The Spectrum of Echocardiographic Abnormalities in Hypothyroidism and the Effect of Hormonal Treatment
1991; King Faisal Specialist Hospital and Research Centre; Volume: 11; Issue: 6 Linguagem: Inglês
10.5144/0256-4947.1991.611
ISSN0975-4466
AutoresMohamed S. Nouh, Olufunsho O. Famuyiwa, Riad A. Sulimani, Abdulrahman Al-Nuaim,
Tópico(s)Cardiovascular Effects of Exercise
ResumoOriginal ArticlesThe Spectrum of Echocardiographic Abnormalities in Hypothyroidism and the Effect of Hormonal Treatment Mohamed S. Nouh, MD Olufunsho O. Famuyiwa, FACP Riad A. Sulimani, and FRCP, FACP Abdulrahman Al-NuaimFRCP(C), FACP Mohamed S. Nouh Address reprint requests and correspondence to Dr. Nouh: Department of Medicine (38), College of Medicine, and King Khalid University Hospital, P.O. Box 2925, Riyadh 11461, Saudi Arabia. From the Department of Medicine, College of Medicine and King Khalid University Hospital, Riyadh. Search for more papers by this author , Olufunsho O. Famuyiwa From the Department of Medicine, College of Medicine and King Khalid University Hospital, Riyadh. Search for more papers by this author , Riad A. Sulimani From the Department of Medicine, College of Medicine and King Khalid University Hospital, Riyadh. Search for more papers by this author , and Abdulrahman Al-Nuaim From the Department of Medicine, College of Medicine and King Khalid University Hospital, Riyadh. Search for more papers by this author Published Online:1 Nov 1991https://doi.org/10.5144/0256-4947.1991.611SectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutAbstractCross-sectional echocardiography was used to identify and quantify different cardiac abnormalities in 85 patients with hypothyroidism. Pericardial effusion was the most common and was found in 32 patients (37.6%), while abnormal increase in left ventricular dimensions with impairment of function followed next in frequency (16.4%). Asymmetrical septal hypertrophy as well as segmental wall motion abnormality were each detected in 11.76%. Holosystolic prolapse of the mitral valve was present in only 4.7% of the cases. Different combinations of abnormalities were observed in a total of 22 patients (25.76%), and pericardial effusion was a constant finding. Some of the abnormalities were reversed with physiological thyroxin replacement, but abnormal regional abnormal wall motion remained unimproved.IntroductionThe notion that the heart could be affected in hypothyroidism is at least a hundred years old, but the concept of a myxedema heart was first proposed by Zondek [1] in 1918. This concept was further advanced by Fahr [2] and Kern et al [3] in their clinical studies. Kern et al attributed most of the cardiac features of hypothyroidism to the presence of pericardial effusion, namely: clinical cardiomegaly, distant heart sounds, radiological enlargement of the heart, and low-voltage QRS complex on the electrocardiogram. For a long time thereafter, there was disagreement as to whether all the findings in myxedema heart were due to pericardial effusion or there was an associated intrinsic cardiac muscle abnormality, i.e., a cardiomyopathy. Early autopsy studies indicated the existence of structural abnormalities in the myocardium [4, 5].Hemodynamic techniques [6] and noninvasive methods such as systolic time intervals [7] were subsequently used to demonstrate depressed myocardial contractility with reduced stroke volume and low cardiac output in untreated hypothyroidism. Kerber and Sherman [8] were perhaps the first to systematically use echocardiography to demonstrate pericardial effusion in hypothyroidism, while Santos et al [9] first used this method to draw attention to other types of cardiac abnormality, such as asymmetrical septal thickening.Subsequently, there have been several publications on the echocardiographic findings in adults with hypothyroid [10, 12], as well as children [13, 14] and even neonates [15] with the condition. However, some of these studies had a relatively small number of patients [10, 12], relied only on M-mode echocardiography [10, 11], or focused primarily on pericardial effusion [9–11].In the present report, which we believe is the first such study in an Arab population, both M-mode and two-dimensional echocardiography were used to evaluate a large number of hypothyroid patients for the purpose of establishing not only the spectrum of abnormalities in the pericardium, myocardium, and valvular apparatus, but also the effect of hormonal treatment on the detected abnormalities.PATIENTS AND METHODSEighty-five patients (66 females, 19 males) were studied at King Khalid University Hospital, Riyadh, Saudi Arabia. Their ages ranged from 20 to 70 years (mean, 43 years). All patients were evaluated by an endocrinologist, and