Ambulatory Risk Stratification for Worsening Heart Failure in Patients with Reduced and Preserved Ejection Fraction Using Diagnostic Parameters Available in Implantable Cardiac Monitors

BACKGROUND

Ambulatory risk stratification for worsening heart failure (HF) using diagnostics measured by insertable cardiac monitors (ICM) may depend on the left ventricular ejection fraction (LVEF). We evaluated risk stratification performance in patients with reduced versus preserved LVEF.

METHODS

ICM patients with a history of HF events (HFEs) were included from the Optum® de-identified Electronic Health Record dataset merged with ICM device-collected data during 2007-2021. ICM measures nighttime heart rate (NHR), heart rate variability (HRV), atrial fibrillation (AF) burden, rate during AF, and activity duration (ACT) daily. Each diagnostic was categorized into high, medium, or low risk using previously defined features. HFEs were HF-related inpatient, observation unit, or emergency department stays with IV diuresis administration. Patients were divided into two cohorts: LVEF ≤ 40% and LVEF > 40%. A marginal Cox proportional hazards model compared HFEs for different risk groups.

RESULTS

A total of 1020 ICM patients with 18,383 follow-up months and 301 months with HFEs (1.6%) were included. Monthly evaluations with a high risk were 2.3, 4.2, 5.0, and 4.5 times (p < 0.001 for all) more likely to have HFEs in the next 30 days compared to those with a low risk for AF, ACT, NHR, and HRV, respectively. HFE rates were higher for patients with LVEF > 40% compared to LVEF ≤ 40% (2.0% vs. 1.3%), and the relative risk between high-risk and low-risk for each diagnostic parameter was higher for patients with LVEF ≤ 40%.

CONCLUSIONS

Diagnostics measured by ICM identified patients at risk for impending HFEs. Patients with preserved LVEF showed a higher absolute risk, and the relative risk between risk groups was higher in patients with reduced LVEF.

Age-Dependent Detection of Atrial Fibrillation with Implantable Cardiac Monitors in Patients with Cryptogenic Stroke

Background  Continuous monitoring using implantable cardiac monitors (ICMs) results in atrial fibrillation (AF) detection rates of up to 30% in patients with cryptogenic stroke (CS). Although higher age is an independent risk factor for AF, there are no age-specific recommendations for the implantation of ICM. Objective  The aim of this study was to analyze age-related AF rates in patients with CS and continuous rhythm monitoring, to determine the rates of oral anticoagulation (OAC) and recurrent cerebrovascular events (stroke or transient ischemic attack) in patients with ICM-detected AF, and to describe the temporal relationship of AF detection and recurrent cerebrovascular events. Methods  In this observational study, patients with CS provided with ICMs were systematically followed. All patients underwent 72-hour electrocardiography monitoring, transcranial Doppler ultrasound, and transthoracic echocardiography prior to ICM insertion. Follow-up included a regular outpatient presentation every 3 months with medical history, physical examination, and interrogation of the ICM. Results  One-hundred eighty-six patients (mean age: 65 ± 12 years, 54% female) were included in this analysis. AF was detected in 6, 27, 56, and 65% ( p  < 0.001) of patients aged less than 60, 60 to 69, 70 to 79, and more than or equal to 80 years, respectively. All patients with AF under 60 years had an impaired left ventricular systolic function. OAC was initiated in 85% of the patients with AF. Recurrent cerebrovascular events occurred in 34 patients of whom 14 had a diagnosis of AF. In nine patients, AF was diagnosed before the occurrence of a recurrent cerebrovascular event. Conclusion  AF prevalence increased with age and was absent in CS patients younger than 60 years and with preserved left ventricular ejection fraction. The temporal relationship of AF and recurrent cerebrovascular events was weak.

Heart rate characteristic based modelling of atrial fibrillatory rate using implanted cardiac monitor data

Objective. The objective of the present study is to investigate the feasibility of using heart rate characteristics to estimate atrial fibrillatory rate (AFR) in a cohort of atrial fibrillation (AF) patients continuously monitored with an implantable cardiac monitor. We will use a mixed model approach to investigate population effect and patient specific effects of heart rate characteristics on AFR, and will correct for the effect of previous ablations, episode duration, and onset date and time.Approach. The f-wave signals, from which AFR is estimated, were extracted using a QRST cancellation process of the AF episodes in a cohort of 99 patients (67% male; 57 ± 12 years) monitored for 9.2(0.2-24.3) months as median(min-max). The AFR from 2453 f-wave signals included in the analysis was estimated using a model-based approach. The association between AFR and heart rate characteristics, prior ablations, and episode-related features were modelled using fixed-effect and mixed-effect modelling approaches.Main results. The mixed-effect models had a better fit to the data than fixed-effect models showing h.c. of determination (R2 = 0.49 versusR2 = 0.04) when relating the variations of AFR to the heart rate features. However, when correcting for the other factors, the mixed-effect model showed the best fit (R2 = 0.04). AFR was found to be significantly affected by previous catheter ablations (p< 0.05), episode duration (p< 0.05), and irregularity of theRRinterval series (p< 0.05).Significance. Mixed-effect models are more suitable for AFR modelling. AFR was shown to be faster in episodes with longer duration, less organizedRRintervals and after several ablation procedures.

population

Implantable cardiac monitors (ICMs) provide long-term electrocardiographic monitoring for a number of indications. However, frequencies of use by indication and temporal changes have not been characterized on a national scale. We sought to characterize overall use and changes between 2011 and 2018. We used generalized linear models to characterize the incidence rate per 1,000,000 patient-quarters at risk and an autoregressive integrated moving average model to account for autocorrelation in this time series data. We studied commercially-insured patients and their insured dependents in the IBM MarketScan Commercial Database who had an ICM placed. We described the characteristics of individuals who received ICMs and the frequency of placements into 3 guideline concordance groups. We estimated the mean change per quarter in ICM placements (mean quarterly change in incidence rate per 1,000,000 patient-quarters at risk) for quarter (Q)1 2011 through Q1 2014, Q1 2014 to Q2 2014, and Q2 2014 through Q4 2018 for each guideline concordance group. The most common indications for categorizable ICM placement were syncope (24%), atrial fibrillation (11%), and stroke (11%). For each of the 3 guideline concordance groups except guideline unaddressed inpatient ICM placements, there was a significant increase in use either during the Q1 2014 to Q2 2014 or the Q2 2014 through Q4 2018 periods. A significant portion of ICM placements were for indications that lack strong evidence, such as established atrial fibrillation. The incidence of ICM placement for most of the indications and settings increased after miniaturization and technical improvements.

[Remote monitoring of implantable monitors : Towards coverage ? Evaluation of the procedure by the French National Authority for Health]

Implantable cardiac monitors are recommended and reimbursed in two specific cases: the etiological diagnosis of unexplained recurrent syncope and the etiological diagnosis of a cryptogenic ischemic stroke. According to the French National Authority for Health (HAS), remote monitoring "leads to early diagnosis and therapeutic care". However, remote tracking of these devices for diagnostic purposes is not included in the ETAPES program, which will end soon. This article presents a summary of the evaluation by HAS of the remote monitoring of implantable cardiac monitors. It also addresses the question of its reimbursement, as for therapeutic implantable devices.