European Journal of Cardiovascular Medicine

Coronary arterial dominance refers to the anatomical pattern by which the posterior descending artery (PDA), also termed the posterior interventricular artery, originates and supplies the posterior interventricular sulcus and the inferior part of the interventricular septum. In practical anatomical terms, dominance is defined by the artery giving rise to the PDA and, in most hearts, the posterolateral branches to the diaphragmatic surface of the left ventricle [1]. In right dominance, the right coronary artery (RCA) gives the PDA; in left dominance, the PDA arises from the left circumflex artery (LCx); and in co-dominance, branches from both RCA and LCx contribute to the posterior interventricular region. Because the dominant artery supplies a greater share of inferior wall and septal myocardium, dominance provides a structural basis for estimating myocardium at risk in proximal occlusion, and it is closely linked to the concept of functional RCA dominance described in anatomical literature [6].

Across populations studied by autopsy, coronary angiography, and computed tomographic angiography (CTA), right dominance is generally the commonest pattern, whereas left dominance and balanced/co-dominant circulation occur less frequently and show inter-study variability [2]. Knaapen and colleagues, using a cohort with pathological correlation, reported that the prevalence of left and balanced dominance decreases with increasing age, indicating that demographic structure can influence observed proportions [2]. Cadaveric series from teaching institutions have also reported predominance of right-sided PDA origin, but the proportion of left and co-dominant patterns differs by geographic setting, sample selection, and operational definitions [3,4]. Such variation supports the value of region-specific morphologic documentation for teaching and for contextualizing local imaging practice.

Beyond the dominance label itself, several morphological correlates add procedural relevance. The crux cordis is a key landmark at the junction of the atrioventricular and posterior interventricular grooves, and distal RCA or LCx continuation here determines posterolateral perfusion. Morphometric work demonstrates diversity in distal RCA termination around the crux and variability in posterior ventricular branch patterns [5]. Nerantzis and colleagues described variations in the origin and course of the posterior interventricular artery in relation to the crux [7]. In left-coronary-dominant hearts, the terminal branching of the RCA can also differ, reinforcing the need to assess both arterial systems [8]. CTA and angiographic descriptions of the peri-crux region further support PDA origin and crux reach as practical anatomic landmarks [9-11].

Coronary dominance is not only an anatomical descriptor; it has been evaluated as a modifier of clinical outcomes in acute coronary syndromes and after percutaneous coronary intervention. Large observational datasets and trial analyses have examined associations between dominance patterns and adverse events, supporting continued attention to dominance during risk assessment and procedural planning [12-14]. Against this background, the present study provides a cadaveric morphological profile of coronary dominance in adult hearts examined at Government Medical College, Karimnagar. The objectives were to determine the prevalence of right, left, and co-dominant patterns and to document the origin of the PDA, the artery reaching/crossing the crux cordis, and the predominant inferior ventricular surface supply.

Study design and setting: This descriptive cross-sectional morphological study was conducted in the Department of Anatomy, Government Medical College, Karimnagar, Telangana, India, during February 2025 to November 2025.

Study material and sample size: Eighty adult human hearts (n = 80) available for routine teaching and demonstration in the department were examined. Specimens were de-identified prior to assessment. Hearts were preserved in formalin after standard embalming procedures. The study focused on epicardial coronary arterial patterns, particularly at the atrioventricular groove, crux cordis, and posterior interventricular sulcus.

Inclusion and exclusion criteria: Adult hearts with intact epicardial coronary vessels were included. Hearts with gross disruption of the atrioventricular groove, severe postmortem damage, previous surgical manipulation, or extensive atherosclerotic calcification obscuring vessel tracking were excluded. Specimens with obvious congenital anomalies of the great vessels were also excluded.

Dissection and observation protocol: Each heart was oriented in the anatomical position. Epicardial fat over the coronary sulci was carefully cleared using blunt dissection and fine scissors to avoid iatrogenic disruption of small branches. The RCA was traced from its ostium along the right atrioventricular groove to its distal segments near the crux. The left main coronary artery was identified, and the LCx was traced along the left atrioventricular groove toward the posterior surface. The posterior interventricular sulcus was examined to identify the PDA and its source vessel. The vessel(s) reaching or crossing the crux cordis were recorded. The predominant inferior ventricular supply was assigned based on the observed PDA origin and associated posterolateral branches.

Operational definitions: Coronary dominance was categorized as right dominant when the PDA arose from the RCA; left dominant when the PDA arose from the LCx; and co-dominant when both RCA and LCx contributed to the posterior interventricular region and/or when separate PDA and posterolateral branches indicated shared inferior supply [1,7]. The “crux cordis reach” was defined as the artery entering the crux region at the intersection of the atrioventricular and posterior interventricular grooves [7,9].

Data recording and statistical analysis: Observations were recorded on a structured proforma. Two observers independently verified the origin of the PDA and the artery reaching/crossing the crux; discrepancies were resolved by joint re-examination. Data were summarized as counts and percentages. As the study was descriptive, no hypothesis testing was undertaken. Data were checked for completeness and internal consistency before tabulation.

Ethics considerations: The study used de-identified cadaveric teaching specimens handled according to institutional policies and applicable ethical standards for anatomical research.

