Hyperthyroidism and sick sinus syndrome, a rare but challenging association: A study of three cases

Abstract

Hyperthyroidism is usually associated with sinus tachycardia or supraventricular tachyarrhythmias, but rarely with dysfunction of the sinus node or other conduction disturbances. Evidence of bradyarrhythmia in patients with hyperthyroidism is clinically relevant, but the fact that several drugs with negative chronotropic effects (beta-blockers and calcium channel antagonists) are frequently used in the management of these patients must be taken into account. In the presence of sick sinus syndrome (SSS) or other conductance disturbances, therapy with agents that delay the activity of sinus node or atrioventricular conduction can lead to extreme bradycardia with syncope. In this paper, aspects of diagnosis and therapy in three patients with SSS and hyperthyroidism, admitted in the Clinic of Endocrinology or/and Cardiology of the County Hospital, Timisoara, have been presented.

Key Messages: This study presents particularities of diagnosis and evolution of sick sinus syndrome in three patients with hyperthyroidism, the therapeutic implications of this association, and the best management of these patients.

Keywords: Arrhythmias, bradycardia, hyperthyroidism, sick sinus syndrome