Increased or reduced action of thyroid hormone on certain molecular pathways in the heart and vasculature causes relevant cardiovascular derangements. It is well established that overt hyperthyroidism induces a hyperdynamic cardiovascular state (high cardiac output with low systemic vascular resistance), which is associated with a faster heart rate, enhanced left ventricular (LV) systolic and diastolic function, and increased prevalence of supraventricular tachyarrhythmias -namely, atrial fibrillation -whereas overt hypothyroidism is characterized by the opposite changes. However, whether changes in cardiac performance associated with overt thyroid dysfunction are due mainly to alterations of myocardial contractility or to loading conditions remains unclear. Extensive evidence indicates that the cardiovascular system responds to the minimal but persistent changes in circulating thyroid hormone levels, which are typical of individuals with subclinical thyroid dysfunction. Subclinical hyperthyroidism is associated with increased heart rate, atrial arrhythmias, increased LV mass, impaired ventricular relaxation, reduced exercise performance, and increased risk of cardiovascular mortality. Subclinical hypothyroidism is associated with impaired LV diastolic function and subtle systolic dysfunction and an enhanced risk for atherosclerosis and myocardial infarction. Because all cardiovascular abnormalities are reversed by restoration of euthyroidism ("subclinical hypothyroidism") or blunted by ␤-blockade and L-thyroxine (L-T4) dose tailoring ("subclinical hyperthyroidism"), timely treatment is advisable in an attempt to avoid adverse cardiovascular effects. Interestingly, some data indicate that patients with acute and chronic cardiovascular disorders and those undergoing cardiac surgery may have altered peripheral thyroid hormone metabolism that, in turn, may contribute to altered cardiac function. Preliminary clinical investigations suggest that administration of thyroid hormone or its analogue 3,5-diiodothyropropionic acid greatly benefits these patients, highlighting the potential role of thyroid hormone treatment in patients with acute and chronic cardiovascular disease.

Subclinical Cushing's syndrome (SCS) is increasingly being reported in incidentally discovered adrenal adenomas; its hallmark is mild autonomous cortisol hyperproduction without specific clinical signs of cortisol excess. Increased prevalence of hypertension, obesity, and impaired glucose tolerance have been described in SCS, but there is no specific study of the risk factors for cardiovascular diseases. In this cross-sectional study we assessed the cardiovascular profile in 28 consecutive SCS patients (19 women and 9 men; aged 56 +/- 10.6 yr) compared with 100 controls matched for age, gender, and body mass index. Systolic (P < 0.001) and diastolic (P < 0.005) blood pressures were higher in patients, as were fasting glucose, insulin, total cholesterol, triglycerides (all P < 0.001), and fibrinogen (P < 0.05). Moreover, the insulin resistance index was increased in patients as was the waist to hip ratio and mean carotid artery intima-media thickness (all P < 0.001). Of the patients, 60.7% had arterial hypertension, 71.4% had lipid abnormalities, 28.6% had impaired glucose tolerance, 35.7% type 2 diabetes mellitus, and 53.6% had abnormalities in hemostatic parameters. Atherosclerotic plaques were more frequent in patients (P < 0.0001). Only 4 (14.3%) patients did not have multiple risk factors for cardiovascular events. Six (21.3%) had clinical evidence of cardiovascular disease; another 11 (39.3%) had cardiovascular abnormalities as revealed by ultrasound scanning of carotid arteries and/or electrocardiogram records. These results strongly suggest that an increased cardiovascular risk profile, similar to that described in overt Cushing's syndrome, is present in SCS subjects. This finding supports the concept that chronic mild endogenous cortisol excess may have important systemic effects on the human body.

The heart responds to the minimal but persistent changes in circulating thyroid hormone levels typical of subclinical thyroid dysfunction. Thus, the condition is not a compensated biochemical change sensu strictu, and timely treatment should be considered in an attempt to avoid adverse cardiovascular effects.

Recombinant human growth hormone administered for three months to patients with idiopathic dilated cardiomyopathy increased myocardial mass and reduced the size of the left ventricular chamber, resulting in improvement in hemodynamics, myocardial energy metabolism, and clinical status.

SUMMARY We studied 10 obese volunteers, mean age 36.5 ± 10.3 years, who weighed 123.56 ± 28.7 kg and were 69.96 ± 22.5 kg overweight. The subjects did not have diabetes, arterial hypertension or signs of cardiac and respiratory failure or disease and all underwent right-and left-heart catheterization. Cardiac output and stroke volume were high, according to increased oxygen consumption and to the degree of obesity. Ventricular end-diastolic and atrial pressures ranged from normal to high and correlated with body weight, signs of volume overloading and reduced left ventricular (LV) compliance. The mean pulmonary artery pressure was elevated and correlated well with weight, pulmonary resistance being normal; mean aortic pressure did not correlate with weight, and systemic arterial resistance tended to have a negative correlation. The LV function curve showed impaired ventricular function, particularly for the heaviest subjects, in whom Vma, and the ratio of the stroke work index to LV end-diastolic pressure were reduced. These indexes correlated well with each other and both correlated negatively with the degree of obesity. In contrast, maximal dP/dt was normal and did not correlate with excess weight. These observations show that depressed LV function is already present in relatively young obese people, even if they are free from signs of cardiopathy and other associate diseases. The degree of impairment of heart function seems to parallel the degree of obesity.HEART FAILURE occurs frequently in obese patients and appears to be the predominant cause of death in grossly obese subjects.1`3 Hemodynamic features contributing to the development of cardiac failure have been identified; particularly in obese people, changes in the factors that determine the preload and afterload stresses of the heart are present before cardiac failure occurs.3"-Few studies on the contractile function of the ventricle have been done.3 However, many features that depend on conditions that are often associated with contractile function, including arterial hypertension, diabetes, arteriosclerotic changes and respiratory disease, can interfere directly or indirectly with cardiac function, adding their own variations to those deriving from obesity. Therefore, we studied the changes of cardiac function in 10 relatively young volunteers who had varying degrees of obesity and were free from such pathologic conditions. MethodsThe 10 obese subjects ( significant ECG changes, x-ray cardiothoracic ratio exceeding 0.55 and stable arterial diastolic hypertension (diastolic arterial pressure > 100 mm Hg). None of the patients had treatment with digitalis or antihypertensive or diuretic drugs. These subjects underwent both right-and left-heart catheterization. Ten patients gave informed consent for the procedure. Left-heart catheterization was performed through a brachial arteriotomy. The first derivative of left ventricular pressure was obtained simultaneously with the pressure curve by Millar microtip transducer catheter and was recorded at a paper sp...