title: Hyperthyroidism-induced left ventricular diastolic dysfunction: implication in hyperthyroidism-related heart failure.
abstract: BACKGROUND
  Heart failure occurs in 6% of hyperthyroid patients. Nonetheless, only half of those with hyperthyroidism-related heart failure have impaired left ventricular (LV) systolic function. Thus, diastolic dysfunction may play an important role in the pathogenesis.
  
  
  RESULTS
  We performed serial echocardiographic examinations in 70 consecutive patients with hyperthyroidism (39 ± 2 years, 47 women) to determine their diastolic function and repeated the examinations 6 months after achieving a euthyroid state. All patients had normal LV systolic function, but diastolic dysfunction was detected in 22 cases (mild: 3, moderate: 15 and severe: 4). The prevalence of diastolic dysfunction increased with age from 17·9 % in patients <40 years to 100% in those >60 years. Increasing age was the only independent predictor for diastolic dysfunction in hyperthyroid patients. After achievement of a euthyroid state, most patients (16/22, 72%) had completely normalized diastolic function: 100% of patients <40 years, 33·3 % of those ≥ 60 years. Further analyses revealed significant age-related differences in the cardiovascular response to hyperthyroidism. Among patients <40 years, hyperthyroidism resulted in a marked reduction in total peripheral vascular resistance, increased cardiac output and enhanced diastolic function as determined by E'. No such significant change in total peripheral vascular resistance or cardiac output was observed in hyperthyroid patients ≥ 40 years. In addition, hyperthyroidism was associated with reduced E', signifying diastolic dysfunction in older hyperthyroid patients.
  
  
  CONCLUSIONS
  Hyperthyroidism is associated with diastolic dysfunction, particularly in older patients. It is partly reversible following achievement of a euthyroid state.
authors.affiliation: Cardiology Division, Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Yue
authors.forename: Boon-Hor
authors.initials: BH
authors.lastname: Chong
authors.forename: Xue-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Song-Yan
authors.initials: SY
authors.lastname: Liao
authors.forename: Man-Hong
authors.initials: MH
authors.lastname: Jim
authors.forename: Annie W C
authors.initials: AW
authors.lastname: Kung
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
mesh_terms: D000328:Adult; D000367:Age Factors; D003971:Diastole; D005260:Female; D006333:Heart Failure / Q000209:etiology*; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D014463:Ultrasonography; D014655:Vascular Resistance; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology