The Correlation Between Left Ventricular Failure and Right Ventricular Systolic Dysfunction Occurring in Thyrotoxicosis

Background and Objectives: Heart failure rarely occurs in patients with thyrotoxicosis (6%), with half of the cases having left ventricular dysfunction (LVD). Although a few studies reported isolated right heart failure in thyrotoxicosis, there has been no evaluation of relationship between LVD and right ventricular dysfunction (RVD). Subjects and Methods: We enrolled 12 patients (mean age: 51${\pm}$11 years, 9 females) diagnosed as having thyrotoxicosis with heart failure and LVD {left ventricular ejection fraction (LVEF) <40%}, and divided them into two groups {Group I with RVD defined as tricuspid annular plane excursion (TAPSE) less than 15 mm and Group II without RVD}. Clinical features, laboratory variables, and echocardiographic parameters were compared between two groups. Results: RVD was found in 6 (50%) patients. On admission, there were no significant differences between the two groups in clinical features, laboratory variables, or echocardiographic parameters including atrial fibrillation {6 vs. 5, not significant (NS)}, heart rate (149${\pm}$38 vs. 148${\pm}$32/min, NS), LVEF (36.7${\pm}$9.5 vs. 35.1${\pm}$6.3%, NS), or the tricuspid regurgitation peak pressure gradient (TRPPG, 30.9${\pm}$2.0 vs. 36.3${\pm}$9.3 mmHg, NS). After antithyroid treatment, all achieved an euthyroid state and both ventricular functions were recovered. All data, including the recovery time of LVEF and the change of heart rate between two groups, displayed no significant differences. Conclusion: In half of patients, RVD was combined with thyrotoxicosis-associated LVD. There were no differences in clinical factors or hemodynamic parameters between patients with and without RVD. This suggests that RVD is not secondary to thyrotoxicosis-associated LVD.