According to Dr. Stephen A. Hoption Cann“Iodine deficiency can have deleterious effects on the cardiovascular system, and correspondingly, that a higher iodine intake may benefit cardiovascular function.” Both hypothyroidism and hyperthyroidism have been shown to have negative effects on the heart. Clinical cardiovascular features of hypothyroidism include: bradycardia, reduced cardiac output, increased pericardial and pleural effusions, increased diastolic blood pressure and peripheral vasoconstriction.
Dr. Michael Donaldson says, “Iodine stabilizes the heart rhythm, lowers serum cholesterol, lowers blood pressure, and is known to make the blood thinner as well, judging by longer clotting times seen by clinicians. Iodine is not only good for the cardiovascular system, it is vital.
 Journal of the American College of Nutrition, Vol. 25, No. 1, 1-11 (2006)Hypothesis: Dietary Iodine Intake in the Etiology of Cardiovascular Disease