Introduction

Hyperthyroidism is a thyroid hormone excess condition, and is the second most common thyroid dysfunction after hypothyroidism, showing a five to tenfold lower prevalence. At present, epidemiological data on hyperthyroidism are scarce and depend mainly on biochemical thyroid function tests (e.g., TSH and FT₄) ¹ . Many of the clinical manifestations of hyperthyroidism derive from thyroid hormones capacity to change cardiovascular hemodynamics². Clinical appearances related with cardiovascular illnesses vary between persons and can consist of sinus tachycardia in together inactive or active state and atrial arrhythmias, in specific atrial fibrillation in old persons with pre-existing heart illnesses³. Some features of cardiovascular hemodynamics like heart production, blood stream and pressure of pulmonary artery are better in person with hyperthyroidism, whereas the mean systemic pressure is reduced⁴. Cardiac contractility is improved, for both systolic and diastolic functions, and hyperthyroidism increases cardiac production and resting heart rate². Echocardiography is very important in diagnosis and detection of heart function and is necessary in management of patients with thyrotoxicosis. The early Echo for patients with thyrotoxicosis can detected LV-enhanced systolic and diastolic functions⁵. Conventional Echo is a broadly presented procedure to identify subclinical heart failure in hyperthyroidism patients. Tissue Doppler imaging (TDI) is a relatively new echocardiographic technique can used widely to overcome some problems of conventional echocardiography. However, no recent studies have used TDI parameters for evaluation of left and right ventricle in hyperthyroidism patients, so this study was justifying that function.

Methods

A case control study (45 case of hyperthyroidism and 45 healthy control participants) that conducted between the first of March and the first of June of 2020. The data collection was carried out in echocardiography unit in medical department of Marjan medical city in Hilla city, Iraq and among patients attended diabetes and endocrine center in same hospital. where all participants who were: Age more than 18 years and overt hyperthyroidism confirmed by endocrinologist were included and Excluded every participant with: Smoking history, Alcohol consumption, Medical history of hypertension, diabetic mellitus and renal diseases, History of cardiac surgery, Medical history of ischemic heart disease, valvular heart disease, history of CABG and arrhythmia. Blood samples collect from patients from the antecubital vein after patient fasting for 12 hours, the blood collect without any anticoagulant, centrifuged for 15 min and then collect serum, thyroid hormone profile (T3, T4 and TSH) assessment. TheEchocardiography was performed on all participants with use of GE Medical System Vivid nine-ultrasound machine equipped with 1.5- 5 MHz sector transducer probe. With participants located in left lateral decubitus plus ECG of 3 leads linked to apparatus analogous used to symmetrical record electrical activity of the heart throughout the echocardiographic check, echocardiographic checks were done subsequent the strategies of the American Society of Echocardiography. EF, designed by usage of the Simpson's technique. TDI was done via a 1.5- to 4-MHz transducer TDI imaging moreover needs great edge rates (>100fps) for image achievement with brilliant temporal perseverance. Longitudinal annulus motions calculated by color Doppler from top of 4 chambers. Systolic velocity of myocardial (s´) calculate systolic plus diastolic function of LV, early and late velocity of diastolic myocardial (e´& a´), isovolumic contraction and relaxation time (IRT & ICT), function of LV diastole assessed by velocity of blood inside mitral valve in initial diastole (E) as well as in delay diastole (A), mitral annular velocity: initial diastolic (e'), delay diastole (a'). Ratio (e'/a', E/ a', E/e') assessed by dividing early peak wave of transmitral stream of blood in initial velocity of diastolic myocardial that detect from systolic functions of TDI RV and LV that also evaluated by used TDI. Myocardial presentation show index of RV and LV. TDI (LMPI, RMPI) assessed by (a-b)/b, (a) represented the time of starting isovolumic contraction to finish of IVRT and (b) the time of ejection. Septal and lateral mitral annulus Doppler, measures of S' wave (systolic speed of the mitral ring) and E/E' ratio; S wave of the right ventricle (cm/s); indexed left atrial size (mL/m.). To assess left ventricular function, the following transmitral inflow parameters were measured (pulsed wave Doppler registration with gate placed at the tip of open mitral valve leaflets sample volume 1-3 mm): highest velocity of the initial E-wave transmitral stream (E), highest velocity of late A-wave transmitral stream (A), and the ratio (E/A) was resulting. Approvals of the scientific committee in the department of Medicine in Babil College of Medicine where obtained. The purpose of study explained to participant to get their verbal consent. Data was analyzed using SPSS version 23. Analytic statistics as Student –t test used to find association between categorical variables and continuous variables. The P-value below or equal to 0.05 considered statistically significant for a 95% CI.

