Accuracy of the Apple watch for detection of AF: A multicenter experience.

INTRODUCTION: The Apple watch (AW) irregular rhythm notification (IRN) feature uses photoplethysmography to identify prolonged episodes of irregular rhythm suggestive of atrial fibrillation (AF). IRN is FDA cleared for those with no previous history of AF, however, these devices are increasingly being used for AF management.  The objective of the present study was to determine the accuracy of the IRN in subjects with a previous diagnosis of nonpermanent AF. METHODS: Subjects with a history of nonpermanent AF and either an insertable cardiac monitor (ICM) or cardiac implanted electronic device (CIED) with <5% ventricular pacing were fitted with an AW Series 5 for 6 months. AF episodes were compared between the ICM/CIED and IRN. The primary endpoints were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the IRN by subject for AF ≥1 h. Secondary endpoints were sensitivity and PPV by AF episode ≥1 h. Analysis was limited to a maximum of 10 ICM/CIED episodes per subject and included only those AF episodes occurring during active AW use confirmed by activity data. RESULTS: Thirty participants were enrolled. Mean age was 65.4 ± 12.2 years and 40% were female. There were 10 ICMs and 20 CIEDs. Eleven subjects had AF on ICM/CIED while the AW was worn, of whom 8 were detected by IRN. There were no false positive IRN detections by subject ("by subject" 72% sensitivity, 100% specificity, 100% PPV, and 90% NPV). Five subjects had AF only when the AW was not worn. There were a total of 70 AF episodes on ICM/CIED, 35 of which occurred while the AW was being worn. Of these, 21 were detected by IRN with 1 false positive ("by episode" sensitivity = 60.0%, PPV = 95.5%). CONCLUSION: In a population with known AF, the AW IRN had a low rate of false positive detections and high specificity. Sensitivity for detection by subject and by AF episode was lower. The current IRN algorithm appears accurate for AF screening as currently cleared, but increased sensitivity and wear times would be necessary for disease management.

Outcomes using a single tapered dilator for Micra leadless pacemaker implant.

OBJECTIVES: Comparison of outcomes, device deployment time (DT), and total time (TT) using a single tapered Coons dilator versus sequential serial dilation for implantation of the Micra leadless pacemaker. BACKGROUND: Micra leadless pacemaker placement requires a 23 French Micra introducer sheath (MIS) for percutaneous delivery. We sought to evaluate outcomes with use of a single tapered Coons dilator (CD) versus sequential serial dilatation (SD) method to facilitate insertion of the Micra introducer sheath. METHODS: 35 patients were included in the SD arm and 49 in the CD arm. DT and TT were recorded in minutes and cost in dollars. Analysis was performed using independent t-test between two groups and one-way ANOVA to evaluate inter-operator variability in the CD arm. RESULTS: Both DT and TT were significantly lower for the CD arm (15.1 ± 5.1 vs 23.5 ± 9.3, p < 0.0005 and 29.9 ± 14 vs 39.3 ± 13.5 min, p = 0.000374; respectively). The cost was also significantly lower using a CD versus SD. There was no inter-operator variability in the CD arm between 6 operators (p = 0.177 for DT and p = 0.304 for TT). No complications occurred in the SD arm. There were 3 vascular access site complications in the CD arm, all of which occurred early in the operator's experience. CONCLUSION: Coons dilator is an efficient and cost-effective method for vascular dilatation to facilitate Micra leadless pacemaker insertion. Rate of complications is low and expected to improve with greater experience.

Clinical management and prevention of sudden cardiac death.

Despite the revolutionary advancements in the past 3 decades in the treatment of ventricular tachyarrhythmias with device-based therapy, sudden cardiac death (SCD) remains an enormous public health burden. Survivors of SCD are generally at high risk for recurrent events. The clinical management of such patients requires a multidisciplinary approach from postresuscitative care to a thorough cardiovascular investigation in an attempt to identify the underlying substrate, with potential to eliminate or modify the triggers through catheter ablation and ultimately an implantable cardioverter-defibrillator (ICD) for prompt treatment of recurrences in those at risk. Early recognition of low left ventricular ejection fraction as a strong predictor of death and association of ventricular arrhythmias with sudden death led to significant investigation with antiarrhythmic drugs. The lack of efficacy and the proarrhythmic effects of drugs catalyzed the development and investigation of the ICD through several major clinical trials that proved the efficacy of ICD as a bedrock tool to detect and promptly treat life-threatening arrhythmias. The ICD therapy is routinely used for primary prevention of SCD in patients with cardiomyopathy and high risk inherited arrhythmic conditions and secondary prevention in survivors of sudden cardiac arrest. This compendium will review the clinical management of those surviving SCD and discuss landmark studies of antiarrhythmic drugs, ICD, and cardiac resynchronization therapy in the primary and secondary prevention of SCD.

