title: Atrial fibrillation in hypertrophic cardiomyopathy: prevalence, clinical correlations, and mortality in a large high-risk population.
abstract: BACKGROUND
  Atrial fibrillation (AF) is a common sequela of hypertrophic cardiomyopathy (HCM), but evidence on its prevalence, risk factors, and effect on mortality is sparse. We sought to evaluate the prevalence of AF, identify clinical and echocardiographic correlates, and assess its effect on mortality in a large high-risk HCM population.
  
  
  RESULTS
  We identified HCM patients who underwent evaluation at our institution from 1975 to 2012. AF was defined by known history (either chronic or paroxysmal), electrocardiogram, or Holter monitoring at index visit. We examined clinical and echocardiographic variables in association with AF. The effect of AF on overall and cause-specific mortality was evaluated with multivariate Cox proportional hazards models. Of 3673 patients with HCM, 650 (18%) had AF. Patients with AF were older and more symptomatic (P<0.001). AF was less common among patients with obstructive HCM phenotype and was associated with larger left atria, higher E/e' ratios, and worse cardiopulmonary exercise tolerance (all P values<0.001). During median (interquartile range) follow-up of 4.1 (0.2 to 10) years, 1069 (29%) patients died. Patients with AF had worse survival compared to those without AF (P<0.001). In multivariate analysis adjusted for established risk factors of mortality in HCM, the hazard ratio (95% confidence interval) for the effect of AF on overall mortality was 1.48 (1.27 to 1.71). AF did not have an effect on sudden or nonsudden cardiac death.
  
  
  CONCLUSIONS
  In this large referral HCM population, approximately 1 in 5 patients had AF. AF was a strong predictor of mortality, even after adjustment for established risk factors.
authors: Department of Medicine, Mayo Clinic, Rochester, MN (K.C.S.).
authors: Konstantinos C
authors: KC
authors: Siontis
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.B.G., K.O., R.A.N., S.R.O., B.J.G.).
authors: Jeffrey B
authors: JB
authors: Geske
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.B.G., K.O., R.A.N., S.R.O., B.J.G.).
authors: Kevin
authors: K
authors: Ong
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.B.G., K.O., R.A.N., S.R.O., B.J.G.).
authors: Rick A
authors: RA
authors: Nishimura
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.B.G., K.O., R.A.N., S.R.O., B.J.G.).
authors: Steve R
authors: SR
authors: Ommen
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.B.G., K.O., R.A.N., S.R.O., B.J.G.).
authors: Bernard J
authors: BJ
authors: Gersh
mesh_terms: D000367:Age Factors; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000473:pathology; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: atrial fibrillation; hypertrophic cardiomyopathy; mortality