Result

90 participants were enrolled in this study. The two samples were homogenous in age and gender (p=0.24 and 0.13 respectively), table -1-.

Table 1
Characteristic of participants

* Student T test ** chisquare test significant ≤005

Characteristic of participants		Participant			P value
		Case No (%)		Control No (%)
Age	<30 years	7(15.6%)		12(26.7%)	O.24*
	30-39 years	23(51.1%)		21(46.7%)
	40-45 years	15(33.3%)		12(26.7%)
	Mean ±SD	36.2 ±5.6	32.8± 6
Gender	Male	15(33.3%)		22(48.9%)	0.13**
	Female	30(66.7%)		23(51.1%)

The duration of hyperthyroidism for cases shown in figure -1-.

Figure 1.
Duration of hyperthyroidism in cases.

The thyroid function test for two groups shown that: the cases had significantly lower TSH than control participants (p<0.001) and T3, T4 were significantly higher in cases than control participants (p=0.036, <0.001 respectively), table -2-.

Table 2
Difference in Thyroid function test for both groups

* Student T test significant ≤005

Thyroid function test		Mean	Std. Deviation	P value
TSH	Case	0.2552	0.22118	<0.001*
	Control	2.4378	1.26979
T3	Case	2.2287	1.55667	0.036*
	Control	1.7149	0.43078
T4	Case	133.3660	39.01952	<0.001*
	Control	79.8807	13.89587

*Student T test, significant ≤0.05.

Ejection fraction assessment for both groups shown that, the mean ±SD EF% for cases was 63.3±4.1%, median was 62 % and ranging between 55%-70% while the mean ±SD EF% for control was 63.7±3.9%, median was 64 % and ranging between 55%-70% and there were no significant differences in EF% between two groups (p=0.62), figure -2-.

Figure 2.
Difference in EF% between studied groups.

TDI examination for left ventricle shown that: S´ was significantly lower in cases than control participants (8.28 VS 10.77, p<0.0001), Tei index was significantly higher in cases than control participants (0.7 vs 0.38 p=0.021), E/A was significantly lower in cases than control participants (p=0.01), e´ significantly decrease in cases than control participants (10.95 vs 14.53 p<0.0001), E/e´ was significantly higher in cases than control participants (8.65 vs 6.9 p=0.001) and a´ shown no significant difference between cases and control participants (12.73 vs 11.7, p=0.073), table -3-.

Table 3
Difference in Left ventricle parameters by TDI

* Student T test significant ≤005

Parameters	Participants	Mean	Std. Deviation	P value
S´	Case	8.2889	1.53182	<o.ooo1*
	Control	10.7778	1.67724
Tei index	Case	0.7022	0.88946	0.021*
	Control	0.3889	0.07454
E/A	Case	0.8822	0.31282	0.011*
	Control	1.4089	1.31630
e´	Case	10.9556	2.89949	<0.0001*
	Control	14.5333	2.62505
E/e´	Case	8.6556	2.93068	0.001*
	Control	6.9156	1.86413
a´	Case	12.7333	2.51721	0.073*
	Control	11.7000	2.86515

*Student T test, significant ≤0.05.

TDI examination for right ventricle shown that: S´ was no significant difference between cases than control participants ( p=0.93), Tei index was significantly higher in cases than control participants (0.86 vs 0.36 p=0.015), E/A was no any significant difference between normal persons and hyperthyroidism (p=0.47), e´ no any significant difference between normal persons and hyperthyroidism ( p=87), E/e´ no any significant difference between normal persons and hyperthyroidism (p=0.85) and a´ was significantly higher in cases than control participants (15.77 vs 12.7, p<0.0001), table -4-.