Case Report: Leadless and left bundle branch area pacemakers, complementary advantages require a personalized approach.

Traditional transvenous pacemakers consist of a pacemaker generator usually positioned surgically in the upper left chest on the pectoral muscle fascia and one or more leads positioned through the veins to the right atrium and across the tricuspid valve to the right ventricular apex. While these devices reduce symptoms and improve survival among patients with symptomatic bradycardia, they are associated with an increased risk of infection, venous occlusion, heart failure, and tricuspid valve regurgitation. Although new pacemaker designs minimize these risks, none of the current-generation pacemaker designs effectively eliminate all of them. A personalized approach to selecting the appropriate pacemaker for each patient is needed to optimize outcomes.

Appropriateness of implantable cardioverter-defibrillator device implants in the United States.

BACKGROUND: The appropriate use criteria (AUCs) are a diverse group of indications aimed to better evaluate the benefits of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy. OBJECTIVE: The purpose of this study was to quantify the proportion of ICD and cardiac resynchronization therapy with defibrillator (CRT-D) implants as appropriate, may be appropriate (MA), or rarely appropriate (RA) on the basis of the AUC guidelines. METHODS: This is a multicenter retrospective study of patients within the National Cardiovascular Data Registry undergoing ICD implantation between April 2018 and March 2019 at >1500 US hospitals. The appropriateness of ICD implants was adjudicated using the AUC. RESULTS: Of 309,318 ICDs, 241,438 were primary prevention implants (78.1%) and 67,880 secondary prevention implants (21.9%); 243,532 (79%) were mappable to the AUC. For primary prevention, 185,431 ICDs (96.4%) were appropriate, 5660 (2.9%) MA, and 1205 (0.6%) RA. For secondary prevention, 47,498 ICDs (92.7%) were appropriate, 2581 (5%) MA, and 1157 (2.3%) RA. A significant number of RA devices were implanted in patients with New York Heart Association class IV heart failure who were ineligible for advanced therapies (53.9%) and those with myocardial infarction within 40 days (18.1%). The appropriateness of the pacing lead was more variable, with 48,470 dual-chamber ICD implants (62%) being classified as appropriate, 29,209 (37.4%) MA, and 448 (0.6%) RA. Among CRT-D implants, 63,848 (82.2%) were appropriate, 9900 (12.7%) MA, and 3940 (5.1%) RA for left ventricular pacing. A total of 99,754 implants were deemed appropriate but excluded from Centers for Medicare & Medicaid Services National Coverage Determination. More than 92% of hospitals had an RA implant rate of <4%. CONCLUSION: In this large national registry, 95% of mappable ICD and CRT-D implants were considered appropriate, with <2% of RA implants. Nearly 100,000 appropriate implants are excluded by Centers for Medicare & Medicaid Services National Coverage Determination.

Cigarette smoking and clopidogrel interaction.

Dual antiplatelet therapy (DAPT) with aspirin and an adenosine diphosphate receptor antagonist is central to the modern management of acute coronary syndromes and percutaneous revascularization. The most widely used adenosine diphosphate receptor antagonist, clopidogrel therapy is limited by inter-individual variability in platelet inhibition. Recent data suggest a potential role of smoking in the metabolism of clopidogrel and high on-treatment platelet reactivity. Pharmacodynamic studies and post-hoc analyses of large clinical trials support a link between smoking status and the efficacy of clopidogrel therapy. The mechanism of the interaction between smoking status and clopidogrel efficacy remains unclear but may be mediated by cytochrome P450 (CYP)1A2. There is less evidence available on the influence of smoking status on platelet reactivity and clinical outcomes during prasugrel and ticagrelor therapy.

