Figure 1.

Experimental studies – effects of danicamtiv on left ventricular (LV) and left atrial (LA) function, both ex vivo (A–C) and in vivo (heart failure dogs, D and E). Danicamtiv increased ATP turnover (ATPase) rates in LV and LA swine myofibrils (A), increasing Ca²⁺ sensitivity (pCa) in fibres (B and C; B: LV tension/pCa curve); LA muscle was less Ca²⁺ sensitive but had faster turnover rates than the left ventricle. In dogs with induced heart failure, danicamtiv prolonged systolic ejection time (SET), increasing indices of systolic LV function and stroke volume (D), while decreasing size and improving performance in the left atrium (E). (A–E) Mean ± standard error of the mean. (D–E) mean change (blue text). CTRL, control; 5HR, 5 h post‐treatment; LAEF, left atrial emptying fraction; LAFI, left atrial function index; LVFS, left ventricular fractional shortening; LVSV, left ventricular stroke volume; PRE, before dosing (i.e. baseline); Vol_min, minimal volume.