Morphofunctional considerations on the atrioventricular node arterial vascularization

Abstract

The atrioventricular node (AVN) is the relay station for electrical impulses passing from the atria to the ventricles. The arterial resources of the AVN are functionally relevant and may be interfered by various surgical procedures which deal with the cardiac valves. Our study aim to bring detailed evidences on the arterial supply of the AVN. We dissected and microdissected 50 human adult hearts without any known history or evident cardiac pathology, in order to evidence the arterial suppliers of the AVN; subepicardial dissections were continued in the interatrial septum (the triangle of Koch). We were able to define 5 morphological types (each with distinctive subtypes) of the atrioventricular node artery (AVNA) emerged at crux cordis: type I (22%, AVNA from the U-turn of the right coronary artery (RCA), the left retroventricular artery (RVA) absent), type II (18%, AVNA from PIVA, left RVA present), type III (34%, AVNA from the left RVA, PIVA from the RCA), type IV (AVNA from the bifurcation of the RCA into the PIVA and the left RVA-trifurcated RCA) and type V (AVNA from the circumflex artery). In 18% of specimens we found duplicated AVNA. In 22% of specimens, the AVN area was additionally supplied by the descending septal artery (right descending superior artery) originating from the sinoatrial artery, on the right side of the aorta. The origin of the AVNA, which is variable, and the accessory resources, such as the descending septal artery, can explain the possible individual occurrences of the cardiac rhythm alterations determined by coronary ischemia. Our AVNA types are all related to the atrioventricular and aortic valves and thus liable to damage during specific surgical procedures, interfering with the respective valves. Duplicated AVNAs must be kept in mind during the selective atrioventricular nodal artery catheterizations and AVNA must be evaluated angiographically prior to the interventions. Our study demonstrates that classical dissections combined with microdissections can still offer valuable informations for a pathologist assigning not only the mechanisms but also the morphological conditions of the cardiac arrest. A seek and search investigation is launched in every sudden cardiac death: the forensic pathologist make a good team with the anatomist retrieving very useful etiological data.

Anatomical Study of the Atrioventricular Nodal Branch of the Heart

“…The AVNb is most often a branch of the right coronary artery in approximately 90% of cases entering into the triangle of Koch [ 20 , 21 ]. In some cases, the AVNb is a terminal branch of the LCxA, and in others, both coronary arteries supply the AV node [ 22 ]. For the origin of the AVNb, we classified our specimens as AVNb originating from the RCA proximal to the IVb (type I), AVNb originating from the junction of the RCA and IVb (type II), AVNb originating from the RCA distal to the IVb (type III), AVNb originating from the IVb (type IV), and AVNb originating from the LCxA (type V) [ 18 , 23 ].…”

“…The AVNb originated from the RCA distal to the IVb in approximately 65% of our specimens (type III). The anatomical importance of the left AVNb is also important in, for example, surgical manipulation of the right fibrous ring [ 22 , 28 ]. Damage to the AV node and/or the AVNb has been shown to produce pathological conditions related to the pacing of the heart.…”

The anatomy of the atrioventricular nodal artery: A meta‐analysis with implications for cardiothoracic surgery and ablation procedures

“…The dual arterial supply should be highly noted due to its rare occurrence, which was also mentioned in the study performed by Kazemisaeid et al (2012), detecting dual‐supply in 0.01% of subjects studied. In regards to morphological patterns of the AVNA, Rusu et al (2009) reported five different patterns found via dissections of 50 hearts. The discovered patterns in Rusu et al study were type 1 in 22% (AVNA originated from U‐shape turn of RCA), type 2 in 18% (AVNA originated from the IIVA), type 3 in 34% (AVNA originated from the left RVA), type 4 in 8% (AVNA originated from trifurcation of RCA), and type 5 in 18% (AVNA originated from the circumflex artery).…”

“…A total of 5028 articles were initially evaluated by two independent reviewers. Eventually, 33 articles met the required criteria and were used in this meta‐analysis (James & Burch, 1958; Romhilt et al, 1968; Vieweg et al, 1975, 1982; Hutchinson, 1978; Anderson & Murphy, 1983; Brugada et al, 1990; Wang et al, 1990; Sneddon et al, 1991; Burke et al, 1993; Krupa, 1993; Sow et al, 1996; Arid et al, 2000; Lin, 2000; Sanchez‐Quintana et al, 2001; Futami et al, 2003; Kaplana, 2003; Berdajs et al, 2008; Pejković et al, 2008; Saremi et al, 2008; Nerantzis et al, 2009; Paulsen & Vetner, 2009; Ramanathan et al, 2009; Rusu et al, 2009; Ballesteros et al, 2010; El‐Maasarany et al, 2010; Cezlan et al, 2012; Kazemisaeid et al, 2012; Sabnis & Silotry, 2012; Verma et al, 2014; Divyaprakash et al, 2016; Kawashima & Sato, 2018; Iwanaga et al, 2023). The overall data collection process can be found in Figure 1.…”

“…terns of the AVNA,Rusu et al (2009) reported five different patterns found via dissections of 50 hearts. The discovered patterns in Rusu et al study were type 1 in 22% (AVNA originated from U-shape turn of RCA), type 2 in 18% (AVNA originated from the IIVA), type 3 in 34% (AVNA originated from the left RVA), type 4 in 8% (AVNA originated from trifurcation of RCA), and type 5 in 18% (AVNA originated from the circumflex artery).…”