title: Incidence, clinical characteristics and outcome of congestive heart failure as the initial presentation in patients with primary hyperthyroidism.
abstract: BACKGROUND
  There are limited systematic data on the incidence, clinical characteristics and outcomes of congestive heart failure (CHF) in patients with hyperthyroidism. The aim of this study was to investigate the incidence, clinical characteristics and outcome of CHF as the initial presentation in patients with primary hyperthyroidism.
  
  
  METHODS
  The prevalence, clinical characteristics and outcome of CHF was studied in 591 consecutive patients (mean (SD) age 45 (1) years, 140 men) who presented with primary hyperthyroidism.
  
  
  RESULTS
  CHF was the presenting condition in 34 patients (5.8%) with hyperthyroidism. The presence of atrial fibrillation at presentation (OR 37.4, 95% CI 9.72 to 144.0, p<0.001) was an independent predictor for the occurrence of CHF. Of the 34 patients with CHF, 16 (47%) had systolic left ventricular dysfunction with left ventricular ejection fraction (LVEF)<50%. They were predominantly male (OR 26.6, 95% CI 2.6 to 272.5, p = 0.006) and had a lower serum thyroxine level (OR 0.93, 95% CI 0.87 to 0.99, p = 0.044) than patients with preserved left ventricular systolic function. In these patients, LVEF (55 (4)% vs 30 (2)%, p<0.001) and New York Heart Association functional class (1.2 (0.1) vs 2.5 (0.2), p<0.001) improved significantly 3 months after achieving euthyroid status. Systolic left ventricular dysfunction (mean (SD) LVEF 38 (4)%) persisted on long-term follow-up in five
  
  
  METHODS
  no clinical parameter could be identified to predict the occurrence of this persistent cardiomyopathy (p>0.05).
  
  
  CONCLUSIONS
  CHF was the initial clinical presentation in approximately 6% of patients with hyperthyroidism, and half of them had left ventricular systolic dysfunction. Symptoms of CHF subsided and LVEF improved after treatment for hyperthyroidism. Nonetheless, one-third of these patients developed persistent dilated cardiomyopathy.
authors.affiliation: Cardiology Division, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
authors.forename: Chun-Yip
authors.initials: CY
authors.lastname: Yeung
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Annie W C
authors.initials: AW
authors.lastname: Kung
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology*; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012737:Sex Factors