SummarySubclinical hypothyroidism and hyperthyroidism have been recognized as clinical entities with negative effects on the cardiovascular system. Moreover, the effect of treated thyroid dysfunction on parameters associated with the cardiovascular control system has been poorly investigated. In the present study we analyzed time-domain heart rate variability in coronary artery disease (CAD) patients with known thyroid diseases. Twenty-four hour ECG monitoring was performed in 344 patients with coronary artery disease (174 with thyroid dysfunction and 170 without thyroid dysfunction used as a control group), using a 3-channel tape recorder. Time domain parameters of heart rate variability (HRV) were defi nitely lower both in patients with subclinical hypothyroidism and subclinical hyperthyroidism than in the control group, with statistically signifi cant differences in SDNN, RMSSD, TINN, and mean RR for both subgroups. Furthermore, patients on L-thyroxine treatment and restored euthyroidism had generally higher HRV values than patients with subclinical hypothyroidism, nevertheless SDNN, RMSSD, SDNN index, TINN, and mean RR were signifi cantly lower when compared to those of the control group. Signifi cant differences in HRV were also found between hyperthyroid patients under treatment and control group subjects with respect to RMSSD, TINN, and mean RR values. In conclusion, patients with cardiac disease and known thyroid disease, even when the disease is in the subclinical range or despite treatment, should be regarded as patients at additional risk conveyed by thyroid hormone disturbances. (Int Heart J 2014; 55: 33-38) Key words: Hyperthyroidism, Hypothyroidism, Autonomic, Regulation, Cardiovascular risk T hyroid hormones perform a fundamental role in maintaining cardiovascular homeostasis, since they act both directly on the heart muscle and by modulating the autonomic nervous system. Typical clinical signs of hyperthyroidism such as increases in heart rate, cardiac output, systolic blood pressure, myocardial contractility, and basal metabolism and the presence of tremor suggest a hyperadrenergic state. This is possibly due to a greater sensitivity to catecholamines, since their plasmatic concentration in hyperthyroid patients is normal.1) It has been hypothesized that hyperthyroid patients could have alterations either in the number or in the affinity of adrenergic receptors.2) Hypothyroidism instead seems to evoke a hypoadrenergic state due to the presence of bradycardia, reduced cardiac output, and reduced basal metabolism. Intracellular catecholamine production from circulating lymphocytes has been found to be lower during short-term hypothyroidism in patients who have undergone thyroidectomy for differentiated thyroid carcinomas, as compared to the values found during hormone replacement therapy.3) Nevertheless, in contrast with the reduced adrenergic reactions at the cardiac, metabolic, and cellular levels, the plasmatic concentration of norepinephrine is increased in those patients.4) Through the ev...

The circadian periodicity of some endocrine (PRL, cortisol, GH) and vegetative (oral temperature, blood pressure) functions has been studied in cluster headache, common migraine, atypical facial pain, and "mixed" headache. Changes in several biological rhythms have been found not only in cluster headache (CH) but also in other kinds of headache. Although a great individual variability of rhythometric changes has been observed, particularly in CH, the dysrhythmic condition seems to be more evident in chronic than in episodic CH. The clinical and chronobiological effects of lithium administration and of a short-term sleep deprivation have been studied in CH.

The aim of the study was to analyze the frequency of incidental thyroid carcinoma (unknown tumor smaller than or equal to 10 mm) in a consecutive series of 462 total thyroidectomies for multinodular goiter and to investigate the clinical risk factors for this type of malignancy. A retrospective, single-center study of outcome data collected from patients with preoperative diagnosis of multinodular goiter who underwent total thyroidectomy at the General Surgery Unit of Pavia (Italy) between January 2000 and December 2008 was performed. Possible risk factors for malignancy were: gender, age, time of evolution of goiter, presence of a dominant nodule in multinodular goiter, hyperthyroidism, history of radiation to the neck, residence in an area of endemic goiter, prior thyroid surgery, calcifications in the goiter detected by neck ultrasound or chest X-rays, and a family history of thyroid diseases. In a 9-year period, 462 patients underwent total thyroidectomy. We found 41 cases of incidental thyroid carcinoma; the most common histopathological type was papillary. The multivariable analysis demonstrated that the clinical variables associated with occult carcinoma were a personal history of radiation therapy to the neck, the presence of calcifications detected by ultrasound or neck X-rays, and a family history of thyroid diseases; residence in an area of endemic goiter was a protective factor. A personal history of radiation to the neck, detection of calcifications by ultrasound or by neck X-rays, and a family history of thyroid diseases should be considered clinical risk factors for malignancy in multinodular goiter.

Although we studied only a small sample, our preliminary results confirmed that Addison's disease is associated with coeliac disease, being present in 5.9% of patients with Addison's disease. Since the symptoms can be similar and treatment of Addison's disease can mask coeliac disease, this association should always be actively investigated.