... and heart murmurs. ... She treats patients with heart failure, congenital heart ... Jennifer Brown, MD, Cardiologist, MedStar Heart & Vascular Institute. Jennifer Brown, MD is a cardiologst at MedStar Heart & ... Rachel Marcus, MD, Cardiologist, MedStar Heart & Vascular Institute. Rachel Marcus, MD, is a cardiologist with MedStar Heart & ... and also for MedStar Heart and Vascular Institute, including the Nancy and Harold Zirkin Heart & Vascular Hospital. ...