An Analysis of Telehealth in the Outpatient Management of Atrial Fibrillation During the COVID-19 Pandemic.

The COVID-19 pandemic accelerated adaption of a telehealth care model. We studied the impact of telehealth on the management of atrial fibrillation (AF) by electrophysiology providers in a large, multisite clinic. Clinical outcomes, quality metrics, and indicators of clinical activity for patients with AF during the 10-week period of March 22, 2020 to May 30, 2020 were compared with those from the 10-week period of March 24, 2019 to June 1, 2019. There were 1946 unique patient visits for AF (1,040 in 2020 and 906 in 2019). During 120 days after each encounter, there was no difference in hospital admissions (11.7% vs 13.5%, p = 0.25) or emergency department visits (10.4% vs 12.5%, p = 0.15) in 2020 compared with 2019. There was a total of 31 deaths within 120 days, with similar rates in 2020 and 2019 (1.8% vs 1.3%, p = 0.38). There was no significant difference in quality metrics. The following clinical activities occurred less frequently in 2020 than in 2019: offering escalation of rhythm control (16.3% vs 23.3%, p <0.001), ambulatory monitoring (29.7% vs 51.7%, p <0.001), and electrocardiogram review for patients on antiarrhythmic drug therapy (22.1% vs 90.2%, p <0.001). Discussions about risk factor modification were more frequent in 2020 compared with 2019 (87.9% vs 74.8%, p <0.001). In conclusion, the use of telehealth in the outpatient management of AF was associated with similar clinical outcomes and quality metrics but differences in clinical activity compared with traditional ambulatory encounters. Longer-term outcomes warrant further investigation.

Comparative outcomes of vascular access closure methods following atrial fibrillation/flutter catheter ablation: insights from VAscular Closure for Cardiac Ablation Registry.

PURPOSE: This registry compared the safety and efficacy of vascular closure device Perclose (PC) with figure-of-eight stitch (Fo8) and manual compression (MC) following catheter ablation of atrial fibrillation/flutter. METHODS: VAscular Closure for Cardiac Ablation Registry (VACCAR) is a prospective, observational registry that assessed the time to hemostasis (TTH), time to ambulation (TTA), length of stay (LOS), complications, patient-reported outcomes, and pain medication use. RESULTS: A total of 434 patients (mean age 64.0±11.0 years; 38% female; 94.9% white) were enrolled between October 2017 and May 2019: 156 in MC, 203 in Fo8, and 75 in the PC group. Median TTH was significantly reduced in the PC and Fo8 group at 7 and 9 min respectively vs. the MC group at 20 min (p<0.001). Median TTA was significantly reduced in both the PC and Fo8 group at 2.2 h vs. the MC group at 6.5 h (p<0.001 for both). Median LOS for the PC group was significantly reduced at 27.5 h compared to the MC and Fo8 group at 29 h (p<0.01). A higher proportion of same-day discharges were noted in the PC and Fo8 groups at 14 (18.7%) and 25 (12.3%), respectively, compared to 5 (3.2%) in the MC group (p<0.01 for all). There was no significant difference in complications between the three groups. CONCLUSIONS: Both PC and Fo8 are safe with improved TTH, TTA, LOS, and a higher number of same-day discharges compared to MC.

Prospective evaluation of the effect of smartphone electrocardiogram usage on anticoagulant medication compliance.

PURPOSE: Compliance with anticoagulation treatment for atrial fibrillation is highly variable. Smartphone electrocardiograms that allow patients to have greater insight into their arrhythmia burden may improve anticoagulant compliance. METHODS: Patients were enrolled if they had atrial fibrillation with a CHA2DS2-VASc score of 2 or more, were eligible for anticoagulation and had a smartphone. Participants were randomly assigned to receive a smartphone electrocardiogram (AliveCor Kardia) to record their electrocardiograms 5 times/week or to the control group. All patients received 6 months of anticoagulant (apixaban) dispensed as 1-month pre-loaded pill boxes. RESULTS: A total of 100 patients were enrolled from July 2017 to August 2019, but 5 patients in the monitor arm and 1 in the control arm withdrew prematurely. The monitor and control groups did not differ in age, gender, CHA2DS2-VASc score, or comorbidities. Median medication compliance was 99.7%, with nonsignificantly greater compliance in the monitor group (100%) than in the control group (99.7%) (p-value = 0.247). There was also no significant difference between missing any dose and use/nonuse of the smartphone monitor (48.9% vs. 55.1%; p-value = 0.692). Mean monitor compliance was 86.8% ± 14.0% with an average of 4.34 recorded electrocardiograms per week. Monitor group patients with perfect medication compliance had significantly higher monitor compliance than those patients who missed doses (median 95.3% vs 86.7%; p-value = 0.02). CONCLUSIONS: In a study population with higher-than-expected medication compliance, the use of smartphone electrocardiogram did not demonstrate an improvement in medication compliance as compared to usual care. Greater monitor compliance was associated with greater medication compliance. CLINICAL TRIAL REGISTRATION: BOAT-OAR ClinicalTrials.gov number, NCT03515083.

