methimazole and Heart-Diseases

Structural myocardial abnormalities have been extensively documented in hypothyroidism. Experimental studies in animal models have also shown involvement of thyroid hormones in gene expression of myocardial collagen. This study was planned to investigate the ability of ultrasonic tissue characterization, as evaluated by integrated backscatter (IBS), to early identify myocardial involvement in thyroid dysfunction.. We studied 15 patients with hyperthyroidism (HYPER), 8 patients with hypothyroidism (HYPO), 14 patients with subclinical hypothyroidism (SCH) and 19 normal (N) subjects, who had normal LV systolic function. After treatment, 10 HYPER, 6 HYPO, and 8 SCH patients were reevaluated. IBS images were obtained and analyzed in parasternal short axis (papillary muscle level) view, at left ventricular (LV) posterior wall. The following IBS variables were analyzed: 1) the corrected coefficient (CC) of IBS, obtained by dividing IBS intensity by IBS intensity measured in a rubber phantom, using the same equipment adjustments, at the same depth; 2) cardiac cyclic variation (CV) of IBS--peak-to-peak difference between maximal and minimal values of IBS during cardiac cycle; 3) cardiac cyclic variation index (CVI) of IBS--percentual relationship between the cyclic variation (CV) and the mean value of IBS intensity.. CC of IBS was significantly larger (p < 0.05) in HYPER (1.57 +/- 0.6) and HYPO (1.53 +/- 0.3) as compared to SCH (1.32 +/- 0.3) or N (1.15 +/- 0.27). The CV (dB) (HYPO: 7.5 +/- 2.4; SCH: 8.2 +/- 3.1; HYPER: 8.2 +/- 2.0) and the CVI (HYPO: 35.6 +/- 19.7%; SCH: 34.7 +/- 17.5%; HYPER: 37.8 +/- 11.6%) were not significantly different in patients with thyroid dysfunction as compared to N (7.0 +/- 2.0 and 44.5 +/- 15.1%).. CC of IBS was able to differentiate cardiac involvement in patients with overt HYPO and HYPER who had normal LV systolic function. These early myocardial structural abnormalities were partially reversed by drug therapy in HYPER group. On the other hand, although mean IBS intensity tended to be slightly larger in patients with SCH as compared to N, this difference was not statistical significant.

Topics: Adult; Antithyroid Agents; Diagnosis, Differential; Echocardiography, Doppler; Female; Heart Diseases; Humans; Hyperthyroidism; Hypothyroidism; Male; Methimazole; Middle Aged; Severity of Illness Index; Systole; Thyroxine; Ventricular Function, Left

Subclinical hyperthyroidism has been associated with harmful cardiac effects, but its treatment remains controversial. This study was designed to assess the cardiac effects of the normalization of serum TSH concentration in patients with endogenous subclinical hyperthyroidism. Ten patients (median age, 59 yr; range, 16-72 yr) with normal serum free T(4) and free T(3) concentration and a stable suppression of serum TSH levels were evaluated by Doppler-echocardiography, by standard and 24-h electrocardiography monitoring (Holter), and by the clinical Wayne index. Ten subjects, matched for age and sex, were used as controls. Patients were reevaluated 6 months after achieving stabilized euthyroidism by using methimazole with a median initial dose of 20 mg daily (10-30 mg daily). After reaching euthyroidism, we found a significant decrease in the heart rate (P = 0.008), the total number of beats during 24 h (P = 0.004), and the number of atrial (P = 0.002) and ventricular (P = 0.003) premature beats. Echocardiographical data resulted in a reduction of the left ventricular mass index (P = 0.009), interventricular septum thickness (P = 0.008), and left ventricular posterior wall thickness (P = 0.004) at diastole. Furthermore, the early diastolic peak flow velocity deceleration rate was significantly higher (P = 0.02) in the untreated patients compared with controls. The Wayne clinical index was higher in patients than in controls (P = 0.001) and decreased after treatment (P = 0.004). Serum TSH concentration returned to normal values after 2.5 months (range, 1.0-7.0 months) on methimazole therapy (0.05 vs. 1.42 mU/liter; P = 0.002). Serum free T(4) values were normal in patients before treatment but significantly decreased after reaching the euthyroidism (16.9 vs. 11.5 pmol/liter; P = 0.002). In contrast, serum free T(3) concentration did not differ among the groups. In conclusion, our findings support that early antithyroid therapy should be considered in patients with endogenous subclinical hyperthyroidism, where it is needed to prevent potential progression to a more advanced heart disease.

Topics: Adolescent; Adult; Aged; Antithyroid Agents; Arrhythmias, Cardiac; Diastole; Echocardiography; Electrocardiography; Female; Heart Diseases; Heart Rate; Heart Ventricles; Humans; Hyperthyroidism; Male; Methimazole; Middle Aged; Systole; Thyroid Gland; Thyrotropin; Thyroxine; Triiodothyronine

Cardiac structure and function are affected both by acromegaly and hyperthyroidism. Whereas the former is mainly characterized by ventricular hypertrophy as well as diastolic and systolic impairment, the latter frequently leads to increased heart rate and enhancement of contractility and cardiac output. To further investigate this issue, we designed this two-arm study. In the first cross-sectional study, we compared echocardiography and radionuclide angiography results obtained in eight hyperthyroid acromegalic patients, eight hyperthyroid nonacromegalic patients, and eight healthy subjects. All acromegalic patients were receiving treatment for acromegaly at the onset of hyperthyroidism. In the second longitudinal study, performed in the group of acromegalic patients, we compared the cardiovascular results obtained during hyperthyroidism with the retrospective data obtained at the initial diagnosis of acromegaly and after 1-yr treatment for this disease and those prospective data obtained during the remission of hyperthyroidism. In the cross-sectional study, hyperthyroid acromegalic patients showed an increase in the left ventricular (LV) mass index (LVMi) compared to healthy and hyperthyroid controls (P < 0.05), with evidence of LVMi hypertrophy in five of them (62.5%). A significant correlation was found between LVMi and GH levels (r = 0.785; P < 0.05). The LV ejection fraction (LVEF) at rest was higher in the control hyperthyroid population than in healthy controls (P < 0.05), whereas the LVEF response to exercise was reduced in acromegalic patients (P < 0.05 vs. healthy controls). In acromegalics, the exercise-induced change in LVEF was significantly reduced compared to that in healthy controls (P < 0.001), but not to that in hyperthyroid controls (P < 0.07), being abnormal (<5% increase vs. baseline values) in six patients. Four of these six patients (66%) had elevated GH and insulin-like growth factor I levels during the treatment of acromegaly. An inverse correlation between GH and LVEF at rest (r = -0.896;P < 0.05) and at peak exercise (r = -0.950; P < 0.001) was recorded. The peak filling rate was reduced in hyperthyroid acromegalic patients compared to those in both control populations (P < 0.05). In the longitudinal study, acromegalic patients showed an increased LVMi during hyperthyroidism compared to that observed after successful treatment of acromegaly (P < 0.05); resting LVEF was increased compared to both basal (P < 0.001) and posttreatme

Topics: Acromegaly; Antithyroid Agents; Echocardiography; Female; Heart Diseases; Human Growth Hormone; Humans; Hypertrophy, Left Ventricular; Insulin-Like Growth Factor I; Iodine Radioisotopes; Longitudinal Studies; Male; Methimazole; Middle Aged; Radionuclide Angiography; Thyrotoxicosis; Ventricular Function, Left

Topics: Echocardiography; Electrocardiography; Female; Graves Disease; Heart Diseases; Humans; Methimazole; Middle Aged