Intercaval block in normal canine hearts : role of the terminal crest.

نویسندگان

  • R Becker
  • A Bauer
  • S Metz
  • R Kinscherf
  • J C Senges
  • K D Schreiner
  • F Voss
  • W Kuebler
  • W Schoels
چکیده

BACKGROUND The intriguing monotony in the occurrence of intercaval conduction block during typical atrial flutter suggests an anatomic or electrophysiological predisposition for conduction abnormalities. METHODS AND RESULTS To determine the location of and potential electrophysiological basis for conduction block in the terminal crest region, a high-density patch electrode (10x10 bipoles) was placed on the terminal crest and on the adjacent pectinate muscle region in 10 healthy foxhounds. With a multiplexer mapping system, local activation patterns were reconstructed during constant pacing (S(1)S(1)=200 ms) and introduction of up to 2 extrastimuli (S(2), S(3)). Furthermore, effective refractory periods were determined across the patch. If evident through online analysis, the epicardial location of conduction block was marked for postmortem verification of its endocardial projection. Marked directional differences in activation were found in the terminal crest region, with fast conduction parallel to and slow conduction perpendicular to the intercaval axis (1.1+/-0.4 versus 0.5+/-0.2 m/s, P<0.01). In the pectinate muscle region, however, conduction velocities were similar in both directions (0.5+/-0.3 versus 0.6+/-0.2 m/s, P=NS). Refractory patterns were relatively homogeneous in both regions, with local refractory gradients not >30 ms. During S(3) stimulation, conduction block parallel to the terminal crest was inducible in 40% of the dogs compared with 0% in the pectinate muscle region. CONCLUSIONS Even in normal hearts, inducible intercaval block is a relatively common finding. Anisotropic conduction properties would not explain conduction block parallel to the intercaval axis in the terminal crest region, and obviously, refractory gradients do not seem to play a role either. Thus, the change in fiber direction associated with the terminal crest/pectinate muscle junction might form the anatomic/electrophysiological basis for intercaval conduction block.

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

The terminal crest: morphological features relevant to electrophysiology.

OBJECTIVE To investigate the detailed anatomy of the terminal crest (crista terminalis) and its junctional regions with the pectinate muscles and intercaval area to provide the yardstick for structural normality. DESIGN 97 human necropsy hearts were studied from patients who were not known to have medical histories of atrial arrhythmias. The dimensions of the terminal crest were measured in w...

متن کامل

Evaluation of the Occlusion and Arch Dimensions in the Primary Dentition of an Iranian Population

Introduction: The objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an Iranian population. Methods: This descriptive cross-sectional study was performed on 68 children from the city of Mashhad in the 3-5 age range. Dental arch dimensions, interrelationships of primary canine and second molars, overbite ...

متن کامل

The right auricle tunnel as intercaval tunnel in total cavopulmonary connection may prevent atrial flutter.

OBJECTIVE Total cavopulmonary connection (TCPC) is a routine operation for palliation of children with cardiac anomalies in whom biventricular repair is impossible. The original technique consists of the creation of a semi-prosthetic intercaval tunnel. A substantial proportion of these patients develop atrial flutter. We developed a technique for creating an intercaval tunnel that uses the tiss...

متن کامل

Electrocardiogram of bundle-branch block in the bovine heart.

• Severing either right or left bundle branch in the canine heart produces prolongation of QRS and a deformity of that complex specific for the branch severed. Analogous deformities of QRS have been identified in human electrocardiograms. In both species, increment of QRS interval in association with bundle-branch block has been ascribed primarily to slow speed of transmission over muscular non...

متن کامل

Estimation of Genetic Control Model for Agronomic Traits in the Progeny of Marvdasht and MV-17 Wheat Cross under Normal and Terminal Drought Stress Conditions

The study of the genetic structure controlling agronomic traits is one of the preconditions for selecting the appropriate breeding method. In order to analyze genetic of some agronomic traits of bread wheat using generation mean analysis, parents and different generations resulting from the cross of Marvdasht × MV-17 wheat cultivars were assessed in a randomized complete block design with three...

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

دوره 103 20  شماره 

صفحات  -

تاریخ انتشار 2001