Evaluation of left atrial volume and functions by real time three-dimensional echocardiography in patients with subclinical hypothyroidism before and after levothyroxine therapy

Systematic review and meta-analysis of levothyroxine effect on blood pressure in patients with subclinical hypothyroidism

This study aims to evaluate the effect of levothyroxine therapy on blood pressure (BP) in patients with subclinical hypothyroidism (SCH). Were searched Six databases, and randomized controlled trials (RCT) and prospective cohort studies evaluating the effect of levothyroxine therapy on BP in patients with SCH were included. 37 articles (9 RCTs and 28 prospective cohorts) were included in this meta-analysis. Pooled analysis of RCT studies was insignificant; however, pooled analysis of 28 prospective cohort studies showed a significant difference before and after the therapy, reducing both systolic blood pressure (SBP) and diastolic blood pressure (DBP) (MD=-4.02 [-6.45, -4.58] and MD=-2.13 [-3.69, -0.56], both P-values<0.05). Levothyroxine therapy can play a role in lowering BP in patients with SCH. However, this effect is more observed in Caucasians, SCH patients with higher initial TSH followed by more remarkable TSH change to normal levels, and SCH patients with hypertension.

Cardiovascular outcomes in subclinical thyroid disease: an update

PURPOSE OF REVIEW

Subclinical thyroid disease is defined by a thyroid stimulating hormone (TSH) level outside of the normal range with normal circulating thyroid hormone levels. Excess adverse cardiovascular outcomes have been observed in certain patient populations with subclinical hypothyroidism (SCH) and hyperthyroidism (SCHr). The role of thyroid hormone and antithyroid treatments for subclinical thyroid disease remains debated.

RECENT FINDINGS

Cardiovascular disease appears to be a major mediator of all-cause mortality in patients with SCH, in particular those aged at least 60 years of age. In contrast, pooled clinical trial results did not find that levothyroxine reduced the incidence of cardiovascular events or mortality in this patient population. The association between SCHr and atrial fibrillation is well established; however, a 5-year follow-up of older patients with mild (TSH 0.1-0.4 mIU/l) SCHr found no increased incidence of atrial fibrillation. Separately, SCHr was associated with derangements in endothelial progenitor cell function that may underlie vascular disease independent from effects on cardiac function.

SUMMARY

The impact of treatment of subclinical thyroid disease on cardiovascular outcomes remains uncertain. Additional prospective and trial data are needed to evaluate treatment effects on cardiovascular outcomes in younger populations.

The assessment of Tp-e interval and Tp-e/QT ratio in patients with hyperthyroidism before and after thyroid surgery

BACKGROUND

Ventricular repolarisation is assessed using the Tp-e interval and QT interval corrected by the heart rate (QTc) via an electrocardiogram (ECG). Prolonged Tp-e/QTc is related with an increased risk of arrhythmias and cardiac mortality.

OBJECTIVE

This study was conducted at a single centre in collaboration with general surgery and cardiology clinics. We aimed to appraise the assessment of Tp-e interval and Tp-e/QT ratio in patients with hyperthyroidism before and after thyroid surgery.

METHODS

Totally 65 patients with hyperthyroidism before and after thyroid surgery were enrolled in our study. In presurgical hospitalisation and six months after the thyroid surgery, we measured the electrocardiographic parameters again on same patients. All subjects who were investigated in this study were in sinus rhythm. Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were measured from the 12-lead electrocardiogram.

RESULTS

Heart rate (P = .073), QT interval (P = .432) and QTc interval (P = .179) were similar before and after thyroid surgery. Tp-e interval (84.6 ± 13.1 vs 77.2 ± 10.9; P = .031), Tp-e/QT ratio (0.23 ± 0.04 vs 0.21 ± 0.04; P < .001), Tp-e/QTc ratio (0.21 ± 0.04 vs 0.19 ± 0.03; P < .001) and QTc dispersion (52.4 ± 7.2 vs 48.4 ± 7.4; P < .001) were significantly different before and after thyroid surgery. In correlation analysis, there was a significant correlation between preprocedural Tp-e/QTc ratio and preprocedural fT4 in patients with hyperthyroidism (r = 0.275, P = .026).

CONCLUSION

Our study demonstrated that Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were shortened in patients with hyperthyroidism after thyroid surgery than before procedure. This study is considerable to display that hyperthyroidism may have a negative effect on cardiac conduction system, which potentially may induce formation of ventricular arrhythmias.

Assessment of real-time three-dimensional echocardiography as a tool for evaluating left atrial volume and function in patients with type 2 diabetes mellitus

Objective: To assess the value of real-time three-dimensional echocardiography (RT-3DE) in evaluating changes in left atrial volume and function in type 2 diabetes mellitus (DM) and type 2 diabetic nephropathy (DN) patients.

Method: 104 control subjects, 109 DN patients, and 111 DM patients were recruited and underwent RT-3DE. Data pertaining to the left atrium were analyzed using the 3DQA software in order to determine left atrial maximum volume index (LAVImax), left atrial pre-systolic volume index (LAVIp), left atrial minimum volume index (LAVImin), total left atrial ejection fraction (LAEFt), passive left atrial ejection fraction (LAEFp), and active left atrial ejection fraction (LAEFa). Differences between these three groups and correlations between individual index values and E/e' ratios were additionally assessed.

Result: LAVImax, LAVIp, and LAVImin were higher in the DN and DM groups relative to controls, whereas LAEFt and LAEFp were higher in controls relative to DM and DN patients (P < 0.05). LAVImax, LAVIp, and LAVImin in the DN group were significantly higher than those in the DM group, while LAEFt, LAEFp were higher in DM patients relative to DN patients (P < 0.05). The E/e' ratio was also found to be significantly correlated with LAVImax, LAVIp, and LAVImin.

Conclusion: Our results indicate that RT-3DE can be used to assess changes in left atrial volume and function in patients with diabetes and can be used to monitor disease progression-related damage to such left atrial functionality.

Impact of Hypothyroidism on Echocardiographic Characteristics of Patients With Heart Valve Disease: A Single-Center Propensity Score-Based Study

Background: Hypothyroidism is known to be correlated with multiple heart diseases. However, the influence of hypothyroidism on the patients with heart valve disease (HVD) is still unclear. The purpose of our study was to investigate the impact of hypothyroidism on echocardiographic characteristics of patients with heart valve disease. Methods: We conducted a retrospective cohort study which included 2,128 patients with HVD, and they were divided into euthyroid, subclinical hypothyroidism (SCHypoT), and overt hypothyroidism (OHypoT) group. Echocardiographic characteristics before and after valve surgery between groups were compared by using propensity score (PS) analysis. Kaplan-Meier analysis was used to compare the percent of recovery of left atrial (LA) enlargement between groups. Results: Overall, 463 patients had hypothyroidism (404 SCHypoT patients and 59 OHypoT patients), and 1,665 patients were euthyroid. At baseline, hypothyroidism was associated with significantly higher left atrial diameter (LAD), interventricular septum thickness, left ventricular posterior wall thickness, pulmonary artery systolic pressure, and lower left ventricular ejection fraction. After valve surgery, only LAD remained significantly higher in the patients with hypothyroidism. Additionally, patients with hypothyroidism had a significantly lower recovery rate of LA enlargement after valve surgery compared with euthyroid patients. Conclusion: Hypothyroidism was associated with a larger LAD in patients with HVD before and after surgery, which may suggest that hypothyroidism is a risk factor of LA enlargement of HVD. Besides, hypothyroidism was associated with a significantly lower recovery rate of LA enlargement after valve surgery.