Six-Month Pilot Testing of a Digital Health Tool to Support Effective Self-Care in People With Heart Failure: Mixed Methods Study

BACKGROUND

Digital tools may support people to self-manage their heart failure (HF). Having previously outlined the human-centered design development of a digital tool to support self-care of HF, the next step was to pilot the tool over a period of time to establish people's acceptance of it in practice.

OBJECTIVE

This study aims to conduct an observational pilot study to examine the usability, adherence, and feasibility of a digital health tool for HF within the Irish health care system.

METHODS

A total of 19 participants with HF were provided with a digital tool comprising a mobile app and the Fitbit Charge 4 and Aria Air smart scales for a period of 6 months. Changes to their self-care were assessed before and after the study with the 9-item European HF Self-care Behavior Scale (EHFScBS) and the Minnesota Living with HF Questionnaire (MLwHFQ) using a Wilcoxon signed rank test. After the study, 3 usability questionnaires were implemented and descriptively analyzed: the System Usability Scale (SUS), Wearable Technology Motivation Scale (WTMS), and Comfort Rating Scale (CRS). Participants also undertook a semistructured interview regarding their experiences with the digital tool. Interviews were analyzed deductively using the Theoretical Domains Framework.

RESULTS

Participants wore their devices for an average of 86.2% of the days in the 6-month testing period ranging from 40.6% to 98%. Although improvements in the EHFScBS and MLwHFQ were seen, these changes were not significant (P=.10 and P=.70, respectively, where P>.03, after a Bonferroni correction). SUS results suggest that the usability of this system was not acceptable with a median score of 58.8 (IQR 55.0-60.0; range 45.0-67.5). Participants demonstrated a strong motivation to use the system according to the WTMS (median 6.0, IQR 5.0-7.0; range 1.0-7.0), whereas the Fitbit was considered very comfortable as demonstrated by the low CRS results (median 0.0, IQR 0.0-0.0; range 0.0-2.0). According to participant interviews, the digital tool supported self-management through increased knowledge, improved awareness, decision-making, and confidence in their own data, and improving their social support through a feeling of comfort in being watched.

CONCLUSIONS

The digital health tool demonstrated high levels of adherence and acceptance among participants. Although the SUS results suggest low usability, this may be explained by participants uncertainty that they were using it fully, rather than it being unusable, especially given the experiences documented in their interviews. The digital tool targeted key self-management behaviors and feelings of social support. However, a number of changes to the tool, and the health service, are required before it can be implemented at scale. A full-scale feasibility trial conducted at a wider level is required to fully determine its potential effectiveness and wider implementation needs.

Neopterin as a Potential Biomarker for the Early Diagnosis of Heart Failure: A Systematic Review and Meta-analysis

BACKGROUND

Neopterin (NEO) is an inflammatory biomarker with proposed diagnostic value in cardiovascular diseases. Some correlations have been discovered between NEO levels and the incidence, severity, and adverse outcomes of heart failure (HF). However, there are discrepancies in the results reported in the literature.

METHODS

We conducted a systematic review and meta-analysis of studies comparing urinary and blood NEO concentrations between individuals with HF, cardiac insufficiency, or dilated cardiomyopathy (DCM) with control groups or those monitoring the role of NEO concentrations as a predictive marker of adverse outcomes in HF patients.

RESULTS

A total of 24 studies that met the inclusion criteria were reviewed. The studies demonstrated the alteration of NEO in blood or urine samples in subjects with HF, cardiac insufficiency, or DCM compared with control groups. Also, reviewing the studies suggested a link between reduced ejection fraction, higher NYHA classes, and a higher risk of adverse cardiac outcomes with increased NEO levels. The meta-analysis of three studies revealed a significant increase in serum NEO levels in HF cases compared to that in healthy controls with an effect size of 3.72 (95 % CI 0.16 to 7.28; p = 0.04).

CONCLUSION

Meta-analysis demonstrated a significant difference between serum NEO levels of HF cases and healthy subjects. This evidence implies the potential of serum NEO as a valuable diagnostic biomarker in HF patients. Also, the review of the studies revealed the prognostic potential of NEO. Further research is required to assess the usefulness of NEO as a diagnostic/prognostic biomarker for HF.

