Ignite Creation Date:
2024-05-06 @ 3:48 PM
Last Modification Date:
2024-10-26 @ 1:57 PM
Study NCT ID:
NCT04764123
Status:
UNKNOWN
Last Update Posted:
2021-02-25
First Post:
2021-01-23
Brief Title:
Typical and Atypical AVNRT High-resolution Mapping
Sponsor:
Cardiovascular Research Society Greece
Organization:
Cardiovascular Research Society Greece
Study Overview
Official Title:
To Investigate Whether Remnants of the Ring Tissues Constitute the Substrate of the Circuit of Atrioventricular Nodal Reentrant Tachycardia
Status:
UNKNOWN
Status Verified Date:
2021-02
Last Known Status:
NOT_YET_RECRUITING
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
AVNRTmap
Brief Summary:
This study is aimed at
1 Identifying the exact location of the circuit of typical and atypical AVNRT by applying high-resolution electroanatomic mapping
2 Investigating the possibility that the recently described ring tissues participate in the AVNRT circuit
1 Identifying the exact location of the circuit of typical and atypical AVNRT by applying high-resolution electroanatomic mapping
2 Investigating the possibility that the recently described ring tissues participate in the AVNRT circuit
Detailed Description:
Background The exact circuit of atrioventricular nodal reentrant tachycardia still remains unknown despite advances in high-density mapping tissue histochemistry and connexin genotyping Theoretical calculations have derived a range of 08 to 52 cm for the length of the slow pathway whereas that of the fast pathway should be within the range of 24 to 112 cm Recent histology data also indicate that the distance of the right inferior extension of the atrioventricular node within the tricuspid vestibule as judged histologically and as measured from the site of penetration of the conduction axis in 31 hearts is 8224 mm with a range from 52 to 136 mm These results are compatible with theoretical calculations of the slow pathway previously performed by the investigators On 3-dimensional reconstructed fluoroscopic images the average distance between the compact AV node and the ablating electrode in cases of successful AVNRT ablation however is 17216 to 17809 mm This clearly suggests that successful ablation interrupts the AVNRT circuit at a point beyond the identifiable right posterior extension and at a consistent area on the the septal isthmus between the CS ostium and the TV This site is beyond the histologically identifiable inferior extensions of the node
There is additional evidence in animal studies that the right inferior extension continues within the vestibule of the tricuspid valve as ring tissue ie a remnant of the primary ring while the left atrial vestibule is derived from the initial atrioventricular canal of the developing heart which is itself known to be slow conducting but cannot be distinguished histologically from the left atrial myocardium In the human heart the primary ring extends through the atrioventricular node and includes the bundle of His which is rapidly conducting
Hypothesis The investigators hypothesized that in humans the extent of ring tissues varies in such a way that some subjects are susceptible to atrioventricular nodal re-entry whereas others are not Thus the entirety of the tricuspid vestibule or even part of the mitral vestibule are parts of the re-entry circuit at least in some atypical forms with prolonged His-atrial intervals The circumference of the right atrioventricular orifice has been measured at between 9 and 11 centimeters in patients aged less than 65 years whereas that of the mitral orifice is from 7 to 9 centimeters The possibility of the vestibules being involved in the circuit therefore cannot theoretically be excluded Recently high-density mapping of the re-entry circuit has provided valuable insights into the electrophysiologic patterns of this arrhythmia identifying the circuit in the vicinity of the nodal area All these mapping studies however were conducted in patients with typical AVNRT In this setting the remnants of the ring tissues might be short enough as not to allow proper discrimination of the circuit limbs The investigators propose to apply high-resolution electroanatomic mapping in patients with both typical atypical AVNRT in which the circuit may contain longer circuit components Mapping should be focused on both the septal area and the tricuspid and if feasible the mitral ring
Aims of the Study
This study therefore is aimed at
1 Identifying the exact location of the circuit of typical and atypical AVNRT by applying high-resolution electroanatomic mapping
2 Investigating the possibility that the recently described ring tissues participate in the AVNRT circuit
Methods Clinical Studies Patients Patients with typical and atypical AVNRT will be recruited following informed consent The investigators anticipate to study 30 patients with typical and 10 patients with atypical AVNRT within the next two years
Definitions AVNRT is diagnosed by fulfillment of established criteria during detailed atrial and ventricular pacing maneuvers Typical slow-fast AVNRT is defined by an atrial-HisHis-atrial ratio AHHA 1 and HA interval 70 ms Atypical AVNRT is defined by delayed retrograde atrial activation with HA70 ms
Mapping Electroanatomic mapping will be performed with CARTO Rhythmia or Ensite programs at the operators discretion High-resolution mapping of the atrial vestibules is inherently difficult in this setting nonetheless because of the problems in separating a large ventricular electrogram from the atrial tracing During atrioventricular nodal reentry all these areas should show a fused signal consisting of nodal activation Any mapping system will struggle to annotate the fused signal appropriately in the window and during tachycardia It may also preferentially annotate the His bundle electrogram because of its high frequency dvdt The implication of this error is that a site annotated as representing the earliest atrial activity may be representing activity in the His bundle Conversely a site marked as late may in fact be early being obscured by far field ventricular activity These limitations may also apply to animal models using micro-electrode mapping To overcome this problem pacing maneuvers with ventricular extrastimuli are used to differentiate atrial from ventricular electrogram components where activation appeared to be superimposed owing to simultaneous local activation In addition the investigators will exclude points that result in discrepant activation relative to the surrounding isochronal information due to the movement of the CS reference catheter Activation points from ectopic beats will be excluded manually The voltage map will be automatically acquired according to the same criteria After automated mapping an offline retrospective analysis will be performed by 2 independent observers in order to manually over-read the sites of earliest atrial activation at an override activation strength of 100 mV in cases in which 1 the earliest activation on automated mapping appeared diffuse or 2 automated annotation tagged the local ventricular component at the annulus The His-bundle signal is generally automatically annotated by the system
