Thyroid dysfunction has an impact on the cardiovascular system, but there has not been established if there is some association between hypothyroidism and the presence of cardiovascular complications such as heart failure, postinfarction angina, arrhythmias and death in the context of an acute coronary syndrome. Objective: To determine the association between thyroid dysfunction (subclinical and clinical hypothyroidism) and the presence of cardiovascular complications (heart failure, arrhythmia, angina, infarction and death) in patients with acute coronary syndromes admitted to the Coronary Care Unit at Fundación Cardioinfantil (UCC - FCI). Materials and methods: Cohort analytic study. Exposed cohort (129 patients with high TSH) and unexposed (258 patients with normal TSH) who entered the UCC of the FCI, diagnosed with acute coronary syndrome in the period between January 2009 and March 2010. Associations were assessed using relative risk and confidence intervals and chi-square test. Results: We studied a total of 387 patients, 258 euthyroid patients and 129 with thyroid dysfunction. We demonstrated that patients with clinical or subclinical hypothyroidism are twice at risk of heart failure (RR = 2.2 CI 95%:1.1 - 4.3) and have 3 times more risk of atrial fibrillation (RR = 4, 95% CI: 1.22- 13.0). There was no statistically significant differences in other outcomes. Multivariate analysis showed that hypothyroidism is a risk factor sufficient to produce heart failure and atrial fibrillation. Conclusions: The clinical and subclinical hypothyroidism increases the risk of developing heart failure and atrial fibrillation in patients with acute coronary syndrome.
