Geometry of Koch's triangle

Slow-Pathway Visualization by Using Panoramic View: A Novel Ablation Technique for Ablation of Atrioventricular Nodal Reentrant Tachycardia

(1) Background: The panoramic view of a novel wide-band dielectric mapping system could show the individual anatomy. We aimed to compare the feasibility, efficacy and safety of the panoramic view guided approach for ablation of AVNRT with the conventional approach. (2) Methods: Ablation distributions in eight patients were retrospectively analyzed using the panoramic view. The para-slow-pathway (para-SP) region was divided into three regions, and the region that most frequently appeared with the appropriate junctional rhythm or eliminated the slow-pathway was defined as the adaptive slow-pathway (aSP) region. Twenty patients with AVNRT were then ablated in the aSP region under the panoramic view and compared with 40 patients using the conventional approach. (3) Results: Thirty ablation points were analyzed. The majority of effective points (95.0%) were located in the inferior and anterior portions of the para-SP region and defined as the aSP region. Baseline characteristics, fluoroscopic duration, and mean number of ablations were similar among the two groups. The panoramic view group had a significantly higher percentage of appropriate junctional rhythm (81.9% ± 26.0% vs. 55.7% ± 30.5%, p = 0.002) than the conventional group. (4) Conclusions: The use of the panoramic view for AVNRT ablation achieved similar clinical endpoints with higher ablation efficiency than the conventional approach.

Transient complete heart block: a case report of a rare complication of tricuspid valve infective endocarditis

Background

Right-sided tricuspid valve (TV) endocarditis can be difficult to identify and may be under-recognized in the absence of traditional risk factors. While generally identified with aortic valve pathology, infective endocarditis that extends beyond the leaflets of the TV have been reported to cause conduction disease.

Case summary

We present the case of a 63-year-old patient who presented with haemodynamically unstable complete heart block requiring temporary venous pacemaker support. Despite the absence of traditional risk factors or significant valvular disease on transthoracic echocardiogram, she was found to be persistently bacteraemic and subsequent transoesophageal echocardiogram identified large vegetation on the septal leaflet of the TV. Conduction disease was noted to reverse with antibiotic therapy and resolution of bacteraemia.

Discussion

Although rare, right-sided endocarditis involving the triangle of Koch may present with conduction disease due to local inflammation and mechanical compression. Conduction disease associated with right-sided disease appears to be readily reversible with medical therapy and temporary device support may be appropriate in the acute setting.

Age-Related Changes in the Anatomy of the Triangle of Koch: Implications for Catheter Ablation of Atrioventricular Nodal Re-entry Tachycardia

Background

Atrioventricular nodal re-entrant tachycardia is the most common type of paroxysmal supraventricular tachycardia. We sought to assess whether important anatomic factors, such as the location of the slow pathway, proximity to the bundle of His, and coronary sinus ostium dimensions, varied with patient age, and whether these factors had an impact on procedural duration, acute success, and complications.

Methods

Baseline demographic and procedural data were collected, and the maps were analyzed. Linear regression models were performed to evaluate the associations between age and these anatomic variations. Associations were also assessed, with age categorized as being ≥ 60 years or < 60 years.

Results

The slow pathway was more commonly located in a superior location relative to the coronary sinus ostium in older patients. The location of the slow pathway moved in a superior direction by 1 mm for every increase in 2 years from the mean estimate of age. Additionally the slow pathway tended to be closer to the coronary sinus ostium in older patients, and the diameter of the ostium was larger in older patients. This resulted in longer procedure time, longer ablation times, and a greater need for long sheaths for stability.

Conclusions

The location of the slow pathway becomes more superior and closer to the coronary sinus ostium with increasing age. Additionally, the coronary sinus diameter increases with age. These factors result in longer ablation and procedural times in older patients.

Morphology and Position of the Right Atrioventricular Valve in Relation to Right Atrial Structures

The right atrioventricular valve (RAV) is an important anatomical structure that prevents blood backflow from the right ventricle to the right atrium. The complex anatomy of the RAV has lowered the success rate of surgical and transcatheter procedures performed within the area. The aim of this study was to describe the morphology of the RAV and determine its spatial position in relation to selected structures of the right atrium. We examined 200 randomly selected human adult hearts. All leaflets and commissures were identified and measured. The position of the RAV was defined. Notably, 3-leaflet configurations were present in 67.0% of cases, whereas 4-leaflet configurations were present in 33.0%. Septal and mural leaflets were both significantly shorter and higher in 4-leaflet than in 3-leaflet RAVs. Significant domination of the muro-septal commissure in 3-leflet valves was noted. The supero-septal commissure was the most stable point within RAV circumference. In 3-leaflet valves, the muro-septal commissure was placed within the cavo-tricuspid isthmus area in 52.2% of cases, followed by the right atrial appendage vestibule region (20.9%). In 4-leaflet RAVs, the infero-septal commissure was located predominantly in the cavo-tricuspid isthmus area and infero-mural commissure was always located within the right atrial appendage vestibule region. The RAV is a highly variable structure. The supero-septal part of the RAV is the least variable component, whereas the infero-mural is the most variable. The number of detected RAV leaflets significantly influences the relative position of individual valve components in relation to right atrial structures.

