1. Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
2. Department of Obstetrics, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
3. Unit for Inherited Cardiac Diseases, The Heart Centre, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
4. Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark4Department of Clinical Medicine, Copenhagen University, Copenhagen, Denmark5Department of Medicine, Stanford University School of Medicine, Stanford, California