The Role of Transesophageal Echocardiography in Clinical Decision-Making in Patients with Stroke or Atrial Fibrillation
Sammanfattning: The subject of this thesis is the clinical use of transesophageal echocardiography (TEE) in patients with stroke or atrial fibrillation. Subjects were examined with echocardiography and sonography of the carotid artery. A control group of randomly selected volunteers without cerebrovascular disease was compared to patients with ischemic stroke. Cardiac pathology was classified as minor potential embolic sources (PCES) without a certain causative role of stroke (patent foramen ovale, atrial septal aneurysm, protruding plaques of the aorta and mitral annular calcification) or major PCES, often related to heart disease (atrial fibrillation, left atrial/ventricular thrombus, impaired left ventricular function). Among controls, the prevalence of minor PCES was about 30%. Comparing control subjects to patients, the prevalence of minor PCES did not differ. The prevalence of major PCES differed significantly, (patients 27% versus controls 4%). In 80% of patients with a major PCES, they had a history of heart disease, but one fifth had no overt clinical heart disease. The prevalence of minor PCES did not differ between clinical sub-types of ischemic stroke. Patients with symptoms from anterior or middle cerebral artery territories were more likely to exhibit a major PCES and carotid artery disease compared to patients with lacunar syndromes. In clinical practice cardioversion of persistent atrial fibrillation/flutter is only attempted after treatment with warfarin for at least three weeks before cardioversion to exclude cardioversion related embolism. With TEE it is possible to select a low risk group for immediate cardioversion after exclusion of thrombi and signs of stasis of the left atrium (spontaneous echo contrast, low velocities of the left atrial appendage). Using these exclusion criteria we describe the safety of immediate cardioversion in 145 patients compared to traditional treatment of 58 patients. No embolic event occurred in either group after cardioversion and maintenance of sinus rhythm at one month was 75% of patients with immediate cardioversion compared to 45% of patients with pre treatment with warfarin. Using TEE to derive a velocity index (left atrial appendage outflow/ left atrial diameter), a value of >0.009 could predict maintenance of sinus rhythm at one month post cardioversion better than previously used clinical parameters.
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