Entrainment Entrainment of AVNRT is feasible at sites close to the nodal extensions Attempts will be made to entrain the tachycardia from various points on the TV annulus in order to investigate potential participation of the right-sided ring tissue into circuit
Catheter ablation Being on the operation discretion before conventional catheter ablation of the slow pathway at least two 30 sec lesions will be delivered on the TV annulus near the isthmus if this feasible Interruption of the tachycardia or evoked junctional beats will be sought Conventional catheter ablation of the slow pathway will be performed as previously described
Histology Studies Databases from human hearts specimens will be examined and tissue-characterized in an attempt to identify the presence and extent of ring tissues in the human myocardium
There is additional evidence in animal studies that the right inferior extension continues within the vestibule of the tricuspid valve as ring tissue ie a remnant of the primary ring while the left atrial vestibule is derived from the initial atrioventricular canal of the developing heart which is itself known to be slow conducting but cannot be distinguished histologically from the left atrial myocardium In the human heart the primary ring extends through the atrioventricular node and includes the bundle of His which is rapidly conducting
Hypothesis The investigators hypothesized that in humans the extent of ring tissues varies in such a way that some subjects are susceptible to atrioventricular nodal re-entry whereas others are not Thus the entirety of the tricuspid vestibule or even part of the mitral vestibule are parts of the re-entry circuit at least in some atypical forms with prolonged His-atrial intervals The circumference of the right atrioventricular orifice has been measured at between 9 and 11 centimeters in patients aged less than 65 years whereas that of the mitral orifice is from 7 to 9 centimeters The possibility of the vestibules being involved in the circuit therefore cannot theoretically be excluded Recently high-density mapping of the re-entry circuit has provided valuable insights into the electrophysiologic patterns of this arrhythmia identifying the circuit in the vicinity of the nodal area All these mapping studies however were conducted in patients with typical AVNRT In this setting the remnants of the ring tissues might be short enough as not to allow proper discrimination of the circuit limbs The investigators propose to apply high-resolution electroanatomic mapping in patients with both typical atypical AVNRT in which the circuit may contain longer circuit components Mapping should be focused on both the septal area and the tricuspid and if feasible the mitral ring
Aims of the Study
This study therefore is aimed at
1 Identifying the exact location of the circuit of typical and atypical AVNRT by applying high-resolution electroanatomic mapping
2 Investigating the possibility that the recently described ring tissues participate in the AVNRT circuit
Methods Clinical Studies Patients Patients with typical and atypical AVNRT will be recruited following informed consent The investigators anticipate to study 30 patients with typical and 10 patients with atypical AVNRT within the next two years
Definitions AVNRT is diagnosed by fulfillment of established criteria during detailed atrial and ventricular pacing maneuvers Typical slow-fast AVNRT is defined by an atrial-HisHis-atrial ratio AHHA 1 and HA interval 70 ms Atypical AVNRT is defined by delayed retrograde atrial activation with HA70 ms
Mapping Electroanatomic mapping will be performed with CARTO Rhythmia or Ensite programs at the operators discretion High-resolution mapping of the atrial vestibules is inherently difficult in this setting nonetheless because of the problems in separating a large ventricular electrogram from the atrial tracing During atrioventricular nodal reentry all these areas should show a fused signal consisting of nodal activation Any mapping system will struggle to annotate the fused signal appropriately in the window and during tachycardia It may also preferentially annotate the His bundle electrogram because of its high frequency dvdt The implication of this error is that a site annotated as representing the earliest atrial activity may be representing activity in the His bundle Conversely a site marked as late may in fact be early being obscured by far field ventricular activity These limitations may also apply to animal models using micro-electrode mapping To overcome this problem pacing maneuvers with ventricular extrastimuli are used to differentiate atrial from ventricular electrogram components where activation appeared to be superimposed owing to simultaneous local activation In addition the investigators will exclude points that result in discrepant activation relative to the surrounding isochronal information due to the movement of the CS reference catheter Activation points from ectopic beats will be excluded manually The voltage map will be automatically acquired according to the same criteria After automated mapping an offline retrospective analysis will be performed by 2 independent observers in order to manually over-read the sites of earliest atrial activation at an override activation strength of 100 mV in cases in which 1 the earliest activation on automated mapping appeared diffuse or 2 automated annotation tagged the local ventricular component at the annulus The His-bundle signal is generally automatically annotated by the system
Entrainment Entrainment of AVNRT is feasible at sites close to the nodal extensions Attempts will be made to entrain the tachycardia from various points on the TV annulus in order to investigate potential participation of the right-sided ring tissue into circuit
Catheter ablation Being on the operation discretion before conventional catheter ablation of the slow pathway at least two 30 sec lesions will be delivered on the TV annulus near the isthmus if this feasible Interruption of the tachycardia or evoked junctional beats will be sought Conventional catheter ablation of the slow pathway will be performed as previously described
Histology Studies Databases from human hearts specimens will be examined and tissue-characterized in an attempt to identify the presence and extent of ring tissues in the human myocardium
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None