Revisiting right anterior oblique projections for the triangle of Koch: implications from computed tomography

Background

Variability in the anatomy and orientation of the triangle of Koch (TK) complicates ablation procedures involving the atrioventricular (AV) node. We used CT angiography (CTA) to assess the anatomical TK orientation, the CS ostium direction, and the relationship between the two, and we validated an individualized CS-guided projection during ablation procedures.

Methods

In 104 patients without structural heart disease undergoing computed tomography (CT) angiography, TK orientations were determined in relation to the coronary sinus ostium (CSo) as well as two standard right anterior oblique (RAO) projection angles (30^o and 45^o) commonly used in ablation procedures.

Results

A CS-guided RAO projection (RAOCS) was shown to best track the orientation of the TK compared to RAO30° and 45°, with TK orientation strongly correlating with the CSo direction (r = 0.86, P < 0.001). In addition, the mean relative difference between the angle of the CSo and TK orientation was 5.54 ± 0.48°, consistent with a reduction in the degree of image shortening compared to traditional RAOs. Moreover, in vivo validation following ablation revealed that using a CS-guided projection limited the degree of on-screen image shortening compared to both the RAO30° and 45° in 25 patients with catheter ablation procedures.

Conclusion

In hearts with a normal structure, the CSo direction offers a reliable predictor of the TK orientation which can be used to guide the projection of the TK during ablation procedures.

High-density mapping of Koch's triangle during sinus rhythm and typical AV nodal reentrant tachycardia: new insight

BACKGROUND

Atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) exhibits anatomic variability and spatially heterogeneous propagation inside the Koch's triangle (KT). The mechanism of the reentrant circuit has not been elucidated yet. Aim of this study is to describe the distribution of Jackman and Haïssaguerre potentials within the KT and to explore the activation mode of the KT, in sinus rhythm and during the slow-fast AVNRT.

METHODS

Forty-five consecutive cases of successful slow pathway (SP) ablation of typical slow-fast AVNRT from the CHARISMA registry were included.

RESULTS

The KT geometry was obtained on the basis of the electroanatomic information using the Rhythmia mapping system (Boston Scientific) (mean number of points acquired inside the KT = 277 ± 47, mean mapping time = 11.9 ± 4 min). The postero-septal regions bounded anteriorly by the tricuspid annulus and posteriorly by the lateral wall toward the crista terminalis showed a higher prevalence of Jackman potentials than mid-postero-septal regions along the tendon of Todaro and coronary sinus (CS) (98% vs. 16%, p < 0.0001). Haïssaguerre potentials seemed to have a converse distribution across the KT (0% vs. 84%, p < 0.0001). Fast pathway insertion, as located during AVNRT, was mostly recorded in an antero-septal position (n = 36, 80%), rather than in a mid-septal (n = 6, 13.3%) or even postero-septal (n = 3, 7%) location. During typical slow-fast AVNRT, two types of propagation around the CS were discernible: anterior and posterior, n = 31 (69%), or only anterior, n = 14 (31%). During the first procedure, the SP was eliminated, and acute procedural success was achieved (median of 4 [3-5] RF ablations).

CONCLUSION

High-density mapping of KT in AVNRT patients both during sinus rhythm and during tachycardia provides new electrophysiological insights. A better understanding and a more precise definition of the arrhythmogenic substrate in AVNRT patients may have prognostic value, especially in high-risk cases.

TRIAL REGISTRATION

Catheter Ablation of Arrhythmias With High Density Mapping System in the Real World Practice (CHARISMA) URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

Coronary artery anatomy in peri-crux cordis area on computed coronary tomography angiography

Background

The peri-crux area is an anatomical structure of the heart. Unfortunately, important information on this area mainly derives from autopsy heart with a small, under-representative sample size, resulting in limited clinical applications. Furthermore, little has been done to standardize the definition of the peri-crux area on coronary computed tomography angiography (CCTA) images or to investigate coronary artery anatomy wherein potential values are attracting experienced inventional cardiologists in terms of the revascularization strategies. The current study aimed to identify the peri-crux cordis area and to observe coronary artery anatomical distributions in this area on CCTA.

Methods

A total of 1,006 consecutive patients undergoing CCTA exams were enrolled. We delineated the peri-crux cordis area based on the posterior interatrial sulcus, posterior interventricular sulcus (PIS), left and right posterior atrioventricular groove on the diaphragmatic surface of the heart. Then we observed the coronary artery distributions in the peri-crux cordis area in different sexes.

Results

We have defined the peri-crux cordis area according to the anatomical landmarks on the diaphragmatic surface of the heart on CCTA images. We have observed 8 coronary artery distributions in the peri-crux cordis area. Right dominance has 4 types (types 1-4); left, 1 type (type 0) and balanced, 3 types (types 5-7). Out of the 1,006 cases, the type 1 is commonest with 834 cases (82.9%). There are no statistically significant differences in terms of coronary dominances and coronary artery distributions in the peri-crux cordis area between sexes (P>0.05).

Conclusions

We have defined the peri-crux cordis area utilizing the anatomical landmarks of the heart on CCTA images, where 8 types of coronary artery distributions have been identified. The current study may provide interventional cardiologists with useful information on recognition of coronary artery dominance, use of collateral channels for revascularization of chronic total occluded lesions, and evaluation of prognosis in patients with coronary artery disease (CAD).