What perceived ailment has kept Jeanie from pursuing a life outside of the homestead in the novel, Unsettled Ground?

Throughout her life, Jeanie believed that she was living with a debilitating heart condition. She allowed this alleged diagnosis to keep her from pursuing a life outside the insular sphere of her family homestead. By the end of the novel, however, Jeanie learns that the condition never existed, and that the pangs she believed she felt in her heart for years, were false.