CRH and atrial fibrillation: Somewhat higher proportions of CRH users had diagnoses of atrial fibrillation or flutter (CRH users: 316/804, 39.3% and CRH nonusers: 6300/19,583, 32.2%), heart failure (CRH users: 149/804, 18.5% and CRH nonusers: 3405/19,583, 17.4%), and valvular heart disease (CRH users: 158/804, 19.7% and CRH nonusers: 2530/19,583, 12.9%); however, the proportion of CRH nonusers with a diagnosis of ischemic heart disease was higher than for CRH users (CRH nonusers: 8137/19,583, 41.6% and CRH users: 256/19,583, 31.8%).