Stroke in thyrotoxicosis with atrial fibrillation.

Abstract

Chronic atrial fibrillation is associated with an increased risk of stroke. In elderly patients with thyrotoxicosis, atrial fibrillation is frequently encountered, and the true risk of cerebrovascular events in these patients is controversial. We retrospectively studied 610 patients with initially untreated thyrotoxicosis, 91 (14.9%) of whom had atrial fibrillation, with the highest frequency in the elderly patients. The risk of cerebro vascular events, with special attention to the first year after the diagnosis of thyrotoxicosis, was calculated using logistic regression methods with age, sex, and atrial fibrillation as independent variables. Only age was an important risk factor (p<0.005), whereas sex and atrial fibrillation were not significant (p = 0.09 and p = 0.17, respectively) as independent risk factors. This is contrary to other studies of patients with thyrotoxic atrial fibrillation, and the need for further clarification of this issue is clear. From our study the indication for prophylactic treatment with anticoagulants for prevention of stroke in thyrotoxic atrial fibrillation seems doubtful, especially as no controlled studies of such treatment in patients with atrial fibrillation are currently available. Thyrotoxicosis may be complicated with AF, 10 and several recent studies have found a high frequency of cerebral thromboembolism in such patients."-14 Anticoagulation has been recommended for patients with thyrotoxicosis and AF to prevent embolic complications. 15The above studies were not sufficiently controlled, and therefore, the aim of our study was to evaluate whether patients with thyrotoxicosis and AF have increased risk of cerebrovascular events compared with age-matched controls with thyrotoxicosis in sinus rhythm. Subjects and MethodsOur study was retrospective and included a total of 610 consecutive patients with thyrotoxicosis admitted from 1976 to 1985 to a department of internal medicine and endocrinology in a hospital in Copenhagen. All patients had the diagnosis of thyrotoxicosis made according to established criteria.l6 All except one patient had the type of goiter confirmed by thyroid scintigraphy, and all patients had an electrocardiogram (ECG) on admission. The patients were followed in the out-patient clinic at scheduled intervals, and they were examined by the same consultant physician. Patients Supported by a research fellowship from the Danish Heart Foundation to P.P.Address for correspondence: Palle Petersen, MD, Department of Neurology, University Hospital, Rigshospitalet, 9, Blegdamsvej, DK-2100 Copenhagen, Denmark.Received February 9, 1987; accepted July 14, 1987. followed for < 1 year (n = 57) were excluded from the statistical analysis of cerebrovascular events, as were patients receiving anticoagulant treatment (n = 2). None of these excluded patients had cerebrovascular events during follow-up. The criteria for cerebrovascular events were clinical signs or a medically confirmed history of the acute onset of a neurologic deficit of presumed vascular origin. The pa...

Thyroid hormone in health and disease

“…Twelve of 30 patients in AF had an embolic event (40%) compared with none in sinus rhythm (112 patients); the mean age of the patients in AF was significantly higher than those in sinus rhythm (56 vs 39 years). A further retrospective study investigating 610 patients with thyrotoxicosis, indicated that age -rather than the presence of AF -was the main risk factor for embolisation, a finding which may be explained by the relatively small number of patients in AF (Petersen & Hansen 1988). Twelve (13%) of those in AF had an embolic event compared with 15 of the 519 patients (2·9%) in sinus rhythm.…”

Thyroid Disease and the Heart

“…It may be that a combination of genomic and nongenomic actions on atrial ion channels plus the enlargement of the atrium as a result of the expanded blood volume are the underlying causes. 6,50 It has been suggested that hyperthyroidism resembles a hyperadrenergic state; however, no evidence suggests that thyroid hormone excess enhances the sensitivity of the heart to adrenergic stimulation. 51 In hyperthyroidism, serum levels of catecholamines remain low or normal.…”

“…87 Anticoagulation of patients with hyperthyroidism and atrial fibrillation is controversial. 1,50 The risk of systemic or cerebral embolization must be weighed against the potential for bleeding and other complications of this therapy. The risk for systemic embolization in the setting of thyrotoxicosis is not precisely known.…”

“…81,88 In patients with hyperthyroidism it was advancing age rather than the presence of atrial fibrillation that was the main risk factor. 50 Review of large series of patients failed to demonstrate a prevalence of thromboembolic events greater than the risk reported for major bleeding events from warfarin therapy. 6 We conclude that in younger patients with hyperthyroidism and atrial fibrillation, in the absence of organic heart disease, hypertension, or other independent risk factors for embolization, the benefits of anticoagulation may be outweighed by the risk.…”

Cardiomiopatia dilatada reversível relacionada a hipertireoidismo

“…Caso haja necessidade de manutenção do digital, deve-se lembrar da necessidade de doses maiores em função do hipertiroidismo concomitante. Há controvérsias em relação à necessidade de anticoagulação de pacientes com FA secundárias a hipertiroidismo (14), mas dados sugerem que esses pacientes não apresentam risco de tromboembolismo maior que os com FA por outras causas, notadamente nos pacientes com menos de 55 anos de idade (15). Como se tratava de um paciente jovem, no qual foi realizado ecocardiograma transesofágico que não evidenciou trombos, foi optado por não iniciar anticoagulação com cumarínicos, sendo mantido apenas AAS em dose baixa.…”