ectopic thyroid tissue results from abnormal embryologic development and migration of the thyroid gland. true malignant transformation in ectopic thyroid tissue is extremely rare and is always diagnosed after surgical excision of the lesion by pathology examinations. there are well-documented cases of ectopic thyroid cancer while primary tumoral lesion occurs in the orthotopic thyroid, but only...

Disturbances in atrial conduction or rhythm, or both, were found in 16 of 27 patients undergoing the surgical creation of an atrial septal defect by the Blalock-Hanlon technique. These included P-wave aberrations of intra-atrial block and ectopic atrial rhythm, A-V rhythm, A-V dissociation, sinus bradycardia, atrial flutter, escape-capture bigeminy, and atrial premature beats. Some of these wer...

A37-year-old man with frequent episodes of paroxysmal atrial fibrillation refractory to antiarrhythmic therapy (and no other documented arrhythmias on multiple Holter examinations) underwent an attempt at radiofrequency ablation of the atrial fibrillation. Catheter positions are shown in the left anterior oblique view in Figure 1 and include 2 catheters in the left and right upper pulmonary vei...

A case of persistent fetal bradycardia first detected at 32 weeks of gestational age is described. The diagnosis of atrial ectopic beats was made by means of M-mode echocardiography. Since the fetus was normally grown and showed no signs of distress, the vaginal route of delivery was allowed, also because continuous M-mode echocardiographic monitoring was possible during labour.

The pulmonary vein contains a myocardial layer extending from the left atrium, which is receiving attention as the source of ectopic electrical activity underlying atrial fibrillation. Electrophysiological and pharmacological analysis of the pulmonary vein myocardium performed in various experimental animal species have revealed characteristics such as presence of intracellular Ca(2+) oscillati...

The present case reports on a patient presenting the cardiac form of Chagas disease, with left ventricular dysfunction and second-degree atrioventricular block Mobitz type II, associated with several syncope episodes. The patient underwent a double-chamber definitive artificial pacemaker implant. One year after the implant, the displacement of the atrial electrode was diagnosed and the patient ...

Invasive electrophysiological studies were performed in 2 symptomatic patients with recurrent arrhythmias in which impulse formation presumably occured within atrioventricular nodal bypass tracts. Case 1 had ectopic beats arising within, or close to, the upper end of a left-sided atrioventricular nodal bypass tract of the type described by Brechenmacher. In addition, this conduction was 'concea...

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is an important contributor to population morbidity and mortality. An arrhythmia that is particularly common in the elderly, AF is growing in prevalence with the aging of the population. Our understanding of the basic mechanisms that govern AF occurrence and persistence has been increasing rapidly. This article reviews the ...

Abstract: Mechanoelectric feedback (MEF) is the process by which mechanical forces on the myocardium can alter its electrical properties. The effect can be large enough to induce ectopic beats or fibrillation. However, the role of MEF at physiological levels of mechanical stress is not clear. We have investigated alteration in action potential morphology in rat and guinea pig ventricle and in r...