Trends and Outcomes of Catheter Ablation for Ventricular Tachycardia in a Community Cohort.

OBJECTIVES: This study examined the trend in growth of catheter ablation for ventricular tachycardia (VT) performed in the United States with analysis of rates and predictors of major adverse events. BACKGROUND: Sustained VT is a significant cause of sudden death, heart failure (HF), and recurrent shocks in implantable cardioverter-defibrillator (ICD) recipients. Catheter ablation for VT reduces arrhythmia recurrence. Limited data are available regarding the use, safety, and long-term outcomes after VT ablation. METHODS: Using the U.S. Medicare database linked to the Social Security Death Index, we examined the annual use of VT ablation in 21,073 patients over 12 years, with 30-day risk of mortality, nonfatal major adverse events (MAEs), 1-year risk of mortality, re-hospitalization, repeat ablation, and factors associated with adverse outcomes. RESULTS: Among 21,073 patients (age 70 ± 9 years; 77% men; 90% white), there were 1,581 (7.5%) non-fatal MAEs within 30 days. There were 963 (4.6%) vascular complications, 485 (2.3%) pericardial complications, and 201 (1%) strokes and/or transient ischemic attacks. Mechanical circulatory support use was infrequent (2.3%). The 30-day and 1-year mortality rates were 4.2% and 15.0%, respectively. The 1-year incidence of repeat ablation was 10.2 per 100 person-years and re-hospitalization for HF or VT was 15.4 per 100 person-years and 18 per 100 person-years, respectively. Patients with an ICD had increased 30-day (4.9% vs. 0.86%) and 1-year mortality (17.5% vs. 2.54% [22.9 per 100 person-years vs. 3.1 per 100 person-years]; hazard ratio [HR]: 2.93; 95% confidence interval [CI]: 2.21 to 3.88). Rates of hospitalization for HF (18 per 100 person-years vs. 1.8 per 100 person-years; HR: 4.00; 95% CI: 2.78 to 5.78) or VT recurrence (22.7 per 100 person-years vs. 2.1 per 100 person-years; HR: 5.70; 95% CI: 4.09 to 7.96) were also higher at 1 year. Between 2000 and 2012, annual VT ablation volumes increased >4-fold. CONCLUSIONS: Catheter ablation for VT is frequently performed. Short-term MAEs and 1-year mortality is significant and is highest in patients with an ICD. These findings may provide greater insight of outcomes in an unselected real-world population undergoing VT ablation.

High-Sensitivity Troponin as a Biomarker in Heart Rhythm Disease.

Biomarkers are important prognostic tools in various cardiovascular conditions, including coronary artery disease and heart failure. Although their utility in cardiac electrophysiology (EP) is less established, biomarkers may guide EP clinical practice by identifying patients at risk for developing arrhythmias and their complications, in addition to augmenting therapeutic decisions by targeting appropriate pharmacologic and interventional therapies to patients who may benefit most. In this review, we focus on the prognostic role of high-sensitivity cardiac troponin (hs-cTn) assays-which detect subclinical cardiac myocyte damage-in cardiac arrhythmias and their sequelae. We review the current literature on hs-cTn and its impact on various arrhythmia disease states and also provide suggestions for future research in this field. In conclusion, although the utility of hs-cTn assays remains at an investigational stage in cardiac EP, studies to date have suggested value as a prognostic biomarker in atrial fibrillation and as a screening marker for patients at high risk of sudden cardiac death (both in the general population and among those with hypertrophic cardiomyopathy).