Cirrhotic Cardiomyopathy Following Bile Duct Ligation in Rats-A Matter of Time?

Cirrhotic patients often suffer from cirrhotic cardiomyopathy (CCM). Previous animal models of CCM were inconsistent concerning the time and mechanism of injury; thus, the temporal dynamics and cardiac vulnerability were studied in more detail. Rats underwent bile duct ligation (BDL) and a second surgery 28 days later. Cardiac function was assessed by conductance catheter and echocardiography. Histology, gene expression, and serum parameters were analyzed. A chronotropic incompetence (P_d31 < 0.001) and impaired contractility at rest and a reduced contractile reserve (P_d31 = 0.03, P_dob-d31 < 0.001) were seen 31 days after BDL with increased creatine (P_d35, P_d42, and P_d56 < 0.05) and transaminases (P_d31 < 0.001). A total of 56 days after BDL, myocardial fibrosis was seen (P_d56 < 0.001) accompanied by macrophage infiltration (CD68: P_group < 0.001) and systemic inflammation (TNFα: P_group < 0.001, white blood cell count: P_group < 0.001). Myocardial expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) was increased after 31 (P_d31 < 0.001) and decreased after 42 (P_d42 < 0.001) and 56 days (P_d56 < 0.001). Caspase-3 expression was increased 31 and 56 days after BDL (P_d31 = 0.005; P_d56 = 0.005). Structural changes in the myocardium were seen after 8 weeks. After the second surgery (second hit), transient myocardial insufficiency with secondary organ dysfunction was seen, characterized by reduced contractility and contractile reserve.

β-adrenergic receptor-mediated cardiac contractility is inhibited via vasopressin type 1A-receptor-dependent signaling

BACKGROUND

Enhanced arginine vasopressin levels are associated with increased mortality during end-stage human heart failure, and cardiac arginine vasopressin type 1A receptor (V1AR) expression becomes increased. Additionally, mice with cardiac-restricted V1AR overexpression develop cardiomyopathy and decreased β-adrenergic receptor (βAR) responsiveness. This led us to hypothesize that V1AR signaling regulates βAR responsiveness and in doing so contributes to development of heart failure.

METHODS AND RESULTS

Transaortic constriction resulted in decreased cardiac function and βAR density and increased cardiac V1AR expression, effects reversed by a V1AR-selective antagonist. Molecularly, V1AR stimulation led to decreased βAR ligand affinity, as well as βAR-induced Ca(2+) mobilization and cAMP generation in isolated adult cardiomyocytes, effects recapitulated via ex vivo Langendorff analysis. V1AR-mediated regulation of βAR responsiveness was demonstrated to occur in a previously unrecognized Gq protein-independent/G protein receptor kinase-dependent manner.

CONCLUSIONS

This newly discovered relationship between cardiac V1AR and βAR may be informative for the treatment of patients with acute decompensated heart failure and elevated arginine vasopressin.

Evaluation of changes in left ventricular myocardial function observed in canine myocardial dysfunction model using a two-dimensional tissue tracking technique

This study was conducted to assess the ability of two-dimensional tissue tracking (2DTT) to evaluate changes in left ventricular (LV) myocardial function associated with sustained high electrical pacing. Pacemakers were implanted at the right ventricular (RV) apex of five female Beagles, and sustained high electrical pacing of 250 beats per minute (bpm) was performed for three consecutive weeks. Conventional echocardiography and 2DTT were performed at baseline, and at every week for three weeks with pacing. The baseline parameters were then compared to those of weeks 1, 2, and 3. Three weeks of pacing resulted in significant reduction of radial and circumferential global strains (p < 0.001). Regional analysis revealed reduction of segmental strains in both radial and circumferential directions, as well as increased dyssynchrony after three weeks of pacing in the radial direction (p = 0.0007). The results of this study revealed the ability of 2DTT to measure radial and circumferential strains in dogs with sustained high-electrical pacing, and allowed assessment of global and regional myocardial function and the degree of dyssynchrony.