Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium
نویسندگان
چکیده
منابع مشابه
Functional characteristics of sinoatrial and subsidiary pacemaker activity in the canine right atrium.
A canine in vitro right atrial preparation was developed to study the functional characteristics of subsidiary atrial pacemaker (SAP) activity and to compare them with those of sinoatrial node (SAN) activity. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Ligation of the SAN artery at the midportion of the sulcus terminalis s...
متن کاملSubsidiary pacemaker function in complete heart block after His-bundle ablation.
To investigate the electrophysiological properties of ventricular impulse formation after His-bundle ablation in 11 patients, incremental ventricular overdrive stimulation studies were performed. The studies, which were spread over a follow-up period of up to 601 days, were carried out invasively with temporary leads as well as noninvasively with the implanted pacemakers and chest wall inhibiti...
متن کاملMechanisms of automaticity in subsidiary pacemakers from cat right atrium.
Intracellular recordings were made from eustachian ridge of cat right atrium to determine mechanisms responsible for subsidiary pacemaker automaticity. Pacemaker action potentials exhibited two phases of diastolic depolarization: an initial steeper slope (D1) followed by a more gradual slope (D2). Cesium (1 mM) decreased D1 (-45.6%) to a significantly greater extent than D2 (-33.6%) and increas...
متن کاملThe origins of the sinus node pacemaker complex in man: demonstration of dominant and subsidiary foci.
To test the hypothesis that the human sinus node is capable of demonstrating multiple sites of impulse generation, we assessed spontaneous shifts in the sinus node pacemaker complex, and shifts after overdrive atrial pacing, premature atrial stimulation and carotid sinus massage. A total of 24 patients aged 59 +/- 15 years (mean +/- SD) in whom stable sinus node electrograms were obtained were ...
متن کاملTachybradycardia in the isolated canine right atrium induced by chronic sympathetic stimulation and pacemaker current inhibition.
The mechanisms of sinoatrial node (SAN) dysfunction in patients with chronically elevated sympathetic tone and reduced pacemaker current (I(f); such as heart failure) are poorly understood. We simultaneously mapped membrane potential and intracellular Ca(2+) in the Langendorff-perfused canine right atrium (RA). Blockade of either I(f) (ZD-7288) or sarcoplasmic reticulum Ca(2+) release (ryanodin...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of the American College of Cardiology
سال: 1984
ISSN: 0735-1097
DOI: 10.1016/s0735-1097(84)80098-4