JACC in a Flash | Featured Topics and Editors' Picks From All of ACC's JACC Journals

Featured topics and Editors' Picks from all of ACC's JACC Journals.

Automated Algorithm Using Smartwatch Technology Accurately Detects Atrial Fibrillation

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The Kardia Band (KB) smartwatch automated algorithm for detection of atrial fibrillation (AFib), supported by physician review of the recordings, reliably differentiates AFib from sinus rhythm (SR), according to results of a single-center study presented by Joseph M. Bumgarner, MD, at ACC.18. The results were published simultaneously in the Journal of the American College of Cardiology.

The KB handheld cardiac rhythm recorder is a smartwatch accessory that records a rhythm strip equivalent to lead I for 30 seconds and has an algorithm for instantaneous diagnosis of AFib. The study examined whether the KB could differentiate SR from AFib compared with physician-interpreted 12-lead electrocardiogram (ECG) and KB recordings. Read more >>>

A total of 100 consecutive patients with AFib scheduled for cardioversion received a KB connected to a smartwatch paired via Bluetooth to a smartphone. The patients underwent pre-cardioversion ECG followed immediately by KB recording. If cardioversion was performed, post-cardioversion and KB recordings were obtained. The KB algorithm measures rhythm irregularity and P wave absence in real time to classify the rhythm strip as “possible AFib.” The automated KB interpretations were compared with electrophysiologist-interpreted KB rhythm strips and simultaneous ECGs.

Cardioversion was performed in 85 percent of the patients. A total of 169 simultaneous 12-lead ECG and KB recordings were obtained, of which 57 were unclassified by the KB algorithm. Of the classified KB strips, KB correctly diagnosed AFib with 93 percent sensitivity, 84 percent specificity and a K coefficient of 0.77 compared with electrophysiologist-interpreted 12-lead ECG. Electrophysiologist interpretation of KB recordings had 99 percent sensitivity, 83 percent specificity and a K coefficient of 0.83. Of the 57 KB unclassified recordings, the electrophysiologists correctly diagnosed AFib with 100 percent sensitivity, 80 percent specificity and a K coefficient of 0.74. Among interpretable KB recordings, the KB and electrophysiologist agreement was excellent (K coefficient 0.88).

While the results demonstrated the reliable differentiation of AFib from SR with the KB automated algorithm supported by physician review of the recordings, the authors note that the small sample size at their tertiary referral center had a known history of AFib with a burden sufficient to prompt electrical cardioversion. “The performance of the KB smartwatch algorithm may be more variable in a population with a lower AFib burden,” they wrote. Other factors that may affect the generalizability of the results are the low representation of women, exclusion of patients with cardiac implantable electronic devices and lack of prior use the KB by participants. The Kardia Band has been approved by the U.S. Food and Drug Administration.

Bumgarner JM, Lambert CT, Hussein AA, et al. J Am Coll Cardiol 2018;March 10:[Epub ahead of print].

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Male Sex and Diabetes Predict Sudden Death in Patients with HFpEF

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Male sex and insulin-treated diabetes were independently associated with sudden death (SD) in patients with heart failure with preserved ejection fraction (HFpEF), which accounted for 19 percent of deaths in a TOPCAT trial analysis presented by Muthiah Vaduganathan, MD, MPH, at ACC.18. The results were published simultaneously in JACC: Heart Failure.

The competing risk analysis investigated the incidence rates of the composite of SD or aborted cardiac arrest (ACA), unique predictors of SD or ACA, and response to spironolactone in patients with HFpEF. This analysis was performed in the TOPCAT patient cohort from the Americas, which included 1,767 patients. All eligible patients had a left ventricular ejection fraction (LVEF) ≥45 percent. The patients were randomized to either spironolactone or matching placebo. Predictors of composite SD and ACA were identified using a step-wise backward selection with competing risks regression analysis accounting for non-SD causes of death. Read more >>>

During a median 3.0 years of follow-up, a total of 385 patients died, of whom 19 percent were due to SD and 81 percent to non-SD causes. Six ACA events occurred during that time. During 5,426 person-years of observation, incidence rates of SD/ACA vs. non-SD/ACA were 1.4 and 5.8 events/100 patient-years, respectively.

Patients with SD/ACA were younger, male and had higher body mass indexes and rates of diabetes. The final competing risks regression model showed that male sex and insulin-treated diabetes were independent predictors of SD/ACA with modest discrimination. Male sex and insulin-treated diabetes remained independent predictors of SD/ACA in sensitivity analyses excluding patients with implantable cardioverter-defibrillators and when predicting SD alone.

Incidence rates of SD/ACA in patients receiving spironolactone vs. placebo were 1.2 vs. 1.6 per patient-years, respectively. Competing risks regression analysis showed that the difference between the treatment groups was not statistically significant.

The authors concluded that further studies are needed to define mechanisms contributing to SD, build more robust SD risk prediction models integrating imaging and biomarkers, and develop strategies to attenuate SD risk in patients with HFpEF.

Vaduganathan M, Claggett BL, Chatterjee NA, et al. JACC: Heart Fail 2018:March 11:[Epub ahead of print].

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Therapy-Related Changes in Natriuretic Peptides Inconsistently Predict Outcomes

Therapy-related changes in natriuretic peptides (NPs) modestly correlated with longer-term treatment effects on hospitalization for heart failure (HF) but not with effects on all-cause mortality, according to results of a study presented by Muthiah Vaduganathan, MD, MPH, at ACC.18. The results were also published in JACC: Heart Failure.

