Although extending the duration of ambulatory electrocardiographic monitoring beyond 24 to 48 hours can improve the detection of arrhythmias, lead-based (Holter) monitors might be limited by patient compliance and other factors. We, therefore, evaluated compliance, analyzable signal time, interval to arrhythmia detection, and diagnostic yield of the Zio Patch, a novel leadless, electrocardiographic monitoring device in 26,751 consecutive patients. The mean wear time was 7.6 ± 3.6 days, and the median analyzable time was 99% of the total wear time. Among the patients with detected arrhythmias (60.3% of all patients), 29.9% had their first arrhythmia and 51.1% had their first symptom-triggered arrhythmia occur after the initial 48-hour period. Compared with the first 48 hours of monitoring, the overall diagnostic yield was greater when data from the entire Zio Patch wear duration were included for any arrhythmia (62.2% vs 43.9%, p <0.0001) and for any symptomatic arrhythmia (9.7% vs 4.4%, p <0.0001). For paroxysmal atrial fibrillation (AF), the mean interval to the first detection of AF was inversely proportional to the total AF burden, with an increasing proportion occurring after 48 hours (11.2%, 10.5%, 20.8%, and 38.0% for an AF burden of 51% to 75%, 26% to 50%, 1% to 25%, and <1%, respectively). In conclusion, extended monitoring with the Zio Patch for ≤14 days is feasible, with high patient compliance, a high analyzable signal time, and an incremental diagnostic yield beyond 48 hours for all arrhythmia types. These findings could have significant implications for device selection, monitoring duration, and care pathways for arrhythmia evaluation and AF surveillance.

The capacity of sorbent systems to increase solute clearances above the levels that are provided by hemodialysis has not been well defined. This study assessed the extent to which solute clearances can be increased by addition of a sorbent to the dialysate. Attention was focused on the clearance of protein-bound solutes, which are cleared poorly by conventional hemodialysis. A reservoir that contained test solutes and artificial plasma was dialyzed first with the plasma flow set at 46 ؎ 3 ml/min and the dialysate flow (Q d ) set at 42 ؎ 3 ml/min using a hollow fiber kidney with mass transfer area coefficients greater than Q d for each of the solutes. Under these conditions, the clearance of urea (Cl urea ) was 34 ؎ 1 ml/min, whereas the clearances of the protein-bound solutes indican (Cl ind ), p-cresol sulfate (Cl pcs ), and p-cresol (Cl pc ) averaged only 5 ؎ 1, 4 ؎ 1, and 14 ؎ 1 ml/min, respectively The effect of addition of activated charcoal to the dialysate then was compared with the effect of increasing Q d without addition of any sorbent. Addition of charcoal increased Cl ind , Cl pcs , and Cl pc to 12 ؎ 1, 9 ؎ 2, and 35 ؎ 4 ml/min without changing Cl urea . Increasing Q d without the addition of sorbent had a similar effect on the clearance of the protein-bound solutes. Mathematical modeling predicted these changes and showed that the maximal effect of addition of a sorbent to the dialysate is equivalent to that of an unlimited increase in Q d . These results suggest that as an adjunct to conventional hemodialysis, addition of sorbents to the dialysate could increase the clearance of protein-bound solutes without greatly altering the clearance of unbound solutes. S olute uptake by sorbents long has been considered a possible treatment for uremia (1-4), but the extent to which sorbents can increase solute clearances above the levels that are obtained by hemodialysis remains uncertain. In most sorbent systems, blood is separated from the sorbent by a semipermeable membrane to avoid the adverse effects of direct blood-sorbent contact. Solutes therefore must diffuse through the membrane before binding to the sorbent. Our study sought to define better the capacity for solute clearance of this two-step process. We first modeled the effect of adding a sorbent to the dialysate when dialysis is carried out by countercurrent flow of plasma and dialysate on opposite sides of a semipermeable membrane. The predicted effect of a sorbent in this case is to lower the free solute concentration in the dialysate, and adding a sorbent to the dialysate can increase solute clearances to the same extent as increasing dialysate flow (Q d ).One potential application of sorbents is to increase the clearance of solutes that bind to plasma proteins. These solutes are cleared poorly by conventional hemodialysis (5-9). Moreover, although not conclusive, a variety of evidence suggests that protein-bound solutes contribute to uremic toxicity (5,6,10 -12), and mathematical modeling predicts that the clearance of protein-bound solutes c...