all had definite hypothyroidism based on clinical and laboratory criteria. Patients with rheumatic valvular lesions, hypertension, and ischemic heart disease were excluded from the study. The following were done in all patients before and after initiation of thyroid hormone replacement: echocardiogram, echocardiography, and serum thyroxine (T4) as well as thyroid stimulating hormone (TSH) measurement by radioimmunoassay using standard commercial kits.Echocardiographic examination was carried out using both M-mode and cross-sectional methods in the parasternal long and short axis views as well as apical four-chamber views. A Hewlett Packard ultrasound imaging system (model 77020A or ATL MK 600 ultrasound system with 2.5 mHz transducer with a 0.5-inch diameter) was used. Results were recorded on videotape. Particular care was taken to define the best position and motion of the pericardium, myocardium (left ventricular wall thickness), and mitral valve and its chordae. The criteria defined by Horowitz et al [16] were used to diagnose pericardial effusion, where there is persistence of echo-free space between the left ventricular posterior wall and the pericardium throughout the cardiac cycle. Small effusions were indicated if there was parallel movement of the left ventricular posterior wall and the parietal pericardium; large effusion was indicated if the parietal pericardium was immobile. Gross pericardial effusion was denoted by the characteristic rocking motion of the heart, in which the interventricular septum and free wall of the two ventricles both move in parallel. The internal dimensions of the left ventricle were measured in the standard manner as described by Sahn et al [17]. The measurements taken followed the recommendations of the American Society of Echocardiography, whereby end-diastolic and end-systolic distances between the endocardium of the interventricular septum and left ventricular posterior wall were recorded at the chordal level; these provided the main data for calculation of left ventricular dimension and performance.RESULTSBased on the clinical, hormonal (T4 and TSH levels), and other data, such as antithyroid antibody titers and pituitary function studies, primary hypothyroidism was diagnosed in 77 patients (90.58%) and secondary hypothyroidism due to Sheehan's syndrome was present in eight cases (9.4%).Echocardiographic FindingsThe overall pattern of cardiac abnormalities observed in the studied cases is illustrated in Table 1. Pericardial effusion of different degrees was most common, present in 32 patients (37.6%). An abnormal increase in the left ventricular dimensions with reduction of shortening fraction was detected in 14 patients (16.4%) (Table 2). Asymmetrical septal thickening represents a characteristic abnormality in the shape of the left ventricle. This was found in ten cases (11.76%) in which the interventricular septum was thicker than the left ventricular posterior wall, but characteristically the size of the left ventricular cavity remained normal.Table 1. Spectrum of echocardiographic findings in patients with hypothyroidism.Table 1. Spectrum of echocardiographic findings in patients with hypothyroidism.Table 2. Measurements in 14 patients with abnormal left ventricular dimension and function.Table 2. Measurements in 14 patients with abnormal left ventricular dimension and function.Segmental left ventricular systolic wall motion abnormalities were found in ten patients (11.76%; 7 females, 3 males; age range, 51–70 years; mean, 62.1 years) with the following pattern: mild apical hypokinesia (N = 3), moderate severe posterior wall hypokinesia (N = 3), and left ventricular lateral wall hypokinesia (N = 4) (Table 3). These changes have been used reliably to denote the existence of contractile dysfunction and graded hypokinesia of different severity. Finally, the diagnosis of mitral valve prolapse based on the superior motion of mitral valve leaflets into the left atrium during the whole of systole, seen as bowing or excessive co-aptation behind the atrioventricular junction, was detected in four patients (4.7%).Table 3. Segmental wall motion abnormality in 10 patients.Table 3. Segmental wall motion abnormality in 10 patients.Table 4 summarizes the occurrence of combined abnormalities, which were detected in a total of 22 patients (25.88%). Pericardial effusion was a constant finding.Table 4. Combinations of abnormality during echocardiography in hypothyroid patients.Table 4. Combinations of abnormality during echocardiography in hypothyroid patients.Follow-up StudiesAfter a period of thyroxine replacement ranging from 6 to 18 months, all patients were clinically euthyroid with normal serum T4 levels and suppressed TSH levels in those