Subclinical thyroid issues and heart failure

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Subclinical means that the thyroid is not working as well as it used to, but is not testing low enough to be considered abnormal.http://heartdisease.about.com/b/2008/09/25/does-subclinical-hypothyroidism-cause-diastolic-heart-failure.htmDoes Subclinical Hypothyroidism Cause Diastolic Heart Failure?

Thursday September 25, 2008

A new study appearing in the Journal of the American College of Cardiology suggests that individuals whose thyroid tests indicate they have subclinical hypothyroidism

are at an increased risk of developing heart failure over the next

several years. Furthermore, it appears that the heart failure they

develop is likely to be diastolic heart failure.

Subclinical hypothyroidism is a condition in which the thyroid gland

is having trouble producing enough thyroid hormone, so the thyroid

gland requires higher levels of "thyroid stimulating hormone" (TSH -

the hormone that "whips" the thyroid gland into doing its work). In

patients with subclinical hypothyroidism, the actual amount of thyroid

hormone in the blood is normal - but levels of TSH are elevated.

Previous studies have suggested that patients with subclinical

hypothyroidism have a higher risk of heart disease. What is new about

this latest study is that it identifies subclinical hypothyroidism as a

potentially important cause of diastolic heart failure.

In diastolic heart failure, the pumping function of the heart

is largely normal, but the ability of the heart to fill with blood

before it pumps is impaired. Doctors have been puzzled about the cause

of diastolic heart failure. The possibility that subclinical

hypothyroidism may cause diastolic heart failure is an attractive one.

First, it turns out that the kind of people who develop diastolic heart

failure - middle aged or older women - are the same kind who tend to

develop subclinical hypothyroidism. And second, subclinical

hypothyroidism is a treatable condition. (It is treated the same way

that "clinical" hypothyroidism is treated - with thyroid replacement

hormone pills.)

At this point, it is not proven that subclinical hypothyroidism

causes heart disease. However, the evidence grows ever stronger. Women

whose TSH levels are 10.0 mIU/L or higher should certainly discuss with

their doctors whether treatment is in order.

You can read more about the thyroid and heart disease here.