AimsSynchronized diaphragmatic stimulation (SDS) modulates intrathoracic and intra‐abdominal pressures with favourable effects on cardiac function for patients with a reduced left ventricular ejection fraction (LVEF) and heart failure (HFrEF). VisONE‐HF is a first‐in‐patient, observational study assessing the feasibility and 1 year effects of a novel, minimally invasive SDS device.Methods and resultsThe SDS system comprises a pulse generator and two laparoscopically delivered, bipolar, active‐fixation leads on the inferior diaphragmatic surface. Fifteen symptomatic men with HFrEF and ischaemic heart disease receiving guideline‐recommended therapy were enrolled (age 60 [56, 67] years, New York Heart Association class II [53%] /III [47%], LVEF 27 [23, 33] %, QRSd 117 [100, 125] ms, & N terminal pro brain natriuretic peptide [NT‐proBNP] 1779 [911, 2,072] pg/mL). Implant success was 100%. Patients were evaluated at 3, 6, and 12 months for device‐related or lead‐related complications, quality of life (SF‐36 QOL), 6 min hall walk distance (6MHWd), and by echocardiography. No implant procedure or SDS‐related adverse event occurred, and patients were unaware of diaphragmatic stimulation. By 12 months, left ventricular end‐systolic volume decreased (136 [123, 170] mL to 98 [89, 106] mL; P = 0.05), 6MHWd increased (315 [300, 330] m to 340 [315, 368] m; P = 0.004), and SF‐36 QOL improved (physical scale 0 [0, 0] to 25 [0, 50], P = 0.006; emotional scale 0 [0, 33] to 33 [33, 67], P = 0.001). Although neither reached statistical significance, LVEF decreased (28 [23, 40]% vs. 34 [29, 38]%; P = ns) and NT‐proBNP was lower (1784 [920, 2540] pg/mL vs. 1492 [879, 2028] pg/mL; P = ns).ConclusionsThese data demonstrate the feasibility of laparoscopic implantation and delivery of SDS without raising safety concerns. These encouraging findings should be investigated further in adequately powered randomized trials.