Endocrine Abstracts

Purpose: To assess the dynamics of cardiac complications, the efficacy of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) in patients with thyrotoxicosis

Materials and methods: Prospective 4 years study implicated 340 patients with thyrotoxicosis divided into three age groups: I, 80 patients below 40; II, 132 patients of 40–60; and III, 128 patients above 60. By the beginning of the study atrial fibrillation (AF) was diagnosed in 36% of patients of II group, in 41% – of III group; diastolic dysfunction – in 19% of I group, in 49% of II, in 50% of III; systolic dysfunction in 36% of II group, 41% of III; left atrial dilatation in 21% of patients of II group, in 30% of III. All patients were treated with Thiamazole (by the 6 month of study were euthyroid), cardioselective beta-blockers. Patients with AF and left auricle dilatation additionally got ACE inhibitors or ARBs. The reference group included 25 patients treated without ACE inhibitors and ARBs.

Results: Diastolic dysfunction remained by the 6th month only in 17% of patients of II group, in 20% – of III; in 24 months – in 16 and 19%, accordingly. Systolic dysfunction remained only in 3% of patients of III group by the 6th month and 1.6% by the year of observation. In patients with ACE inhibitors or ARBs left atrial size and sinus rhythm normalized in 43% in II group and 32% in III group. In reference group only 4% exhibited normalization of the corresponding parametrs.

Conclusion: Cardiac changes in thyrotoxicosis are characterized not only with disturbance of heart rhythm, systolic and diastolic dysfunctions, but also left atrium dilatation. Addition of ACE inhibitors or ARBs permit to decrease left atrium size and to recover sinus rhythm in 43% of middle aged and 32% of senior patients.