OBJECTIVES We prospectively evaluated the mechanism of syncope in patients with positive adenosine triphosphate (ATP) tests (defined as the induction of atrioventricular [AV] block with a ventricular pause >/=6 s after an intravenous bolus of 20 mg ATP). BACKGROUND Patients with unexplained syncope tend to have more positive ATP tests results than those without syncope. METHODS An implantab...

Although some vascular lesions of the central nervous system are known to cause abnormalities in the control of breathing, association between astrocytoma and combined cardiorespiratory abnormalities in the adult is distinctly unusual. We present a case of a 52-year-old man whose only features of astrocytoma consisted of episodes of apnea and sinus arrest followed by prolonged alveolar hypovent...

Carotid sinus hypersensitivity (CSH) is an exaggerated response to carotid sinus baroreceptor stimulation. Bradycardia, hypotension, and syncope are common manifestations of CSH. A 31-year-old female patient was scheduled for a robotically assisted endoscopic total thyroidectomy. No problems occurred during anesthetic induction. Sudden cardiac arrest occurred near dissection of the diseased thy...

Though an association between autoimmune diseases and sick sinus syndrome has been reported, there has been no report on the association of hypopituitarism and sick sinus syndrome. Herein, we provide the first case report of hypopituitarism accompanying sick sinus syndrome in a 51-year-old woman presented to our hospital with syncope due to cardiac arrest. The patient was successfully managed b...

Carotid sinus syndrome is a serious manifestation of head and neck malignancy. The purpose of this study was to clarify the presence of carotid sinus syndrome in a patient with cystadenolymphoma. To our knowledge carotid sinus syndrome secondary to cystadenolymphoma has not been reported to date. A 45-year-old woman with one-week-old swelling in the left mandibular angle having disturbing sympt...

Prolonged sinus or atrial pause occurred in six patients with paroxysmal supraventricular tachycardia after drug administration. All six patients had normal sinus node function during control electrophysiologic study; the sinus cycle length ranged from 510 to 900 ms (mean 743 +/- 141) and the longest sinus node recovery time ranged from 800 to 1,230 ms (mean 1,018 +/- 168). A long sinus or atri...

Two patients with mild aortic insufficiency inhaled amyl nitrite during routine echocardiographic examinations. One developed sinus arrest and syncope and the other had pronounced sinus bradycardia. The mechanism of this paradoxical response is unclear. Caution should be exercised when amyl nitrite is administered for diagnostic purposes.