Thyroid hormones modulate every component of the cardiovascular system necessary for normal cardiovascular development and function. When cardiovascular disease is present, thyroid function tests are characteristically indicated to determine if overt thyroid disorders or even subclinical dysfunction exists. As hypothyroidism, hypertension and cardiovascular disease all increase with advancing age monitoring of TSH, the most sensitive test for hypothyroidism, is important in this expanding segment of our population. A better understanding of the impact of thyroid hormonal status on cardiovascular physiology will enable health care providers to make decisions regarding thyroid hormone evaluation and therapy in concert with evaluating and treating hypertension and cardiovascular disease. The goal of this review is to access contemporary understanding of the effects of thyroid hormones on normal cardiovascular function and the potential role of overt and subclinical hypothyroidism and hyperthyroidism in a variety of cardiovascular diseases.

The clinical, features, serial electrocardiograms, and autopsy findings of a patient with symptomatic complete AV block, who had received mediastinal radiation therapy 8 1/2 years previously, are presented. The cardiac histopathology disclosed immense fibrosis of the conduction system and of the atria and ventricles. The enormous amount of fibrosis was similar in location and intensity to that observed in our previously reported patient (Cohen et al., Arch Intern Med 1981; 141:676-679) who had undergone mediastinal radiation. We conclude that the severe fibrosis was primarily due to radiation, rather than secondary to atherosclerotic coronary artery disease, which also has been described as a consequence of mediastinal radiotherapy. This patient's serial electrocardiograms disclosed evidence of complete block both in the AV nodal area and infra His system, which correlated well with the histopathology. The characteristic clinical features of patients with symptomatic complete AV block post mediastinal radiation therapy are presented, along with a review of the world literature.

The success rate for catheter ablation of atrial flutter has been reported to be approximately 90%, but recurrences are common and can be seen in up to 20% of cases. Most of these recurrences are seen within a few weeks following ablation. We report on a patient who developed a recurrence of type I atrial flutter 2 years after an initially successful radiofrequency catheter ablation procedure. Whether the recurrent atrial flutter is due to a new reentrant circuit resulting from slow progression of atrial disease or due to the changes produced by radiofrequency energy in the nearby myocardium is not clear. Further work to define the electrophysiological changes in the atrial myocardium produced by radiofrequency energy, as well as long-term follow-up of patients undergoing radiofrequency catheter ablation for atrial flutter may help in answering these questions.

Background: Auscultation of patients with mitral annular calcification on echocardiography revealed a particular constellation of findings. Objective: To test the hypothesis that a particular auscultatory constellation provides a high degree of certainty in diagnosing the combination of mitral annular calcification and aortic sclerosis so often found in the elderly. Methods: Two groups of patients were studied to evaluate the particular auscultatory constellation under consideration which consisted of: (1) a harsh ejection systolic murmur heard from the 2nd right interspace to the cardiac apex and usually loudest between the 3rd left interspace and the apex; (2) the murmur radiates from the apex towards the left axilla and radiates poorly or not at all from the 2nd right interspace to the neck, and (3) the 2nd heart sound at the cardiac base is normal in intensity, and no ejection clicks are present. Group 1 consisted of patients with mitral annular calcification on echocardiographic examination, and group 2 consisted of patients in whom the particular constellation of auscultatory findings was present and who were then referred for echocardiographic assessment. Results: The particular auscultatory constellation under investigation allowed the diagnosis of the presence of the combination of mitral annular calcification and aortic sclerosis with substantial accuracy. Conclusion: The findings in this exploratory study suggest that the pathologic combination of mitral annular calcification and aortic sclerosis can be diagnosed with a reasonably high degree of certainty in elderly patients, if the particular auscultatory configuration is identified.