In patients with atrial fibrillation and congestive heart failure, a routine strategy of rhythm control does not reduce the rate of death from cardiovascular causes, as compared with a rate-control strategy. (ClinicalTrials.gov number, NCT00597077.)

The results from the present study demonstrate that trandolapril treatment reduces the incidence of atrial fibrillation in patients with left ventricular dysfunction after acute myocardial infarction.

Heart failure is the leading cause of an increased cardiovascular mortality in both overt and subclinical hyperthyroidism. Subclinical hypothyroidism with TSH 5-10 mIU/L might be associated with a lower risk of all-cause mortality.

Objectives To examine the risk of atrial fibrillation in relation to the whole spectrum of thyroid function in a large cohort of patients.Design Population based cohort study of general practice patients identified by linkage of nationwide registries at the individual level.Setting Primary care patients in the city of Copenhagen.Subjects Registry data for 586 460 adults who had their thyroid function evaluated for the first time by their general practitioner during 2000-10 and who were without previously recorded thyroid disease or atrial fibrillation.Main outcome measure Poisson regression models used to estimate risk of atrial fibrillation by thyroid function. Results Of the 586 460 individuals in the study population (mean (SD) age 50.2 (16.9) years, 39% men), 562 461 (96.0%) were euthyroid, 1670 (0.3%) had overt hypothyroidism, 12 087 (2.0%) had subclinical hypothyroidism, 3966 (0.7%) had overt hyperthyroidism, and 6276 (1.0%) had subclinical hyperthyroidism. Compared with the euthyroid individuals, the risk of atrial fibrillation increased with decreasing levels of thyroid stimulating hormone (TSH) from high normal euthyroidism (incidence rate ratio 1.12 (95% CI 1.03 to 1.21)) to subclinical hyperthyroidism with reduced TSH (1.16 (0.99 to 1.36)) and subclinical hyperthyroidism with supressed TSH (1.41 (1.25 to 1.59)). Both overt and subclinical hypothyroidism were associated with a lower risk of atrial fibrillation.Conclusion The risk of atrial fibrillation was closely associated with thyroid activity, with a low risk in overt hypothyroidism, high risk in hyperthyroidism, and a TSH level dependent association with risk of atrial fibrillation across the spectrum of subclinical thyroid disease.

Atrial fibrillation/-flutter often occurs after acute myocardial infarction and our analysis demonstrated that it was an independent predictor of an increased short and long-term mortality.