with primary hypothyroidism. All patients with a small pericardial effusion had a normal echocardiogram on re-examination and there was significant reduction in the epicardial-pericardial separation (echo-free space) in those with moderate and large effusions. There was slight improvement in the left ventricular size and function, with noticeable reduction of the abnormally increased left ventricular dimensions and improvement of the shortening fractions. Regional wall motion abnormalities, however, showed no changes. Ventricular arrhythmias developed in four patients, and two patients, who failed to come for follow-up, were reported by their families to have died.DISCUSSIONThe advent of noninvasive cardiac techniques, especially echocardiography, has facilitated the evaluation of the heart in patients with thyroid diseases such as hyper- or hypothyroidism. With this, lesions have been demonstrated that were mostly clinically silent. Pericardial effusion has long been known to be a feature of so-called myxedema heart [3]. However, it was the use of echocardiography that established the presence of not previously suspected lesions, indicated by such characteristics as thickening of the interventricular septum [9] and other abnormalities of cardiac muscle [12–18]. In our study, a wide variety of lesions were found in hypothyroid patients (Tables 1–3). Pericardial effusion was the most frequent abnormality, occurring in 37.6% of our patients. Echocardiographic demonstration of pericardial effusion in adult patients with hypothyroidism has ranged from about 30% [11] to 80% [10]. Two studies on hypothyroid children reported similar frequencies of about 73% [13, 14]. There have been case reports of pericardial tamponade in hypothyroidism [19, 20], although it is considered rare. None was encountered in our series.Other lesions noted in this study were an abnormal increase in the left ventricular dimension and functional impairment as shown by reduction of the shortening fraction. This has been previously reported by Shenoy and Goldman [18], who also described increased right ventricular wall thickness as well as global impairment of left ventricular function in their patients. Asymmetrical septal hypertrophy or thickening, which was prësent in 14% of our patients, was first described by Santos et al [9]. A regional wall motion abnormality other than in the septum was also present in 11.76%, and it has not been commented on in other studies. Mitral valve prolapse, which was the least common abnormality, has been described in association with chronic thyroiditis [21].Following thyroid hormone replacement and the establishment of euthyroidism, many of the abnormalities resolved completely or were considerably improved. Small effusions disappeared and medium or large ones got smaller. Abnormal left ventricular dimensions and asymmetrical septal thickening also abated. Such resolution of cardiac abnormalities after hormone therapy has been previously documented [8, 10, 12, 18]. However, one notable exception in our patients was regional wall motion abnormality. This abnormality could represent areas of previous myocardial infarction, and this could account for the non-resolution. Ischemic heart disease has been suggested to be relatively common in hypothyroidism [22]. Kurtzman et al [23] suggested that coronary atherosclerosis is either part of the basic disease or superimposed on it. This regional wall motion abnormality deserves further investigation, especially in view of the fact that ventricular arrhythmias developed in four patients and two other patients were reported to have died during follow up. The role of all these echocardiographic abnormalities in the morbidity and mortality events in our patients still remains speculative. Although sudden cardiac death was once noted to be rare in the presence of hypothyroidism [24], such an event has been reported and was attributed to spontaneous ventricular arrhythmias [25].In conclusion, a broad spectrum of echocardiographic abnormalities was observed in most of our adult patients with hypothyroidism, and pericardial effusion was the most common. Most of the abnormalities were reversed following hormone therapy, with the exception of régional wall motion abnormality. This particular abnormality most likely represents areas of previous myocardial infarction and may explain the potential for ventricular arrhythmias and even sudden death in some patients with hypothyroidism.ARTICLE REFERENCES:1. Zondek H. "Das myxodemherz" . Munchen Wochenschr. 1918; 65: 1180–2. Google Scholar2. Fahr G. "Myxedema heart" . JAMA. 1925; 84: 345–9. Google Scholar3. Kern RA, Soloff LA, Shape WJ, Bello CT. 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