<div class="wrap">
  <div class="heart"></div>
</div>

/* just to center heart in codepen preview */
.wrap{
  position:absolute;
  top:50%;
  left:50%;
  transform:translate(-50%,-50%);
}
.heart{
  width:7vw;
  height:4vw;
  background:red;
  transform:rotate(45deg);
  border-top-left-radius:4vw;
  border-bottom-left-radius:4vw;
}
.heart::after{
  content:"";
  position:absolute;
  left:1.5vw;
  top:-1.5vw;
  width:7vw;
  height:4vw;
  background:red;
  transform:rotate(90deg);
  border-top-left-radius:4vw;
  border-bottom-left-radius:4vw;
}