A trial-level analysis was conducted of 16 phase III randomized HF trials including 48,844 patients. Trial-level estimates of treatment effects on NPs and clinical outcomes were determined using data on the change in NPs in the two treatment groups over ≥1 month follow-up. The analysis focused on data for all-cause mortality and hospitalization for HF. Between-group differences in the change in log-transformed NPs were plotted against the magnitude of the treatment effect on clinical endpoints. Weighted Pearson correlation coefficients were calculated for average control- or placebo-corrected changes in NPs and the longer-term treatment effects on clinical endpoints. Read more >>>

The median follow-up for clinical endpoints was 28 months. NP data were available for a median 748 patients. The analysis showed that treatment-induced changes in NPs were not well correlated with treatment effects on all-cause mortality (weighted r=0.12). No correlations between changes in NPs and treatment effects on all-cause mortality were observed according to timing of NP sampling and other major trial factors.

Treatment-induced effects on NPs were signficantly correlated with treatment effects on hospitalization for HF (weighted r=0.63). Correlations between NP changes and treatment effects were consistently observed with respect to timing of NP assessment. Significant correlations between NP changes and hospitalization for HF were observed across key trial-level subgroups, including trials completed in the last decade, trials using NT-proBNP assays, and trials assessing renin-angiotensin-aldosterone system inhibitors.

According to the investigators, this analysis highlights issues with reliance on short-term NP changes in phase II trials to predict the long-term response in a subsequent phase III trial. “The use of NPs cannot reliably be utilized to estimate the probable effect of a drug or device on the risk of death,” they wrote.

The investigators urged caution in using NPs as the primary strategy for decision-making in phase II trials or for determining the most appropriate drug doses to evaluate in phase III trials.

In an editorial comment, James L. Januzzi Jr., MD, FACC, wrote “The authors found changes in NP concentrations were surprisingly not correlated to effect of treatment on all-cause mortality, but appeared modestly correlated to occurrence of HF hospitalization. The correlation with hospitalization was much stronger in studies of renin-angiotensin-aldosterone system inhibitors.” Their results affirm that more knowledge is required before biomarkers can be acceptable clinical trial endpoints.

Vaduganathan M, Claggett B, Packer M, et al. JACC: Heart Fail 2018;March 11:[Epub ahead of print].

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Partners YOUNG-MI: Cocaine, Marijuana Use Associated with Worse Mortality in Younger Patients After MI

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Cocaine or marijuana use was associated with worse all-cause and cardiovascular mortality among younger patients who experienced a myocardial infarction (MI). This was the finding from the Partners YOUNG-MI study presented by Ersilia M. DeFilippis, MD, at ACC.18 and simultaneously published in the Journal of the American College of Cardiology.

The retrospective registry study assessed the prevalence of cocaine and marijuana use and its association with outcomes in young adults presenting with their first MI at ≤50 years of age. Patients who used both drugs were included in the cocaine group for the analysis. The primary endpoints were cardiovascular and all-cause mortality. Secondary endpoints included cardiac arrest at presentation and coronary revascularization. Read more >>>

The study included 2,097 patients with Type I MI. Cocaine or marijuana use was present in 10.7 percent of patients, with 4.7 percent using marijuana and 6.0 percent using cocaine. Both substances were used by 36 patients. Patients with substance use were younger and male. A significantly higher percentage of STEMIs occurred in the substance use group vs. the non-substance use group (64.7 vs. 52.1 percent).

Patients with substance use had significantly lower rates of diabetes and hyperlipidemia but significantly higher rates of tobacco use.

Out-of-hospital cardiac arrest occurred significantly more often in patients with substance use vs. those without (8.0 vs. 3.5 percent). This difference was largely driven by increased cardiac arrest in the marijuana group. There were no significant differences in the rates of coronary revascularization.

During a median follow-up of 11.2 years, patients with substance use had significantly higher all-cause mortality vs. those without (18.8 vs. 11.3 percent). The adjusted hazard ratios for all-cause death were 1.99 for any substance use, 2.09 for marijuana and 1.91 for cocaine. Cardiovascular mortality was significantly higher among patients with substance use vs. those without (9.4 vs. 5.3 percent). The adjusted hazard ratios for cardiovascular death were 2.22 for any substance use, 2.13 for marijuana use and 2.32 for cocaine use.

“These findings reinforce current recommendations for screening for substance abuse among adults who experience an MI at a young age, and highlight the need for implementation of therapies and counseling that could prevent future adverse events,” write the authors.

DeFilippis EM, Singh A, Divakaran S, et al. J Am Coll Cardiol 2018;March 10:[Epub ahead of print].

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Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Dyslipidemia, Heart Failure and Cardiomyopathies, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Smoking

Keywords: ACC Publications, Cardiology Magazine, Algorithms, Atrial Fibrillation, Biological Markers, Cannabis, Cause of Death, Cocaine, Counseling, Death, Sudden, Decision Making, Defibrillators, Implantable, Diabetes Mellitus, Electric Countershock, Electrocardiography, Follow-Up Studies, Heart Arrest, Heart Failure, Hospitalization, Hyperlipidemias, Insulin, Marijuana Smoking, Myocardial Infarction, Natriuretic Peptide, Brain, Natriuretic Peptides, Out-of-Hospital Cardiac Arrest, Peptide Fragments, Registries, Regression Analysis, Renin-Angiotensin System, Research Personnel, Retrospective Studies, Spironolactone, Stroke Volume, Tertiary Care Centers, Tobacco Use, United States Food and Drug Administration

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