Classically, the 3 pillars of atrial fibrillation (AF) management have included anticoagulation for prevention of thromboembolism, rhythm control, and rate control. In both prevention and management of AF, a growing body of evidence supports an increased role for comprehensive cardiac risk factor modification (RFM), herein defined as management of traditional modifiable cardiac risk factors, weight loss, and exercise. In this narrative review, we summarize the evidence demonstrating the importance of each facet of RFM in AF prevention and therapy. Additionally, we review emerging data on the importance of weight loss and cardiovascular exercise in prevention and management of AF.

BackgroundIdentification of silent atrial fibrillation (AF) could prevent stroke and other sequelae.HypothesisScreening for AF using continuous ambulatory electrocardiographic (ECG) monitoring can detect silent AF in asymptomatic in patients with known risk factors.MethodsWe performed a single-center prospective screening study using a wearable patch-based device that provides up to 2 weeks of continuous ambulatory ECG monitoring (iRhythm Technologies, Inc.). Inclusion criteria were age ≥55 years and ≥2 of the following risk factors: coronary disease, heart failure, hypertension, diabetes, sleep apnea. We excluded patients with prior AF, stroke, transient ischemic attack, implantable pacemaker or defibrillator, or with palpitations or syncope in the prior year.ResultsOut of 75 subjects (all male, age 69 ± 8.0 years; ejection fraction 57% ± 8.7%), AF was detected in 4 subjects (5.3%; AF burden 28% ± 48%). Atrial tachycardia (AT) was present in 67% (≥4 beats), 44% (≥8 beats), and 6.7% (≥60 seconds) of subjects. The combined diagnostic yield of sustained AT/AF was 11%. In subjects without sustained AT/AF, 11 (16%) had ≥30 supraventricular ectopic complexes per hour.ConclusionsOutpatient extended ECG screening for asymptomatic AF is feasible, with AF identified in 1 in 20 subjects and sustained AT/AF identified in 1 in 9 subjects, respectively. We also found a high prevalence of asymptomatic AT and frequent supraventricular ectopic complexes, which may be relevant to development of AF or stroke. If confirmed in a larger study, primary screening for AF could have a significant impact on public health.

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In patients undergoing AF ablation, uninterrupted periprocedural NOACs are associated with a low incidence of stroke or TIA and a significant reduction in major bleeding as compared with uninterrupted VKAs.

There is a growing population of patients with implanted electronic cardiac devices and a concomitant increase in the use of magnetic resonance (MR). There are theoretical safety risks posed to such devices by MR. However, there are now considerable laboratory data and clinical experience demonstrating safety in this setting, assuming appropriate device selection and patient monitoring. Herein, we review these data and our safety protocol and the new generation of devices that have been prospectively designed and tested to be safe for MR scanning, assuming certain conditions are met (i.e., devices that are MR-conditional). We also argue that the available data do not support a complete transition to implantation of MR-conditional devices.

Background: Transition zones between healthy myocardium and scar form a spatially complex substrate that may give rise to reentrant ventricular arrhythmias (VAs). We sought to assess the utility of a novel machine learning approach for quantifying 3-dimensional spatial complexity of grayscale patterns on late gadolinium enhanced cardiac magnetic resonance images to predict VAs in patients with ischemic cardiomyopathy. Methods: One hundred twenty-two consecutive ischemic cardiomyopathy patients with left ventricular ejection fraction ≤35% without prior history of VAs underwent late gadolinium enhanced cardiac magnetic resonance images. From raw grayscale data, we generated graphs encoding the 3-dimensional geometry of the left ventricle. A novel technique, adapted to these graphs, assessed global regularity of signal intensity patterns using Fourier-like analysis and generated a substrate spatial complexity profile for each patient. A machine learning statistical algorithm was employed to discern which substrate spatial complexity profiles correlated with VA events (appropriate implantable cardioverter-defibrillator firings and arrhythmic sudden cardiac death) at 5 years of follow-up. From the statistical machine learning results, a complexity score ranging from 0 to 1 was calculated for each patient and tested using multivariable Cox regression models. Results: At 5 years of follow-up, 40 patients had VA events. The machine learning algorithm classified with 81% overall accuracy and correctly classified 86% of those without VAs. Overall negative predictive value was 91%. Average complexity score was significantly higher in patients with VA events versus those without (0.5±0.5 versus 0.1±0.2; P <0.0001) and was independently associated with VA events in a multivariable model (hazard ratio, 1.5 [1.2–2.0]; P =0.002). Conclusions: Substrate spatial complexity analysis of late gadolinium enhanced cardiac magnetic resonance images may be helpful in refining VA risk in patients with ischemic cardiomyopathy, particularly to identify low-risk patients who may not benefit from prophylactic implantable cardioverter-defibrillator therapy. Visual Overview: A visual overview is available for this article.