An implantable prosthetic heart valve configured to be radially collapsible to a collapsed or crimped state for introduction into the body on a balloon delivery catheter and radially expandable using a balloon of the balloon delivery catheter to an expanded state for implanting the prosthetic heart valve at a native aortic valve, the prosthetic heart valve comprising: a radially collapsible and expandable annular frame , the frame having a plurality of angularly spaced, axial struts that are interconnected by a plurality of rows of circumferential struts ; wherein at least one row of circumferential struts include pairs of circumferential struts extending between two axial struts , wherein each strut of the pair of circumferential struts has one end connected to a respective axial strut (18 30) and another end interconnected to an adjacent end of the other strut of the same pair of circumferential struts by a crown portion such that a gap exists between the adjacent ends of the circumferential struts ; an annular skirt member positioned inside of and secured to the frame ; the skirt member having an outflow edge having an undulated shape, following the shape of one row of the plurality of rows of circumferential struts (20, 22; 24), the skirt member being secured inside the frame along the outflow edge to the one row of the plurality of rows of circumferential struts (20; 22; 24) with sutures; and a leaflet structure comprising a plurality of leaflets , the leaflet structure having a scalloped inflow edge portion secured to an inner surface of the skirt member , each leaflet having an outflow edge, a curved inflow edge and two side flaps extending between respective ends of the outflow edge and the inflow edge , wherein each side flap is secured to an adjacent side flap of another leaflet to form commissures of the leaflet structure , each commissure being attached to one of the axial struts , and wherein the scalloped inflow edge portion of the leaflet structure is sutured to an inner surface of the skirt member along a scalloped suture line . a radially collapsible and expandable annular frame , the frame having a plurality of angularly spaced, axial struts that are interconnected by a plurality of rows of circumferential struts ; wherein at least one row of circumferential struts include pairs of circumferential struts extending between two axial struts , wherein each strut of the pair of circumferential struts has one end connected to a respective axial strut (18 30) and another end interconnected to an adjacent end of the other strut of the same pair of circumferential struts by a crown portion such that a gap exists between the adjacent ends of the circumferential struts ; an annular skirt member positioned inside of and secured to the frame ; the skirt member having an outflow edge having an undulated shape, following the shape of one row of the plurality of rows of circumferential struts (20, 22; 24), the skirt member being secured inside the frame along the outflow edge to the one row of the plurality of rows of circumferential struts (20; 22; 24) with sutures; and a leaflet structure comprising a plurality of leaflets , the leaflet structure having a scalloped inflow edge portion secured to an inner surface of the skirt member , each leaflet having an outflow edge, a curved inflow edge and two side flaps extending between respective ends of the outflow edge and the inflow edge , wherein each side flap is secured to an adjacent side flap of another leaflet to form commissures of the leaflet structure , each commissure being attached to one of the axial struts , and wherein the scalloped inflow edge portion of the leaflet structure is sutured to an inner surface of the skirt member along a scalloped suture line . <EOS>