Prognostic significance of blood pressure response during vasodilator stress Rb-82 positron emission tomography myocardial perfusion imaging.

BACKGROUND: A drop in blood pressure (BP) or blunted BP response is an established high-risk marker during exercise myocardial perfusion imaging (MPI); however, data are sparse regarding the prognostic value of BP response in patients undergoing vasodilator stress rubidium-82 (Rb-82) Positron Emission Tomography (PET) MPI. METHODS AND RESULTS: From the PET Prognosis Multicenter Registry, a cohort of 3413 patients underwent vasodilator stress Rb-82 PET MPI with dipyridamole or adenosine. We used multivariable Cox proportional hazard regression to analyze the association with mortality of four BP variables: stress minus rest systolic BP (∆SBP), stress minus rest diastolic BP (∆DBP), resting systolic BP (rSBP), and resting diastolic BP (rDBP). Covariates that had univariate P values <.10 were entered into the multivariable model. After median 1.7 years follow-up, 270 patients died. In univariate analyses, ∆SBP (P = .082), rSBP (P = .008), and rDBP (P < .001) were of potential prognostic value (P < .10), but ∆DBP was not (P = .96). After adjustment for other clinical and MPI variables, ∆SBP no longer independently predicted mortality (P = .082); only lower rSBP (P = .026) and lower rDBP (P = .045) remained independently prognostic. CONCLUSIONS: In patients undergoing vasodilator stress MPI, only lower resting BP is an independent predictor of mortality along with other clinical and MPI variables; BP response does not appear to add to risk stratification in these patients.

Assessing Smart Phones for Generating Life-space Indicators.

Life-space is a promising method for estimating older adults' functional status. However, traditional life-space measures are costly and time consuming because they often rely on active subject participation. This study assesses the feasibility of using the global positioning system (GPS) function of smart phones to generate life-space indicators. We first evaluated the location accuracy of smart phone collected GPS points versus those acquired by a commercial GPS unit. We then assessed the specificity of the smart phone processed life-space information against the traditional diary method. Our results suggested comparable location accuracy between the smart phone and the standard GPS unit in most outdoor situations. In addition, the smart phone method revealed more comprehensive life-space information than the diary method, which leads to higher and more consistent life-space scores. We conclude that the smart phone method is more reliable than traditional methods for measuring life-space. Further improvements will be required to develop a robust application of this method that is suitable for health-related practices.

Feasibility of a Smartphone-enabled Cardiac Rehabilitation Program in Male Veterans With Previous Clinical Evidence of Coronary Heart Disease.

Cardiac rehabilitation (CR) is recommended for patients with coronary heart disease, however, participation among veterans remains poor. Smartphones may facilitate data transfer and communication between patients and providers, among other benefits. We evaluated the feasibility of a smartphone-enabled CR program in a population of veterans. Qualifying veterans were prospectively enrolled in a single-arm, nonrandomized feasibility study of a smartphone-enabled, home-based CR program, featuring an app with daily reminders to exercise, log vitals, and review educational materials. A coach remotely monitored patients through an online dashboard and scheduled telephone visits. Clinical end points were assessed as an exploratory aim. After 21 veterans provided informed consent, 18 were enrolled and successfully completed at least 30days of the program; 13 completed the entire 12-week intervention. Mean (standard deviation) age was 62 (7) years and 96% were male. Program completers logged a mean (standard deviation) of 3.5 (1.4) exercise sessions and 150 (86) exercise minutes per week. The majority (84%) of program completers reported being satisfied overall with the program. Mean functional capacity improved by 1.0 metabolic equivalents (5.3 to 6.3, 95% confidence interval 0.3 to 1.7; p = 0.008) and mean systolic blood pressure at rest improved by 9.6mm Hg (mean difference 9.6, 95% confidence interval -19.0 to -0.7; p = 0.049) among completers. Smartphone-enabled, home-based CR is feasible in veterans with heart disease and is associated with moderate to high levels of engagement and patient satisfaction.

THE FUTURE OF MOBILE HEALTH APPLICATIONS AND DEVICES IN CARDIOVASCULAR HEALTH.

Mobile health (mHealth) is the utilisation of mobile technologies in healthcare and has particular relevance in improving lifestyle behaviours which may ultimately reduce cardiovascular disease risk. Various intervention studies for example integrate self-monitoring of diet and physical activity with text messaging systems to improve intermediate outcomes. Currently the future progress of mHealth technologies in formal diagnostic and therapeutic roles is pending and includes the need to validate and standardise accelerometer and heart rate data from various devices. Data also needs to be integrated from such devices into the medical record system to facilitate communication between providers and patients. Although short-term behaviour changes have been found with technologies such as Fitbit® (Fitbit, Inc., San Francisco, California, USA), whether such technologies/interventions lead to sustained behaviour change and reduced risk of myocardial infarction and death remains to be seen.

Cellular telephones measure activity and lifespace in community-dwelling adults: proof of principle.

OBJECTIVES: To describe a system that uses off-the-shelf sensor and telecommunication technologies to continuously measure individual lifespace and activity levels in a novel way. DESIGN: Proof of concept involving three field trials of 30, 30, and 21 days. SETTING: Omaha, Nebraska, metropolitan and surrounding rural region. PARTICIPANTS: Three participants (48-year-old man, 33-year-old woman, and 27-year-old male), none with any functional limitations. MEASUREMENTS: Cellular telephones were used to detect in-home position and in-community location and to measure physical activity. Within the home, cellular telephones and Bluetooth transmitters (beacons) were used to locate participants at room-level resolution. Outside the home, the same cellular telephones and global positioning system (GPS) technology were used to locate participants at a community-level resolution. Physical activity was simultaneously measured using the cellular telephone accelerometer. RESULTS: This approach had face validity to measure activity and lifespace. More importantly, this system could measure the spatial and temporal organization of these metrics. For example, an individual's lifespace was automatically calculated across multiple time intervals. Behavioral time budgets showing how people allocate time to specific regions within the home were also automatically generated. CONCLUSION: Mobile monitoring shows much promise as an easily deployed system to quantify activity and lifespace, important indicators of function, in community-dwelling adults.