Hyperthyroidism directly affects the cardiovascular system, altering the heart\'s normal function and leading to high cardiovascular mortality. Excess thyroid hormones are associated with significantly increased risk and prevalence of cardiac arrhythmias, particularly atrial fibrillation (AF). This article reviewed the hemodynamic changes and the risk of cardiac arrhythmias, including atrial and ventricular arrhythmias associated with hyperthyroidism. It has also discussed the multi-level pathophysiology of thyrotoxic AF, sinus tachycardia, and different treatment modalities such as anti-thyroid drugs, beta-blockers, and the role of cardioversion and catheter ablation. This article has explored different studies that have concluded that AF and sinus tachycardia are the most common arrhythmias associated with thyrotoxicosis.

Numerous studies have shown the detrimental effects of overt hyperthyroidism on sexual functioning but a quantitative result has not yet been synthesized.
To conduct a systematic review and meta-analysis that quantifies the association between overt hyperthyroidism and the risk of sexual dysfunction (SD).
A meta-analysis of studies in the literature published prior to February 1, 2020, from 4 electronic databases (MEDLINE, Embase, Cochrane Library databases, and PsychINFO) was conducted. All analyses were performed using the random-effects model comparing individuals with and without overt hyperthyroidism.
The strength of the association between overt hyperthyroidism and risk of SD was quantified by calculating the relative risk (RR) and the standard mean difierences with 95% CI. The quality of evidence for the reported outcome was based on the Grading of Recommendations Assessment, Development, and Evaluation approach.
Of 571 publications, a total of 7 studies involving 323,257 individuals were included. Synthetic results from 7 eligible studies indicated that overt hyperthyroidism led to significant SD in both sexes (pooled RR = 2.59, 95% CI: 1.3-5.17, P = .007; heterogeneity: I2 = 98.8%, P < .001). When we analyzed the data of men and women independently, the pooled results consistently showed that men and women with overt hyperthyroidism were at over 2-fold higher risk of SD than the general populations (RR for males = 2.59, 95% CI: 1.03-6.52, P = .044; RR for females = 2.51, 95% CI: 1.47-4.28, P = .001). Combined standard mean diffierences from those studies providing the Female Sexual Function Index (FSFI) suggested that women with overt hyperthyroidism were associated with a significantly lower FSFI value in FSFI total scores, subscale sexual arousal, lubrication, orgasm, and satisfaction domain (all P < .05). The overall quality of evidence in our study was considered to be moderate.
Clinicians should know the detrimental effects of overt hyperthyroidism on sexual functioning in clinical practice. Measurement of thyroid hormones should be included in the assessment of patients presenting with SD when they show symptoms of clinical hyperthyroidism.
This is the first meta-analysis quantifying the relationship between overt hyperthyroidism and the risks of SD. However, the combined results were derived from limited retrospective studies along with substantial heterogeneities.
Our study has confirmed the potentially devastating sexual health consequences caused by overt hyperthyroidism. However, additional rigorous studies with sizable samples are still needed to better elucidate this evidence. Pan Y, Xie Q, Zhang Z, et al. Association Between Overt Hyperthyroidism and Risk of Sexual Dysfunction in Both Sexes: A Systematic Review and Meta-Analysis. J Sex Med 2020;17:2198-2207.

Cardiovascular complications are important in hyperthyroidism because of their high frequency in clinical presentation and increased mortality and morbidity risk. The cause of hyperthyroidism, factors related to the patient, and the genetic basis for complications are associated with risk and the basic underlying mechanisms are important for treatment and management of the disease. Besides cellular effects, hyperthyroidism also causes hemodynamic changes, such as increased preload and contractility and decreased systemic vascular resistance causes increased cardiac output. Besides tachyarrythmias, impaired systolic ventricular dysfunction and diastolic dysfunction may cause thyrotoxic cardiomyopathy in a small percentage of the patients, as another high mortality complication. Although the medical literature has some conflicting data about benefits of treatment of subclinical hyperthyroidism, even high-normal thyroid function may cause cardiovascular problems and it should be treated. This review summarizes the cardiovascular consequences of hyperthyroidism with underlying mechanisms.