The implantable cardioverter-defibrillator: An update.

The implantable cardioverter-defibrillator (ICD) provides life-saving therapy to prevent sudden cardiac death. ICDs have been implanted in millions of patients worldwide since the first human implant in 1980. Clinical trials have helped establish guidelines for ICD implantation in primary and secondary prevention of sudden cardiac death. Recent trials have also tested and compared various programing strategies to avoid unnecessary shocks and improve survival among ICD recipients. ICDs may also assist with monitoring for heart failure management. In this review, we discuss the clinical science to date that has helped define the role of ICDs in current practice.

Development of a method for automated and stable myocardial perfusion measurement using coronary X-ray angiography images.

The purpose of this study was to develop a method for automatic and stable determination of the optimal time range for fitting with a Patlak plot model in order to measure myocardial perfusion using coronary X-ray angiography images. A conventional two-compartment model is used to measure perfusion, and the slope of the Patlak plot is calculated to obtain a perfusion image. The model holds for only a few seconds while the contrast agent flows from artery to myocardium. Therefore, a specific time range should be determined for fitting with the model. To determine this time range, automation is needed for routine examinations. The optimal time range was determined to minimize the standard error between data points and their least-squares regression straight line in the Patlak plot. A total of 28 datasets were tested in seven porcine models. The new method successfully detected the time range when contrast agent flowed from artery to myocardium. The mean cross correlation in the linear regression analysis (R(2)) was 0.996 ± 0.004. The mean length of the optimal time range was 3.61 ± 1.29 frames (2.18 ± 1.40 s). This newly developed method can automatically determine the optimal time range for fitting with the model.

Development of a theory for generating regional cardiac perfusion images during coronary angiography in the coronary angiography lab.

The purpose of this study was to develop a novel theory and method for generating regional myocardial perfusion images using fluoroscopy in the coronary angiography lab. We modified the Kety model to introduce the Patlak plot method for two-dimensional fluoroperfusion (FP) imaging. For evaluation, seven porcine models of myocardial ischemia with stenosis in the left coronary artery were prepared. Rest and stress FP imaging were performed using cardiovascular X-ray imaging equipment during the injection of iopamidol via the left main coronary artery. Images were acquired and retrospectively ECG gated at 80 % of the R-R interval. FP myocardial blood flow (MBF) was obtained using the Patlak plot method applied to time-intensity curve data of the proximal artery and myocardium. The results were compared to microsphere MBF measurements. Time-intensity curves were also used to generate color-coded FP maps. There was a moderate linear correlation between the calculated FP MBF and the microsphere MBF (y = 0.9758x + 0.5368, R² = 0.61). The color-coded FP maps were moderately correlated with the regional distribution of flow. This novel method of first-pass contrast-enhanced two-dimensional fluoroscopic imaging can quantify MBF and provide color coded FP maps representing regional myocardial perfusion.

High-sensitivity C-reactive protein and cardiovascular disease: a resolute belief or an elusive link?

The role of inflammation in the propagation of atherosclerosis and susceptibility to cardiovascular (CV) events is well established. Of the wide array of inflammatory biomarkers that have been studied, high-sensitivity C-reactive protein (hsCRP) has received the most attention for its use in screening and risk reclassification and as a predictor of clinical response to statin therapy. Although CRP is involved in the immunologic process that triggers vascular remodeling and plaque deposition and is associated with increased CV disease (CVD) risk, definitive randomized evidence for its role as a causative factor in atherothrombosis is lacking. Whether measurement of hsCRP levels provides consistent, clinically meaningful incremental predictive value in risk prediction and reclassification beyond conventional factors remains debated. Despite publication of guidelines on the use of hsCRP in CVD risk prediction by several leading professional organizations, there is a lack of clear consensus regarding the optimal clinical use of hsCRP. This article reviews 4 distinct points from the literature to better understand the current state and application of hsCRP in clinical practice: 1) the biology of hsCRP and its role in atherosclerosis; 2) the epidemiological association of hsCRP with CVD; 3) the quality of hsCRP as a biomarker of risk; and 4) the use of hsCRP as a tool to initiate or tailor statin therapy. Furthermore, we highlight recommendations from societies and important considerations when using hsCRP to guide treatment decisions in the primary prevention setting.