by 20% after adjustment for baseline comorbidities and medications (hazard ratio [HR] 1.20, 95% confidence interval [CI] 1.11-1.30). A longer DAT was associated with an increased risk of hospitalization (HR 1.08 per DAT year, 95% CI 1.02-1.15). DAT was a stronger predictor of AF recurrence postablation than traditional clinical risk factors, including age, prior heart failure, or renal failure. CONCLUSION: Increasing duration between AF diagnosis and catheter ablation is associated with higher AF recurrence rates and all-cause hospitalization. Our findings are consistent with a growing body of evidence supporting the benefits of prioritizing early restoration of sinus rhythm.

Clinical and Economic Outcomes Associated With Remote Monitoring for Cardiac Implantable Electronic Devices: A Population-Based Analysis.

BACKGROUND: Despite expert recommendations advocating use of remote monitoring (RM) of cardiac implantable electronic devices, implementation in routine clinical practice remains modest due to inconsistent funding policies across health systems and uncertainty regarding the efficacy of RM to reduce adverse cardiovascular outcomes. METHODS: We conducted a population-based cohort study of patients with de novo implantable cardioverter-defibrillators (ICDs) with or without cardiac resynchronization therapy (CRT-D), using administrative health data in Alberta, Canada, from 2010 to 2016. We assessed RM status as a predictor of all-cause mortality and cardiovascular (CV) hospitalization using Cox proportional hazards modelling, and direct health costs by generalized linear models. From this real-world data, we then constructed a decision-analytic Markov model to estimate the projected costs and benefits associated with RM compared with in-clinic visit follow-up alone. RESULTS: Among 2799 ICD and CRT-D patients, 1830 (63.4%) were followed by RM for a mean follow-up of 50.3 months. After adjustment for age, sex, and comorbidities, RM was associated with a lower risk of death (hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.36-0.52; P < 0.001) and CV hospitalization (HR 0.76, 95% CI 0.64-0.91; P = 0.002). In the economic model, cost savings were observed over 5 years with an estimated savings of $12,195 per person (95% CI -$21,818 to -$4,790). The model estimated a cost-savings associated with RM strategy in 99% of simulations. CONCLUSIONS: These population data support more widespread implementation of RM technology to facilitate better patient outcomes and improve health system efficiency.