Table 4
Difference in right ventricle parameters by TDI

* Student T test significant ≤005

Parameters	Participants	Mean	Std. Deviation	P value
S´	Case	12.6222	1.21148	0.93*
	Control	12.8667	1.50151
Tei index	Case	0.8667	1.34028	0.015*
	Control	O.3689	0.09001
E/A	Case	1.3311	1.68494	0.47
	Control	1.6422	2.40619
e´	Case	13.2444	4.52345	0.87
	Control	13.1136	2.72982
E/e´	Case	5.3311	1.12812	0.85
	Control	5.2956	0.71190
a´	Case	15.7778	3.65494	<0.0001*
	Control	12.7500	2.58011

*Student T test, significant ≤0.05.

Discussion

In current study, there were harmful properties of hyperthyroidism on left ventricle systolic plus diastolic jobs. In adding, alike but fewer distinct variations happened in right ventricle systolic plus diastolic roles, thus designating that hyperthyroidism pretentious together left ventricle and right ventricle role unrelatedly of thyroid hormone heights. The current study showed that hyperthyroidism cases had female predominance (66%), which coincides with Bal et al.⁶, who also found female preponderance (83%), suggesting the disease being more common in female population. Most left ventricle size occur at end (diastole or systolic) is greatest typical structures in hyperthyroidism patients. LVEF differences controversy between studies^7-9, in current study there was no significant difference in LVEF between cases and control. s’ velocity that processes LV contraction longitudinally and is a spare of LV systolic job, in current study S´ was significantly lower in cases than control participants (8.28 VS 10.77, p<0.0001) this may interpret by contraction of endocardial longitudinal fiber this highly in charge for extended axis purpose, which is liable in a variability of heart situations with also subsequent hypertrophy of LV. Myocardial ischemia, cardiomyopathies, hypertension, coronary artery illness and heart failure have change in function of sub endocardial fiber with decrease in s’ velocity, notwithstanding pre-served LVEF^10,11. Tei-index in patients with hyperthyroidism had a significant higher value than control, which is an indicator of impaired LV systolic function .LV Tei-index was significantly higher in hyperthyroidism compared with control patients¹². (e’ Velocity) is a measure of LV reduction in initial diastole plus it is comparatively load free. In patients with initial DD e’ velocity is decreased, occur 10-15 years before decreased of mitral E velocity¹⁴. e´ significantly lower in hyperthyroidism patients than control patients (p<0.0001). For assessment of function of atrium by late diastolic TDI, a’ velocity is a good parameter for function of atrium¹⁵. e’ velocity decrease wide size of left atrium is parameter of cardiac death¹⁶, in current study there is no difference between hyperthyroidism compared with control patients (p=0.073). in patients with hyperthyroidisms and also normal patients the mean E/E’ ratio in the same and was good appear at edge of 15, also, there is significant progress in hyperthyroidism compared with control patients characteristic an advanced LV rich pressure in the hyperthyroidism as in Turkey study¹². In current study documented enhanced systolic and diastolic functions when hyperthyroidism compared with control patients, similar to study in Nigeria stated that the found of abnormal features in patients with hyperthyroidism in left ventricles as the following: 30% associated with systolic function, 34% associated with diastolic function, 10% associated with heart failure and preserved ejection fraction, 6% associated with heart failure and decrease ejection fraction finally 34% associated with left ventricular hypertrophy⁵, Anther study in Egypt shown Thyroid disorders have a significant effect on LV systolic and diastolic functions and TDI was useful indices for detection of LV functions in patients with Thyroid disease¹². Decrease in Tei index and tissue Doppler resulting diastolic parameters in spite of usual results by conservative echocardiography. E/E’ ratio increased significantly in patients with thyroid diseases¹⁷. In patients with Thyroid disease, TDI is a useful echocardiographic parameter in assessment of LV systolic function. However, the influence of thyroid illnesses on RV arrangement and functions still unknown and no recent studies have used this parameter. In this study, using TDI analysis, increase RV index of Tei and A’ value in cases compared to the control. This study was limited by it was a Hospital base study; hence, the findings cannot be generalized to the community level.

Conclusions

Thyroid derangement especially hyperthyroidism, have a significant effect on cardiac functions. TDI measurements are useful, inexpensive, and easy to perform indices for detection of early LV and RV systolic and diastolic functional abnormalities in patients with hyperthyroidism. Early diagnostic approach in patients with thyroid dysfunctional states is important for avoidance of cardiac complications that might affect these patients.

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