Contribution to the study of the blood supply of the sinus node in zebu cattle

Abstract

The arterial blood supply of the sinus node has been studied in 100 zebu cattle (87 males and 13 females). In 75 hearts (75.0% ± 4.3) the sinus node is nourished through collaterals of both the a. coronaria dextra and the a coronaria sinistra: in 73 hearts (73.0% ± 4.4) from the ramus proximalis atrii sinistri plus, in 48 cases (48.0% ± 5.0) the ramus intermedins atrii dextri, in 5 cases (5.0% ± 2.2) the ramus proximalis atrii dextri, in 3 cases (3.0% ± 1.7) the ramus distalis atrii dextri, in 13 cases (13.0% ± 3.4) the ramus proximalis atrii dextri plus the ramus intermedins atrii dextri and in 4 cases (4.0% ± 2.0) the ramus intermedins atrii dextri plus one collateral from the ramus ventricularis dexter. In the remaining 2 cases (2.0% ± 1.4) the arterial blood supply to the sinus node is through the ramus proximalis atrii dextri, plus one collateral from the ramus ventricularis dexter, in 1 case (1.0% ± 1.0), and by that collateral plus the ramus intermedins atrii dextri, in 1 case (1.0% ± 1.0). In 19 hearts (19.0% ± 3.9) the sinus node is nourished exclusively by collaterals of the a. coronaria dextra: in 2 cases (2.0% ± 1.4) only by the ramus proximalis atrii dextri, in 17 cases  (17.0% ± 3.8) from the ramus proximalis atrii dextri plus, in 13 cases (13.0% ± 3.4) the ramus intermedins atrii dextri, in 3 cases (3.0% ± 1.7) the ramus distalis atrii dextri and in 1 case (1.0% ± 1.0) the ramus intermedius atrii dextri plus the ramus distalis atrii dextri. In 6 remaining hearts (6.0% ± 2.4) the sinus node is nourished exclusively by collaterals of the a. coronaria sinistra; in 3 cases (3.0% ± 1.7) only by the ramus proximalis atrii sinistri and in 3 cases (3.0% ± 1.7) by that branch and one collateral from the ramus ventricularis dexter. Arterial anastomosis were observed in 37 cases (37.0% ± 4.8) between collaterals from rami proximalis atrii sinistri and proximalis atrii dextri, in 19 cases (19.0% ± 3.9) between collaterals from the rami proximalis atrii sinistri and intermedius atrii sinistri, in 9 cases (9.0% ± 2.9) between one collateral from the ramus ventricularis dexter, that is directed to the sulcus terminalis and vessels originated from the ramus circumflexus dexter, in 8 cases (8.0% ± 2.7) between collaterals from the ramus proximalis atrii sinistri, in 7 cases (7.0% ± 2.6) between collaterals from the ramus proximalis atrii dextri and from the a. coronaria sinistra, in 6 cases (6.0% ± 2.4) between collaterals from the ramus proximalis atrii dextri and, in 3 cases (3.0% ± 1.7) between collaterals from the rami proximalis atrii dextri and intermedius atrii sinistri. There was no sexual influence in the pattern of the blood supply to the sinus node.