Mohandas M. Shenoy

Hypothyroid Cardiomyopathy: Echocardiographic Documentation of Reversibility

ABSTRACT: The concept of hypothyroid heart disease remains controversial. Although hemodynamic abnormalities have been describecd, the presence of underlying abnormal cardiac structures has not been confirmed. The authors studied 20 hypothyroid patients using M-mode echocardiography before and after 1-thyroxine therapy. Fifteen additional hypothyroid patients were studied using two-dinensional echocardiography to confirm the data of the first study. The findings were the same in both studies: during hypothyroidism, the interventricular septum is thickened, the ratio of septal thickness to left ventricular posterior wall thickening is increased, the right ventricular wall is thickened, regional wall motion of interventricular septum and right ventricular wall is decreased, and global function of the left ventricle is decreased. These findings are reversed with 1-thyroxine therapy; they occur within 6 months of the development of hypothyroidism, but appear unrelated to elevated TSH levels. Whether the thickened interventricular septum and right ventricular wall represent true muscular hypertrophy requires further elucidation. Nevertheless, these data demonstrate the existence of a hypothyroid cardiomyopathy.

Transesophageal echocardiography in emergency medicine and critical care

Echocardiography has become a widely available and frequently used diagnostic technique in cardiovascular medicine. Due to the simplicity of its application and its noninvasive nature, it is often the test of choice when comprehensive information of the structure and the function of the heart is needed. Since it can be readily performed at the bedside and easily repeated at intervals with little discomfort to the patient, echocardiography is well suited for use in emergency situations and intensive care settings. Coupled with the newer ultrasound modalities such as the spectral and color-flow Doppler imaging, echocardiography can provide critical anatomic and hemodynamic information. It is, however, not without shortcomings. A diagnostically adequate examination depends on the availability of an optimal acoustic window-an area on the chest such as the intercostal spaces, cardiac apex, suprasternal. or the subcostal space, over which the transducer can be applied and the ultrasonic beam can be directed at the heart. Narrow intercostal spaces, calcified rib cartilages. obesity, muscular chest wall, emphysema, and abdominal distension are some of the anatomic factors which impede the ultrasound transmission through the chest or render the transducer placement difficult. In the postcardiac-surgical patient, the surgical dressings, drainage tubes, pacing wires, and air in the mediastinum can interfere with echocardiography. In these situations, the images and the data obtained with the conventional echocardiographic examination are often suboptimal. Many of these difficulties can be overcome by transesophageal echocardiography (TEE).’ An ultrasound transducer mounted at the tip of a flexible endoscope is introduced into the esophagus (Figures 1 and 2). Since there are virtually no interposing structures between the esophagus and the heart, the images obtained are exquisite in detail and clarity. In addition, anatomic details that are seldom seen by conventional echocardiography, such as the proximal coronary arteries, atrial appendages. and pulmonary veins and are easily visualized (Figures 3 and 4).

Hypertrophic cardiomyopathy. Why is it often overlooked in elderly patients

The lack of awareness that hypertrophic cardiomyopathy is indeed seen in older patients is widespread. The resulting low index of suspicion, coupled with the fact that the clinical presentation of this condition closely resembles the presentations of several common disorders of the elderly, can lead to misdiagnosis and inappropriate and possibly harmful treatment. When an elderly patient presents with dyspnea, angina, or syncope, the presence of a systolic murmur that changes in intensity with appropriate diagnostic maneuvers should prompt consideration of hypertrophic cardiomyopathy, which can be easily verified (or excluded) by echocardiography. This approach minimizes diagnostic and therapeutic errors.