Eighty adult human hearts were examined. The coronary dominance pattern showed a predominance of right dominance (56/80; 70.0%), followed by left dominance (16/80; 20.0%) and co-dominance (8/80; 10.0%) (Table 1).

Table 1. Coronary dominance pattern (n = 80)

The source of the PDA mirrored the dominance categories. The PDA originated from the RCA in 56 hearts (70.0%) and from the LCx in 16 hearts (20.0%), while dual contribution consistent with co-dominance was observed in 8 hearts (10.0%) (Table 2).

Table 2. Origin of the posterior descending artery (PDA) (n = 80)

Figure 1: Origin of the posterior descending artery (PDA)

At the crux cordis, the RCA crossed the crux in 56 hearts (70.0%), whereas the LCx reached the crux in 16 hearts (20.0%). Both arteries reached the crux in 8 hearts (10.0%), corresponding to co-dominance (Table 3).

Table 3. Artery reaching/crossing the crux cordis (n = 80)

Figure 2: Artery reaching/crossing the crux cordis

The predominant arterial supply to the inferior ventricular surface was provided by the RCA in 56 hearts (70.0%), by the left coronary system in 16 hearts (20.0%), and was balanced in 8 hearts (10.0%) (Table 4).

Table 4. Predominant inferior ventricular surface supply (n = 80)

In the present series of 80 adult hearts, right coronary dominance constituted 70%, left dominance 20%, and co-dominance 10%. This distribution fits the broad pattern described in the literature, where right dominance is usually predominant and left or balanced circulation accounts for a smaller fraction [1,2]. Tiwari and Budhathoki reported right dominance as the most frequent pattern in cadaveric hearts, whereas the relative proportions of left and co-dominant patterns varied across series, reflecting differences in sampling and definitions [3]. Lane and colleagues also emphasized variability in dominance and distal branching when analyzing cadaveric coronary anatomy [4].

A notable internal consistency in this study was the concordance between dominance category and three related morphological features: origin of the PDA, the artery reaching or crossing the crux cordis, and the predominant inferior ventricular surface supply. The PDA arose from the RCA in all right-dominant hearts and from the LCx in all left-dominant hearts, while co-dominant hearts showed dual contribution. This close correspondence supports the practical use of PDA origin as an operational marker of dominance in cadaveric material, and it mirrors the definitions used in contemporary anatomical reviews [1].

The crux cordis relationships observed in this work add an applied dimension to dominance classification. Morphometric examinations of the RCA describe diversity in distal termination around the crux and variability in posterior ventricular branch patterns, which can change the extent of inferior wall perfusion [5]. Nerantzis and colleagues highlighted how the origin and course of the posterior interventricular artery relative to the crux can alter its relationship to the posterior interventricular vein, a feature that becomes important during posterior sulcus dissection and when interpreting posterior interventricular groove anatomy [7]. In addition, studies focusing on left-coronary-dominant hearts show that RCA terminal branching patterns can differ, reinforcing the need to trace both coronary systems to the crux before assigning dominance [8].

Imaging-based evidence also supports the practical relevance of the peri-crux region. CTA descriptions of peri-crux coronary anatomy and of arterial supply to the posterior interventricular sulcus demonstrate that the PDA source and crux reach are reproducible landmarks that can be identified non-invasively [9,10]. Angiographic assessments of coronary anatomy and variations likewise document dominance-related differences that can influence catheter engagement, interpretation of inferior wall ischemia, and selection of revascularization targets [11].

Finally, clinical studies underline why anatomic dominance matters beyond classification. In the CONFIRM registry, coronary dominance was evaluated in relation to prognosis among patients undergoing coronary CTA [12]. In acute coronary syndromes treated with percutaneous coronary intervention, dominance has been reported as an outcome modifier, potentially reflecting differences in myocardium at risk and collateral potential [13]. Similarly, analyses from drug-eluting stent trials have examined dominance in relation to adverse events after implantation [14].

Overall, the present findings add to existing evidence by providing institution-specific prevalence data from Telangana and by documenting correlated crux and PDA features in a uniform sample of adult hearts. Such baseline anatomy supports teaching and offers a structural reference for regional clinical practice.

Limitations

This study used embalmed, de-identified teaching specimens; therefore age, sex, comorbidity, and clinical coronary disease status were unavailable for correlation. Coronary caliber, ostial dimensions, and perfusion territories were not quantified. Coronary casting, micro-CT, and histology were not performed, so small-caliber branches and intramyocardial courses could be under-recognized. Interobserver reliability statistics were not computed. Single-institution sampling limits generalizability to wider populations

This morphological study of 80 adult human hearts from a teaching institution in Telangana documented a predominance of right coronary dominance (70%), followed by left dominance (20%) and co-dominance (10%). The dominance pattern showed clear correspondence with the origin of the posterior descending artery, the artery reaching or crossing the crux cordis, and the predominant inferior ventricular surface supply. Recognizing these patterns is essential for accurate interpretation of coronary imaging, safer posterior sulcus dissection, and selection of target vessels during bypass grafting or interventional procedures. The findings provide baseline regional anatomical data that can complement clinical and imaging studies of coronary circulation. Such knowledge strengthens anatomy teaching and operative planning.

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