Physical Activity, Subclinical Myocardial Injury, and Risk of Heart Failure Subtypes in Black Adults.

OBJECTIVES: This study sought to evaluate the independent associations and interactions between high-sensitivity cardiac troponin I (hs-cTnI) and physical activity (PA) with risk of heart failure (HF) subtypes, HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). BACKGROUND: Black adults are at high risk for developing HF. Physical inactivity and subclinical myocardial injury, as assessed by hs-cTnI concentration, are independent risk factors for HF. METHODS: Black adults from the Jackson Heart Study without prevalent HF who had hs-cTnI concentration and self-reported PA assessed at baseline were included. Adjusted Cox models were used to evaluate the independent and joint associations and interaction between hs-cTnI concentrations and PA with risk of HFpEF and HFrEF. RESULTS: Among 3,959 participants, 25.1% had subclinical myocardial injury (hs-cTnI ≥4 and ≥6 ng/l in women and men, respectively), and 48.2% were inactive (moderate-to-vigorous PA = 0 min/week). Over 12.0 years of follow-up, 163 and 150 participants had an incident HFpEF and HFrEF event, respectively. In adjusted analysis, higher hs-cTnI concentration (per 1-U log increase) was associated with higher risk of HFpEF (hazard ratio [HR]: 1.47; 95% confidence interval [CI]: 1.25 to 1.72]) and HFrEF (HR: 1.57; 95% CI: 1.35 to 1.83]). In contrast, higher PA (per 1-U log increase) was associated with a lower risk of HFpEF (HR: 0.93; 95% CI: 0.88 to 0.99]) but not HFrEF. There was a significant interaction between hs-cTnI and PA for risk of HFpEF (p interaction = 0.04) such that inactive participants with subclinical myocardial injury were at higher risk of HFpEF but active participants were not. CONCLUSIONS: Among Black adults with subclinical myocardial injury, higher levels of PA were associated with attenuated risk of HFpEF.

Clinical factors and echocardiographic techniques related to the presence, size, and location of acoustic windows for leadless cardiac pacing.

AIMS: Temporary leadless cardiac pacing using ultrasound energy is feasible in patients. An implantable left ventricular stimulation system being developed for cardiac resynchronization therapy transfers energy from a subcutaneous transmitter to an endocardial receiver through tissue free of interfering lung or rib ('acoustic window'). The aim was to use transthoracic echocardiography to evaluate acoustic window (AW) locations and sizes to determine the implant site for a transmitter, and to investigate clinical predictors of AW location and size. METHODS AND RESULTS: Inclusion criteria were ejection fraction ≤35%, and New York Heart Association functional class III or IV. Acoustic windows were evaluated in intercostal spaces (ICSs) measured in the supine, right lateral, sitting, and standing position during normal respiration and held inspiration. Among 42 patients, at least one adequate AW (≥2 cm(2)) was identified in 41, 19 patients had adequate AWs in 2 ICSs and 20 patients had adequate AWs in 3. Acoustic window areas were generally smallest in the lateral position with held inspiration and largest in the standing position with normal respiration. Patients with ischaemic cardiomyopathy compared with non-ischaemic cardiomyopathy had smaller heart size [left ventricular end-systolic volume index (LVESVI) 78 ± 38 mL/m(2) vs. 104 ± 46 mL/m(2), P = 0.03] but larger AWs in the right lateral position (11.4 ± 6.5 cm(2) vs. 7.3 ± 3.4 cm(2), P = 0.01) and standing position (14.0 ± 7.2 cm(2) vs. 9.4 ± 3.3 cm(2), P = 0.02). CONCLUSIONS: Adequate AWs were present in nearly all patients. Despite smaller hearts, ischaemic cardiomyopathy patients had adequate AWs. A simple procedure performed as an adjunct to pre-implant echocardiography can screen patients and identify transmitter implant locations for an ultrasound-mediated leadless pacing system.