NEW YORK - People with higher levels of underactive thyroid gland (hypothyroidism) may be at risk of severe heart failure, an Indian-origin researcher has found. According to the study, those with an overactive thyroid (hyperthyroidism) may be more likely to have irregular, often rapid heart rate. A thyroid-stimulating hormone (TSH) blood test is used to check thyroid gland problems. TSH causes the thyroid gland to make two...