Excitation sequences of the atrial septum and the AV node in isolated hearts of the dog and rabbit.

نویسندگان

  • M S Spach
  • M Lieberman
  • J G Scott
  • R C Barr
  • E A Johnson
  • J M Kootsey
چکیده

The spread of excitation wave fronts over the atrial septum of puppies, adult dogs, and rabbits was studied in vitro by extracellular measurements with a 50/x-diameter electrode. Wave front spread through the AV node of puppies and rabbits was determined, and the functional location of the junctional region between atrial muscle and the AV node was evaluated during antegrade atrial and retrograde His bundle pacing. For dogs of all ages, the pattern of spread over the septum was greatly affected by the location of the pacemaker site simulating a high or low sinus node position. For all sinus pacing positions, wave fronts spread over the crista terminalis to form a posterior input to the AV node, while the anterior septal wave fronts formed another input. No functional evidence could be found for narrow, specialized intemodal tracts of fixed location. Rather, wave fronts spread over broad areas creating patterns of simultaneous, multiple wave fronts which corresponded in extent to the gross anatomical landmarks of the septum. Only in this fashion were the findings consistent with the idea of three general routes of intemodal conduction in the dog and two general routes in the rabbit. The position of the functional boundary between atrium and AV node could be accounted for only by overlapping of the two tissues of this region; the boundary shifted between antegrade and retrograde conduction. Antegrade wave fronts within the AV node accelerated from the superior border of the node to the exit at the His bundle; retrograde excitation wave fronts from the His bundle decelerated through the AV node. The amplitude of the atrial wave forms as well as the status of die inputs from the posterior and anterior regions of the atrial septum were found to be important factors in AV node conduction.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Modulation of extracellular atrioventricular node field potential pattern and ventricular rhythm by morphine in experimental atrial fibrillation in isolated rabbit heart

Introduction: Endorphins are produced by cardiomyocytes, and exert different effects on the heart. The aim of the present study is to assess morphine effects on extracellular atrioventricular (AV) node field potential pattern and ventricular rhythm of isolated rabbit heart during experimental atrial fibrillation (AF). Methods: Effects of different concentrations of morphine (10, 20, 50 and 1...

متن کامل

Role of nitric oxide on the electrophysiological properties of isolated rabbit atrioventricular node by extracellular field potential during atrial fibrillation

Introduction: The aim of the present study was to determine direct effects of NO modulation on protective electrophysiological properties of atrioventricular node (AV node) in the experimental model of AF in rabbit. Methods: Isolated perfused rabbit AV nodal preparations were used in two groups. In the first group (N=7), LNAME (50μM) was applied. In the second group (N=12), different concent...

متن کامل

Acute direct effects of cyclosporine on extracellular field potential of isolated rabbit AV node during experimental atrial fibrillation

Introduction: Previous studies have indicated a relationship between MPTP pore and AV nodal rate-dependent properties. The aim of present study was to determine acute direct effects of cyclosporine on extracellular field potential of isolated rabbit AV node during experimental atrial fibrillation. Methods: In one group of male New Zealand rabbits (1.5-2.5 kg) cumulative concentrations of cyc...

متن کامل

Effects Of Fast Pathway Ablation On The Concealment Zone And Electrophysiological Behavior Of AV-Node During Atrial Fibrillation.

Objectives: Dual pathways have a determinant role in the occurrence of atrio nodal tachyarrhythmia (AVNRT). The aim of present study is to determine the role of slow pathway (SP) in the concealment zone and protective role of AV node during atrial fibrillation (AF). Material &Methods: In 7 isolated nodal rabbit preparation zone of concealment and concealed conduction is quantified by Specif...

متن کامل

Effect of nitric oxide modulation on the basic and rate-dependent electrophysiological properties of AV-node in the isolated heart of rabbit: The role of adrenergic and cholinergic receptors

Introduction: Recent studies showed that nitrergic system have specific modulatory effects on electrophysiological properties of atrioventricular (AV) node. The aim of this study was to determine the effects of nitric oxide (NO) on the electrophysiological properties of isolated rabbit AV node and to investigate the role of adrenergic and cholinergic receptors in the mechanism of its action...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Circulation research

دوره 29 2  شماره 

صفحات  -

تاریخ انتشار 1971