Morphometry of the triangle of Koch and position of the coronary sinus opening in cadaveric fetal hearts

AIMS: The aim of the present study was to determine the variations in the position of the coronary sinus (CS) ostium in normal cadaveric fetal (28 weeks or more) hearts and to assess the impact that these variations had on the dimensions of the triangle of Koch (TK). METHODS: This cross-sectional analytical study was conducted on 28 fetal hearts. The dimensions and area of the TK were calculated by two methods, M1 (anatomical) and M2 (clinical). The position of the CS was defined with respect to the tendon of Todaro. Differences between M1 and M2 were estimated using the paired T test. Pearson's correlation coefficient and the adjusted correlation coefficient were used to estimate the strength of association between measurements made by the methods. RESULTS: Ten (35.7%) cadavers were male and 18 (64.3%) female. The mean gestational age was 32.4 ± 3.3 weeks. Using M1, the mean dimensions of the triangle in millimeters (mm) were 9.2 ± 2.2, 6.6 ± 1.8, and 6 ± 2.4 respectively for a, b and c. Similarly, the dimensions using M2 were 7 ± 2.1, 4.7 ± 1.5, and 4.8 ± 2.2. The area in mm(2) was 20.4 ± 10.4 and 11.7 ± 6.7 using M1 and M2 respectively. All measurements were significantly greater with M1. All correlation coefficients were high and significant. The CS ostium and tendon of Todaro maintained a relatively constant positional relationship. CONCLUSIONS: Significantly higher values were noted in the dimensions of TK using M1. High significant positive correlations were observed in measurements made by the two methods. The CS ostium was relatively constantly placed within the TK.